Author: luc
Date: Thu Aug 16 10:07:59 2012
New Revision: 1373781
URL: http://svn.apache.org/viewvc?rev=1373781&view=rev
Log:
Added signum to DerivativeStructure.
Modified:
commons/proper/math/trunk/src/main/java/org/apache/commons/math3/analysis/differentiation/DerivativeStructure.java
commons/proper/math/trunk/src/test/java/org/apache/commons/math3/analysis/differentiation/DerivativeStructureTest.java
Modified:
commons/proper/math/trunk/src/main/java/org/apache/commons/math3/analysis/differentiation/DerivativeStructure.java
URL:
http://svn.apache.org/viewvc/commons/proper/math/trunk/src/main/java/org/apache/commons/math3/analysis/differentiation/DerivativeStructure.java?rev=1373781&r1=1373780&r2=1373781&view=diff
==============================================================================
---
commons/proper/math/trunk/src/main/java/org/apache/commons/math3/analysis/differentiation/DerivativeStructure.java
(original)
+++
commons/proper/math/trunk/src/main/java/org/apache/commons/math3/analysis/differentiation/DerivativeStructure.java
Thu Aug 16 10:07:59 2012
@@ -402,6 +402,17 @@ public class DerivativeStructure impleme
return FastMath.round(data[0]);
}
+ /** Compute the signum of the instance.
+ * The signum is -1 for negative numbers, +1 for positive numbers and 0
otherwise
+ * @param a number on which evaluation is done
+ * @return -1.0, -0.0, +0.0, +1.0 or NaN depending on sign of a
+ */
+ public DerivativeStructure signum() {
+ return new DerivativeStructure(compiler.getFreeParameters(),
+ compiler.getOrder(),
+ FastMath.signum(data[0]));
+ }
+
/**
* Returns the instance with the sign of the argument.
* A NaN {@code sign} argument is treated as positive.
Modified:
commons/proper/math/trunk/src/test/java/org/apache/commons/math3/analysis/differentiation/DerivativeStructureTest.java
URL:
http://svn.apache.org/viewvc/commons/proper/math/trunk/src/test/java/org/apache/commons/math3/analysis/differentiation/DerivativeStructureTest.java?rev=1373781&r1=1373780&r2=1373781&view=diff
==============================================================================
---
commons/proper/math/trunk/src/test/java/org/apache/commons/math3/analysis/differentiation/DerivativeStructureTest.java
(original)
+++
commons/proper/math/trunk/src/test/java/org/apache/commons/math3/analysis/differentiation/DerivativeStructureTest.java
Thu Aug 16 10:07:59 2012
@@ -838,6 +838,29 @@ public class DerivativeStructureTest {
}
@Test
+ public void testSignum() {
+
+ DerivativeStructure minusOne = new DerivativeStructure(1, 1, 0, -1.0);
+ Assert.assertEquals(-1.0, minusOne.signum().getPartialDerivative(0),
1.0e-15);
+ Assert.assertEquals( 0.0, minusOne.signum().getPartialDerivative(1),
1.0e-15);
+
+ DerivativeStructure plusOne = new DerivativeStructure(1, 1, 0, +1.0);
+ Assert.assertEquals(+1.0, plusOne.signum().getPartialDerivative(0),
1.0e-15);
+ Assert.assertEquals( 0.0, plusOne.signum().getPartialDerivative(1),
1.0e-15);
+
+ DerivativeStructure minusZero = new DerivativeStructure(1, 1, 0, -0.0);
+ Assert.assertEquals(-0.0, minusZero.signum().getPartialDerivative(0),
1.0e-15);
+
Assert.assertTrue(Double.doubleToLongBits(minusZero.signum().getValue()) < 0);
+ Assert.assertEquals( 0.0, minusZero.signum().getPartialDerivative(1),
1.0e-15);
+
+ DerivativeStructure plusZero = new DerivativeStructure(1, 1, 0, +0.0);
+ Assert.assertEquals(+0.0, plusZero.signum().getPartialDerivative(0),
1.0e-15);
+
Assert.assertTrue(Double.doubleToLongBits(plusZero.signum().getValue()) == 0);
+ Assert.assertEquals( 0.0, plusZero.signum().getPartialDerivative(1),
1.0e-15);
+
+ }
+
+ @Test
public void testCeilFloorRintLong() {
DerivativeStructure x = new DerivativeStructure(1, 1, 0, -1.5);
