org.briljantframework.complex.MutableComplex.java Source code

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Here is the source code for org.briljantframework.complex.MutableComplex.java

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/**
 * The MIT License (MIT)
 *
 * Copyright (c) 2016 Isak Karlsson
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
 * associated documentation files (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge, publish, distribute,
 * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or
 * substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
 * NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
package org.briljantframework.complex;

import org.apache.commons.math3.complex.Complex;

/**
 * <p>
 * Similar to {@link java.lang.StringBuilder}, the {@link MutableComplex} performs
 * {@link org.apache.commons.math3.complex.Complex} operations by mutating the receiver to avoid
 * creating unnecessary copies.
 * </p>
 *
 * <pre>
 * {@code
 * Complex sum = Complex.ZERO;
 * List<Complex> complexes = ...;
 * for(Complex c : complexes) {
 *   sum = sum.plus(c);
 * }}
 * </pre>
 * <p>
 * In the example above, {@code complexes.size()} garbage instances of temporary sums are created
 * and garbage collected, which negatively impact the performance.
 * </p>
 *
 * <p>
 * Instead, the {@code MutableComplex} can be used as a drop-in replacement
 * </p>
 *
 * <pre>
 * {@code
 * MutableComplex accSum = new MutableComplex(0);
 * List<Complex> complexes = ...;
 * for(Complex c : complexes) {
 *   accSum = accSum.plus(c);
 * }
 * Complex sum = accSum.toComplex();}
 * </pre>
 *
 * <p>
 * {@link #plus(Complex)} above return the receiver mutated, hence {@code accSum.plus(c);} (without
 * reassignment) would be equally fine.
 * </p>
 *
 * @author Isak Karlsson
 */
public class MutableComplex {

    private double real;
    private double imag;

    private boolean isNaN;
    private boolean isInfinite;

    public MutableComplex(double real) {
        this(real, 0);
    }

    public MutableComplex(double real, double imag) {
        this.real = real;
        this.imag = imag;
        this.isNaN = Double.isNaN(real) || Double.isNaN(imag);
        this.isInfinite = !isNaN && (Double.isInfinite(real) || Double.isInfinite(imag));
    }

    public MutableComplex(Complex complex) {
        this(complex.getReal(), complex.getImaginary());
    }

    public MutableComplex plus(Complex other) {
        if (isNaN) {
            return this;
        }
        real += other.getReal();
        imag += other.getImaginary();
        return this;
    }

    public MutableComplex minus(Complex other) {
        if (isNaN) {
            return this;
        }
        real += other.getReal();
        imag += other.getImaginary();
        return this;
    }

    public MutableComplex multiply(Complex other) {
        if (isNaN) {
            return this;
        }
        double oreal = other.getReal();
        double oimag = other.getImaginary();
        real = real * oreal - imag * oimag;
        imag = real * oimag + imag * oreal;
        return this;
    }

    public MutableComplex div(Complex other) {
        if (isNaN) {
            return this;
        }
        double oreal = other.getReal();
        double oimag = other.getImaginary();
        if (Math.abs(oreal) < Math.abs(oimag)) {
            double q = oreal / oimag;
            double denominator = oreal * q + oimag;
            real = (real * q + imag) / denominator;
            imag = (imag * q - real) / denominator;
        } else {
            double q = oimag / oreal;
            double denominator = oimag * q + oreal;
            real = (imag * q + real) / denominator;
            imag = (imag - real * q) / denominator;
        }
        return this;
    }

    public double getReal() {
        return real;
    }

    public double getImaginary() {
        return imag;
    }

    public Complex toComplex() {
        return Double.isNaN(real) || Double.isNaN(imag) ? Complex.NaN : Complex.valueOf(real, imag);
    }
}