1 files changed, 72 insertions, 0 deletions
diff --git a/src/main/java/org/apache/commons/math/complex/ComplexUtils.java b/src/main/java/org/apache/commons/math/complex/ComplexUtils.java
new file mode 100644
index 0000000..f7fb392
--- /dev/null
+++ b/src/main/java/org/apache/commons/math/complex/ComplexUtils.java
@@ -0,0 +1,72 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.commons.math.complex;
+
+import org.apache.commons.math.MathRuntimeException;
+import org.apache.commons.math.exception.util.LocalizedFormats;
+import org.apache.commons.math.util.FastMath;
+
+/**
+ * Static implementations of common
+ * {@link org.apache.commons.math.complex.Complex} utilities functions.
+ *
+ * @version $Revision: 990655 $ $Date: 2010-08-29 23:49:40 +0200 (dim. 29 août 2010) $
+ */
+public class ComplexUtils {
+
+    /**
+     * Default constructor.
+     */
+    private ComplexUtils() {
+        super();
+    }
+
+    /**
+     * Creates a complex number from the given polar representation.
+     * <p>
+     * The value returned is <code>r&middot;e<sup>i&middot;theta</sup></code>,
+     * computed as <code>r&middot;cos(theta) + r&middot;sin(theta)i</code></p>
+     * <p>
+     * If either <code>r</code> or <code>theta</code> is NaN, or
+     * <code>theta</code> is infinite, {@link Complex#NaN} is returned.</p>
+     * <p>
+     * If <code>r</code> is infinite and <code>theta</code> is finite,
+     * infinite or NaN values may be returned in parts of the result, following
+     * the rules for double arithmetic.<pre>
+     * Examples:
+     * <code>
+     * polar2Complex(INFINITY, &pi;/4) = INFINITY + INFINITY i
+     * polar2Complex(INFINITY, 0) = INFINITY + NaN i
+     * polar2Complex(INFINITY, -&pi;/4) = INFINITY - INFINITY i
+     * polar2Complex(INFINITY, 5&pi;/4) = -INFINITY - INFINITY i </code></pre></p>
+     *
+     * @param r the modulus of the complex number to create
+     * @param theta  the argument of the complex number to create
+     * @return <code>r&middot;e<sup>i&middot;theta</sup></code>
+     * @throws IllegalArgumentException  if r is negative
+     * @since 1.1
+     */
+    public static Complex polar2Complex(double r, double theta) {
+        if (r < 0) {
+            throw MathRuntimeException.createIllegalArgumentException(
+                  LocalizedFormats.NEGATIVE_COMPLEX_MODULE, r);
+        }
+        return new Complex(r * FastMath.cos(theta), r * FastMath.sin(theta));
+    }
+
+}