Author: erans
Date: Mon Nov 26 23:02:29 2012
New Revision: 1413916
URL: http://svn.apache.org/viewvc?rev=1413916&view=rev
Log:
MATH-904.
Fixed wrong assumption in "pow" method.
Modified:
commons/proper/math/trunk/src/changes/changes.xml
commons/proper/math/trunk/src/main/java/org/apache/commons/math3/util/FastMath.java
commons/proper/math/trunk/src/test/java/org/apache/commons/math3/util/FastMathTest.java
Modified: commons/proper/math/trunk/src/changes/changes.xml
URL:
http://svn.apache.org/viewvc/commons/proper/math/trunk/src/changes/changes.xml?rev=1413916&r1=1413915&r2=1413916&view=diff
==============================================================================
--- commons/proper/math/trunk/src/changes/changes.xml (original)
+++ commons/proper/math/trunk/src/changes/changes.xml Mon Nov 26 23:02:29 2012
@@ -52,6 +52,9 @@ If the output is not quite correct, chec
<body>
<release version="3.1" date="TBD" description="
">
+ <action dev="erans" type="fix" issue="MATH-904" due-to="Jeff Hain">
+ Fixed "pow" method in class "FastMath".
+ </action>
<action dev="erans" type="update" issue="MATH-902" due-to="Bruce A.
Johnson">
Created a "maximum number of iterations" stopping criterion in the
convergence checkers (package "o.a.c.m.optimization") that allows the
Modified:
commons/proper/math/trunk/src/main/java/org/apache/commons/math3/util/FastMath.java
URL:
http://svn.apache.org/viewvc/commons/proper/math/trunk/src/main/java/org/apache/commons/math3/util/FastMath.java?rev=1413916&r1=1413915&r2=1413916&view=diff
==============================================================================
---
commons/proper/math/trunk/src/main/java/org/apache/commons/math3/util/FastMath.java
(original)
+++
commons/proper/math/trunk/src/main/java/org/apache/commons/math3/util/FastMath.java
Mon Nov 26 23:02:29 2012
@@ -309,6 +309,8 @@ public class FastMath {
/** 2^52 - double numbers this large must be integral (no fraction) or NaN
or Infinite */
private static final double TWO_POWER_52 = 4503599627370496.0;
+ /** 2^53 - double numbers this large must be even. */
+ private static final double TWO_POWER_53 = 2 * TWO_POWER_52;
/** Constant: {@value}. */
private static final double F_1_3 = 1d / 3d;
@@ -1537,7 +1539,7 @@ public class FastMath {
/* Handle special case x<0 */
if (x < 0) {
// y is an even integer in this case
- if (y >= TWO_POWER_52 || y <= -TWO_POWER_52) {
+ if (y >= TWO_POWER_53 || y <= -TWO_POWER_53) {
return pow(-x, y);
}
Modified:
commons/proper/math/trunk/src/test/java/org/apache/commons/math3/util/FastMathTest.java
URL:
http://svn.apache.org/viewvc/commons/proper/math/trunk/src/test/java/org/apache/commons/math3/util/FastMathTest.java?rev=1413916&r1=1413915&r2=1413916&view=diff
==============================================================================
---
commons/proper/math/trunk/src/test/java/org/apache/commons/math3/util/FastMathTest.java
(original)
+++
commons/proper/math/trunk/src/test/java/org/apache/commons/math3/util/FastMathTest.java
Mon Nov 26 23:02:29 2012
@@ -158,6 +158,16 @@ public class FastMathTest {
}
@Test
+ public void testMath904() {
+ final double x = -1;
+ final double y = (5 + 1e-15) * 1e15;
+ Assert.assertEquals(Math.pow(x, y),
+ FastMath.pow(x, y), 0);
+ Assert.assertEquals(Math.pow(x, -y),
+ FastMath.pow(x, -y), 0);
+ }
+
+ @Test
public void testMath905LargePositive() {
final double start = StrictMath.log(Double.MAX_VALUE);
final double endT = StrictMath.sqrt(2) *
StrictMath.sqrt(Double.MAX_VALUE);
