, Serializable {
real * rhs.imaginary + imaginary * rhs.real);
}
+ /**
+ * Return the product of this complex number and the given scalar number.
+ *
+ * Implements preliminary checks for NaN and infinity followed by
+ * the definitional formula:
+ *
+ * c(a + bi) = (ca) + (cb)i
+ *
+ *
+ *
+ * Returns {@link #NaN} if either this or rhs has one or more
+ * NaN parts.
+ *
+ * Returns {@link #INF} if neither this nor rhs has one or more
+ * NaN parts and if either this or rhs has one or more
+ * infinite parts (same result is returned regardless of the sign of the
+ * components).
+ *
+ *
+ * Returns finite values in components of the result per the
+ * definitional formula in all remaining cases.
+ *
+ *
+ * @param rhs the scalar number
+ * @return the complex number product
+ */
+ public Complex multiply(double rhs) {
+ if (isNaN() || Double.isNaN(rhs)) {
+ return NaN;
+ }
+ if (Double.isInfinite(real) || Double.isInfinite(imaginary) ||
+ Double.isInfinite(rhs)) {
+ // we don't use Complex.isInfinite() to avoid testing for NaN again
+ return INF;
+ }
+ return createComplex(real * rhs, imaginary * rhs);
+ }
+
/**
* Return the additive inverse of this complex number.
*
diff --git a/src/site/xdoc/changes.xml b/src/site/xdoc/changes.xml
index e3802376e..1682ce538 100644
--- a/src/site/xdoc/changes.xml
+++ b/src/site/xdoc/changes.xml
@@ -45,6 +45,9 @@ The type attribute can be add,update,fix,remove.
Added robust locally weighted regression (Loess).
+
+ Added a scalar multiply to the Complex class
+
Added curve fitting with a general case and two specific cases (polynomial and harmonic).
diff --git a/src/test/org/apache/commons/math/complex/ComplexTest.java b/src/test/org/apache/commons/math/complex/ComplexTest.java
index 0112f9dcd..97cf65b0a 100644
--- a/src/test/org/apache/commons/math/complex/ComplexTest.java
+++ b/src/test/org/apache/commons/math/complex/ComplexTest.java
@@ -219,6 +219,31 @@ public class ComplexTest extends TestCase {
assertTrue(Double.isNaN(w.getImaginary()));
}
+ public void testScalarMultiply() {
+ Complex x = new Complex(3.0, 4.0);
+ double y = 2.0;
+ Complex z = x.multiply(y);
+ assertEquals(6.0, z.getReal(), 1.0e-5);
+ assertEquals(8.0, z.getImaginary(), 1.0e-5);
+ }
+
+ public void testScalarMultiplyNaN() {
+ Complex x = new Complex(3.0, 4.0);
+ Complex z = x.multiply(Double.NaN);
+ assertTrue(z.isNaN());
+ }
+
+ public void testScalarMultiplyInf() {
+ Complex z = new Complex(1,1);
+ Complex w = z.multiply(Double.POSITIVE_INFINITY);
+ assertEquals(w.getReal(), inf, 0);
+ assertEquals(w.getImaginary(), inf, 0);
+
+ w = z.multiply(Double.NEGATIVE_INFINITY);
+ assertEquals(w.getReal(), inf, 0);
+ assertEquals(w.getImaginary(), inf, 0);
+ }
+
public void testNegate() {
Complex x = new Complex(3.0, 4.0);
Complex z = x.negate();