## The Commons Math *ComplexUtils.java* source code

/*
* 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;
/**
* Static implementations of common
* {@link org.apache.commons.math.complex.Complex} utilities functions.
*
* @version $Revision: 811685 $ $Date: 2009-09-05 13:36:48 -0400 (Sat, 05 Sep 2009) $
*/
public class ComplexUtils {
/**
* Default constructor.
*/
private ComplexUtils() {
super();
}
/**
* Creates a complex number from the given polar representation.
* <p>
* The value returned is <code>r·e^{i·theta},
* computed as <code>r·cos(theta) + r·sin(theta)i
* <p>
* If either <code>r or `theta`

is NaN, or
* <code>theta is infinite, {@link Complex#NaN} is returned.
* <p>
* If <code>r is infinite and `theta`

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, π/4) = INFINITY + INFINITY i
* polar2Complex(INFINITY, 0) = INFINITY + NaN i
* polar2Complex(INFINITY, -π/4) = INFINITY - INFINITY i
* polar2Complex(INFINITY, 5π/4) = -INFINITY - INFINITY i </code>

*
* @param r the modulus of the complex number to create
* @param theta the argument of the complex number to create
* @return <code>r·e

^{i·theta}
* @throws IllegalArgumentException if r is negative
* @since 1.1
*/
public static Complex polar2Complex(double r, double theta) {
if (r < 0) {
throw MathRuntimeException.createIllegalArgumentException(
"negative complex module {0}", r);
}
return new Complex(r * Math.cos(theta), r * Math.sin(theta));
}
}

## Other Commons Math examples (source code examples)

Here is a short list of links related to this Commons Math ComplexUtils.java source code file: