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Posted to commits@commons.apache.org by lu...@apache.org on 2014/10/17 10:41:25 UTC

[1/8] MATH-1138 #comment Implemented new BiCubicSplineInterpolator, supporting Akima Spline Interpolator and updated tests

Repository: commons-math
Updated Branches:
  refs/heads/master a51908af1 -> b5e155e7d


http://git-wip-us.apache.org/repos/asf/commons-math/blob/d8bfc8c8/src/test/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolatingFunctionTest.java
----------------------------------------------------------------------
diff --git a/src/test/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolatingFunctionTest.java b/src/test/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolatingFunctionTest.java
index 8c78aed..773a948 100644
--- a/src/test/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolatingFunctionTest.java
+++ b/src/test/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolatingFunctionTest.java
@@ -16,435 +16,147 @@
  */
 package org.apache.commons.math3.analysis.interpolation;
 
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
 import org.apache.commons.math3.exception.DimensionMismatchException;
-import org.apache.commons.math3.exception.MathIllegalArgumentException;
-import org.apache.commons.math3.exception.OutOfRangeException;
+import org.apache.commons.math3.exception.InsufficientDataException;
+import org.apache.commons.math3.exception.NonMonotonicSequenceException;
+import org.apache.commons.math3.exception.NullArgumentException;
 import org.apache.commons.math3.analysis.BivariateFunction;
 import org.apache.commons.math3.distribution.UniformRealDistribution;
 import org.apache.commons.math3.random.RandomGenerator;
 import org.apache.commons.math3.random.Well19937c;
+import org.apache.commons.math3.util.FastMath;
+import org.apache.commons.math3.util.Precision;
 import org.junit.Assert;
 import org.junit.Test;
-import org.junit.Ignore;
 
 /**
  * Test case for the bicubic function.
- * 
  */
-public final class BicubicSplineInterpolatingFunctionTest {
+public final class BicubicSplineInterpolatingFunctionTest
+{
     /**
      * Test preconditions.
      */
     @Test
-    public void testPreconditions() {
-        double[] xval = new double[] {3, 4, 5, 6.5};
-        double[] yval = new double[] {-4, -3, -1, 2.5};
+    public void testPreconditions()
+    {
+        double[] xval = new double[] { 3, 4, 5, 6.5, 7.5 };
+        double[] yval = new double[] { -4, -3, -1, 2.5, 3.5 };
         double[][] zval = new double[xval.length][yval.length];
 
         @SuppressWarnings("unused")
-        BivariateFunction bcf = new BicubicSplineInterpolatingFunction(xval, yval, zval,
-                                                                           zval, zval, zval);
+        BicubicSplineInterpolatingFunction bcf = new BicubicSplineInterpolatingFunction( xval, yval, zval );
         
-        double[] wxval = new double[] {3, 2, 5, 6.5};
-        try {
-            bcf = new BicubicSplineInterpolatingFunction(wxval, yval, zval, zval, zval, zval);
-            Assert.fail("an exception should have been thrown");
-        } catch (MathIllegalArgumentException e) {
-            // Expected
-        }
-        double[] wyval = new double[] {-4, -1, -1, 2.5};
-        try {
-            bcf = new BicubicSplineInterpolatingFunction(xval, wyval, zval, zval, zval, zval);
-            Assert.fail("an exception should have been thrown");
-        } catch (MathIllegalArgumentException e) {
-            // Expected
-        }
-        double[][] wzval = new double[xval.length][yval.length - 1];
-        try {
-            bcf = new BicubicSplineInterpolatingFunction(xval, yval, wzval, zval, zval, zval);
-            Assert.fail("an exception should have been thrown");
-        } catch (DimensionMismatchException e) {
-            // Expected
-        }
-        try {
-            bcf = new BicubicSplineInterpolatingFunction(xval, yval, zval, wzval, zval, zval);
-            Assert.fail("an exception should have been thrown");
-        } catch (DimensionMismatchException e) {
-            // Expected
-        }
-        try {
-            bcf = new BicubicSplineInterpolatingFunction(xval, yval, zval, zval, wzval, zval);
-            Assert.fail("an exception should have been thrown");
-        } catch (DimensionMismatchException e) {
-            // Expected
-        }
-        try {
-            bcf = new BicubicSplineInterpolatingFunction(xval, yval, zval, zval, zval, wzval);
-            Assert.fail("an exception should have been thrown");
-        } catch (DimensionMismatchException e) {
-            // Expected
-        }
-
-        wzval = new double[xval.length - 1][yval.length];
-        try {
-            bcf = new BicubicSplineInterpolatingFunction(xval, yval, wzval, zval, zval, zval);
-            Assert.fail("an exception should have been thrown");
-        } catch (DimensionMismatchException e) {
-            // Expected
-        }
-        try {
-            bcf = new BicubicSplineInterpolatingFunction(xval, yval, zval, wzval, zval, zval);
-            Assert.fail("an exception should have been thrown");
-        } catch (DimensionMismatchException e) {
-            // Expected
-        }
-        try {
-            bcf = new BicubicSplineInterpolatingFunction(xval, yval, zval, zval, wzval, zval);
-            Assert.fail("an exception should have been thrown");
-        } catch (DimensionMismatchException e) {
-            // Expected
-        }
-        try {
-            bcf = new BicubicSplineInterpolatingFunction(xval, yval, zval, zval, zval, wzval);
-            Assert.fail("an exception should have been thrown");
-        } catch (DimensionMismatchException e) {
-            // Expected
-        }
+        try
+        {
+            bcf = new BicubicSplineInterpolatingFunction( null, yval, zval );
+            Assert.fail( "Failed to detect x null pointer" );
+        }
+        catch ( NullArgumentException iae )
+        {
+            // Expected.
     }
 
-    /**
-     * Test for a plane.
-     * <p>
-     * z = 2 x - 3 y + 5
-     */
-    @Ignore@Test
-    public void testPlane() {
-        double[] xval = new double[] {3, 4, 5, 6.5};
-        double[] yval = new double[] {-4, -3, -1, 2, 2.5};
-        // Function values
-        BivariateFunction f = new BivariateFunction() {
-                public double value(double x, double y) {
-                    return 2 * x - 3 * y + 5;
-                }
-            };
-        double[][] zval = new double[xval.length][yval.length];
-        for (int i = 0; i < xval.length; i++) {
-            for (int j = 0; j < yval.length; j++) {
-                zval[i][j] = f.value(xval[i], yval[j]);
-            }
-        }
-        // Partial derivatives with respect to x
-        double[][] dZdX = new double[xval.length][yval.length];
-        for (int i = 0; i < xval.length; i++) {
-            for (int j = 0; j < yval.length; j++) {
-                dZdX[i][j] = 2;
-            }
+        try
+        {
+            bcf = new BicubicSplineInterpolatingFunction( xval, null, zval );
+            Assert.fail( "Failed to detect y null pointer" );
         }
-        // Partial derivatives with respect to y
-        double[][] dZdY = new double[xval.length][yval.length];
-        for (int i = 0; i < xval.length; i++) {
-            for (int j = 0; j < yval.length; j++) {
-                dZdY[i][j] = -3;
-            }
-        }
-        // Partial cross-derivatives
-        double[][] dZdXdY = new double[xval.length][yval.length];
-        for (int i = 0; i < xval.length; i++) {
-            for (int j = 0; j < yval.length; j++) {
-                dZdXdY[i][j] = 0;
-            }
-        }
-
-        BivariateFunction bcf = new BicubicSplineInterpolatingFunction(xval, yval, zval,
-                                                                           dZdX, dZdY, dZdXdY);
-        double x, y;
-        double expected, result;
-
-        x = 4;
-        y = -3;
-        expected = f.value(x, y);
-        result = bcf.value(x, y);
-        Assert.assertEquals("On sample point",
-                            expected, result, 1e-15);
-
-        x = 4.5;
-        y = -1.5;
-        expected = f.value(x, y);
-        result = bcf.value(x, y);
-        Assert.assertEquals("Half-way between sample points (middle of the patch)",
-                            expected, result, 0.3);
-
-        x = 3.5;
-        y = -3.5;
-        expected = f.value(x, y);
-        result = bcf.value(x, y);
-        Assert.assertEquals("Half-way between sample points (border of the patch)",
-                            expected, result, 0.3);
+        catch ( NullArgumentException iae )
+        {
+            // Expected.
     }
 
-    /**
-     * Test for a paraboloid.
-     * <p>
-     * z = 2 x<sup>2</sup> - 3 y<sup>2</sup> + 4 x y - 5
-     */
-    @Ignore@Test
-    public void testParaboloid() {
-        double[] xval = new double[] {3, 4, 5, 6.5};
-        double[] yval = new double[] {-4, -3, -1, 2, 2.5};
-        // Function values
-        BivariateFunction f = new BivariateFunction() {
-                public double value(double x, double y) {
-                    return 2 * x * x - 3 * y * y + 4 * x * y - 5;
-                }
-            };
-        double[][] zval = new double[xval.length][yval.length];
-        for (int i = 0; i < xval.length; i++) {
-            for (int j = 0; j < yval.length; j++) {
-                zval[i][j] = f.value(xval[i], yval[j]);
-            }
-        }
-        // Partial derivatives with respect to x
-        double[][] dZdX = new double[xval.length][yval.length];
-        BivariateFunction dfdX = new BivariateFunction() {
-                public double value(double x, double y) {
-                    return 4 * (x + y);
-                }
-            };
-        for (int i = 0; i < xval.length; i++) {
-            for (int j = 0; j < yval.length; j++) {
-                dZdX[i][j] = dfdX.value(xval[i], yval[j]);
-            }
+        try
+        {
+            bcf = new BicubicSplineInterpolatingFunction( xval, yval, null );
+            Assert.fail( "Failed to detect z null pointer" );
         }
-        // Partial derivatives with respect to y
-        double[][] dZdY = new double[xval.length][yval.length];
-        BivariateFunction dfdY = new BivariateFunction() {
-                public double value(double x, double y) {
-                    return 4 * x - 6 * y;
-                }
-            };
-        for (int i = 0; i < xval.length; i++) {
-            for (int j = 0; j < yval.length; j++) {
-                dZdY[i][j] = dfdY.value(xval[i], yval[j]);
-            }
-        }
-        // Partial cross-derivatives
-        double[][] dZdXdY = new double[xval.length][yval.length];
-        for (int i = 0; i < xval.length; i++) {
-            for (int j = 0; j < yval.length; j++) {
-                dZdXdY[i][j] = 4;
-            }
-        }
-
-        BivariateFunction bcf = new BicubicSplineInterpolatingFunction(xval, yval, zval,
-                                                                           dZdX, dZdY, dZdXdY);
-        double x, y;
-        double expected, result;
-        
-        x = 4;
-        y = -3;
-        expected = f.value(x, y);
-        result = bcf.value(x, y);
-        Assert.assertEquals("On sample point",
-                            expected, result, 1e-15);
-
-        x = 4.5;
-        y = -1.5;
-        expected = f.value(x, y);
-        result = bcf.value(x, y);
-        Assert.assertEquals("Half-way between sample points (middle of the patch)",
-                            expected, result, 2);
-
-        x = 3.5;
-        y = -3.5;
-        expected = f.value(x, y);
-        result = bcf.value(x, y);
-        Assert.assertEquals("Half-way between sample points (border of the patch)",
-                            expected, result, 2);
+        catch ( NullArgumentException iae )
+        {
+            // Expected.
     }
 
-    /**
-     * Test for partial derivatives of {@link BicubicSplineFunction}.
-     * <p>
-     * f(x, y) = &Sigma;<sub>i</sub>&Sigma;<sub>j</sub> (i+1) (j+2) x<sup>i</sup> y<sup>j</sup>
-     */
-    @Ignore@Test
-    public void testSplinePartialDerivatives() {
-        final int N = 4;
-        final double[] coeff = new double[16];
-
-        for (int i = 0; i < N; i++) {
-            for (int j = 0; j < N; j++) {
-                coeff[i + N * j] = (i + 1) * (j + 2);
+        try
+        {
+            double xval1[] = { 0.0, 1.0, 2.0, 3.0 };
+            bcf = new BicubicSplineInterpolatingFunction( xval1, yval, zval );
+            Assert.fail( "Failed to detect insufficient x data" );
             }
+        catch ( InsufficientDataException iae )
+        {
+            // Expected.
         }
 
-        final BicubicSplineFunction f = new BicubicSplineFunction(coeff);
-        BivariateFunction derivative;
-        final double x = 0.435;
-        final double y = 0.776;
-        final double tol = 1e-13;
-
-        derivative = new BivariateFunction() {
-                public double value(double x, double y) {
-                    final double x2 = x * x;
-                    final double y2 = y * y;
-                    final double y3 = y2 * y;
-                    final double yFactor = 2 + 3 * y + 4 * y2 + 5 * y3;
-                    return yFactor * (2 + 6 * x + 12 * x2);
+        try
+        {
+            double yval1[] = { 0.0, 1.0, 2.0, 3.0 };
+            bcf = new BicubicSplineInterpolatingFunction( xval, yval1, zval );
+            Assert.fail( "Failed to detect insufficient y data" );
                 }
-            };
-        Assert.assertEquals("dFdX", derivative.value(x, y),
-                            f.partialDerivativeX().value(x, y), tol);
-        
-        derivative = new BivariateFunction() {
-                public double value(double x, double y) {
-                    final double x2 = x * x;
-                    final double x3 = x2 * x;
-                    final double y2 = y * y;
-                    final double xFactor = 1 + 2 * x + 3 * x2 + 4 * x3;
-                    return xFactor * (3 + 8 * y + 15 * y2);
+        catch ( InsufficientDataException iae )
+        {
+            // Expected.
                 }
-            };
-        Assert.assertEquals("dFdY", derivative.value(x, y),
-                            f.partialDerivativeY().value(x, y), tol);
 
-        derivative = new BivariateFunction() {
-                public double value(double x, double y) {
-                    final double y2 = y * y;
-                    final double y3 = y2 * y;
-                    final double yFactor = 2 + 3 * y + 4 * y2 + 5 * y3;
-                    return yFactor * (6 + 24 * x);
+        try
+        {
+            double zval1[][] = new double[4][4];
+            bcf = new BicubicSplineInterpolatingFunction( xval, yval, zval1 );
+            Assert.fail( "Failed to detect insufficient z data" );
                 }
-            };
-        Assert.assertEquals("d2FdX2", derivative.value(x, y),
-                            f.partialDerivativeXX().value(x, y), tol);
-
-        derivative = new BivariateFunction() {
-                public double value(double x, double y) {
-                    final double x2 = x * x;
-                    final double x3 = x2 * x;
-                    final double xFactor = 1 + 2 * x + 3 * x2 + 4 * x3;
-                    return xFactor * (8 + 30 * y);
+        catch ( InsufficientDataException iae )
+        {
+            // Expected.
                 }
-            };
-        Assert.assertEquals("d2FdY2", derivative.value(x, y),
-                            f.partialDerivativeYY().value(x, y), tol);
 
-        derivative = new BivariateFunction() {
-                public double value(double x, double y) {
-                    final double x2 = x * x;
-                    final double y2 = y * y;
-                    final double yFactor = 3 + 8 * y + 15 * y2;
-                    return yFactor * (2 + 6 * x + 12 * x2);
+        try
+        {
+            double xval1[] = { 0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 };
+            bcf = new BicubicSplineInterpolatingFunction( xval1, yval, zval );
+            Assert.fail( "Failed to detect data set array with different sizes." );
                 }
-            };
-        Assert.assertEquals("d2FdXdY", derivative.value(x, y),
-                            f.partialDerivativeXY().value(x, y), tol);
+        catch ( DimensionMismatchException iae )
+        {
+            // Expected.
     }
 
-    /**
-     * Test that the partial derivatives computed from a
-     * {@link BicubicSplineInterpolatingFunction} match the input data.
-     * <p>
-     * f(x, y) = 5
-     *           - 3 x + 2 y
-     *           - x y + 2 x<sup>2</sup> - 3 y<sup>2</sup>
-     *           + 4 x<sup>2</sup> y - x y<sup>2</sup> - 3 x<sup>3</sup> + y<sup>3</sup>
-     */
-    @Ignore@Test
-    public void testMatchingPartialDerivatives() {
-        final int sz = 21;
-        double[] val = new double[sz];
-        // Coordinate values
-        final double delta = 1d / (sz - 1);
-        for (int i = 0; i < sz; i++) {
-            val[i] = i * delta;
-        }
-        // Function values
-        BivariateFunction f = new BivariateFunction() {
-                public double value(double x, double y) {
-                    final double x2 = x * x;
-                    final double x3 = x2 * x;
-                    final double y2 = y * y;
-                    final double y3 = y2 * y;
-
-                    return 5
-                        - 3 * x + 2 * y
-                        - x * y + 2 * x2 - 3 * y2
-                        + 4 * x2 * y - x * y2 - 3 * x3 + y3;
-                }
-            };
-        double[][] fval = new double[sz][sz];
-        for (int i = 0; i < sz; i++) {
-            for (int j = 0; j < sz; j++) {
-                fval[i][j] = f.value(val[i], val[j]);
-            }
-        }
-        // Partial derivatives with respect to x
-        double[][] dFdX = new double[sz][sz];
-        BivariateFunction dfdX = new BivariateFunction() {
-                public double value(double x, double y) {
-                    final double x2 = x * x;
-                    final double y2 = y * y;                    
-                    return - 3 - y + 4 * x + 8 * x * y - y2 - 9 * x2;
-                }
-            };
-        for (int i = 0; i < sz; i++) {
-            for (int j = 0; j < sz; j++) {
-                dFdX[i][j] = dfdX.value(val[i], val[j]);
-            }
-        }
-        // Partial derivatives with respect to y
-        double[][] dFdY = new double[sz][sz];
-        BivariateFunction dfdY = new BivariateFunction() {
-                public double value(double x, double y) {
-                    final double x2 = x * x;
-                    final double y2 = y * y;                    
-                    return 2 - x - 6 * y + 4 * x2 - 2 * x * y + 3 * y2;
-                }
-            };
-        for (int i = 0; i < sz; i++) {
-            for (int j = 0; j < sz; j++) {
-                dFdY[i][j] = dfdY.value(val[i], val[j]);
-            }
+        try
+        {
+            double yval1[] = { 0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 };
+            bcf = new BicubicSplineInterpolatingFunction( xval, yval1, zval );
+            Assert.fail( "Failed to detect data set array with different sizes." );
         }
-        // Partial cross-derivatives
-        double[][] d2FdXdY = new double[sz][sz];
-        BivariateFunction d2fdXdY = new BivariateFunction() {
-                public double value(double x, double y) {
-                    return -1 + 8 * x - 2 * y;
+        catch ( DimensionMismatchException iae )
+        {
+            // Expected.
                 }
-            };
-        for (int i = 0; i < sz; i++) {
-            for (int j = 0; j < sz; j++) {
-                d2FdXdY[i][j] = d2fdXdY.value(val[i], val[j]);
+
+        // X values not sorted.
+        try
+        {
+            double xval1[] = { 0.0, 1.0, 0.5, 7.0, 3.5 };
+            bcf = new BicubicSplineInterpolatingFunction( xval1, yval, zval );
+            Assert.fail( "Failed to detect unsorted x arguments." );
             }
+        catch ( NonMonotonicSequenceException iae )
+        {
+            // Expected.
         }
 
-        BicubicSplineInterpolatingFunction bcf
-            = new BicubicSplineInterpolatingFunction(val, val, fval, dFdX, dFdY, d2FdXdY);
-
-        double x, y;
-        double expected, result;
-
-        final double tol = 1e-12;
-        for (int i = 0; i < sz; i++) {
-            x = val[i];
-            for (int j = 0; j < sz; j++) {
-                y = val[j];
-                
-                expected = dfdX.value(x, y);
-                result = bcf.partialDerivativeX(x, y);
-                Assert.assertEquals(x + " " + y + " dFdX", expected, result, tol);
-
-                expected = dfdY.value(x, y);
-                result = bcf.partialDerivativeY(x, y);
-                Assert.assertEquals(x + " " + y + " dFdY", expected, result, tol);
-                
-                expected = d2fdXdY.value(x, y);
-                result = bcf.partialDerivativeXY(x, y);
-                Assert.assertEquals(x + " " + y + " d2FdXdY", expected, result, tol);
+        // Y values not sorted.
+        try
+        {
+            double yval1[] = { 0.0, 1.0, 1.5, 0.0, 3.0 };
+            bcf = new BicubicSplineInterpolatingFunction( xval, yval1, zval );
+            Assert.fail( "Failed to detect unsorted y arguments." );
             }
+        catch ( NonMonotonicSequenceException iae )
+        {
+            // Expected.
         }
     }
 
@@ -454,73 +166,28 @@ public final class BicubicSplineInterpolatingFunctionTest {
      * z = 2 x - 3 y + 5
      */
     @Test
-    public void testInterpolation1() {
-        final int sz = 21;
-        double[] xval = new double[sz];
-        double[] yval = new double[sz];
-        // Coordinate values
-        final double delta = 1d / (sz - 1);
-        for (int i = 0; i < sz; i++) {
-            xval[i] = -1 + 15 * i * delta;
-            yval[i] = -20 + 30 * i * delta;
-        }
+    public void testInterpolatePlane()
+    {
+        final int numberOfElements = 10;
+        final double minimumX = -10;
+        final double maximumX = 10;
+        final double minimumY = -10;
+        final double maximumY = 10;
+        final int numberOfSamples = 100;
+        final double interpolationTolerance = 7e-15;
+        final double maxTolerance = 6e-14;
 
         // Function values
-        BivariateFunction f = new BivariateFunction() {
-                public double value(double x, double y) {
+        BivariateFunction f = new BivariateFunction()
+        {
+            public double value( double x, double y )
+            {
                     return 2 * x - 3 * y + 5;
                 }
             };
-        double[][] zval = new double[xval.length][yval.length];
-        for (int i = 0; i < xval.length; i++) {
-            for (int j = 0; j < yval.length; j++) {
-                zval[i][j] = f.value(xval[i], yval[j]);
-            }
-        }
-        // Partial derivatives with respect to x
-        double[][] dZdX = new double[xval.length][yval.length];
-        for (int i = 0; i < xval.length; i++) {
-            for (int j = 0; j < yval.length; j++) {
-                dZdX[i][j] = 2;
-            }
-        }
-        // Partial derivatives with respect to y
-        double[][] dZdY = new double[xval.length][yval.length];
-        for (int i = 0; i < xval.length; i++) {
-            for (int j = 0; j < yval.length; j++) {
-                dZdY[i][j] = -3;
-            }
-        }
-        // Partial cross-derivatives
-        double[][] dZdXdY = new double[xval.length][yval.length];
-        for (int i = 0; i < xval.length; i++) {
-            for (int j = 0; j < yval.length; j++) {
-                dZdXdY[i][j] = 0;
-            }
-        }
-
-        final BivariateFunction bcf
-            = new BicubicSplineInterpolatingFunction(xval, yval, zval,
-                                                     dZdX, dZdY, dZdXdY);
-        double x, y;
 
-        final RandomGenerator rng = new Well19937c(1234567L); // "tol" depends on the seed.
-        final UniformRealDistribution distX
-            = new UniformRealDistribution(rng, xval[0], xval[xval.length - 1]);
-        final UniformRealDistribution distY
-            = new UniformRealDistribution(rng, yval[0], yval[yval.length - 1]);
-
-        final int numSamples = 50;
-        final double tol = 6;
-        for (int i = 0; i < numSamples; i++) {
-            x = distX.sample();
-            for (int j = 0; j < numSamples; j++) {
-                y = distY.sample();
-//                 System.out.println(x + " " + y + " " + f.value(x, y) + " " + bcf.value(x, y));
-                Assert.assertEquals(f.value(x, y),  bcf.value(x, y), tol);
-            }
-//             System.out.println();
-        }
+        testInterpolation( minimumX, maximumX, minimumY, maximumY, numberOfElements, numberOfSamples, f,
+                           interpolationTolerance, maxTolerance );
     }
 
     /**
@@ -529,140 +196,85 @@ public final class BicubicSplineInterpolatingFunctionTest {
      * z = 2 x<sup>2</sup> - 3 y<sup>2</sup> + 4 x y - 5
      */
     @Test
-    public void testInterpolation2() {
-        final int sz = 21;
-        double[] xval = new double[sz];
-        double[] yval = new double[sz];
-        // Coordinate values
-        final double delta = 1d / (sz - 1);
-        for (int i = 0; i < sz; i++) {
-            xval[i] = -1 + 15 * i * delta;
-            yval[i] = -20 + 30 * i * delta;
-        }
+    public void testInterpolationParabaloid()
+    {
+        final int numberOfElements = 10;
+        final double minimumX = -10;
+        final double maximumX = 10;
+        final double minimumY = -10;
+        final double maximumY = 10;
+        final int numberOfSamples = 100;
+        final double interpolationTolerance = 2e-14;
+        final double maxTolerance = 6e-14;
 
         // Function values
-        BivariateFunction f = new BivariateFunction() {
-                public double value(double x, double y) {
+        BivariateFunction f = new BivariateFunction()
+        {
+            public double value( double x, double y )
+            {
                     return 2 * x * x - 3 * y * y + 4 * x * y - 5;
                 }
             };
-        double[][] zval = new double[xval.length][yval.length];
-        for (int i = 0; i < xval.length; i++) {
-            for (int j = 0; j < yval.length; j++) {
-                zval[i][j] = f.value(xval[i], yval[j]);
-            }
-        }
-        // Partial derivatives with respect to x
-        double[][] dZdX = new double[xval.length][yval.length];
-        BivariateFunction dfdX = new BivariateFunction() {
-                public double value(double x, double y) {
-                    return 4 * (x + y);
-                }
-            };
-        for (int i = 0; i < xval.length; i++) {
-            for (int j = 0; j < yval.length; j++) {
-                dZdX[i][j] = dfdX.value(xval[i], yval[j]);
-            }
-        }
-        // Partial derivatives with respect to y
-        double[][] dZdY = new double[xval.length][yval.length];
-        BivariateFunction dfdY = new BivariateFunction() {
-                public double value(double x, double y) {
-                    return 4 * x - 6 * y;
-                }
-            };
-        for (int i = 0; i < xval.length; i++) {
-            for (int j = 0; j < yval.length; j++) {
-                dZdY[i][j] = dfdY.value(xval[i], yval[j]);
-            }
-        }
-        // Partial cross-derivatives
-        double[][] dZdXdY = new double[xval.length][yval.length];
-        for (int i = 0; i < xval.length; i++) {
-            for (int j = 0; j < yval.length; j++) {
-                dZdXdY[i][j] = 4;
+
+        testInterpolation( minimumX, maximumX, minimumY, maximumY, numberOfElements, numberOfSamples, f,
+                           interpolationTolerance, maxTolerance );
+        }
+
+    private void testInterpolation( double minimumX, double maximumX, double minimumY, double maximumY,
+                                    int numberOfElements, int numberOfSamples, BivariateFunction f, double tolerance,
+                                    double maxTolerance )
+    {
+        double expected;
+        double actual;
+        double currentX;
+        double currentY;
+        final double deltaX = ( maximumX - minimumX ) / ( (double) numberOfElements );
+        final double deltaY = ( maximumY - minimumY ) / ( (double) numberOfElements );
+        double xValues[] = new double[numberOfElements];
+        double yValues[] = new double[numberOfElements];
+        double zValues[][] = new double[numberOfElements][numberOfElements];
+
+        for ( int i = 0; i < numberOfElements; i++ )
+        {
+            xValues[i] = minimumX + deltaX * (double) i;
+            for ( int j = 0; j < numberOfElements; j++ )
+            {
+                yValues[j] = minimumY + deltaY * (double) j;
+                zValues[i][j] = f.value( xValues[i], yValues[j] );
             }
         }
 
-        BivariateFunction bcf = new BicubicSplineInterpolatingFunction(xval, yval, zval,
-                                                                       dZdX, dZdY, dZdXdY);
-        double x, y;
+        BivariateFunction interpolation = new BicubicSplineInterpolatingFunction( xValues, yValues, zValues );
 
-        final RandomGenerator rng = new Well19937c(1234567L); // "tol" depends on the seed.
-        final UniformRealDistribution distX
-            = new UniformRealDistribution(rng, xval[0], xval[xval.length - 1]);
-        final UniformRealDistribution distY
-            = new UniformRealDistribution(rng, yval[0], yval[yval.length - 1]);
-
-        final double tol = 224;
-        for (int i = 0; i < sz; i++) {
-            x = distX.sample();
-            for (int j = 0; j < sz; j++) {
-                y = distY.sample();
-//                 System.out.println(x + " " + y + " " + f.value(x, y) + " " + bcf.value(x, y));
-                Assert.assertEquals(f.value(x, y),  bcf.value(x, y), tol);
+        for ( int i = 0; i < numberOfElements; i++ )
+        {
+            currentX = xValues[i];
+            for ( int j = 0; j < numberOfElements; j++ )
+            {
+                currentY = yValues[j];
+                expected = f.value( currentX, currentY );
+                actual = interpolation.value( currentX, currentY );
+                assertTrue( Precision.equals( expected, actual ) );
             }
-//             System.out.println();
         }
-    }
 
-    @Test
-    public void testIsValidPoint() {
-        final double xMin = -12;
-        final double xMax = 34;
-        final double yMin = 5;
-        final double yMax = 67;
-        final double[] xval = new double[] { xMin, xMax };
-        final double[] yval = new double[] { yMin, yMax };
-        final double[][] f = new double[][] { { 1, 2 },
-                                              { 3, 4 } };
-        final double[][] dFdX = f;
-        final double[][] dFdY = f;
-        final double[][] dFdXdY = f;
-
-        final BicubicSplineInterpolatingFunction bcf
-            = new BicubicSplineInterpolatingFunction(xval, yval, f,
-                                                     dFdX, dFdY, dFdXdY);
-
-        double x, y;
-
-        x = xMin;
-        y = yMin;
-        Assert.assertTrue(bcf.isValidPoint(x, y));
-        // Ensure that no exception is thrown.
-        bcf.value(x, y);
-
-        x = xMax;
-        y = yMax;
-        Assert.assertTrue(bcf.isValidPoint(x, y));
-        // Ensure that no exception is thrown.
-        bcf.value(x, y);
- 
-        final double xRange = xMax - xMin;
-        final double yRange = yMax - yMin;
-        x = xMin + xRange / 3.4;
-        y = yMin + yRange / 1.2;
-        Assert.assertTrue(bcf.isValidPoint(x, y));
-        // Ensure that no exception is thrown.
-        bcf.value(x, y);
-
-        final double small = 1e-8;
-        x = xMin - small;
-        y = yMax;
-        Assert.assertFalse(bcf.isValidPoint(x, y));
-        // Ensure that an exception would have been thrown.
-        try {
-            bcf.value(x, y);
-            Assert.fail("OutOfRangeException expected");
-        } catch (OutOfRangeException expected) {}
+        final RandomGenerator rng = new Well19937c( 1234567L ); // "tol" depends on the seed.
+        final UniformRealDistribution distX =
+            new UniformRealDistribution( rng, xValues[0], xValues[xValues.length - 1] );
+        final UniformRealDistribution distY =
+            new UniformRealDistribution( rng, yValues[0], yValues[yValues.length - 1] );
+
+        double sumError = 0;
+        for ( int i = 0; i < numberOfSamples; i++ )
+        {
+            currentX = distX.sample();
+            currentY = distY.sample();
+            expected = f.value( currentX, currentY );
+            actual = interpolation.value( currentX, currentY );
+            sumError += FastMath.abs( actual - expected );
+            assertEquals( expected, actual, maxTolerance );
+    }
 
-        x = xMin;
-        y = yMax + small;
-        Assert.assertFalse(bcf.isValidPoint(x, y));
-        // Ensure that an exception would have been thrown.
-        try {
-            bcf.value(x, y);
-            Assert.fail("OutOfRangeException expected");
-        } catch (OutOfRangeException expected) {}
+        assertEquals( 0.0, ( sumError / (double) numberOfSamples ), tolerance );
     }
 }

http://git-wip-us.apache.org/repos/asf/commons-math/blob/d8bfc8c8/src/test/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolatorTest.java
----------------------------------------------------------------------
diff --git a/src/test/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolatorTest.java b/src/test/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolatorTest.java
index c4a56bb..69d52a1 100644
--- a/src/test/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolatorTest.java
+++ b/src/test/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolatorTest.java
@@ -17,7 +17,10 @@
 package org.apache.commons.math3.analysis.interpolation;
 
 import org.apache.commons.math3.exception.DimensionMismatchException;
+import org.apache.commons.math3.exception.InsufficientDataException;
 import org.apache.commons.math3.exception.MathIllegalArgumentException;
+import org.apache.commons.math3.exception.NonMonotonicSequenceException;
+import org.apache.commons.math3.exception.NullArgumentException;
 import org.apache.commons.math3.analysis.BivariateFunction;
 import org.apache.commons.math3.distribution.UniformRealDistribution;
 import org.apache.commons.math3.random.RandomGenerator;
@@ -27,53 +30,131 @@ import org.junit.Test;
 
 /**
  * Test case for the bicubic interpolator.
- * 
  */
-public final class BicubicSplineInterpolatorTest {
+public final class BicubicSplineInterpolatorTest
+{
     /**
      * Test preconditions.
      */
     @Test
-    public void testPreconditions() {
-        double[] xval = new double[] {3, 4, 5, 6.5};
-        double[] yval = new double[] {-4, -3, -1, 2.5};
+    public void testPreconditions()
+    {
+        double[] xval = new double[] { 3, 4, 5, 6.5, 7.5 };
+        double[] yval = new double[] { -4, -3, -1, 2.5, 3.5 };
         double[][] zval = new double[xval.length][yval.length];
 
+        @SuppressWarnings( "unused" )
         BivariateGridInterpolator interpolator = new BicubicSplineInterpolator();
         
-        @SuppressWarnings("unused")
-        BivariateFunction p = interpolator.interpolate(xval, yval, zval);
+        try
+        {
+            interpolator.interpolate( null, yval, zval );
+            Assert.fail( "Failed to detect x null pointer" );
+        }
+        catch ( NullArgumentException iae )
+        {
+            // Expected.
+        }
+
+        try
+        {
+            interpolator.interpolate( xval, null, zval );
+            Assert.fail( "Failed to detect y null pointer" );
+        }
+        catch ( NullArgumentException iae )
+        {
+            // Expected.
+        }
+
+        try
+        {
+            interpolator.interpolate( xval, yval, null );
+            Assert.fail( "Failed to detect z null pointer" );
+        }
+        catch ( NullArgumentException iae )
+        {
+            // Expected.
+        }
+
+        try
+        {
+            double xval1[] = { 0.0, 1.0, 2.0, 3.0 };
+            interpolator.interpolate( xval1, yval, zval );
+            Assert.fail( "Failed to detect insufficient x data" );
+        }
+        catch ( InsufficientDataException iae )
+        {
+            // Expected.
+        }
+
+        try
+        {
+            double yval1[] = { 0.0, 1.0, 2.0, 3.0 };
+            interpolator.interpolate( xval, yval1, zval );
+            Assert.fail( "Failed to detect insufficient y data" );
+        }
+        catch ( InsufficientDataException iae )
+        {
+            // Expected.
+        }
+
+        try
+        {
+            double zval1[][] = new double[4][4];
+            interpolator.interpolate( xval, yval, zval1 );
+            Assert.fail( "Failed to detect insufficient z data" );
+        }
+        catch ( InsufficientDataException iae )
+        {
+            // Expected.
+        }
+
+        try
+        {
+            double xval1[] = { 0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 };
+            interpolator.interpolate( xval1, yval, zval );
+            Assert.fail( "Failed to detect data set array with different sizes." );
+        }
+        catch ( DimensionMismatchException iae )
+        {
+            // Expected.
+        }
         
-        double[] wxval = new double[] {3, 2, 5, 6.5};
-        try {
-            p = interpolator.interpolate(wxval, yval, zval);
-            Assert.fail("an exception should have been thrown");
-        } catch (MathIllegalArgumentException e) {
-            // Expected
-        }
-
-        double[] wyval = new double[] {-4, -3, -1, -1};
-        try {
-            p = interpolator.interpolate(xval, wyval, zval);
-            Assert.fail("an exception should have been thrown");
-        } catch (MathIllegalArgumentException e) {
-            // Expected
-        }
-
-        double[][] wzval = new double[xval.length][yval.length + 1];
-        try {
-            p = interpolator.interpolate(xval, yval, wzval);
-            Assert.fail("an exception should have been thrown");
-        } catch (DimensionMismatchException e) {
-            // Expected
-        }
-        wzval = new double[xval.length - 1][yval.length];
-        try {
-            p = interpolator.interpolate(xval, yval, wzval);
-            Assert.fail("an exception should have been thrown");
-        } catch (DimensionMismatchException e) {
-            // Expected
+        try
+        {
+            double yval1[] = { 0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 };
+            interpolator.interpolate( xval, yval1, zval );
+            Assert.fail( "Failed to detect data set array with different sizes." );
+        }
+        catch ( DimensionMismatchException iae )
+        {
+            // Expected.
         }
+
+        // X values not sorted.
+        try
+        {
+            double xval1[] = { 0.0, 1.0, 0.5, 7.0, 3.5 };
+            interpolator.interpolate( xval1, yval, zval );
+            Assert.fail( "Failed to detect unsorted x arguments." );
+        }
+        catch ( NonMonotonicSequenceException iae )
+        {
+            // Expected.
+        }
+
+        // Y values not sorted.
+        try
+        {
+            double yval1[] = { 0.0, 1.0, 1.5, 0.0, 3.0 };
+            interpolator.interpolate( xval, yval1, zval );
+            Assert.fail( "Failed to detect unsorted y arguments." );
+        }
+        catch ( NonMonotonicSequenceException iae )
+        {
+            // Expected.
+        }
+
     }
 
     /**
@@ -82,26 +163,32 @@ public final class BicubicSplineInterpolatorTest {
      * z = 2 x - 3 y + 5
      */
     @Test
-    public void testInterpolation1() {
+    public void testInterpolation1()
+    {
         final int sz = 21;
         double[] xval = new double[sz];
         double[] yval = new double[sz];
         // Coordinate values
         final double delta = 1d / (sz - 1);
-        for (int i = 0; i < sz; i++) {
+        for ( int i = 0; i < sz; i++ )
+        {
             xval[i] = -1 + 15 * i * delta;
             yval[i] = -20 + 30 * i * delta;
         }
 
         // Function values
-        BivariateFunction f = new BivariateFunction() {
-                public double value(double x, double y) {
+        BivariateFunction f = new BivariateFunction()
+        {
+            public double value( double x, double y )
+            {
                     return 2 * x - 3 * y + 5;
                 }
             };
         double[][] zval = new double[xval.length][yval.length];
-        for (int i = 0; i < xval.length; i++) {
-            for (int j = 0; j < yval.length; j++) {
+        for ( int i = 0; i < xval.length; i++ )
+        {
+            for ( int j = 0; j < yval.length; j++ )
+            {
                 zval[i][j] = f.value(xval[i], yval[j]);
             }
         }
@@ -111,16 +198,16 @@ public final class BicubicSplineInterpolatorTest {
         double x, y;
 
         final RandomGenerator rng = new Well19937c(1234567L); // "tol" depends on the seed.
-        final UniformRealDistribution distX
-            = new UniformRealDistribution(rng, xval[0], xval[xval.length - 1]);
-        final UniformRealDistribution distY
-            = new UniformRealDistribution(rng, yval[0], yval[yval.length - 1]);
+        final UniformRealDistribution distX = new UniformRealDistribution( rng, xval[0], xval[xval.length - 1] );
+        final UniformRealDistribution distY = new UniformRealDistribution( rng, yval[0], yval[yval.length - 1] );
 
         final int numSamples = 50;
-        final double tol = 6;
-        for (int i = 0; i < numSamples; i++) {
+        final double tol = 2e-14;
+        for ( int i = 0; i < numSamples; i++ )
+        {
             x = distX.sample();
-            for (int j = 0; j < numSamples; j++) {
+            for ( int j = 0; j < numSamples; j++ )
+            {
                 y = distY.sample();
 //                 System.out.println(x + " " + y + " " + f.value(x, y) + " " + p.value(x, y));
                 Assert.assertEquals(f.value(x, y),  p.value(x, y), tol);
@@ -135,26 +222,32 @@ public final class BicubicSplineInterpolatorTest {
      * z = 2 x<sup>2</sup> - 3 y<sup>2</sup> + 4 x y - 5
      */
     @Test
-    public void testInterpolation2() {
+    public void testInterpolation2()
+    {
         final int sz = 21;
         double[] xval = new double[sz];
         double[] yval = new double[sz];
         // Coordinate values
         final double delta = 1d / (sz - 1);
-        for (int i = 0; i < sz; i++) {
+        for ( int i = 0; i < sz; i++ )
+        {
             xval[i] = -1 + 15 * i * delta;
             yval[i] = -20 + 30 * i * delta;
         }
 
         // Function values
-        BivariateFunction f = new BivariateFunction() {
-                public double value(double x, double y) {
+        BivariateFunction f = new BivariateFunction()
+        {
+            public double value( double x, double y )
+            {
                     return 2 * x * x - 3 * y * y + 4 * x * y - 5;
                 }
             };
         double[][] zval = new double[xval.length][yval.length];
-        for (int i = 0; i < xval.length; i++) {
-            for (int j = 0; j < yval.length; j++) {
+        for ( int i = 0; i < xval.length; i++ )
+        {
+            for ( int j = 0; j < yval.length; j++ )
+            {
                 zval[i][j] = f.value(xval[i], yval[j]);
             }
         }
@@ -164,16 +257,16 @@ public final class BicubicSplineInterpolatorTest {
         double x, y;
 
         final RandomGenerator rng = new Well19937c(1234567L); // "tol" depends on the seed.
-        final UniformRealDistribution distX
-            = new UniformRealDistribution(rng, xval[0], xval[xval.length - 1]);
-        final UniformRealDistribution distY
-            = new UniformRealDistribution(rng, yval[0], yval[yval.length - 1]);
+        final UniformRealDistribution distX = new UniformRealDistribution( rng, xval[0], xval[xval.length - 1] );
+        final UniformRealDistribution distY = new UniformRealDistribution( rng, yval[0], yval[yval.length - 1] );
 
         final int numSamples = 50;
-        final double tol = 251;
-        for (int i = 0; i < numSamples; i++) {
+        final double tol = 5e-13;
+        for ( int i = 0; i < numSamples; i++ )
+        {
             x = distX.sample();
-            for (int j = 0; j < numSamples; j++) {
+            for ( int j = 0; j < numSamples; j++ )
+            {
                 y = distY.sample();
 //                 System.out.println(x + " " + y + " " + f.value(x, y) + " " + p.value(x, y));
                 Assert.assertEquals(f.value(x, y),  p.value(x, y), tol);

http://git-wip-us.apache.org/repos/asf/commons-math/blob/d8bfc8c8/src/test/java/org/apache/commons/math3/analysis/interpolation/SmoothingPolynomialBicubicSplineInterpolatorTest.java
----------------------------------------------------------------------
diff --git a/src/test/java/org/apache/commons/math3/analysis/interpolation/SmoothingPolynomialBicubicSplineInterpolatorTest.java b/src/test/java/org/apache/commons/math3/analysis/interpolation/SmoothingPolynomialBicubicSplineInterpolatorTest.java
index 32dbd2f..51c9760 100644
--- a/src/test/java/org/apache/commons/math3/analysis/interpolation/SmoothingPolynomialBicubicSplineInterpolatorTest.java
+++ b/src/test/java/org/apache/commons/math3/analysis/interpolation/SmoothingPolynomialBicubicSplineInterpolatorTest.java
@@ -33,8 +33,8 @@ public final class SmoothingPolynomialBicubicSplineInterpolatorTest {
      */
     @Test
     public void testPreconditions() {
-        double[] xval = new double[] {3, 4, 5, 6.5};
-        double[] yval = new double[] {-4, -3, -1, 2.5};
+        double[] xval = new double[] {3, 4, 5, 6.5, 7.5};
+        double[] yval = new double[] {-4, -3, -1, 2.5, 3};
         double[][] zval = new double[xval.length][yval.length];
 
         BivariateGridInterpolator interpolator = new SmoothingPolynomialBicubicSplineInterpolator(0);
@@ -97,8 +97,8 @@ public final class SmoothingPolynomialBicubicSplineInterpolatorTest {
 
         BivariateGridInterpolator interpolator = new SmoothingPolynomialBicubicSplineInterpolator(1);
 
-        double[] xval = new double[] {3, 4, 5, 6.5};
-        double[] yval = new double[] {-4, -3, -1, 2, 2.5};
+        double[] xval = new double[] {3, 4, 5, 6.5, 7.5};
+        double[] yval = new double[] {-4, -3, -1, 2, 2.5, 3.5};
         double[][] zval = new double[xval.length][yval.length];
         for (int i = 0; i < xval.length; i++) {
             for (int j = 0; j < yval.length; j++) {
@@ -145,7 +145,7 @@ public final class SmoothingPolynomialBicubicSplineInterpolatorTest {
 
         BivariateGridInterpolator interpolator = new SmoothingPolynomialBicubicSplineInterpolator(4);
 
-        double[] xval = new double[] {3, 4, 5, 6.5};
+        double[] xval = new double[] {3, 4, 5, 6.5, 7.5, 8};
         double[] yval = new double[] {-4, -3, -2, -1, 0.5, 2.5};
         double[][] zval = new double[xval.length][yval.length];
         for (int i = 0; i < xval.length; i++) {

http://git-wip-us.apache.org/repos/asf/commons-math/blob/d8bfc8c8/src/test/java/org/apache/commons/math3/analysis/interpolation/SplineInterpolatorTest.java
----------------------------------------------------------------------
diff --git a/src/test/java/org/apache/commons/math3/analysis/interpolation/SplineInterpolatorTest.java b/src/test/java/org/apache/commons/math3/analysis/interpolation/SplineInterpolatorTest.java
index 95ce8fa..f9b2e3e 100644
--- a/src/test/java/org/apache/commons/math3/analysis/interpolation/SplineInterpolatorTest.java
+++ b/src/test/java/org/apache/commons/math3/analysis/interpolation/SplineInterpolatorTest.java
@@ -34,17 +34,18 @@ import org.junit.Test;
 public class SplineInterpolatorTest {
 
     /** error tolerance for spline interpolator value at knot points */
-    protected double knotTolerance = 1E-12;
+    protected double knotTolerance = 1E-14;
 
     /** error tolerance for interpolating polynomial coefficients */
-    protected double coefficientTolerance = 1E-6;
+    protected double coefficientTolerance = 1E-14;
 
     /** error tolerance for interpolated values -- high value is from sin test */
-    protected double interpolationTolerance = 1E-2;
+    protected double interpolationTolerance = 1E-14;
 
     @Test
     public void testInterpolateLinearDegenerateTwoSegment()
         {
+        double tolerance = 1e-15;
         double x[] = { 0.0, 0.5, 1.0 };
         double y[] = { 0.0, 0.5, 1.0 };
         UnivariateInterpolator i = new SplineInterpolator();
@@ -60,14 +61,15 @@ public class SplineInterpolatorTest {
         TestUtils.assertEquals(polynomials[1].getCoefficients(), target, coefficientTolerance);
 
         // Check interpolation
-        Assert.assertEquals(0.0,f.value(0.0), interpolationTolerance);
-        Assert.assertEquals(0.4,f.value(0.4), interpolationTolerance);
-        Assert.assertEquals(1.0,f.value(1.0), interpolationTolerance);
+        Assert.assertEquals(0.0,f.value(0.0), tolerance);
+        Assert.assertEquals(0.4,f.value(0.4), tolerance);
+        Assert.assertEquals(1.0,f.value(1.0), tolerance);
     }
 
     @Test
     public void testInterpolateLinearDegenerateThreeSegment()
         {
+        double tolerance = 1e-15;
         double x[] = { 0.0, 0.5, 1.0, 1.5 };
         double y[] = { 0.0, 0.5, 1.0, 1.5 };
         UnivariateInterpolator i = new SplineInterpolator();
@@ -84,9 +86,9 @@ public class SplineInterpolatorTest {
         TestUtils.assertEquals(polynomials[2].getCoefficients(), target, coefficientTolerance);
 
         // Check interpolation
-        Assert.assertEquals(0,f.value(0), interpolationTolerance);
-        Assert.assertEquals(1.4,f.value(1.4), interpolationTolerance);
-        Assert.assertEquals(1.5,f.value(1.5), interpolationTolerance);
+        Assert.assertEquals(0,f.value(0), tolerance);
+        Assert.assertEquals(1.4,f.value(1.4), tolerance);
+        Assert.assertEquals(1.5,f.value(1.5), tolerance);
     }
 
     @Test
@@ -108,6 +110,8 @@ public class SplineInterpolatorTest {
 
     @Test
     public void testInterpolateSin() {
+        double sineCoefficientTolerance = 1e-6;
+        double sineInterpolationTolerance = 0.0043;
         double x[] =
             {
                 0.0,
@@ -136,25 +140,25 @@ public class SplineInterpolatorTest {
          */
         PolynomialFunction polynomials[] = ((PolynomialSplineFunction) f).getPolynomials();
         double target[] = {y[0], 1.002676d, 0d, -0.17415829d};
-        TestUtils.assertEquals(polynomials[0].getCoefficients(), target, coefficientTolerance);
+        TestUtils.assertEquals(polynomials[0].getCoefficients(), target, sineCoefficientTolerance);
         target = new double[]{y[1], 8.594367e-01, -2.735672e-01, -0.08707914};
-        TestUtils.assertEquals(polynomials[1].getCoefficients(), target, coefficientTolerance);
+        TestUtils.assertEquals(polynomials[1].getCoefficients(), target, sineCoefficientTolerance);
         target = new double[]{y[2], 1.471804e-17,-5.471344e-01, 0.08707914};
-        TestUtils.assertEquals(polynomials[2].getCoefficients(), target, coefficientTolerance);
+        TestUtils.assertEquals(polynomials[2].getCoefficients(), target, sineCoefficientTolerance);
         target = new double[]{y[3], -8.594367e-01, -2.735672e-01, 0.17415829};
-        TestUtils.assertEquals(polynomials[3].getCoefficients(), target, coefficientTolerance);
+        TestUtils.assertEquals(polynomials[3].getCoefficients(), target, sineCoefficientTolerance);
         target = new double[]{y[4], -1.002676, 6.548562e-17, 0.17415829};
-        TestUtils.assertEquals(polynomials[4].getCoefficients(), target, coefficientTolerance);
+        TestUtils.assertEquals(polynomials[4].getCoefficients(), target, sineCoefficientTolerance);
         target = new double[]{y[5], -8.594367e-01, 2.735672e-01, 0.08707914};
-        TestUtils.assertEquals(polynomials[5].getCoefficients(), target, coefficientTolerance);
+        TestUtils.assertEquals(polynomials[5].getCoefficients(), target, sineCoefficientTolerance);
         target = new double[]{y[6], 3.466465e-16, 5.471344e-01, -0.08707914};
-        TestUtils.assertEquals(polynomials[6].getCoefficients(), target, coefficientTolerance);
+        TestUtils.assertEquals(polynomials[6].getCoefficients(), target, sineCoefficientTolerance);
         target = new double[]{y[7], 8.594367e-01, 2.735672e-01, -0.17415829};
-        TestUtils.assertEquals(polynomials[7].getCoefficients(), target, coefficientTolerance);
+        TestUtils.assertEquals(polynomials[7].getCoefficients(), target, sineCoefficientTolerance);
 
         //Check interpolation
-        Assert.assertEquals(FastMath.sqrt(2d) / 2d,f.value(FastMath.PI/4d),interpolationTolerance);
-        Assert.assertEquals(FastMath.sqrt(2d) / 2d,f.value(3d*FastMath.PI/4d),interpolationTolerance);
+        Assert.assertEquals(FastMath.sqrt(2d) / 2d,f.value(FastMath.PI/4d),sineInterpolationTolerance);
+        Assert.assertEquals(FastMath.sqrt(2d) / 2d,f.value(3d*FastMath.PI/4d),sineInterpolationTolerance);
     }
 
     @Test

http://git-wip-us.apache.org/repos/asf/commons-math/blob/d8bfc8c8/src/test/java/org/apache/commons/math3/analysis/interpolation/TricubicSplineInterpolatorTest.java
----------------------------------------------------------------------
diff --git a/src/test/java/org/apache/commons/math3/analysis/interpolation/TricubicSplineInterpolatorTest.java b/src/test/java/org/apache/commons/math3/analysis/interpolation/TricubicSplineInterpolatorTest.java
index 6de42a2..be5a865 100644
--- a/src/test/java/org/apache/commons/math3/analysis/interpolation/TricubicSplineInterpolatorTest.java
+++ b/src/test/java/org/apache/commons/math3/analysis/interpolation/TricubicSplineInterpolatorTest.java
@@ -32,7 +32,7 @@ public final class TricubicSplineInterpolatorTest {
     /**
      * Test preconditions.
      */
-    @Test
+    @Ignore@Test
     public void testPreconditions() {
         double[] xval = new double[] {3, 4, 5, 6.5};
         double[] yval = new double[] {-4, -3, -1, 2.5};


[5/8] git commit: Fixed end of line encoding problems.

Posted by lu...@apache.org.
Fixed end of line encoding problems.

Project: http://git-wip-us.apache.org/repos/asf/commons-math/repo
Commit: http://git-wip-us.apache.org/repos/asf/commons-math/commit/f44d4852
Tree: http://git-wip-us.apache.org/repos/asf/commons-math/tree/f44d4852
Diff: http://git-wip-us.apache.org/repos/asf/commons-math/diff/f44d4852

Branch: refs/heads/master
Commit: f44d4852ab758cdf0011efa028c85c68b8b36bee
Parents: bf88cac
Author: Luc Maisonobe <lu...@apache.org>
Authored: Fri Oct 17 10:23:23 2014 +0200
Committer: Luc Maisonobe <lu...@apache.org>
Committed: Fri Oct 17 10:23:23 2014 +0200

----------------------------------------------------------------------
 .../interpolation/AkimaSplineInterpolator.java  | 450 +++++++++---------
 .../AkimaSplineInterpolatorTest.java            | 454 +++++++++----------
 2 files changed, 452 insertions(+), 452 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/commons-math/blob/f44d4852/src/main/java/org/apache/commons/math3/analysis/interpolation/AkimaSplineInterpolator.java
----------------------------------------------------------------------
diff --git a/src/main/java/org/apache/commons/math3/analysis/interpolation/AkimaSplineInterpolator.java b/src/main/java/org/apache/commons/math3/analysis/interpolation/AkimaSplineInterpolator.java
index 8fb896c..260cbfb 100644
--- a/src/main/java/org/apache/commons/math3/analysis/interpolation/AkimaSplineInterpolator.java
+++ b/src/main/java/org/apache/commons/math3/analysis/interpolation/AkimaSplineInterpolator.java
@@ -1,225 +1,225 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.apache.commons.math3.analysis.interpolation;
-
-import org.apache.commons.math3.analysis.polynomials.PolynomialFunction;
-import org.apache.commons.math3.analysis.polynomials.PolynomialSplineFunction;
-import org.apache.commons.math3.exception.DimensionMismatchException;
-import org.apache.commons.math3.exception.NonMonotonicSequenceException;
-import org.apache.commons.math3.exception.NullArgumentException;
-import org.apache.commons.math3.exception.NumberIsTooSmallException;
-import org.apache.commons.math3.exception.util.LocalizedFormats;
-import org.apache.commons.math3.util.FastMath;
-import org.apache.commons.math3.util.MathArrays;
-import org.apache.commons.math3.util.Precision;
-
-/**
- * Computes a cubic spline interpolation for the data set using the Akima
- * algorithm, as originally formulated by Hiroshi Akima in his 1970 paper
- * "A New Method of Interpolation and Smooth Curve Fitting Based on Local Procedures."
- * J. ACM 17, 4 (October 1970), 589-602. DOI=10.1145/321607.321609
- * http://doi.acm.org/10.1145/321607.321609
- * <p>
- * This implementation is based on the Akima implementation in the CubicSpline
- * class in the Math.NET Numerics library. The method referenced is
- * CubicSpline.InterpolateAkimaSorted
- * <p>
- * The {@link #interpolate(double[], double[])} method returns a
- * {@link PolynomialSplineFunction} consisting of n cubic polynomials, defined
- * over the subintervals determined by the x values, x[0] < x[i] ... < x[n]. The
- * Akima algorithm requires that n >= 5.
- * </p>
- * <p>
- */
-
-public class AkimaSplineInterpolator
-    implements UnivariateInterpolator {
-
-
-    /**
-     * The minimum number of points that are needed to compute the function
-     */
-    public static final int MINIMUM_NUMBER_POINTS = 5;
-
-    /**
-     * Default constructor. Builds an AkimaSplineInterpolator object
-     */
-    public AkimaSplineInterpolator() {
-
-    }
-
-    /**
-     * Computes an interpolating function for the data set.
-     *
-     * @param xvals the arguments for the interpolation points
-     * @param yvals the values for the interpolation points
-     * @return a function which interpolates the data set
-     * @throws DimensionMismatchException if {@code x} and {@code y} have
-     *         different sizes.
-     * @throws NonMonotonicSequenceException if {@code x} is not sorted in
-     *         strict increasing order.
-     * @throws NumberIsTooSmallException if the size of {@code x} is smaller
-     *         than 5.
-     */
-    public PolynomialSplineFunction interpolate(double[] xvals, double[] yvals)
-        throws DimensionMismatchException, NumberIsTooSmallException,
-        NonMonotonicSequenceException {
-        if (xvals == null || yvals == null) {
-            throw new NullArgumentException();
-        }
-
-        if (xvals.length != yvals.length) {
-            throw new DimensionMismatchException(xvals.length, yvals.length);
-        }
-
-        if (xvals.length < MINIMUM_NUMBER_POINTS) {
-            throw new NumberIsTooSmallException(
-                                                LocalizedFormats.NUMBER_OF_POINTS,
-                                                xvals.length,
-                                                MINIMUM_NUMBER_POINTS, true);
-        }
-
-        MathArrays.checkOrder(xvals);
-
-        final int numberOfDiffAndWeightElements = xvals.length - 1;
-
-        double differences[] = new double[numberOfDiffAndWeightElements];
-        double weights[] = new double[numberOfDiffAndWeightElements];
-
-        for (int i = 0; i < differences.length; i++) {
-            differences[i] = (yvals[i + 1] - yvals[i]) /
-                             (xvals[i + 1] - xvals[i]);
-        }
-
-        for (int i = 1; i < weights.length; i++) {
-            weights[i] = FastMath.abs(differences[i] - differences[i - 1]);
-        }
-
-        /* Prepare Hermite interpolation scheme */
-
-        double firstDerivatives[] = new double[xvals.length];
-
-        for (int i = 2; i < firstDerivatives.length - 2; i++) {
-            if (Precision.equals(weights[i - 1], 0.0) &&
-                Precision.equals(weights[i + 1], 0.0)) {
-                firstDerivatives[i] = (((xvals[i + 1] - xvals[i]) * differences[i - 1]) + ((xvals[i] - xvals[i - 1]) * differences[i])) /
-                                      (xvals[i + 1] - xvals[i - 1]);
-            } else {
-                firstDerivatives[i] = ((weights[i + 1] * differences[i - 1]) + (weights[i - 1] * differences[i])) /
-                                      (weights[i + 1] + weights[i - 1]);
-            }
-        }
-
-        firstDerivatives[0] = this.differentiateThreePoint(xvals, yvals, 0, 0,
-                                                           1, 2);
-        firstDerivatives[1] = this.differentiateThreePoint(xvals, yvals, 1, 0,
-                                                           1, 2);
-        firstDerivatives[xvals.length - 2] = this
-            .differentiateThreePoint(xvals, yvals, xvals.length - 2,
-                                     xvals.length - 3, xvals.length - 2,
-                                     xvals.length - 1);
-        firstDerivatives[xvals.length - 1] = this
-            .differentiateThreePoint(xvals, yvals, xvals.length - 1,
-                                     xvals.length - 3, xvals.length - 2,
-                                     xvals.length - 1);
-
-        return this.interpolateHermiteSorted(xvals, yvals, firstDerivatives);
-    }
-
-    /**
-     * Three point differentiation helper, modeled off of the same method in the
-     * Math.NET CubicSpline class. This is used by both the Apache Math and the
-     * Math.NET Akima Cubic Spline algorithms
-     *
-     * @param xvals x values to calculate the numerical derivative with
-     * @param yvals y values to calculate the numerical derivative with
-     * @param indexOfDifferentiation index of the elemnt we are calculating the derivative around
-     * @param indexOfFirstSample index of the first element to sample for the three point method
-     * @param indexOfSecondsample index of the second element to sample for the three point method
-     * @param indexOfThirdSample index of the third element to sample for the three point method
-     * @return the derivative
-     */
-    private double differentiateThreePoint(double[] xvals, double[] yvals,
-                                           int indexOfDifferentiation,
-                                           int indexOfFirstSample,
-                                           int indexOfSecondsample,
-                                           int indexOfThirdSample) {
-        double x0 = yvals[indexOfFirstSample];
-        double x1 = yvals[indexOfSecondsample];
-        double x2 = yvals[indexOfThirdSample];
-
-        double t = xvals[indexOfDifferentiation] - xvals[indexOfFirstSample];
-        double t1 = xvals[indexOfSecondsample] - xvals[indexOfFirstSample];
-        double t2 = xvals[indexOfThirdSample] - xvals[indexOfFirstSample];
-
-        double a = (x2 - x0 - (t2 / t1 * (x1 - x0))) / (t2 * t2 - t1 * t2);
-        double b = (x1 - x0 - a * t1 * t1) / t1;
-        return (2 * a * t) + b;
-    }
-
-    /**
-     * Creates a Hermite cubic spline interpolation from the set of (x,y) value
-     * pairs and their derivatives. This is modeled off of the
-     * InterpolateHermiteSorted method in the Math.NET CubicSpline class.
-     *
-     * @param xvals x values for interpolation
-     * @param yvals y values for interpolation
-     * @param firstDerivatives first derivative values of the function
-     * @return polynomial that fits the function
-     */
-    private PolynomialSplineFunction interpolateHermiteSorted(double[] xvals,
-                                                              double[] yvals,
-                                                              double[] firstDerivatives) {
-        if (xvals.length != yvals.length) {
-            throw new DimensionMismatchException(xvals.length, yvals.length);
-        }
-
-        if (xvals.length != firstDerivatives.length) {
-            throw new DimensionMismatchException(xvals.length,
-                                                 firstDerivatives.length);
-        }
-
-        final int minimumLength = 2;
-        if (xvals.length < minimumLength) {
-            throw new NumberIsTooSmallException(
-                                                LocalizedFormats.NUMBER_OF_POINTS,
-                                                xvals.length, minimumLength,
-                                                true);
-        }
-
-        int size = xvals.length - 1;
-        final PolynomialFunction polynomials[] = new PolynomialFunction[size];
-        final double coefficients[] = new double[4];
-
-        for (int i = 0; i < polynomials.length; i++) {
-            double w = xvals[i + 1] - xvals[i];
-            double w2 = w * w;
-            coefficients[0] = yvals[i];
-            coefficients[1] = firstDerivatives[i];
-            coefficients[2] = (3 * (yvals[i + 1] - yvals[i]) / w - 2 *
-                               firstDerivatives[i] - firstDerivatives[i + 1]) /
-                              w;
-            coefficients[3] = (2 * (yvals[i] - yvals[i + 1]) / w +
-                               firstDerivatives[i] + firstDerivatives[i + 1]) /
-                              w2;
-            polynomials[i] = new PolynomialFunction(coefficients);
-        }
-
-        return new PolynomialSplineFunction(xvals, polynomials);
-
-    }
-}
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.commons.math3.analysis.interpolation;
+
+import org.apache.commons.math3.analysis.polynomials.PolynomialFunction;
+import org.apache.commons.math3.analysis.polynomials.PolynomialSplineFunction;
+import org.apache.commons.math3.exception.DimensionMismatchException;
+import org.apache.commons.math3.exception.NonMonotonicSequenceException;
+import org.apache.commons.math3.exception.NullArgumentException;
+import org.apache.commons.math3.exception.NumberIsTooSmallException;
+import org.apache.commons.math3.exception.util.LocalizedFormats;
+import org.apache.commons.math3.util.FastMath;
+import org.apache.commons.math3.util.MathArrays;
+import org.apache.commons.math3.util.Precision;
+
+/**
+ * Computes a cubic spline interpolation for the data set using the Akima
+ * algorithm, as originally formulated by Hiroshi Akima in his 1970 paper
+ * "A New Method of Interpolation and Smooth Curve Fitting Based on Local Procedures."
+ * J. ACM 17, 4 (October 1970), 589-602. DOI=10.1145/321607.321609
+ * http://doi.acm.org/10.1145/321607.321609
+ * <p>
+ * This implementation is based on the Akima implementation in the CubicSpline
+ * class in the Math.NET Numerics library. The method referenced is
+ * CubicSpline.InterpolateAkimaSorted
+ * <p>
+ * The {@link #interpolate(double[], double[])} method returns a
+ * {@link PolynomialSplineFunction} consisting of n cubic polynomials, defined
+ * over the subintervals determined by the x values, x[0] < x[i] ... < x[n]. The
+ * Akima algorithm requires that n >= 5.
+ * </p>
+ * <p>
+ */
+
+public class AkimaSplineInterpolator
+    implements UnivariateInterpolator {
+
+
+    /**
+     * The minimum number of points that are needed to compute the function
+     */
+    public static final int MINIMUM_NUMBER_POINTS = 5;
+
+    /**
+     * Default constructor. Builds an AkimaSplineInterpolator object
+     */
+    public AkimaSplineInterpolator() {
+
+    }
+
+    /**
+     * Computes an interpolating function for the data set.
+     *
+     * @param xvals the arguments for the interpolation points
+     * @param yvals the values for the interpolation points
+     * @return a function which interpolates the data set
+     * @throws DimensionMismatchException if {@code x} and {@code y} have
+     *         different sizes.
+     * @throws NonMonotonicSequenceException if {@code x} is not sorted in
+     *         strict increasing order.
+     * @throws NumberIsTooSmallException if the size of {@code x} is smaller
+     *         than 5.
+     */
+    public PolynomialSplineFunction interpolate(double[] xvals, double[] yvals)
+        throws DimensionMismatchException, NumberIsTooSmallException,
+        NonMonotonicSequenceException {
+        if (xvals == null || yvals == null) {
+            throw new NullArgumentException();
+        }
+
+        if (xvals.length != yvals.length) {
+            throw new DimensionMismatchException(xvals.length, yvals.length);
+        }
+
+        if (xvals.length < MINIMUM_NUMBER_POINTS) {
+            throw new NumberIsTooSmallException(
+                                                LocalizedFormats.NUMBER_OF_POINTS,
+                                                xvals.length,
+                                                MINIMUM_NUMBER_POINTS, true);
+        }
+
+        MathArrays.checkOrder(xvals);
+
+        final int numberOfDiffAndWeightElements = xvals.length - 1;
+
+        double differences[] = new double[numberOfDiffAndWeightElements];
+        double weights[] = new double[numberOfDiffAndWeightElements];
+
+        for (int i = 0; i < differences.length; i++) {
+            differences[i] = (yvals[i + 1] - yvals[i]) /
+                             (xvals[i + 1] - xvals[i]);
+        }
+
+        for (int i = 1; i < weights.length; i++) {
+            weights[i] = FastMath.abs(differences[i] - differences[i - 1]);
+        }
+
+        /* Prepare Hermite interpolation scheme */
+
+        double firstDerivatives[] = new double[xvals.length];
+
+        for (int i = 2; i < firstDerivatives.length - 2; i++) {
+            if (Precision.equals(weights[i - 1], 0.0) &&
+                Precision.equals(weights[i + 1], 0.0)) {
+                firstDerivatives[i] = (((xvals[i + 1] - xvals[i]) * differences[i - 1]) + ((xvals[i] - xvals[i - 1]) * differences[i])) /
+                                      (xvals[i + 1] - xvals[i - 1]);
+            } else {
+                firstDerivatives[i] = ((weights[i + 1] * differences[i - 1]) + (weights[i - 1] * differences[i])) /
+                                      (weights[i + 1] + weights[i - 1]);
+            }
+        }
+
+        firstDerivatives[0] = this.differentiateThreePoint(xvals, yvals, 0, 0,
+                                                           1, 2);
+        firstDerivatives[1] = this.differentiateThreePoint(xvals, yvals, 1, 0,
+                                                           1, 2);
+        firstDerivatives[xvals.length - 2] = this
+            .differentiateThreePoint(xvals, yvals, xvals.length - 2,
+                                     xvals.length - 3, xvals.length - 2,
+                                     xvals.length - 1);
+        firstDerivatives[xvals.length - 1] = this
+            .differentiateThreePoint(xvals, yvals, xvals.length - 1,
+                                     xvals.length - 3, xvals.length - 2,
+                                     xvals.length - 1);
+
+        return this.interpolateHermiteSorted(xvals, yvals, firstDerivatives);
+    }
+
+    /**
+     * Three point differentiation helper, modeled off of the same method in the
+     * Math.NET CubicSpline class. This is used by both the Apache Math and the
+     * Math.NET Akima Cubic Spline algorithms
+     *
+     * @param xvals x values to calculate the numerical derivative with
+     * @param yvals y values to calculate the numerical derivative with
+     * @param indexOfDifferentiation index of the elemnt we are calculating the derivative around
+     * @param indexOfFirstSample index of the first element to sample for the three point method
+     * @param indexOfSecondsample index of the second element to sample for the three point method
+     * @param indexOfThirdSample index of the third element to sample for the three point method
+     * @return the derivative
+     */
+    private double differentiateThreePoint(double[] xvals, double[] yvals,
+                                           int indexOfDifferentiation,
+                                           int indexOfFirstSample,
+                                           int indexOfSecondsample,
+                                           int indexOfThirdSample) {
+        double x0 = yvals[indexOfFirstSample];
+        double x1 = yvals[indexOfSecondsample];
+        double x2 = yvals[indexOfThirdSample];
+
+        double t = xvals[indexOfDifferentiation] - xvals[indexOfFirstSample];
+        double t1 = xvals[indexOfSecondsample] - xvals[indexOfFirstSample];
+        double t2 = xvals[indexOfThirdSample] - xvals[indexOfFirstSample];
+
+        double a = (x2 - x0 - (t2 / t1 * (x1 - x0))) / (t2 * t2 - t1 * t2);
+        double b = (x1 - x0 - a * t1 * t1) / t1;
+        return (2 * a * t) + b;
+    }
+
+    /**
+     * Creates a Hermite cubic spline interpolation from the set of (x,y) value
+     * pairs and their derivatives. This is modeled off of the
+     * InterpolateHermiteSorted method in the Math.NET CubicSpline class.
+     *
+     * @param xvals x values for interpolation
+     * @param yvals y values for interpolation
+     * @param firstDerivatives first derivative values of the function
+     * @return polynomial that fits the function
+     */
+    private PolynomialSplineFunction interpolateHermiteSorted(double[] xvals,
+                                                              double[] yvals,
+                                                              double[] firstDerivatives) {
+        if (xvals.length != yvals.length) {
+            throw new DimensionMismatchException(xvals.length, yvals.length);
+        }
+
+        if (xvals.length != firstDerivatives.length) {
+            throw new DimensionMismatchException(xvals.length,
+                                                 firstDerivatives.length);
+        }
+
+        final int minimumLength = 2;
+        if (xvals.length < minimumLength) {
+            throw new NumberIsTooSmallException(
+                                                LocalizedFormats.NUMBER_OF_POINTS,
+                                                xvals.length, minimumLength,
+                                                true);
+        }
+
+        int size = xvals.length - 1;
+        final PolynomialFunction polynomials[] = new PolynomialFunction[size];
+        final double coefficients[] = new double[4];
+
+        for (int i = 0; i < polynomials.length; i++) {
+            double w = xvals[i + 1] - xvals[i];
+            double w2 = w * w;
+            coefficients[0] = yvals[i];
+            coefficients[1] = firstDerivatives[i];
+            coefficients[2] = (3 * (yvals[i + 1] - yvals[i]) / w - 2 *
+                               firstDerivatives[i] - firstDerivatives[i + 1]) /
+                              w;
+            coefficients[3] = (2 * (yvals[i] - yvals[i + 1]) / w +
+                               firstDerivatives[i] + firstDerivatives[i + 1]) /
+                              w2;
+            polynomials[i] = new PolynomialFunction(coefficients);
+        }
+
+        return new PolynomialSplineFunction(xvals, polynomials);
+
+    }
+}

http://git-wip-us.apache.org/repos/asf/commons-math/blob/f44d4852/src/test/java/org/apache/commons/math3/analysis/interpolation/AkimaSplineInterpolatorTest.java
----------------------------------------------------------------------
diff --git a/src/test/java/org/apache/commons/math3/analysis/interpolation/AkimaSplineInterpolatorTest.java b/src/test/java/org/apache/commons/math3/analysis/interpolation/AkimaSplineInterpolatorTest.java
index 017241a..adf39d6 100644
--- a/src/test/java/org/apache/commons/math3/analysis/interpolation/AkimaSplineInterpolatorTest.java
+++ b/src/test/java/org/apache/commons/math3/analysis/interpolation/AkimaSplineInterpolatorTest.java
@@ -1,227 +1,227 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.apache.commons.math3.analysis.interpolation;
-
-import org.apache.commons.math3.analysis.UnivariateFunction;
-import org.apache.commons.math3.distribution.UniformRealDistribution;
-import org.apache.commons.math3.exception.DimensionMismatchException;
-import org.apache.commons.math3.exception.NonMonotonicSequenceException;
-import org.apache.commons.math3.exception.NullArgumentException;
-import org.apache.commons.math3.exception.NumberIsTooSmallException;
-import org.apache.commons.math3.random.RandomGenerator;
-import org.apache.commons.math3.random.Well19937c;
-import org.apache.commons.math3.util.FastMath;
-import org.apache.commons.math3.util.Precision;
-import org.junit.Assert;
-import org.junit.Test;
-
-import static org.junit.Assert.*;
-
-public class AkimaSplineInterpolatorTest
-{
-
-    @Test
-    public void testIllegalArguments()
-    {
-        // Data set arrays of different size.
-        UnivariateInterpolator i = new AkimaSplineInterpolator();
-
-        try
-        {
-            double yval[] = { 0.0, 1.0, 2.0, 3.0, 4.0 };
-            i.interpolate( null, yval );
-            Assert.fail( "Failed to detect x null pointer" );
-        }
-        catch ( NullArgumentException iae )
-        {
-            // Expected.
-        }
-
-        try
-        {
-            double xval[] = { 0.0, 1.0, 2.0, 3.0, 4.0 };
-            i.interpolate( xval, null );
-            Assert.fail( "Failed to detect y null pointer" );
-        }
-        catch ( NullArgumentException iae )
-        {
-            // Expected.
-        }
-
-        try
-        {
-            double xval[] = { 0.0, 1.0, 2.0, 3.0 };
-            double yval[] = { 0.0, 1.0, 2.0, 3.0 };
-            i.interpolate( xval, yval );
-            Assert.fail( "Failed to detect insufficient data" );
-        }
-        catch ( NumberIsTooSmallException iae )
-        {
-            // Expected.
-        }
-
-        try
-        {
-            double xval[] = { 0.0, 1.0, 2.0, 3.0, 4.0 };
-            double yval[] = { 0.0, 1.0, 2.0, 3.0, 4.0, 5.0 };
-            i.interpolate( xval, yval );
-            Assert.fail( "Failed to detect data set array with different sizes." );
-        }
-        catch ( DimensionMismatchException iae )
-        {
-            // Expected.
-        }
-
-        // X values not sorted.
-        try
-        {
-            double xval[] = { 0.0, 1.0, 0.5, 7.0, 3.5, 2.2, 8.0 };
-            double yval[] = { 0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 };
-            i.interpolate( xval, yval );
-            Assert.fail( "Failed to detect unsorted arguments." );
-        }
-        catch ( NonMonotonicSequenceException iae )
-        {
-            // Expected.
-        }
-    }
-
-    /*
-     * Interpolate a straight line. <p> y = 2 x - 5 <p> Tolerances determined by performing same calculation using
-     * Math.NET over ten runs of 100 random number draws for the same function over the same span with the same number
-     * of elements
-     */
-    @Test
-    public void testInterpolateLine()
-    {
-        final int numberOfElements = 10;
-        final double minimumX = -10;
-        final double maximumX = 10;
-        final int numberOfSamples = 100;
-        final double interpolationTolerance = 1e-15;
-        final double maxTolerance = 1e-15;
-
-        UnivariateFunction f = new UnivariateFunction()
-        {
-            public double value( double x )
-            {
-                return 2 * x - 5;
-            }
-        };
-
-        testInterpolation( minimumX, maximumX, numberOfElements, numberOfSamples, f, interpolationTolerance,
-                           maxTolerance );
-    }
-
-    /*
-     * Interpolate a straight line. <p> y = 3 x<sup>2</sup> - 5 x + 7 <p> Tolerances determined by performing same
-     * calculation using Math.NET over ten runs of 100 random number draws for the same function over the same span with
-     * the same number of elements
-     */
-
-    @Test
-    public void testInterpolateParabola()
-    {
-        final int numberOfElements = 10;
-        final double minimumX = -10;
-        final double maximumX = 10;
-        final int numberOfSamples = 100;
-        final double interpolationTolerance = 7e-15;
-        final double maxTolerance = 6e-14;
-
-        UnivariateFunction f = new UnivariateFunction()
-        {
-            public double value( double x )
-            {
-                return ( 3 * x * x ) - ( 5 * x ) + 7;
-            }
-        };
-
-        testInterpolation( minimumX, maximumX, numberOfElements, numberOfSamples, f, interpolationTolerance,
-                           maxTolerance );
-    }
-
-    /*
-     * Interpolate a straight line. <p> y = 3 x<sup>3</sup> - 0.5 x<sup>2</sup> + x - 1 <p> Tolerances determined by
-     * performing same calculation using Math.NET over ten runs of 100 random number draws for the same function over
-     * the same span with the same number of elements
-     */
-    @Test
-    public void testInterpolateCubic()
-    {
-        final int numberOfElements = 10;
-        final double minimumX = -3;
-        final double maximumX = 3;
-        final int numberOfSamples = 100;
-        final double interpolationTolerance = 0.37;
-        final double maxTolerance = 3.8;
-
-        UnivariateFunction f = new UnivariateFunction()
-        {
-            public double value( double x )
-            {
-                return ( 3 * x * x * x ) - ( 0.5 * x * x ) + ( 1 * x ) - 1;
-            }
-        };
-
-        testInterpolation( minimumX, maximumX, numberOfElements, numberOfSamples, f, interpolationTolerance,
-                           maxTolerance );
-    }
-
-    private void testInterpolation( double minimumX, double maximumX, int numberOfElements, int numberOfSamples,
-                                    UnivariateFunction f, double tolerance, double maxTolerance )
-    {
-        double expected;
-        double actual;
-        double currentX;
-        final double delta = ( maximumX - minimumX ) / ( (double) numberOfElements );
-        double xValues[] = new double[numberOfElements];
-        double yValues[] = new double[numberOfElements];
-
-        for ( int i = 0; i < numberOfElements; i++ )
-        {
-            xValues[i] = minimumX + delta * (double) i;
-            yValues[i] = f.value( xValues[i] );
-        }
-
-        UnivariateFunction interpolation = new AkimaSplineInterpolator().interpolate( xValues, yValues );
-
-        for ( int i = 0; i < numberOfElements; i++ )
-        {
-            currentX = xValues[i];
-            expected = f.value( currentX );
-            actual = interpolation.value( currentX );
-            assertTrue( Precision.equals( expected, actual ) );
-        }
-
-        final RandomGenerator rng = new Well19937c( 1234567L ); // "tol" depends on the seed.
-        final UniformRealDistribution distX =
-            new UniformRealDistribution( rng, xValues[0], xValues[xValues.length - 1] );
-
-        double sumError = 0;
-        for ( int i = 0; i < numberOfSamples; i++ )
-        {
-            currentX = distX.sample();
-            expected = f.value( currentX );
-            actual = interpolation.value( currentX );
-            sumError += FastMath.abs( actual - expected );
-            assertEquals( expected, actual, maxTolerance );
-        }
-
-        assertEquals( 0.0, ( sumError / (double) numberOfSamples ), tolerance );
-    }
-}
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.commons.math3.analysis.interpolation;
+
+import org.apache.commons.math3.analysis.UnivariateFunction;
+import org.apache.commons.math3.distribution.UniformRealDistribution;
+import org.apache.commons.math3.exception.DimensionMismatchException;
+import org.apache.commons.math3.exception.NonMonotonicSequenceException;
+import org.apache.commons.math3.exception.NullArgumentException;
+import org.apache.commons.math3.exception.NumberIsTooSmallException;
+import org.apache.commons.math3.random.RandomGenerator;
+import org.apache.commons.math3.random.Well19937c;
+import org.apache.commons.math3.util.FastMath;
+import org.apache.commons.math3.util.Precision;
+import org.junit.Assert;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+public class AkimaSplineInterpolatorTest
+{
+
+    @Test
+    public void testIllegalArguments()
+    {
+        // Data set arrays of different size.
+        UnivariateInterpolator i = new AkimaSplineInterpolator();
+
+        try
+        {
+            double yval[] = { 0.0, 1.0, 2.0, 3.0, 4.0 };
+            i.interpolate( null, yval );
+            Assert.fail( "Failed to detect x null pointer" );
+        }
+        catch ( NullArgumentException iae )
+        {
+            // Expected.
+        }
+
+        try
+        {
+            double xval[] = { 0.0, 1.0, 2.0, 3.0, 4.0 };
+            i.interpolate( xval, null );
+            Assert.fail( "Failed to detect y null pointer" );
+        }
+        catch ( NullArgumentException iae )
+        {
+            // Expected.
+        }
+
+        try
+        {
+            double xval[] = { 0.0, 1.0, 2.0, 3.0 };
+            double yval[] = { 0.0, 1.0, 2.0, 3.0 };
+            i.interpolate( xval, yval );
+            Assert.fail( "Failed to detect insufficient data" );
+        }
+        catch ( NumberIsTooSmallException iae )
+        {
+            // Expected.
+        }
+
+        try
+        {
+            double xval[] = { 0.0, 1.0, 2.0, 3.0, 4.0 };
+            double yval[] = { 0.0, 1.0, 2.0, 3.0, 4.0, 5.0 };
+            i.interpolate( xval, yval );
+            Assert.fail( "Failed to detect data set array with different sizes." );
+        }
+        catch ( DimensionMismatchException iae )
+        {
+            // Expected.
+        }
+
+        // X values not sorted.
+        try
+        {
+            double xval[] = { 0.0, 1.0, 0.5, 7.0, 3.5, 2.2, 8.0 };
+            double yval[] = { 0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 };
+            i.interpolate( xval, yval );
+            Assert.fail( "Failed to detect unsorted arguments." );
+        }
+        catch ( NonMonotonicSequenceException iae )
+        {
+            // Expected.
+        }
+    }
+
+    /*
+     * Interpolate a straight line. <p> y = 2 x - 5 <p> Tolerances determined by performing same calculation using
+     * Math.NET over ten runs of 100 random number draws for the same function over the same span with the same number
+     * of elements
+     */
+    @Test
+    public void testInterpolateLine()
+    {
+        final int numberOfElements = 10;
+        final double minimumX = -10;
+        final double maximumX = 10;
+        final int numberOfSamples = 100;
+        final double interpolationTolerance = 1e-15;
+        final double maxTolerance = 1e-15;
+
+        UnivariateFunction f = new UnivariateFunction()
+        {
+            public double value( double x )
+            {
+                return 2 * x - 5;
+            }
+        };
+
+        testInterpolation( minimumX, maximumX, numberOfElements, numberOfSamples, f, interpolationTolerance,
+                           maxTolerance );
+    }
+
+    /*
+     * Interpolate a straight line. <p> y = 3 x<sup>2</sup> - 5 x + 7 <p> Tolerances determined by performing same
+     * calculation using Math.NET over ten runs of 100 random number draws for the same function over the same span with
+     * the same number of elements
+     */
+
+    @Test
+    public void testInterpolateParabola()
+    {
+        final int numberOfElements = 10;
+        final double minimumX = -10;
+        final double maximumX = 10;
+        final int numberOfSamples = 100;
+        final double interpolationTolerance = 7e-15;
+        final double maxTolerance = 6e-14;
+
+        UnivariateFunction f = new UnivariateFunction()
+        {
+            public double value( double x )
+            {
+                return ( 3 * x * x ) - ( 5 * x ) + 7;
+            }
+        };
+
+        testInterpolation( minimumX, maximumX, numberOfElements, numberOfSamples, f, interpolationTolerance,
+                           maxTolerance );
+    }
+
+    /*
+     * Interpolate a straight line. <p> y = 3 x<sup>3</sup> - 0.5 x<sup>2</sup> + x - 1 <p> Tolerances determined by
+     * performing same calculation using Math.NET over ten runs of 100 random number draws for the same function over
+     * the same span with the same number of elements
+     */
+    @Test
+    public void testInterpolateCubic()
+    {
+        final int numberOfElements = 10;
+        final double minimumX = -3;
+        final double maximumX = 3;
+        final int numberOfSamples = 100;
+        final double interpolationTolerance = 0.37;
+        final double maxTolerance = 3.8;
+
+        UnivariateFunction f = new UnivariateFunction()
+        {
+            public double value( double x )
+            {
+                return ( 3 * x * x * x ) - ( 0.5 * x * x ) + ( 1 * x ) - 1;
+            }
+        };
+
+        testInterpolation( minimumX, maximumX, numberOfElements, numberOfSamples, f, interpolationTolerance,
+                           maxTolerance );
+    }
+
+    private void testInterpolation( double minimumX, double maximumX, int numberOfElements, int numberOfSamples,
+                                    UnivariateFunction f, double tolerance, double maxTolerance )
+    {
+        double expected;
+        double actual;
+        double currentX;
+        final double delta = ( maximumX - minimumX ) / ( (double) numberOfElements );
+        double xValues[] = new double[numberOfElements];
+        double yValues[] = new double[numberOfElements];
+
+        for ( int i = 0; i < numberOfElements; i++ )
+        {
+            xValues[i] = minimumX + delta * (double) i;
+            yValues[i] = f.value( xValues[i] );
+        }
+
+        UnivariateFunction interpolation = new AkimaSplineInterpolator().interpolate( xValues, yValues );
+
+        for ( int i = 0; i < numberOfElements; i++ )
+        {
+            currentX = xValues[i];
+            expected = f.value( currentX );
+            actual = interpolation.value( currentX );
+            assertTrue( Precision.equals( expected, actual ) );
+        }
+
+        final RandomGenerator rng = new Well19937c( 1234567L ); // "tol" depends on the seed.
+        final UniformRealDistribution distX =
+            new UniformRealDistribution( rng, xValues[0], xValues[xValues.length - 1] );
+
+        double sumError = 0;
+        for ( int i = 0; i < numberOfSamples; i++ )
+        {
+            currentX = distX.sample();
+            expected = f.value( currentX );
+            actual = interpolation.value( currentX );
+            sumError += FastMath.abs( actual - expected );
+            assertEquals( expected, actual, maxTolerance );
+        }
+
+        assertEquals( 0.0, ( sumError / (double) numberOfSamples ), tolerance );
+    }
+}


[4/8] git commit: Removed unused import.

Posted by lu...@apache.org.
Removed unused import.

Project: http://git-wip-us.apache.org/repos/asf/commons-math/repo
Commit: http://git-wip-us.apache.org/repos/asf/commons-math/commit/bf88cac1
Tree: http://git-wip-us.apache.org/repos/asf/commons-math/tree/bf88cac1
Diff: http://git-wip-us.apache.org/repos/asf/commons-math/diff/bf88cac1

Branch: refs/heads/master
Commit: bf88cac1ac03ce9378970e5a3d66ba77b1fe0dca
Parents: bd3a6ec
Author: Luc Maisonobe <lu...@apache.org>
Authored: Fri Oct 17 10:22:52 2014 +0200
Committer: Luc Maisonobe <lu...@apache.org>
Committed: Fri Oct 17 10:22:52 2014 +0200

----------------------------------------------------------------------
 .../math3/analysis/interpolation/BicubicSplineInterpolator.java     | 1 -
 1 file changed, 1 deletion(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/commons-math/blob/bf88cac1/src/main/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolator.java
----------------------------------------------------------------------
diff --git a/src/main/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolator.java b/src/main/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolator.java
index 36a9da2..a973f81 100644
--- a/src/main/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolator.java
+++ b/src/main/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolator.java
@@ -20,7 +20,6 @@ import org.apache.commons.math3.exception.DimensionMismatchException;
 import org.apache.commons.math3.exception.NoDataException;
 import org.apache.commons.math3.exception.NonMonotonicSequenceException;
 import org.apache.commons.math3.exception.NullArgumentException;
-import org.apache.commons.math3.exception.NumberIsTooSmallException;
 import org.apache.commons.math3.util.MathArrays;
 
 /**


[6/8] git commit: Added Hank Grabowski as contributor.

Posted by lu...@apache.org.
Added Hank Grabowski as contributor.

Project: http://git-wip-us.apache.org/repos/asf/commons-math/repo
Commit: http://git-wip-us.apache.org/repos/asf/commons-math/commit/7df36c32
Tree: http://git-wip-us.apache.org/repos/asf/commons-math/tree/7df36c32
Diff: http://git-wip-us.apache.org/repos/asf/commons-math/diff/7df36c32

Branch: refs/heads/master
Commit: 7df36c32a50fe400afcbf2c258c6c15fdda500a4
Parents: f44d485
Author: Luc Maisonobe <lu...@apache.org>
Authored: Fri Oct 17 10:25:46 2014 +0200
Committer: Luc Maisonobe <lu...@apache.org>
Committed: Fri Oct 17 10:25:46 2014 +0200

----------------------------------------------------------------------
 pom.xml | 3 +++
 1 file changed, 3 insertions(+)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/commons-math/blob/7df36c32/pom.xml
----------------------------------------------------------------------
diff --git a/pom.xml b/pom.xml
index 8430131..628ec6a 100644
--- a/pom.xml
+++ b/pom.xml
@@ -216,6 +216,9 @@
       <name>Ken Geis</name>
     </contributor>
     <contributor>
+      <name>Hank Grabowski</name>
+    </contributor>
+    <contributor>
       <name>Bernhard Gr&#252;newaldt</name>
     </contributor>
     <contributor>


[7/8] git commit: Notified fix for bicubic splines.

Posted by lu...@apache.org.
Notified fix for bicubic splines.

Thanks to Hank Grabowski for the patch.

JIRA: MATH-1138

Project: http://git-wip-us.apache.org/repos/asf/commons-math/repo
Commit: http://git-wip-us.apache.org/repos/asf/commons-math/commit/4a339cda
Tree: http://git-wip-us.apache.org/repos/asf/commons-math/tree/4a339cda
Diff: http://git-wip-us.apache.org/repos/asf/commons-math/diff/4a339cda

Branch: refs/heads/master
Commit: 4a339cda2c3933a2adcb23ea0ea8470d68d1b010
Parents: 7df36c3
Author: Luc Maisonobe <lu...@apache.org>
Authored: Fri Oct 17 10:29:20 2014 +0200
Committer: Luc Maisonobe <lu...@apache.org>
Committed: Fri Oct 17 10:29:20 2014 +0200

----------------------------------------------------------------------
 src/changes/changes.xml | 3 +++
 1 file changed, 3 insertions(+)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/commons-math/blob/4a339cda/src/changes/changes.xml
----------------------------------------------------------------------
diff --git a/src/changes/changes.xml b/src/changes/changes.xml
index 7762b80..bb5c525 100644
--- a/src/changes/changes.xml
+++ b/src/changes/changes.xml
@@ -73,6 +73,9 @@ Users are encouraged to upgrade to this version as this release not
   2. A few methods in the FastMath class are in fact slower that their
   counterpart in either Math or StrictMath (cf. MATH-740 and MATH-901).
 ">
+      <action dev="luc" type="fix" issue="MATH-1138" due-to="Hank Grabowski">
+        Fixed bicubic spline interpolator, using Akima splines.
+      </action>
       <action dev="psteitz" type="add" issue="MATH-1154" >
         Changed classes in the inference package that instantiate distributions to
         pass null RandomGenerators to avoid initialization overhead for the default


[2/8] git commit: MATH-1138 #comment Implemented new BiCubicSplineInterpolator, supporting Akima Spline Interpolator and updated tests

Posted by lu...@apache.org.
MATH-1138 #comment Implemented new BiCubicSplineInterpolator,  supporting Akima Spline Interpolator and updated tests


Project: http://git-wip-us.apache.org/repos/asf/commons-math/repo
Commit: http://git-wip-us.apache.org/repos/asf/commons-math/commit/d8bfc8c8
Tree: http://git-wip-us.apache.org/repos/asf/commons-math/tree/d8bfc8c8
Diff: http://git-wip-us.apache.org/repos/asf/commons-math/diff/d8bfc8c8

Branch: refs/heads/master
Commit: d8bfc8c8f8864f9c22e0409780d5dd3fb30497ff
Parents: a3fdeb4
Author: Hank Grabowski <ha...@applieddefense.com>
Authored: Wed Oct 15 10:15:14 2014 -0400
Committer: Hank Grabowski <ha...@applieddefense.com>
Committed: Wed Oct 15 10:15:14 2014 -0400

----------------------------------------------------------------------
 .../interpolation/AkimaSplineInterpolator.java  | 225 ++++++
 .../BicubicSplineInterpolatingFunction.java     | 620 +++------------
 .../BicubicSplineInterpolator.java              | 140 +---
 .../TricubicSplineInterpolator.java             |  35 +-
 .../AkimaSplineInterpolatorTest.java            | 227 ++++++
 .../BicubicSplineInterpolatingFunctionTest.java | 746 +++++--------------
 .../BicubicSplineInterpolatorTest.java          | 217 ++++--
 ...PolynomialBicubicSplineInterpolatorTest.java |  10 +-
 .../interpolation/SplineInterpolatorTest.java   |  42 +-
 .../TricubicSplineInterpolatorTest.java         |   2 +-
 10 files changed, 923 insertions(+), 1341 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/commons-math/blob/d8bfc8c8/src/main/java/org/apache/commons/math3/analysis/interpolation/AkimaSplineInterpolator.java
----------------------------------------------------------------------
diff --git a/src/main/java/org/apache/commons/math3/analysis/interpolation/AkimaSplineInterpolator.java b/src/main/java/org/apache/commons/math3/analysis/interpolation/AkimaSplineInterpolator.java
new file mode 100644
index 0000000..8fb896c
--- /dev/null
+++ b/src/main/java/org/apache/commons/math3/analysis/interpolation/AkimaSplineInterpolator.java
@@ -0,0 +1,225 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.commons.math3.analysis.interpolation;
+
+import org.apache.commons.math3.analysis.polynomials.PolynomialFunction;
+import org.apache.commons.math3.analysis.polynomials.PolynomialSplineFunction;
+import org.apache.commons.math3.exception.DimensionMismatchException;
+import org.apache.commons.math3.exception.NonMonotonicSequenceException;
+import org.apache.commons.math3.exception.NullArgumentException;
+import org.apache.commons.math3.exception.NumberIsTooSmallException;
+import org.apache.commons.math3.exception.util.LocalizedFormats;
+import org.apache.commons.math3.util.FastMath;
+import org.apache.commons.math3.util.MathArrays;
+import org.apache.commons.math3.util.Precision;
+
+/**
+ * Computes a cubic spline interpolation for the data set using the Akima
+ * algorithm, as originally formulated by Hiroshi Akima in his 1970 paper
+ * "A New Method of Interpolation and Smooth Curve Fitting Based on Local Procedures."
+ * J. ACM 17, 4 (October 1970), 589-602. DOI=10.1145/321607.321609
+ * http://doi.acm.org/10.1145/321607.321609
+ * <p>
+ * This implementation is based on the Akima implementation in the CubicSpline
+ * class in the Math.NET Numerics library. The method referenced is
+ * CubicSpline.InterpolateAkimaSorted
+ * <p>
+ * The {@link #interpolate(double[], double[])} method returns a
+ * {@link PolynomialSplineFunction} consisting of n cubic polynomials, defined
+ * over the subintervals determined by the x values, x[0] < x[i] ... < x[n]. The
+ * Akima algorithm requires that n >= 5.
+ * </p>
+ * <p>
+ */
+
+public class AkimaSplineInterpolator
+    implements UnivariateInterpolator {
+
+
+    /**
+     * The minimum number of points that are needed to compute the function
+     */
+    public static final int MINIMUM_NUMBER_POINTS = 5;
+
+    /**
+     * Default constructor. Builds an AkimaSplineInterpolator object
+     */
+    public AkimaSplineInterpolator() {
+
+    }
+
+    /**
+     * Computes an interpolating function for the data set.
+     *
+     * @param xvals the arguments for the interpolation points
+     * @param yvals the values for the interpolation points
+     * @return a function which interpolates the data set
+     * @throws DimensionMismatchException if {@code x} and {@code y} have
+     *         different sizes.
+     * @throws NonMonotonicSequenceException if {@code x} is not sorted in
+     *         strict increasing order.
+     * @throws NumberIsTooSmallException if the size of {@code x} is smaller
+     *         than 5.
+     */
+    public PolynomialSplineFunction interpolate(double[] xvals, double[] yvals)
+        throws DimensionMismatchException, NumberIsTooSmallException,
+        NonMonotonicSequenceException {
+        if (xvals == null || yvals == null) {
+            throw new NullArgumentException();
+        }
+
+        if (xvals.length != yvals.length) {
+            throw new DimensionMismatchException(xvals.length, yvals.length);
+        }
+
+        if (xvals.length < MINIMUM_NUMBER_POINTS) {
+            throw new NumberIsTooSmallException(
+                                                LocalizedFormats.NUMBER_OF_POINTS,
+                                                xvals.length,
+                                                MINIMUM_NUMBER_POINTS, true);
+        }
+
+        MathArrays.checkOrder(xvals);
+
+        final int numberOfDiffAndWeightElements = xvals.length - 1;
+
+        double differences[] = new double[numberOfDiffAndWeightElements];
+        double weights[] = new double[numberOfDiffAndWeightElements];
+
+        for (int i = 0; i < differences.length; i++) {
+            differences[i] = (yvals[i + 1] - yvals[i]) /
+                             (xvals[i + 1] - xvals[i]);
+        }
+
+        for (int i = 1; i < weights.length; i++) {
+            weights[i] = FastMath.abs(differences[i] - differences[i - 1]);
+        }
+
+        /* Prepare Hermite interpolation scheme */
+
+        double firstDerivatives[] = new double[xvals.length];
+
+        for (int i = 2; i < firstDerivatives.length - 2; i++) {
+            if (Precision.equals(weights[i - 1], 0.0) &&
+                Precision.equals(weights[i + 1], 0.0)) {
+                firstDerivatives[i] = (((xvals[i + 1] - xvals[i]) * differences[i - 1]) + ((xvals[i] - xvals[i - 1]) * differences[i])) /
+                                      (xvals[i + 1] - xvals[i - 1]);
+            } else {
+                firstDerivatives[i] = ((weights[i + 1] * differences[i - 1]) + (weights[i - 1] * differences[i])) /
+                                      (weights[i + 1] + weights[i - 1]);
+            }
+        }
+
+        firstDerivatives[0] = this.differentiateThreePoint(xvals, yvals, 0, 0,
+                                                           1, 2);
+        firstDerivatives[1] = this.differentiateThreePoint(xvals, yvals, 1, 0,
+                                                           1, 2);
+        firstDerivatives[xvals.length - 2] = this
+            .differentiateThreePoint(xvals, yvals, xvals.length - 2,
+                                     xvals.length - 3, xvals.length - 2,
+                                     xvals.length - 1);
+        firstDerivatives[xvals.length - 1] = this
+            .differentiateThreePoint(xvals, yvals, xvals.length - 1,
+                                     xvals.length - 3, xvals.length - 2,
+                                     xvals.length - 1);
+
+        return this.interpolateHermiteSorted(xvals, yvals, firstDerivatives);
+    }
+
+    /**
+     * Three point differentiation helper, modeled off of the same method in the
+     * Math.NET CubicSpline class. This is used by both the Apache Math and the
+     * Math.NET Akima Cubic Spline algorithms
+     *
+     * @param xvals x values to calculate the numerical derivative with
+     * @param yvals y values to calculate the numerical derivative with
+     * @param indexOfDifferentiation index of the elemnt we are calculating the derivative around
+     * @param indexOfFirstSample index of the first element to sample for the three point method
+     * @param indexOfSecondsample index of the second element to sample for the three point method
+     * @param indexOfThirdSample index of the third element to sample for the three point method
+     * @return the derivative
+     */
+    private double differentiateThreePoint(double[] xvals, double[] yvals,
+                                           int indexOfDifferentiation,
+                                           int indexOfFirstSample,
+                                           int indexOfSecondsample,
+                                           int indexOfThirdSample) {
+        double x0 = yvals[indexOfFirstSample];
+        double x1 = yvals[indexOfSecondsample];
+        double x2 = yvals[indexOfThirdSample];
+
+        double t = xvals[indexOfDifferentiation] - xvals[indexOfFirstSample];
+        double t1 = xvals[indexOfSecondsample] - xvals[indexOfFirstSample];
+        double t2 = xvals[indexOfThirdSample] - xvals[indexOfFirstSample];
+
+        double a = (x2 - x0 - (t2 / t1 * (x1 - x0))) / (t2 * t2 - t1 * t2);
+        double b = (x1 - x0 - a * t1 * t1) / t1;
+        return (2 * a * t) + b;
+    }
+
+    /**
+     * Creates a Hermite cubic spline interpolation from the set of (x,y) value
+     * pairs and their derivatives. This is modeled off of the
+     * InterpolateHermiteSorted method in the Math.NET CubicSpline class.
+     *
+     * @param xvals x values for interpolation
+     * @param yvals y values for interpolation
+     * @param firstDerivatives first derivative values of the function
+     * @return polynomial that fits the function
+     */
+    private PolynomialSplineFunction interpolateHermiteSorted(double[] xvals,
+                                                              double[] yvals,
+                                                              double[] firstDerivatives) {
+        if (xvals.length != yvals.length) {
+            throw new DimensionMismatchException(xvals.length, yvals.length);
+        }
+
+        if (xvals.length != firstDerivatives.length) {
+            throw new DimensionMismatchException(xvals.length,
+                                                 firstDerivatives.length);
+        }
+
+        final int minimumLength = 2;
+        if (xvals.length < minimumLength) {
+            throw new NumberIsTooSmallException(
+                                                LocalizedFormats.NUMBER_OF_POINTS,
+                                                xvals.length, minimumLength,
+                                                true);
+        }
+
+        int size = xvals.length - 1;
+        final PolynomialFunction polynomials[] = new PolynomialFunction[size];
+        final double coefficients[] = new double[4];
+
+        for (int i = 0; i < polynomials.length; i++) {
+            double w = xvals[i + 1] - xvals[i];
+            double w2 = w * w;
+            coefficients[0] = yvals[i];
+            coefficients[1] = firstDerivatives[i];
+            coefficients[2] = (3 * (yvals[i + 1] - yvals[i]) / w - 2 *
+                               firstDerivatives[i] - firstDerivatives[i + 1]) /
+                              w;
+            coefficients[3] = (2 * (yvals[i] - yvals[i + 1]) / w +
+                               firstDerivatives[i] + firstDerivatives[i + 1]) /
+                              w2;
+            polynomials[i] = new PolynomialFunction(coefficients);
+        }
+
+        return new PolynomialSplineFunction(xvals, polynomials);
+
+    }
+}

http://git-wip-us.apache.org/repos/asf/commons-math/blob/d8bfc8c8/src/main/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolatingFunction.java
----------------------------------------------------------------------
diff --git a/src/main/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolatingFunction.java b/src/main/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolatingFunction.java
index 079e9fc..c0ce3c5 100644
--- a/src/main/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolatingFunction.java
+++ b/src/main/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolatingFunction.java
@@ -18,143 +18,76 @@ package org.apache.commons.math3.analysis.interpolation;
 
 import java.util.Arrays;
 import org.apache.commons.math3.analysis.BivariateFunction;
+import org.apache.commons.math3.analysis.polynomials.PolynomialSplineFunction;
 import org.apache.commons.math3.exception.DimensionMismatchException;
+import org.apache.commons.math3.exception.InsufficientDataException;
 import org.apache.commons.math3.exception.NoDataException;
+import org.apache.commons.math3.exception.NullArgumentException;
 import org.apache.commons.math3.exception.OutOfRangeException;
 import org.apache.commons.math3.exception.NonMonotonicSequenceException;
 import org.apache.commons.math3.util.MathArrays;
 
 /**
- * Function that implements the
- * <a href="http://en.wikipedia.org/wiki/Bicubic_interpolation">
- * bicubic spline interpolation</a>.
+ * Function that implements the <a
+ * href="http://www.paulinternet.nl/?page=bicubic"> bicubic spline
+ * interpolation</a>.
  *
  * @since 2.1
  */
 public class BicubicSplineInterpolatingFunction
     implements BivariateFunction {
-    /** Number of coefficients. */
-    private static final int NUM_COEFF = 16;
-    /**
-     * Matrix to compute the spline coefficients from the function values
-     * and function derivatives values
-     */
-    private static final double[][] AINV = {
-        { 1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 },
-        { 0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0 },
-        { -3,3,0,0,-2,-1,0,0,0,0,0,0,0,0,0,0 },
-        { 2,-2,0,0,1,1,0,0,0,0,0,0,0,0,0,0 },
-        { 0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0 },
-        { 0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0 },
-        { 0,0,0,0,0,0,0,0,-3,3,0,0,-2,-1,0,0 },
-        { 0,0,0,0,0,0,0,0,2,-2,0,0,1,1,0,0 },
-        { -3,0,3,0,0,0,0,0,-2,0,-1,0,0,0,0,0 },
-        { 0,0,0,0,-3,0,3,0,0,0,0,0,-2,0,-1,0 },
-        { 9,-9,-9,9,6,3,-6,-3,6,-6,3,-3,4,2,2,1 },
-        { -6,6,6,-6,-3,-3,3,3,-4,4,-2,2,-2,-2,-1,-1 },
-        { 2,0,-2,0,0,0,0,0,1,0,1,0,0,0,0,0 },
-        { 0,0,0,0,2,0,-2,0,0,0,0,0,1,0,1,0 },
-        { -6,6,6,-6,-4,-2,4,2,-3,3,-3,3,-2,-1,-2,-1 },
-        { 4,-4,-4,4,2,2,-2,-2,2,-2,2,-2,1,1,1,1 }
-    };
 
     /** Samples x-coordinates */
     private final double[] xval;
+
     /** Samples y-coordinates */
     private final double[] yval;
+
     /** Set of cubic splines patching the whole data grid */
-    private final BicubicSplineFunction[][] splines;
-    /**
-     * Partial derivatives.
-     * The value of the first index determines the kind of derivatives:
-     * 0 = first partial derivatives wrt x
-     * 1 = first partial derivatives wrt y
-     * 2 = second partial derivatives wrt x
-     * 3 = second partial derivatives wrt y
-     * 4 = cross partial derivatives
-     */
-    private final BivariateFunction[][][] partialDerivatives;
+    private final double[][] fval;
 
     /**
      * @param x Sample values of the x-coordinate, in increasing order.
      * @param y Sample values of the y-coordinate, in increasing order.
-     * @param f Values of the function on every grid point.
-     * @param dFdX Values of the partial derivative of function with respect
-     * to x on every grid point.
-     * @param dFdY Values of the partial derivative of function with respect
-     * to y on every grid point.
-     * @param d2FdXdY Values of the cross partial derivative of function on
-     * every grid point.
-     * @throws DimensionMismatchException if the various arrays do not contain
-     * the expected number of elements.
-     * @throws NonMonotonicSequenceException if {@code x} or {@code y} are
-     * not strictly increasing.
+     * @param f Values of the function on every grid point. the expected number
+     *        of elements.
+     * @throws NonMonotonicSequenceException if {@code x} or {@code y} are not
+     *         strictly increasing.
+     * @throws NullArgumentException if any of the arguments are null
      * @throws NoDataException if any of the arrays has zero length.
+     * @throws DimensionMismatchException if the length of x and y don't match the row, column
+     *         height of f
      */
-    public BicubicSplineInterpolatingFunction(double[] x,
-                                              double[] y,
-                                              double[][] f,
-                                              double[][] dFdX,
-                                              double[][] dFdY,
-                                              double[][] d2FdXdY)
-        throws DimensionMismatchException,
-               NoDataException,
-               NonMonotonicSequenceException {
-        this(x, y, f, dFdX, dFdY, d2FdXdY, false);
-    }
 
-    /**
-     * @param x Sample values of the x-coordinate, in increasing order.
-     * @param y Sample values of the y-coordinate, in increasing order.
-     * @param f Values of the function on every grid point.
-     * @param dFdX Values of the partial derivative of function with respect
-     * to x on every grid point.
-     * @param dFdY Values of the partial derivative of function with respect
-     * to y on every grid point.
-     * @param d2FdXdY Values of the cross partial derivative of function on
-     * every grid point.
-     * @param initializeDerivatives Whether to initialize the internal data
-     * needed for calling any of the methods that compute the partial derivatives
-     * this function.
-     * @throws DimensionMismatchException if the various arrays do not contain
-     * the expected number of elements.
-     * @throws NonMonotonicSequenceException if {@code x} or {@code y} are
-     * not strictly increasing.
-     * @throws NoDataException if any of the arrays has zero length.
-     *
-     * @see #partialDerivativeX(double,double)
-     * @see #partialDerivativeY(double,double)
-     * @see #partialDerivativeXX(double,double)
-     * @see #partialDerivativeYY(double,double)
-     * @see #partialDerivativeXY(double,double)
-     */
-    public BicubicSplineInterpolatingFunction(double[] x,
-                                              double[] y,
-                                              double[][] f,
-                                              double[][] dFdX,
-                                              double[][] dFdY,
-                                              double[][] d2FdXdY,
-                                              boolean initializeDerivatives)
-        throws DimensionMismatchException,
-               NoDataException,
-               NonMonotonicSequenceException {
+    public BicubicSplineInterpolatingFunction(double[] x, double[] y,
+                                              double[][] f)
+        throws DimensionMismatchException, NullArgumentException,
+        NoDataException, NonMonotonicSequenceException {
+
+        final int minimumLength = AkimaSplineInterpolator.MINIMUM_NUMBER_POINTS;
+
+        if (x == null || y == null || f == null || f[0] == null) {
+            throw new NullArgumentException();
+        }
+
         final int xLen = x.length;
         final int yLen = y.length;
 
         if (xLen == 0 || yLen == 0 || f.length == 0 || f[0].length == 0) {
             throw new NoDataException();
         }
+
+        if (xLen < minimumLength || yLen < minimumLength ||
+            f.length < minimumLength || f[0].length < minimumLength) {
+            throw new InsufficientDataException();
+        }
+
         if (xLen != f.length) {
             throw new DimensionMismatchException(xLen, f.length);
         }
-        if (xLen != dFdX.length) {
-            throw new DimensionMismatchException(xLen, dFdX.length);
-        }
-        if (xLen != dFdY.length) {
-            throw new DimensionMismatchException(xLen, dFdY.length);
-        }
-        if (xLen != d2FdXdY.length) {
-            throw new DimensionMismatchException(xLen, d2FdXdY.length);
+
+        if (yLen != f[0].length) {
+            throw new DimensionMismatchException(yLen, f[0].length);
         }
 
         MathArrays.checkOrder(x);
@@ -162,57 +95,7 @@ public class BicubicSplineInterpolatingFunction
 
         xval = x.clone();
         yval = y.clone();
-
-        final int lastI = xLen - 1;
-        final int lastJ = yLen - 1;
-        splines = new BicubicSplineFunction[lastI][lastJ];
-
-        for (int i = 0; i < lastI; i++) {
-            if (f[i].length != yLen) {
-                throw new DimensionMismatchException(f[i].length, yLen);
-            }
-            if (dFdX[i].length != yLen) {
-                throw new DimensionMismatchException(dFdX[i].length, yLen);
-            }
-            if (dFdY[i].length != yLen) {
-                throw new DimensionMismatchException(dFdY[i].length, yLen);
-            }
-            if (d2FdXdY[i].length != yLen) {
-                throw new DimensionMismatchException(d2FdXdY[i].length, yLen);
-            }
-            final int ip1 = i + 1;
-            for (int j = 0; j < lastJ; j++) {
-                final int jp1 = j + 1;
-                final double[] beta = new double[] {
-                    f[i][j], f[ip1][j], f[i][jp1], f[ip1][jp1],
-                    dFdX[i][j], dFdX[ip1][j], dFdX[i][jp1], dFdX[ip1][jp1],
-                    dFdY[i][j], dFdY[ip1][j], dFdY[i][jp1], dFdY[ip1][jp1],
-                    d2FdXdY[i][j], d2FdXdY[ip1][j], d2FdXdY[i][jp1], d2FdXdY[ip1][jp1]
-                };
-
-                splines[i][j] = new BicubicSplineFunction(computeSplineCoefficients(beta),
-                                                          initializeDerivatives);
-            }
-        }
-
-        if (initializeDerivatives) {
-            // Compute all partial derivatives.
-            partialDerivatives = new BivariateFunction[5][lastI][lastJ];
-
-            for (int i = 0; i < lastI; i++) {
-                for (int j = 0; j < lastJ; j++) {
-                    final BicubicSplineFunction bcs = splines[i][j];
-                    partialDerivatives[0][i][j] = bcs.partialDerivativeX();
-                    partialDerivatives[1][i][j] = bcs.partialDerivativeY();
-                    partialDerivatives[2][i][j] = bcs.partialDerivativeXX();
-                    partialDerivatives[3][i][j] = bcs.partialDerivativeYY();
-                    partialDerivatives[4][i][j] = bcs.partialDerivativeXY();
-                }
-            }
-        } else {
-            // Partial derivative methods cannot be used.
-            partialDerivatives = null;
-        }
+        fval = f.clone();
     }
 
     /**
@@ -220,13 +103,37 @@ public class BicubicSplineInterpolatingFunction
      */
     public double value(double x, double y)
         throws OutOfRangeException {
-        final int i = searchIndex(x, xval);
-        final int j = searchIndex(y, yval);
+        int index;
+        PolynomialSplineFunction spline;
+        AkimaSplineInterpolator interpolator = new AkimaSplineInterpolator();
+        final int offset = 2;
+        final int count = offset + 3;
+        final int i = searchIndex(x, xval, offset, count);
+        final int j = searchIndex(y, yval, offset, count);
+
+        double xArray[] = new double[count];
+        double yArray[] = new double[count];
+        double zArray[] = new double[count];
+        double interpArray[] = new double[count];
+
+        for (index = 0; index < count; index++) {
+            xArray[index] = xval[i + index];
+            yArray[index] = yval[j + index];
+        }
+
+        for (int zIndex = 0; zIndex < count; zIndex++) {
+            for (index = 0; index < count; index++) {
+                zArray[index] = fval[i + index][j + zIndex];
+            }
+            spline = interpolator.interpolate(xArray, zArray);
+            interpArray[zIndex] = spline.value(x);
+        }
+
+        spline = interpolator.interpolate(yArray, interpArray);
 
-        final double xN = (x - xval[i]) / (xval[i + 1] - xval[i]);
-        final double yN = (y - yval[j]) / (yval[j + 1] - yval[j]);
+        double returnValue = spline.value(y);
 
-        return splines[i][j].value(xN, yN);
+        return returnValue;
     }
 
     /**
@@ -238,9 +145,7 @@ public class BicubicSplineInterpolatingFunction
      * @since 3.3
      */
     public boolean isValidPoint(double x, double y) {
-        if (x < xval[0] ||
-            x > xval[xval.length - 1] ||
-            y < yval[0] ||
+        if (x < xval[0] || x > xval[xval.length - 1] || y < yval[0] ||
             y > yval[yval.length - 1]) {
             return false;
         } else {
@@ -249,385 +154,42 @@ public class BicubicSplineInterpolatingFunction
     }
 
     /**
-     * @param x x-coordinate.
-     * @param y y-coordinate.
-     * @return the value at point (x, y) of the first partial derivative with
-     * respect to x.
-     * @throws OutOfRangeException if {@code x} (resp. {@code y}) is outside
-     * the range defined by the boundary values of {@code xval} (resp.
-     * {@code yval}).
-     * @throws NullPointerException if the internal data were not initialized
-     * (cf. {@link #BicubicSplineInterpolatingFunction(double[],double[],double[][],
-     *             double[][],double[][],double[][],boolean) constructor}).
-     */
-    public double partialDerivativeX(double x, double y)
-        throws OutOfRangeException {
-        return partialDerivative(0, x, y);
-    }
-    /**
-     * @param x x-coordinate.
-     * @param y y-coordinate.
-     * @return the value at point (x, y) of the first partial derivative with
-     * respect to y.
-     * @throws OutOfRangeException if {@code x} (resp. {@code y}) is outside
-     * the range defined by the boundary values of {@code xval} (resp.
-     * {@code yval}).
-     * @throws NullPointerException if the internal data were not initialized
-     * (cf. {@link #BicubicSplineInterpolatingFunction(double[],double[],double[][],
-     *             double[][],double[][],double[][],boolean) constructor}).
-     */
-    public double partialDerivativeY(double x, double y)
-        throws OutOfRangeException {
-        return partialDerivative(1, x, y);
-    }
-    /**
-     * @param x x-coordinate.
-     * @param y y-coordinate.
-     * @return the value at point (x, y) of the second partial derivative with
-     * respect to x.
-     * @throws OutOfRangeException if {@code x} (resp. {@code y}) is outside
-     * the range defined by the boundary values of {@code xval} (resp.
-     * {@code yval}).
-     * @throws NullPointerException if the internal data were not initialized
-     * (cf. {@link #BicubicSplineInterpolatingFunction(double[],double[],double[][],
-     *             double[][],double[][],double[][],boolean) constructor}).
-     */
-    public double partialDerivativeXX(double x, double y)
-        throws OutOfRangeException {
-        return partialDerivative(2, x, y);
-    }
-    /**
-     * @param x x-coordinate.
-     * @param y y-coordinate.
-     * @return the value at point (x, y) of the second partial derivative with
-     * respect to y.
-     * @throws OutOfRangeException if {@code x} (resp. {@code y}) is outside
-     * the range defined by the boundary values of {@code xval} (resp.
-     * {@code yval}).
-     * @throws NullPointerException if the internal data were not initialized
-     * (cf. {@link #BicubicSplineInterpolatingFunction(double[],double[],double[][],
-     *             double[][],double[][],double[][],boolean) constructor}).
-     */
-    public double partialDerivativeYY(double x, double y)
-        throws OutOfRangeException {
-        return partialDerivative(3, x, y);
-    }
-    /**
-     * @param x x-coordinate.
-     * @param y y-coordinate.
-     * @return the value at point (x, y) of the second partial cross-derivative.
-     * @throws OutOfRangeException if {@code x} (resp. {@code y}) is outside
-     * the range defined by the boundary values of {@code xval} (resp.
-     * {@code yval}).
-     * @throws NullPointerException if the internal data were not initialized
-     * (cf. {@link #BicubicSplineInterpolatingFunction(double[],double[],double[][],
-     *             double[][],double[][],double[][],boolean) constructor}).
-     */
-    public double partialDerivativeXY(double x, double y)
-        throws OutOfRangeException {
-        return partialDerivative(4, x, y);
-    }
-
-    /**
-     * @param which First index in {@link #partialDerivatives}.
-     * @param x x-coordinate.
-     * @param y y-coordinate.
-     * @return the value at point (x, y) of the selected partial derivative.
-     * @throws OutOfRangeException if {@code x} (resp. {@code y}) is outside
-     * the range defined by the boundary values of {@code xval} (resp.
-     * {@code yval}).
-     * @throws NullPointerException if the internal data were not initialized
-     * (cf. {@link #BicubicSplineInterpolatingFunction(double[],double[],double[][],
-     *             double[][],double[][],double[][],boolean) constructor}).
-     */
-    private double partialDerivative(int which, double x, double y)
-        throws OutOfRangeException {
-        final int i = searchIndex(x, xval);
-        final int j = searchIndex(y, yval);
-
-        final double xN = (x - xval[i]) / (xval[i + 1] - xval[i]);
-        final double yN = (y - yval[j]) / (yval[j + 1] - yval[j]);
-
-        return partialDerivatives[which][i][j].value(xN, yN);
-    }
-
-    /**
      * @param c Coordinate.
      * @param val Coordinate samples.
-     * @return the index in {@code val} corresponding to the interval
-     * containing {@code c}.
-     * @throws OutOfRangeException if {@code c} is out of the
-     * range defined by the boundary values of {@code val}.
-     */
-    private int searchIndex(double c, double[] val) {
-        final int r = Arrays.binarySearch(val, c);
-
-        if (r == -1 ||
-            r == -val.length - 1) {
+     * @param offset how far back from found value to offset for querying
+     * @param count total number of elements forward from beginning that will be
+     *        queried
+     * @return the index in {@code val} corresponding to the interval containing
+     *         {@code c}.
+     * @throws OutOfRangeException if {@code c} is out of the range defined by
+     *         the boundary values of {@code val}.
+     */
+    private int searchIndex(double c, double[] val, int offset, int count) {
+        int r = Arrays.binarySearch(val, c);
+
+        if (r == -1 || r == -val.length - 1) {
             throw new OutOfRangeException(c, val[0], val[val.length - 1]);
         }
 
         if (r < 0) {
-            // "c" in within an interpolation sub-interval: Return the
-            // index of the sample at the lower end of the sub-interval.
-            return -r - 2;
-        }
-        final int last = val.length - 1;
-        if (r == last) {
-            // "c" is the last sample of the range: Return the index
-            // of the sample at the lower end of the last sub-interval.
-            return last - 1;
-        }
-
-        // "c" is another sample point.
-        return r;
-    }
-
-    /**
-     * Compute the spline coefficients from the list of function values and
-     * function partial derivatives values at the four corners of a grid
-     * element. They must be specified in the following order:
-     * <ul>
-     *  <li>f(0,0)</li>
-     *  <li>f(1,0)</li>
-     *  <li>f(0,1)</li>
-     *  <li>f(1,1)</li>
-     *  <li>f<sub>x</sub>(0,0)</li>
-     *  <li>f<sub>x</sub>(1,0)</li>
-     *  <li>f<sub>x</sub>(0,1)</li>
-     *  <li>f<sub>x</sub>(1,1)</li>
-     *  <li>f<sub>y</sub>(0,0)</li>
-     *  <li>f<sub>y</sub>(1,0)</li>
-     *  <li>f<sub>y</sub>(0,1)</li>
-     *  <li>f<sub>y</sub>(1,1)</li>
-     *  <li>f<sub>xy</sub>(0,0)</li>
-     *  <li>f<sub>xy</sub>(1,0)</li>
-     *  <li>f<sub>xy</sub>(0,1)</li>
-     *  <li>f<sub>xy</sub>(1,1)</li>
-     * </ul>
-     * where the subscripts indicate the partial derivative with respect to
-     * the corresponding variable(s).
-     *
-     * @param beta List of function values and function partial derivatives
-     * values.
-     * @return the spline coefficients.
-     */
-    private double[] computeSplineCoefficients(double[] beta) {
-        final double[] a = new double[NUM_COEFF];
-
-        for (int i = 0; i < NUM_COEFF; i++) {
-            double result = 0;
-            final double[] row = AINV[i];
-            for (int j = 0; j < NUM_COEFF; j++) {
-                result += row[j] * beta[j];
-            }
-            a[i] = result;
-        }
-
-        return a;
-    }
-}
-
-/**
- * 2D-spline function.
- *
- */
-class BicubicSplineFunction implements BivariateFunction {
-    /** Number of points. */
-    private static final short N = 4;
-    /** Coefficients */
-    private final double[][] a;
-    /** First partial derivative along x. */
-    private final BivariateFunction partialDerivativeX;
-    /** First partial derivative along y. */
-    private final BivariateFunction partialDerivativeY;
-    /** Second partial derivative along x. */
-    private final BivariateFunction partialDerivativeXX;
-    /** Second partial derivative along y. */
-    private final BivariateFunction partialDerivativeYY;
-    /** Second crossed partial derivative. */
-    private final BivariateFunction partialDerivativeXY;
-
-    /**
-     * Simple constructor.
-     *
-     * @param coeff Spline coefficients.
-     */
-    public BicubicSplineFunction(double[] coeff) {
-        this(coeff, false);
-    }
-
-    /**
-     * Simple constructor.
-     *
-     * @param coeff Spline coefficients.
-     * @param initializeDerivatives Whether to initialize the internal data
-     * needed for calling any of the methods that compute the partial derivatives
-     * this function.
-     */
-    public BicubicSplineFunction(double[] coeff,
-                                 boolean initializeDerivatives) {
-        a = new double[N][N];
-        for (int i = 0; i < N; i++) {
-            for (int j = 0; j < N; j++) {
-                a[i][j] = coeff[i * N + j];
-            }
-        }
-
-        if (initializeDerivatives) {
-            // Compute all partial derivatives functions.
-            final double[][] aX = new double[N][N];
-            final double[][] aY = new double[N][N];
-            final double[][] aXX = new double[N][N];
-            final double[][] aYY = new double[N][N];
-            final double[][] aXY = new double[N][N];
-
-            for (int i = 0; i < N; i++) {
-                for (int j = 0; j < N; j++) {
-                    final double c = a[i][j];
-                    aX[i][j] = i * c;
-                    aY[i][j] = j * c;
-                    aXX[i][j] = (i - 1) * aX[i][j];
-                    aYY[i][j] = (j - 1) * aY[i][j];
-                    aXY[i][j] = j * aX[i][j];
-                }
-            }
-
-            partialDerivativeX = new BivariateFunction() {
-                    public double value(double x, double y)  {
-                        final double x2 = x * x;
-                        final double[] pX = {0, 1, x, x2};
-
-                        final double y2 = y * y;
-                        final double y3 = y2 * y;
-                        final double[] pY = {1, y, y2, y3};
-
-                        return apply(pX, pY, aX);
-                    }
-                };
-            partialDerivativeY = new BivariateFunction() {
-                    public double value(double x, double y)  {
-                        final double x2 = x * x;
-                        final double x3 = x2 * x;
-                        final double[] pX = {1, x, x2, x3};
-
-                        final double y2 = y * y;
-                        final double[] pY = {0, 1, y, y2};
-
-                        return apply(pX, pY, aY);
-                    }
-                };
-            partialDerivativeXX = new BivariateFunction() {
-                    public double value(double x, double y)  {
-                        final double[] pX = {0, 0, 1, x};
-
-                        final double y2 = y * y;
-                        final double y3 = y2 * y;
-                        final double[] pY = {1, y, y2, y3};
-
-                        return apply(pX, pY, aXX);
-                    }
-                };
-            partialDerivativeYY = new BivariateFunction() {
-                    public double value(double x, double y)  {
-                        final double x2 = x * x;
-                        final double x3 = x2 * x;
-                        final double[] pX = {1, x, x2, x3};
-
-                        final double[] pY = {0, 0, 1, y};
-
-                        return apply(pX, pY, aYY);
-                    }
-                };
-            partialDerivativeXY = new BivariateFunction() {
-                    public double value(double x, double y)  {
-                        final double x2 = x * x;
-                        final double[] pX = {0, 1, x, x2};
-
-                        final double y2 = y * y;
-                        final double[] pY = {0, 1, y, y2};
-
-                        return apply(pX, pY, aXY);
-                    }
-                };
+            // "c" in within an interpolation sub-interval, which returns
+            // negative
+            // need to remove the negative sign for consistency
+            r = -r - offset - 1;
         } else {
-            partialDerivativeX = null;
-            partialDerivativeY = null;
-            partialDerivativeXX = null;
-            partialDerivativeYY = null;
-            partialDerivativeXY = null;
+            r -= offset;
         }
-    }
 
-    /**
-     * {@inheritDoc}
-     */
-    public double value(double x, double y) {
-        if (x < 0 || x > 1) {
-            throw new OutOfRangeException(x, 0, 1);
-        }
-        if (y < 0 || y > 1) {
-            throw new OutOfRangeException(y, 0, 1);
+        if (r < 0) {
+            r = 0;
         }
 
-        final double x2 = x * x;
-        final double x3 = x2 * x;
-        final double[] pX = {1, x, x2, x3};
-
-        final double y2 = y * y;
-        final double y3 = y2 * y;
-        final double[] pY = {1, y, y2, y3};
-
-        return apply(pX, pY, a);
-    }
-
-    /**
-     * Compute the value of the bicubic polynomial.
-     *
-     * @param pX Powers of the x-coordinate.
-     * @param pY Powers of the y-coordinate.
-     * @param coeff Spline coefficients.
-     * @return the interpolated value.
-     */
-    private double apply(double[] pX, double[] pY, double[][] coeff) {
-        double result = 0;
-        for (int i = 0; i < N; i++) {
-            for (int j = 0; j < N; j++) {
-                result += coeff[i][j] * pX[i] * pY[j];
-            }
+        if ((r + count) >= val.length) {
+            // "c" is the last sample of the range: Return the index
+            // of the sample at the lower end of the last sub-interval.
+            r = val.length - count;
         }
 
-        return result;
-    }
-
-    /**
-     * @return the partial derivative wrt {@code x}.
-     */
-    public BivariateFunction partialDerivativeX() {
-        return partialDerivativeX;
-    }
-    /**
-     * @return the partial derivative wrt {@code y}.
-     */
-    public BivariateFunction partialDerivativeY() {
-        return partialDerivativeY;
-    }
-    /**
-     * @return the second partial derivative wrt {@code x}.
-     */
-    public BivariateFunction partialDerivativeXX() {
-        return partialDerivativeXX;
-    }
-    /**
-     * @return the second partial derivative wrt {@code y}.
-     */
-    public BivariateFunction partialDerivativeYY() {
-        return partialDerivativeYY;
-    }
-    /**
-     * @return the second partial cross-derivative.
-     */
-    public BivariateFunction partialDerivativeXY() {
-        return partialDerivativeXY;
+        return r;
     }
 }

http://git-wip-us.apache.org/repos/asf/commons-math/blob/d8bfc8c8/src/main/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolator.java
----------------------------------------------------------------------
diff --git a/src/main/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolator.java b/src/main/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolator.java
index 5e2c92f..36a9da2 100644
--- a/src/main/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolator.java
+++ b/src/main/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolator.java
@@ -16,11 +16,10 @@
  */
 package org.apache.commons.math3.analysis.interpolation;
 
-import org.apache.commons.math3.analysis.UnivariateFunction;
-import org.apache.commons.math3.analysis.polynomials.PolynomialSplineFunction;
 import org.apache.commons.math3.exception.DimensionMismatchException;
 import org.apache.commons.math3.exception.NoDataException;
 import org.apache.commons.math3.exception.NonMonotonicSequenceException;
+import org.apache.commons.math3.exception.NullArgumentException;
 import org.apache.commons.math3.exception.NumberIsTooSmallException;
 import org.apache.commons.math3.util.MathArrays;
 
@@ -30,144 +29,37 @@ import org.apache.commons.math3.util.MathArrays;
  * @since 2.2
  */
 public class BicubicSplineInterpolator
-    implements BivariateGridInterpolator {
-    /** Whether to initialize internal data used to compute the analytical
-        derivatives of the splines. */
-    private final boolean initializeDerivatives;
+    implements BivariateGridInterpolator
+{
 
     /**
      * Default constructor.
-     * The argument {@link #BicubicSplineInterpolator(boolean) initializeDerivatives}
-     * is set to {@code false}.
      */
-    public BicubicSplineInterpolator() {
-        this(false);
-    }
+    public BicubicSplineInterpolator()
+    {
 
-    /**
-     * Creates an interpolator.
-     *
-     * @param initializeDerivatives Whether to initialize the internal data
-     * needed for calling any of the methods that compute the partial derivatives
-     * of the {@link BicubicSplineInterpolatingFunction function} returned from
-     * the call to {@link #interpolate(double[],double[],double[][]) interpolate}.
-     */
-    public BicubicSplineInterpolator(boolean initializeDerivatives) {
-        this.initializeDerivatives = initializeDerivatives;
     }
 
     /**
      * {@inheritDoc}
      */
-    public BicubicSplineInterpolatingFunction interpolate(final double[] xval,
-                                                          final double[] yval,
+    public BicubicSplineInterpolatingFunction interpolate( final double[] xval, final double[] yval,
                                                           final double[][] fval)
-        throws NoDataException, DimensionMismatchException,
-               NonMonotonicSequenceException, NumberIsTooSmallException {
-        if (xval.length == 0 || yval.length == 0 || fval.length == 0) {
-            throw new NoDataException();
+        throws DimensionMismatchException, NullArgumentException, NoDataException, NonMonotonicSequenceException
+    {
+        if ( xval == null || yval == null || fval == null || fval[0] == null )
+        {
+            throw new NullArgumentException();
         }
-        if (xval.length != fval.length) {
-            throw new DimensionMismatchException(xval.length, fval.length);
+
+        if ( xval.length == 0 || yval.length == 0 || fval.length == 0 )
+        {
+            throw new NoDataException();
         }
 
         MathArrays.checkOrder(xval);
         MathArrays.checkOrder(yval);
 
-        final int xLen = xval.length;
-        final int yLen = yval.length;
-
-        // Samples (first index is y-coordinate, i.e. subarray variable is x)
-        // 0 <= i < xval.length
-        // 0 <= j < yval.length
-        // fX[j][i] = f(xval[i], yval[j])
-        final double[][] fX = new double[yLen][xLen];
-        for (int i = 0; i < xLen; i++) {
-            if (fval[i].length != yLen) {
-                throw new DimensionMismatchException(fval[i].length, yLen);
-            }
-
-            for (int j = 0; j < yLen; j++) {
-                fX[j][i] = fval[i][j];
-            }
-        }
-
-        final SplineInterpolator spInterpolator = new SplineInterpolator();
-
-        // For each line y[j] (0 <= j < yLen), construct a 1D spline with
-        // respect to variable x
-        final PolynomialSplineFunction[] ySplineX = new PolynomialSplineFunction[yLen];
-        for (int j = 0; j < yLen; j++) {
-            ySplineX[j] = spInterpolator.interpolate(xval, fX[j]);
-        }
-
-        // For each line x[i] (0 <= i < xLen), construct a 1D spline with
-        // respect to variable y generated by array fY_1[i]
-        final PolynomialSplineFunction[] xSplineY = new PolynomialSplineFunction[xLen];
-        for (int i = 0; i < xLen; i++) {
-            xSplineY[i] = spInterpolator.interpolate(yval, fval[i]);
-        }
-
-        // Partial derivatives with respect to x at the grid knots
-        final double[][] dFdX = new double[xLen][yLen];
-        for (int j = 0; j < yLen; j++) {
-            final UnivariateFunction f = ySplineX[j].derivative();
-            for (int i = 0; i < xLen; i++) {
-                dFdX[i][j] = f.value(xval[i]);
-            }
-        }
-
-        // Partial derivatives with respect to y at the grid knots
-        final double[][] dFdY = new double[xLen][yLen];
-        for (int i = 0; i < xLen; i++) {
-            final UnivariateFunction f = xSplineY[i].derivative();
-            for (int j = 0; j < yLen; j++) {
-                dFdY[i][j] = f.value(yval[j]);
-            }
-        }
-
-        // Cross partial derivatives
-        final double[][] d2FdXdY = new double[xLen][yLen];
-        for (int i = 0; i < xLen ; i++) {
-            final int nI = nextIndex(i, xLen);
-            final int pI = previousIndex(i);
-            for (int j = 0; j < yLen; j++) {
-                final int nJ = nextIndex(j, yLen);
-                final int pJ = previousIndex(j);
-                d2FdXdY[i][j] = (fval[nI][nJ] - fval[nI][pJ] -
-                                 fval[pI][nJ] + fval[pI][pJ]) /
-                    ((xval[nI] - xval[pI]) * (yval[nJ] - yval[pJ]));
-            }
-        }
-
-        // Create the interpolating splines
-        return new BicubicSplineInterpolatingFunction(xval, yval, fval,
-                                                      dFdX, dFdY, d2FdXdY,
-                                                      initializeDerivatives);
-    }
-
-    /**
-     * Computes the next index of an array, clipping if necessary.
-     * It is assumed (but not checked) that {@code i >= 0}.
-     *
-     * @param i Index.
-     * @param max Upper limit of the array.
-     * @return the next index.
-     */
-    private int nextIndex(int i, int max) {
-        final int index = i + 1;
-        return index < max ? index : index - 1;
-    }
-    /**
-     * Computes the previous index of an array, clipping if necessary.
-     * It is assumed (but not checked) that {@code i} is smaller than the size
-     * of the array.
-     *
-     * @param i Index.
-     * @return the previous index.
-     */
-    private int previousIndex(int i) {
-        final int index = i - 1;
-        return index >= 0 ? index : 0;
+        return new BicubicSplineInterpolatingFunction( xval, yval, fval );
     }
 }

http://git-wip-us.apache.org/repos/asf/commons-math/blob/d8bfc8c8/src/main/java/org/apache/commons/math3/analysis/interpolation/TricubicSplineInterpolator.java
----------------------------------------------------------------------
diff --git a/src/main/java/org/apache/commons/math3/analysis/interpolation/TricubicSplineInterpolator.java b/src/main/java/org/apache/commons/math3/analysis/interpolation/TricubicSplineInterpolator.java
index cda6a33..0faa274 100644
--- a/src/main/java/org/apache/commons/math3/analysis/interpolation/TricubicSplineInterpolator.java
+++ b/src/main/java/org/apache/commons/math3/analysis/interpolation/TricubicSplineInterpolator.java
@@ -76,7 +76,7 @@ public class TricubicSplineInterpolator
             }
         }
 
-        final BicubicSplineInterpolator bsi = new BicubicSplineInterpolator(true);
+        final BicubicSplineInterpolator bsi = new BicubicSplineInterpolator();
 
         // For each line x[i] (0 <= i < xLen), construct a 2D spline in y and z
         final BicubicSplineInterpolatingFunction[] xSplineYZ
@@ -103,46 +103,13 @@ public class TricubicSplineInterpolator
         final double[][][] dFdX = new double[xLen][yLen][zLen];
         final double[][][] dFdY = new double[xLen][yLen][zLen];
         final double[][][] d2FdXdY = new double[xLen][yLen][zLen];
-        for (int k = 0; k < zLen; k++) {
-            final BicubicSplineInterpolatingFunction f = zSplineXY[k];
-            for (int i = 0; i < xLen; i++) {
-                final double x = xval[i];
-                for (int j = 0; j < yLen; j++) {
-                    final double y = yval[j];
-                    dFdX[i][j][k] = f.partialDerivativeX(x, y);
-                    dFdY[i][j][k] = f.partialDerivativeY(x, y);
-                    d2FdXdY[i][j][k] = f.partialDerivativeXY(x, y);
-                }
-            }
-        }
 
         // Partial derivatives wrt y and wrt z
         final double[][][] dFdZ = new double[xLen][yLen][zLen];
         final double[][][] d2FdYdZ = new double[xLen][yLen][zLen];
-        for (int i = 0; i < xLen; i++) {
-            final BicubicSplineInterpolatingFunction f = xSplineYZ[i];
-            for (int j = 0; j < yLen; j++) {
-                final double y = yval[j];
-                for (int k = 0; k < zLen; k++) {
-                    final double z = zval[k];
-                    dFdZ[i][j][k] = f.partialDerivativeY(y, z);
-                    d2FdYdZ[i][j][k] = f.partialDerivativeXY(y, z);
-                }
-            }
-        }
 
         // Partial derivatives wrt x and wrt z
         final double[][][] d2FdZdX = new double[xLen][yLen][zLen];
-        for (int j = 0; j < yLen; j++) {
-            final BicubicSplineInterpolatingFunction f = ySplineZX[j];
-            for (int k = 0; k < zLen; k++) {
-                final double z = zval[k];
-                for (int i = 0; i < xLen; i++) {
-                    final double x = xval[i];
-                    d2FdZdX[i][j][k] = f.partialDerivativeXY(z, x);
-                }
-            }
-        }
 
         // Third partial cross-derivatives
         final double[][][] d3FdXdYdZ = new double[xLen][yLen][zLen];

http://git-wip-us.apache.org/repos/asf/commons-math/blob/d8bfc8c8/src/test/java/org/apache/commons/math3/analysis/interpolation/AkimaSplineInterpolatorTest.java
----------------------------------------------------------------------
diff --git a/src/test/java/org/apache/commons/math3/analysis/interpolation/AkimaSplineInterpolatorTest.java b/src/test/java/org/apache/commons/math3/analysis/interpolation/AkimaSplineInterpolatorTest.java
new file mode 100644
index 0000000..017241a
--- /dev/null
+++ b/src/test/java/org/apache/commons/math3/analysis/interpolation/AkimaSplineInterpolatorTest.java
@@ -0,0 +1,227 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.commons.math3.analysis.interpolation;
+
+import org.apache.commons.math3.analysis.UnivariateFunction;
+import org.apache.commons.math3.distribution.UniformRealDistribution;
+import org.apache.commons.math3.exception.DimensionMismatchException;
+import org.apache.commons.math3.exception.NonMonotonicSequenceException;
+import org.apache.commons.math3.exception.NullArgumentException;
+import org.apache.commons.math3.exception.NumberIsTooSmallException;
+import org.apache.commons.math3.random.RandomGenerator;
+import org.apache.commons.math3.random.Well19937c;
+import org.apache.commons.math3.util.FastMath;
+import org.apache.commons.math3.util.Precision;
+import org.junit.Assert;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+public class AkimaSplineInterpolatorTest
+{
+
+    @Test
+    public void testIllegalArguments()
+    {
+        // Data set arrays of different size.
+        UnivariateInterpolator i = new AkimaSplineInterpolator();
+
+        try
+        {
+            double yval[] = { 0.0, 1.0, 2.0, 3.0, 4.0 };
+            i.interpolate( null, yval );
+            Assert.fail( "Failed to detect x null pointer" );
+        }
+        catch ( NullArgumentException iae )
+        {
+            // Expected.
+        }
+
+        try
+        {
+            double xval[] = { 0.0, 1.0, 2.0, 3.0, 4.0 };
+            i.interpolate( xval, null );
+            Assert.fail( "Failed to detect y null pointer" );
+        }
+        catch ( NullArgumentException iae )
+        {
+            // Expected.
+        }
+
+        try
+        {
+            double xval[] = { 0.0, 1.0, 2.0, 3.0 };
+            double yval[] = { 0.0, 1.0, 2.0, 3.0 };
+            i.interpolate( xval, yval );
+            Assert.fail( "Failed to detect insufficient data" );
+        }
+        catch ( NumberIsTooSmallException iae )
+        {
+            // Expected.
+        }
+
+        try
+        {
+            double xval[] = { 0.0, 1.0, 2.0, 3.0, 4.0 };
+            double yval[] = { 0.0, 1.0, 2.0, 3.0, 4.0, 5.0 };
+            i.interpolate( xval, yval );
+            Assert.fail( "Failed to detect data set array with different sizes." );
+        }
+        catch ( DimensionMismatchException iae )
+        {
+            // Expected.
+        }
+
+        // X values not sorted.
+        try
+        {
+            double xval[] = { 0.0, 1.0, 0.5, 7.0, 3.5, 2.2, 8.0 };
+            double yval[] = { 0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 };
+            i.interpolate( xval, yval );
+            Assert.fail( "Failed to detect unsorted arguments." );
+        }
+        catch ( NonMonotonicSequenceException iae )
+        {
+            // Expected.
+        }
+    }
+
+    /*
+     * Interpolate a straight line. <p> y = 2 x - 5 <p> Tolerances determined by performing same calculation using
+     * Math.NET over ten runs of 100 random number draws for the same function over the same span with the same number
+     * of elements
+     */
+    @Test
+    public void testInterpolateLine()
+    {
+        final int numberOfElements = 10;
+        final double minimumX = -10;
+        final double maximumX = 10;
+        final int numberOfSamples = 100;
+        final double interpolationTolerance = 1e-15;
+        final double maxTolerance = 1e-15;
+
+        UnivariateFunction f = new UnivariateFunction()
+        {
+            public double value( double x )
+            {
+                return 2 * x - 5;
+            }
+        };
+
+        testInterpolation( minimumX, maximumX, numberOfElements, numberOfSamples, f, interpolationTolerance,
+                           maxTolerance );
+    }
+
+    /*
+     * Interpolate a straight line. <p> y = 3 x<sup>2</sup> - 5 x + 7 <p> Tolerances determined by performing same
+     * calculation using Math.NET over ten runs of 100 random number draws for the same function over the same span with
+     * the same number of elements
+     */
+
+    @Test
+    public void testInterpolateParabola()
+    {
+        final int numberOfElements = 10;
+        final double minimumX = -10;
+        final double maximumX = 10;
+        final int numberOfSamples = 100;
+        final double interpolationTolerance = 7e-15;
+        final double maxTolerance = 6e-14;
+
+        UnivariateFunction f = new UnivariateFunction()
+        {
+            public double value( double x )
+            {
+                return ( 3 * x * x ) - ( 5 * x ) + 7;
+            }
+        };
+
+        testInterpolation( minimumX, maximumX, numberOfElements, numberOfSamples, f, interpolationTolerance,
+                           maxTolerance );
+    }
+
+    /*
+     * Interpolate a straight line. <p> y = 3 x<sup>3</sup> - 0.5 x<sup>2</sup> + x - 1 <p> Tolerances determined by
+     * performing same calculation using Math.NET over ten runs of 100 random number draws for the same function over
+     * the same span with the same number of elements
+     */
+    @Test
+    public void testInterpolateCubic()
+    {
+        final int numberOfElements = 10;
+        final double minimumX = -3;
+        final double maximumX = 3;
+        final int numberOfSamples = 100;
+        final double interpolationTolerance = 0.37;
+        final double maxTolerance = 3.8;
+
+        UnivariateFunction f = new UnivariateFunction()
+        {
+            public double value( double x )
+            {
+                return ( 3 * x * x * x ) - ( 0.5 * x * x ) + ( 1 * x ) - 1;
+            }
+        };
+
+        testInterpolation( minimumX, maximumX, numberOfElements, numberOfSamples, f, interpolationTolerance,
+                           maxTolerance );
+    }
+
+    private void testInterpolation( double minimumX, double maximumX, int numberOfElements, int numberOfSamples,
+                                    UnivariateFunction f, double tolerance, double maxTolerance )
+    {
+        double expected;
+        double actual;
+        double currentX;
+        final double delta = ( maximumX - minimumX ) / ( (double) numberOfElements );
+        double xValues[] = new double[numberOfElements];
+        double yValues[] = new double[numberOfElements];
+
+        for ( int i = 0; i < numberOfElements; i++ )
+        {
+            xValues[i] = minimumX + delta * (double) i;
+            yValues[i] = f.value( xValues[i] );
+        }
+
+        UnivariateFunction interpolation = new AkimaSplineInterpolator().interpolate( xValues, yValues );
+
+        for ( int i = 0; i < numberOfElements; i++ )
+        {
+            currentX = xValues[i];
+            expected = f.value( currentX );
+            actual = interpolation.value( currentX );
+            assertTrue( Precision.equals( expected, actual ) );
+        }
+
+        final RandomGenerator rng = new Well19937c( 1234567L ); // "tol" depends on the seed.
+        final UniformRealDistribution distX =
+            new UniformRealDistribution( rng, xValues[0], xValues[xValues.length - 1] );
+
+        double sumError = 0;
+        for ( int i = 0; i < numberOfSamples; i++ )
+        {
+            currentX = distX.sample();
+            expected = f.value( currentX );
+            actual = interpolation.value( currentX );
+            sumError += FastMath.abs( actual - expected );
+            assertEquals( expected, actual, maxTolerance );
+        }
+
+        assertEquals( 0.0, ( sumError / (double) numberOfSamples ), tolerance );
+    }
+}


[8/8] git commit: Merge branch 'master' of https://luc@git-wip-us.apache.org/repos/asf/commons-math.git

Posted by lu...@apache.org.
Merge branch 'master' of https://luc@git-wip-us.apache.org/repos/asf/commons-math.git

Project: http://git-wip-us.apache.org/repos/asf/commons-math/repo
Commit: http://git-wip-us.apache.org/repos/asf/commons-math/commit/b5e155e7
Tree: http://git-wip-us.apache.org/repos/asf/commons-math/tree/b5e155e7
Diff: http://git-wip-us.apache.org/repos/asf/commons-math/diff/b5e155e7

Branch: refs/heads/master
Commit: b5e155e7d0448a100e9d4ff7d178a2fb9ea9f659
Parents: 4a339cd a51908a
Author: Luc Maisonobe <lu...@apache.org>
Authored: Fri Oct 17 10:40:35 2014 +0200
Committer: Luc Maisonobe <lu...@apache.org>
Committed: Fri Oct 17 10:40:35 2014 +0200

----------------------------------------------------------------------
 .../apache/commons/math3/exception/MathIllegalStateException.java  | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
----------------------------------------------------------------------



Re: asf git mails (was:: [3/8] git commit: Merge remote-tracking branch 'upstream/master')

Posted by sebb <se...@gmail.com>.
https://issues.apache.org/jira/browse/INFRA-8382

On 17 October 2014 19:06, Bernd Eckenfels <ec...@zusammenkunft.net> wrote:
> Hello,
>
> was this an automatically generated patch mail or is this coming from
> the ASF GIT? In the later case, I wonder if it is possible to
> includethe [Math] tag or at least the repo name/path in the subject?
>
> Gruss
> Bernd
>
>
> Am
> Fri, 17 Oct 2014 08:41:27 -0000 schrieb luc@apache.org:
>
>> Merge remote-tracking branch 'upstream/master'
>>
>>
>> Project: http://git-wip-us.apache.org/repos/asf/commons-math/repo
>> Commit:
>> http://git-wip-us.apache.org/repos/asf/commons-math/commit/bd3a6eca
>> Tree:
>> http://git-wip-us.apache.org/repos/asf/commons-math/tree/bd3a6eca
>> Diff:
>> http://git-wip-us.apache.org/repos/asf/commons-math/diff/bd3a6eca
> ...
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: dev-unsubscribe@commons.apache.org
> For additional commands, e-mail: dev-help@commons.apache.org
>

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asf git mails (was:: [3/8] git commit: Merge remote-tracking branch 'upstream/master')

Posted by Bernd Eckenfels <ec...@zusammenkunft.net>.
Hello,

was this an automatically generated patch mail or is this coming from
the ASF GIT? In the later case, I wonder if it is possible to
includethe [Math] tag or at least the repo name/path in the subject?

Gruss
Bernd


Am
Fri, 17 Oct 2014 08:41:27 -0000 schrieb luc@apache.org:

> Merge remote-tracking branch 'upstream/master'
> 
> 
> Project: http://git-wip-us.apache.org/repos/asf/commons-math/repo
> Commit:
> http://git-wip-us.apache.org/repos/asf/commons-math/commit/bd3a6eca
> Tree:
> http://git-wip-us.apache.org/repos/asf/commons-math/tree/bd3a6eca
> Diff:
> http://git-wip-us.apache.org/repos/asf/commons-math/diff/bd3a6eca
...

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[3/8] git commit: Merge remote-tracking branch 'upstream/master'

Posted by lu...@apache.org.
Merge remote-tracking branch 'upstream/master'


Project: http://git-wip-us.apache.org/repos/asf/commons-math/repo
Commit: http://git-wip-us.apache.org/repos/asf/commons-math/commit/bd3a6eca
Tree: http://git-wip-us.apache.org/repos/asf/commons-math/tree/bd3a6eca
Diff: http://git-wip-us.apache.org/repos/asf/commons-math/diff/bd3a6eca

Branch: refs/heads/master
Commit: bd3a6ecaa777247aaa6175e5c4721bfbd1645451
Parents: d8bfc8c d26810c
Author: Hank Grabowski <ha...@applieddefense.com>
Authored: Wed Oct 15 10:20:34 2014 -0400
Committer: Hank Grabowski <ha...@applieddefense.com>
Committed: Wed Oct 15 10:20:34 2014 -0400

----------------------------------------------------------------------
 pom.xml                                         |  3 +++
 .../exception/MathIllegalStateException.java    |  5 +++--
 .../AbstractIntegerDistributionTest.java        | 21 +++++++++++++++++++-
 3 files changed, 26 insertions(+), 3 deletions(-)
----------------------------------------------------------------------