Author: erans
Date: Fri Sep 2 23:05:01 2011
New Revision: 1164756
URL: http://svn.apache.org/viewvc?rev=1164756&view=rev
Log:
MATH-657
Complex division by zero:
z / 0 = INF if z is not ZERO
0 / 0 = NaN
Modified:
commons/proper/math/trunk/src/main/java/org/apache/commons/math/complex/Complex.java
commons/proper/math/trunk/src/test/java/org/apache/commons/math/complex/ComplexTest.java
Modified:
commons/proper/math/trunk/src/main/java/org/apache/commons/math/complex/Complex.java
URL:
http://svn.apache.org/viewvc/commons/proper/math/trunk/src/main/java/org/apache/commons/math/complex/Complex.java?rev=1164756&r1=1164755&r2=1164756&view=diff
==============================================================================
---
commons/proper/math/trunk/src/main/java/org/apache/commons/math/complex/Complex.java
(original)
+++
commons/proper/math/trunk/src/main/java/org/apache/commons/math/complex/Complex.java
Fri Sep 2 23:05:01 2011
@@ -78,6 +78,8 @@ public class Complex implements FieldEle
private final transient boolean isNaN;
/** Record whether this complex number is infinite. */
private final transient boolean isInfinite;
+ /** Record whether this complex number is zero. */
+ private final transient boolean isZero;
/**
* Create a complex number given only the real part.
@@ -101,6 +103,7 @@ public class Complex implements FieldEle
isNaN = Double.isNaN(real) || Double.isNaN(imaginary);
isInfinite = !isNaN &&
(Double.isInfinite(real) || Double.isInfinite(imaginary));
+ isZero = real == 0 && imaginary == 0;
}
/**
@@ -222,7 +225,10 @@ public class Complex implements FieldEle
* <li>If either {@code this} or {@code divisor} has a {@code NaN} value
* in either part, {@link #NaN} is returned.
* </li>
- * <li>If {@code divisor} equals {@link #ZERO}, {@link #NaN} is returned.
+ * <li>If {@code this} and {@code divisor} are both {@link #ZERO},
+ * {@link #NaN} is returned.
+ * </li>
+ * <li>If {@code divisor} equals {@link #ZERO}, {@link #INF} is returned.
* </li>
* <li>If {@code this} and {@code divisor} are both infinite,
* {@link #NaN} is returned.
@@ -249,16 +255,17 @@ public class Complex implements FieldEle
return NaN;
}
- final double c = divisor.getReal();
- final double d = divisor.getImaginary();
- if (c == 0.0 && d == 0.0) {
- return NaN;
+ if (divisor.isZero) {
+ return isZero ? NaN : INF;
}
if (divisor.isInfinite() && !isInfinite()) {
return ZERO;
}
+ final double c = divisor.getReal();
+ final double d = divisor.getImaginary();
+
if (FastMath.abs(c) < FastMath.abs(d)) {
double q = c / d;
double denominator = c * q + d;
@@ -285,7 +292,7 @@ public class Complex implements FieldEle
return NaN;
}
if (divisor == 0d) {
- return NaN;
+ return isZero ? NaN : INF;
}
if (Double.isInfinite(divisor)) {
return !isInfinite() ? ZERO : NaN;
Modified:
commons/proper/math/trunk/src/test/java/org/apache/commons/math/complex/ComplexTest.java
URL:
http://svn.apache.org/viewvc/commons/proper/math/trunk/src/test/java/org/apache/commons/math/complex/ComplexTest.java?rev=1164756&r1=1164755&r2=1164756&view=diff
==============================================================================
---
commons/proper/math/trunk/src/test/java/org/apache/commons/math/complex/ComplexTest.java
(original)
+++
commons/proper/math/trunk/src/test/java/org/apache/commons/math/complex/ComplexTest.java
Fri Sep 2 23:05:01 2011
@@ -229,6 +229,13 @@ public class ComplexTest {
public void testDivideZero() {
Complex x = new Complex(3.0, 4.0);
Complex z = x.divide(Complex.ZERO);
+ Assert.assertEquals(z, Complex.INF);
+ }
+
+ @Test
+ public void testDivideZeroZero() {
+ Complex x = new Complex(0.0, 0.0);
+ Complex z = x.divide(Complex.ZERO);
Assert.assertEquals(z, Complex.NaN);
}
@@ -349,13 +356,13 @@ public class ComplexTest {
@Test
public void testScalarMultiplyInf() {
- Complex x = new Complex(1,1);
+ Complex x = new Complex(1, 1);
double yDouble = Double.POSITIVE_INFINITY;
Complex yComplex = new Complex(yDouble);
Assert.assertEquals(x.multiply(yComplex), x.multiply(yDouble));
yDouble = Double.NEGATIVE_INFINITY;
- yComplex = new Complex(yDouble);
+ yComplex = new Complex(yDouble);
Assert.assertEquals(x.multiply(yComplex), x.multiply(yDouble));
}
@@ -565,9 +572,16 @@ public class ComplexTest {
}
@Test
+ public void testAtanI() {
+ for (int i = -10; i < 10; i++) {
+ System.out.println(new Complex(0, 1 - 0.1 * i).atan());
+ }
+ Assert.assertTrue(Complex.I.atan().isInfinite());
+ }
+
+ @Test
public void testAtanNaN() {
Assert.assertTrue(Complex.NaN.atan().isNaN());
- Assert.assertTrue(Complex.I.atan().isNaN());
}
@Test
