| /* |
| * 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·e<sup>i·theta</sup></code>, |
| * computed as <code>r·cos(theta) + r·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, 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></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·e<sup>i·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)); |
| } |
| |
| } |