Author: luc
Date: Fri Mar 22 16:25:17 2013
New Revision: 1459887
URL: http://svn.apache.org/r1459887
Log:
Improved speed of FastMath copysign methods.
JIRA: MATH-951
Modified:
commons/proper/math/trunk/pom.xml
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/pom.xml
URL:
http://svn.apache.org/viewvc/commons/proper/math/trunk/pom.xml?rev=1459887&r1=1459886&r2=1459887&view=diff
==============================================================================
--- commons/proper/math/trunk/pom.xml (original)
+++ commons/proper/math/trunk/pom.xml Fri Mar 22 16:25:17 2013
@@ -163,6 +163,9 @@
<name>Dan Checkoway</name>
</contributor>
<contributor>
+ <name>Charles Cooper</name>
+ </contributor>
+ <contributor>
<name>Paul Cowan</name>
</contributor>
<contributor>
Modified: commons/proper/math/trunk/src/changes/changes.xml
URL:
http://svn.apache.org/viewvc/commons/proper/math/trunk/src/changes/changes.xml?rev=1459887&r1=1459886&r2=1459887&view=diff
==============================================================================
--- commons/proper/math/trunk/src/changes/changes.xml (original)
+++ commons/proper/math/trunk/src/changes/changes.xml Fri Mar 22 16:25:17 2013
@@ -55,6 +55,9 @@ This is a minor release: It combines bug
Changes to existing features were made in a backwards-compatible
way such as to allow drop-in replacement of the v3.1[.1] JAR file.
">
+ <action dev="luc" type="update" issue="MATH-951" due-to="Charles Cooper">
+ Improved speed of FastMath copysign methods.
+ </action>
<action dev="erans" type="add" issue="MATH-817" due-to="Jared Becksfort">
Added Multivariate Normal Mixture Model Fitting by Expectation
Maximization.
</action>
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=1459887&r1=1459886&r2=1459887&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
Fri Mar 22 16:25:17 2013
@@ -3630,9 +3630,13 @@ public class FastMath {
* @return the magnitude with the same sign as the {@code sign} argument
*/
public static double copySign(double magnitude, double sign){
- long m = Double.doubleToLongBits(magnitude);
- long s = Double.doubleToLongBits(sign);
- if ((m >= 0 && s >= 0) || (m < 0 && s < 0)) { // Sign is currently OK
+ // The highest order bit is going to be zero if the
+ // highest order bit of m and s is the same and one otherwise.
+ // So (m^s) will be positive if both m and s have the same sign
+ // and negative otherwise.
+ final long m = Double.doubleToLongBits(magnitude);
+ final long s = Double.doubleToLongBits(sign);
+ if ((m^s) >= 0) {
return magnitude;
}
return -magnitude; // flip sign
@@ -3647,9 +3651,13 @@ public class FastMath {
* @return the magnitude with the same sign as the {@code sign} argument
*/
public static float copySign(float magnitude, float sign){
- int m = Float.floatToIntBits(magnitude);
- int s = Float.floatToIntBits(sign);
- if ((m >= 0 && s >= 0) || (m < 0 && s < 0)) { // Sign is currently OK
+ // The highest order bit is going to be zero if the
+ // highest order bit of m and s is the same and one otherwise.
+ // So (m^s) will be positive if both m and s have the same sign
+ // and negative otherwise.
+ final int m = Float.floatToIntBits(magnitude);
+ final int s = Float.floatToIntBits(sign);
+ if ((m^s) >= 0) {
return magnitude;
}
return -magnitude; // flip sign
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=1459887&r1=1459886&r2=1459887&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
Fri Mar 22 16:25:17 2013
@@ -1149,6 +1149,10 @@ public class FastMathTest {
double delta = 0.0;
Assert.assertEquals(1.0, FastMath.copySign(1d, 2.0), delta);
Assert.assertEquals(1.0, FastMath.copySign(1d, 0.0), delta);
+ Assert.assertEquals(-1.0, FastMath.copySign(1d, -0.0), delta);
+ Assert.assertEquals(1.0, FastMath.copySign(1d,
Double.POSITIVE_INFINITY), delta);
+ Assert.assertEquals(-1.0, FastMath.copySign(1d,
Double.NEGATIVE_INFINITY), delta);
+ Assert.assertEquals(1.0, FastMath.copySign(1d, Double.NaN), delta);
Assert.assertEquals(-1.0, FastMath.copySign(1d, -2.0), delta);
}
@@ -1157,6 +1161,10 @@ public class FastMathTest {
float delta = 0.0F;
Assert.assertEquals(1.0F, FastMath.copySign(1d, 2.0F), delta);
Assert.assertEquals(1.0F, FastMath.copySign(1d, 0.0F), delta);
+ Assert.assertEquals(-1.0F, FastMath.copySign(1d, -0.0F), delta);
+ Assert.assertEquals(1.0F, FastMath.copySign(1d,
Float.POSITIVE_INFINITY), delta);
+ Assert.assertEquals(-1.0F, FastMath.copySign(1d,
Float.NEGATIVE_INFINITY), delta);
+ Assert.assertEquals(1.0F, FastMath.copySign(1d, Float.NaN), delta);
Assert.assertEquals(-1.0F, FastMath.copySign(1d, -2.0F), delta);
}
