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Posted to commits@commons.apache.org by er...@apache.org on 2019/09/27 14:35:13 UTC
[commons-geometry] 03/06: GEOMETRY-61: Improvement of "normalize"
functionality for class "Vector2D".
This is an automated email from the ASF dual-hosted git repository.
erans pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/commons-geometry.git
commit 65d0228f1dab8c4f37a06f96270ab0f01a440b79
Author: Gilles Sadowski <gi...@harfang.homelinux.org>
AuthorDate: Fri Sep 27 13:29:18 2019 +0200
GEOMETRY-61: Improvement of "normalize" functionality for class "Vector2D".
"Unit" class defines factory methods "from" to create a normalized instance.
---
.../euclidean/twod/AffineTransformMatrix2D.java | 2 +-
.../commons/geometry/euclidean/twod/Line.java | 2 +-
.../commons/geometry/euclidean/twod/Vector2D.java | 77 +++++++++++++---------
.../geometry/euclidean/twod/Vector2DTest.java | 12 ++--
4 files changed, 55 insertions(+), 38 deletions(-)
diff --git a/commons-geometry-euclidean/src/main/java/org/apache/commons/geometry/euclidean/twod/AffineTransformMatrix2D.java b/commons-geometry-euclidean/src/main/java/org/apache/commons/geometry/euclidean/twod/AffineTransformMatrix2D.java
index 2192f43..ae80335 100644
--- a/commons-geometry-euclidean/src/main/java/org/apache/commons/geometry/euclidean/twod/AffineTransformMatrix2D.java
+++ b/commons-geometry-euclidean/src/main/java/org/apache/commons/geometry/euclidean/twod/AffineTransformMatrix2D.java
@@ -164,7 +164,7 @@ public final class AffineTransformMatrix2D implements AffineTransformMatrix<Vect
*/
@Override
public Vector2D applyDirection(final Vector2D vec) {
- return applyVector(vec, Vector2D::normalize);
+ return applyVector(vec, Vector2D.Unit::from);
}
/** Apply a translation to the current instance, returning the result as a new transform.
diff --git a/commons-geometry-euclidean/src/main/java/org/apache/commons/geometry/euclidean/twod/Line.java b/commons-geometry-euclidean/src/main/java/org/apache/commons/geometry/euclidean/twod/Line.java
index 2fc9446..3ac9d9d 100644
--- a/commons-geometry-euclidean/src/main/java/org/apache/commons/geometry/euclidean/twod/Line.java
+++ b/commons-geometry-euclidean/src/main/java/org/apache/commons/geometry/euclidean/twod/Line.java
@@ -420,7 +420,7 @@ public final class Line implements Hyperplane<Vector2D>, Embedding<Vector2D, Vec
* abscissa (x) axis.
*/
public static Line fromPointAndAngle(final Vector2D pt, final double angle, final DoublePrecisionContext precision) {
- final Vector2D dir = Vector2D.normalize(Math.cos(angle), Math.sin(angle));
+ final Vector2D.Unit dir = Vector2D.Unit.from(Math.cos(angle), Math.sin(angle));
return fromPointAndDirection(pt, dir, precision);
}
diff --git a/commons-geometry-euclidean/src/main/java/org/apache/commons/geometry/euclidean/twod/Vector2D.java b/commons-geometry-euclidean/src/main/java/org/apache/commons/geometry/euclidean/twod/Vector2D.java
index 1b7c797..85dac32 100644
--- a/commons-geometry-euclidean/src/main/java/org/apache/commons/geometry/euclidean/twod/Vector2D.java
+++ b/commons-geometry-euclidean/src/main/java/org/apache/commons/geometry/euclidean/twod/Vector2D.java
@@ -33,16 +33,16 @@ public class Vector2D extends MultiDimensionalEuclideanVector<Vector2D> {
public static final Vector2D ZERO = new Vector2D(0, 0);
/** Unit vector pointing in the direction of the positive x-axis. */
- public static final Vector2D PLUS_X = new UnitVector(1, 0);
+ public static final Vector2D PLUS_X = Unit.PLUS_X;
/** Unit vector pointing in the direction of the negative x-axis. */
- public static final Vector2D MINUS_X = new UnitVector(-1, 0);
+ public static final Vector2D MINUS_X = Unit.MINUS_X;
/** Unit vector pointing in the direction of the positive y-axis. */
- public static final Vector2D PLUS_Y = new UnitVector(0, 1);
+ public static final Vector2D PLUS_Y = Unit.PLUS_Y;
/** Unit vector pointing in the direction of the negative y-axis. */
- public static final Vector2D MINUS_Y = new UnitVector(0, -1);
+ public static final Vector2D MINUS_Y = Unit.MINUS_Y;
// CHECKSTYLE: stop ConstantName
/** A vector with all coordinates set to NaN. */
@@ -123,10 +123,7 @@ public class Vector2D extends MultiDimensionalEuclideanVector<Vector2D> {
/** {@inheritDoc} */
@Override
public Vector2D directionTo(Vector2D v) {
- return normalize(
- v.x - x,
- v.y - y
- );
+ return vectorTo(v).normalize();
}
/** {@inheritDoc} */
@@ -197,7 +194,7 @@ public class Vector2D extends MultiDimensionalEuclideanVector<Vector2D> {
/** {@inheritDoc} */
@Override
public Vector2D normalize() {
- return normalize(x, y);
+ return Unit.from(x, y);
}
/** {@inheritDoc} */
@@ -273,13 +270,13 @@ public class Vector2D extends MultiDimensionalEuclideanVector<Vector2D> {
*/
@Override
public Vector2D orthogonal() {
- return normalize(-y, x);
+ return Unit.from(-y, x);
}
/** {@inheritDoc} */
@Override
public Vector2D orthogonal(Vector2D dir) {
- return dir.getComponent(this, true, Vector2D::normalize);
+ return dir.getComponent(this, true, Vector2D.Unit::from);
}
/** Compute the signed area of the parallelogram with sides formed by this instance
@@ -432,19 +429,6 @@ public class Vector2D extends MultiDimensionalEuclideanVector<Vector2D> {
return new Vector2D(v[0], v[1]);
}
- /** Returns a normalized vector derived from the given values.
- * @param x abscissa (first coordinate value)
- * @param y ordinate (second coordinate value)
- * @return normalized vector instance
- * @throws IllegalNormException if the norm of the given values is zero, NaN, or infinite
- */
- public static Vector2D normalize(final double x, final double y) {
- final double norm = Vectors.checkedNorm(Vectors.norm(x, y));
- final double invNorm = 1.0 / norm;
-
- return new UnitVector(x * invNorm, y * invNorm);
- }
-
/** Parses the given string and returns a new vector instance. The expected string
* format is the same as that returned by {@link #toString()}.
* @param str the string to parse
@@ -531,10 +515,19 @@ public class Vector2D extends MultiDimensionalEuclideanVector<Vector2D> {
LinearCombination.value(a1, v1.y, a2, v2.y, a3, v3.y, a4, v4.y));
}
- /** Private class used to represent unit vectors. This allows optimizations to be performed for certain
- * operations.
+ /**
+ * Represents unit vectors.
+ * This allows optimizations to be performed for certain operations.
*/
- private static final class UnitVector extends Vector2D {
+ public static final class Unit extends Vector2D {
+ /** Unit vector (coordinates: 1, 0). */
+ static final Unit PLUS_X = new Unit(1d, 0d);
+ /** Negation of unit vector (coordinates: -1, 0). */
+ static final Unit MINUS_X = new Unit(-1d, 0d);
+ /** Unit vector (coordinates: 0, 1). */
+ static final Unit PLUS_Y = new Unit(0d, 1d);
+ /** Negation of unit vector (coordinates: 0, -1). */
+ static final Unit MINUS_Y = new Unit(0d, -1d);
/** Serializable version identifier */
private static final long serialVersionUID = 20180903L;
@@ -544,10 +537,34 @@ public class Vector2D extends MultiDimensionalEuclideanVector<Vector2D> {
* @param x abscissa (first coordinate value)
* @param y abscissa (second coordinate value)
*/
- private UnitVector(final double x, final double y) {
+ private Unit(final double x, final double y) {
super(x, y);
}
+ /**
+ * Creates a normalized vector.
+ *
+ * @param x Vector coordinate.
+ * @param y Vector coordinate.
+ * @return a vector whose norm is 1.
+ * @throws IllegalNormException if the norm of the given value is zero, NaN, or infinite
+ */
+ public static Unit from(double x, double y) {
+ final double invNorm = 1 / Vectors.checkedNorm(Vectors.norm(x, y));
+ return new Unit(x * invNorm, y * invNorm);
+ }
+
+ /**
+ * Creates a normalized vector.
+ *
+ * @param v Vector.
+ * @return a vector whose norm is 1.
+ * @throws IllegalNormException if the norm of the given value is zero, NaN, or infinite
+ */
+ public static Unit from(Vector2D v) {
+ return from(v.getX(), v.getY());
+ }
+
/** {@inheritDoc} */
@Override
public double norm() {
@@ -574,8 +591,8 @@ public class Vector2D extends MultiDimensionalEuclideanVector<Vector2D> {
/** {@inheritDoc} */
@Override
- public UnitVector negate() {
- return new UnitVector(-getX(), -getY());
+ public Unit negate() {
+ return new Unit(-getX(), -getY());
}
}
}
diff --git a/commons-geometry-euclidean/src/test/java/org/apache/commons/geometry/euclidean/twod/Vector2DTest.java b/commons-geometry-euclidean/src/test/java/org/apache/commons/geometry/euclidean/twod/Vector2DTest.java
index d619342..70adf0b 100644
--- a/commons-geometry-euclidean/src/test/java/org/apache/commons/geometry/euclidean/twod/Vector2DTest.java
+++ b/commons-geometry-euclidean/src/test/java/org/apache/commons/geometry/euclidean/twod/Vector2DTest.java
@@ -956,19 +956,19 @@ public class Vector2DTest {
double invSqrt2 = 1.0 / Math.sqrt(2.0);
// act/assert
- checkVector(Vector2D.normalize(2.0, -2.0), invSqrt2, -invSqrt2);
- checkVector(Vector2D.normalize(-4.0, 4.0), -invSqrt2, invSqrt2);
+ checkVector(Vector2D.Unit.from(2.0, -2.0), invSqrt2, -invSqrt2);
+ checkVector(Vector2D.Unit.from(-4.0, 4.0), -invSqrt2, invSqrt2);
}
@Test
public void testNormalize_static_illegalNorm() {
- GeometryTestUtils.assertThrows(() -> Vector2D.normalize(0.0, 0.0),
+ GeometryTestUtils.assertThrows(() -> Vector2D.Unit.from(0.0, 0.0),
IllegalNormException.class);
- GeometryTestUtils.assertThrows(() -> Vector2D.normalize(Double.NaN, 1.0),
+ GeometryTestUtils.assertThrows(() -> Vector2D.Unit.from(Double.NaN, 1.0),
IllegalNormException.class);
- GeometryTestUtils.assertThrows(() -> Vector2D.normalize(1.0, Double.NEGATIVE_INFINITY),
+ GeometryTestUtils.assertThrows(() -> Vector2D.Unit.from(1.0, Double.NEGATIVE_INFINITY),
IllegalNormException.class);
- GeometryTestUtils.assertThrows(() -> Vector2D.normalize(1.0, Double.POSITIVE_INFINITY),
+ GeometryTestUtils.assertThrows(() -> Vector2D.Unit.from(1.0, Double.POSITIVE_INFINITY),
IllegalNormException.class);
}