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Posted to commits@commons.apache.org by er...@apache.org on 2011/01/17 14:06:14 UTC
svn commit: r1059909 - in /commons/proper/math/trunk/src:
main/java/org/apache/commons/math/util/MathUtils.java
test/java/org/apache/commons/math/util/MathUtilsTest.java
Author: erans
Date: Mon Jan 17 13:06:13 2011
New Revision: 1059909
URL: http://svn.apache.org/viewvc?rev=1059909&view=rev
Log:
MATH-475
Updated the Javadoc to make clear that 2 adjacent floating point numbers
are considered equal whatever the allowed tolerance.
Modified:
commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/MathUtils.java
commons/proper/math/trunk/src/test/java/org/apache/commons/math/util/MathUtilsTest.java
Modified: commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/MathUtils.java
URL: http://svn.apache.org/viewvc/commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/MathUtils.java?rev=1059909&r1=1059908&r2=1059909&view=diff
==============================================================================
--- commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/MathUtils.java (original)
+++ commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/MathUtils.java Mon Jan 17 13:06:13 2011
@@ -596,13 +596,15 @@ public final class MathUtils {
}
/**
- * Returns true if both arguments are equal or within the range of allowed
+ * Returns {@code true} if there is no double value strictly between the
+ * arguments or the difference between them is within the range of allowed
* error (inclusive).
*
- * @param x first value
- * @param y second value
- * @param eps the amount of absolute error to allow.
- * @return {@code true} if the values are equal or within range of each other.
+ * @param x First value.
+ * @param y Second value.
+ * @param eps Amount of allowed absolute error.
+ * @return {@code true} if the values are two adjacent floating point
+ * numbers or they are within range of each other.
*/
public static boolean equals(double x, double y, double eps) {
return equals(x, y, 1) || FastMath.abs(y - x) <= eps;
Modified: commons/proper/math/trunk/src/test/java/org/apache/commons/math/util/MathUtilsTest.java
URL: http://svn.apache.org/viewvc/commons/proper/math/trunk/src/test/java/org/apache/commons/math/util/MathUtilsTest.java?rev=1059909&r1=1059908&r2=1059909&view=diff
==============================================================================
--- commons/proper/math/trunk/src/test/java/org/apache/commons/math/util/MathUtilsTest.java (original)
+++ commons/proper/math/trunk/src/test/java/org/apache/commons/math/util/MathUtilsTest.java Mon Jan 17 13:06:13 2011
@@ -343,12 +343,30 @@ public final class MathUtilsTest extends
assertTrue(MathUtils.equals(153.0000, 153.0000, .0625));
assertTrue(MathUtils.equals(153.0000, 153.0625, .0625));
assertTrue(MathUtils.equals(152.9375, 153.0000, .0625));
+ assertFalse(MathUtils.equals(153.0000, 153.0625, .0624));
+ assertFalse(MathUtils.equals(152.9374, 153.0000, .0625));
assertFalse(MathUtils.equals(Double.NaN, Double.NaN, 1.0));
assertTrue(MathUtils.equals(Double.POSITIVE_INFINITY, Double.POSITIVE_INFINITY, 1.0));
assertTrue(MathUtils.equals(Double.NEGATIVE_INFINITY, Double.NEGATIVE_INFINITY, 1.0));
assertFalse(MathUtils.equals(Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY, 1.0));
- assertFalse(MathUtils.equals(153.0000, 153.0625, .0624));
- assertFalse(MathUtils.equals(152.9374, 153.0000, .0625));
+ }
+
+ public void testMath475() {
+ final double a = 1.7976931348623182E16;
+ final double b = FastMath.nextUp(a);
+
+ double diff = FastMath.abs(a - b);
+ // Because they are adjacent floating point numbers, "a" and "b" are
+ // considered equal even though the allowed error is smaller than
+ // their difference.
+ assertTrue(MathUtils.equals(a, b, 0.5 * diff));
+
+ final double c = FastMath.nextUp(b);
+ diff = FastMath.abs(a - c);
+ // Because "a" and "c" are not adjacent, the tolerance is taken into
+ // account for assessing equality.
+ assertTrue(MathUtils.equals(a, c, diff));
+ assertFalse(MathUtils.equals(a, c, (1 - 1e-16) * diff));
}
public void testEqualsIncludingNaNWithAllowedDelta() {