jcomplex

Author: monkstone

library/jcomplex/jcomplex.rb

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+java_import Java::MonkstoneComplex::JComplex

src/main/java/monkstone/complex/JComplex.java

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+package monkstone.complex;
+
+import java.util.Objects;
+
+/**
+ * The purpose of this class is to to make Complex operations more efficient
+ * than JRuby RubyComplex, by having a simpler interface, only modest
+ * improvements were obtained (but this is better than nothing on RaspberryPI).
+ */
+public final class JComplex {
+
+    private final double re;   // the real part
+    private final double im;   // the imaginary part
+    private final static JComplex ZERO = new JComplex(0, 0);
+    private final static JComplex NAN = new JComplex(Double.NaN, Double.NaN);
+
+    /**
+     * create a new object with the given real and imaginary parts
+     *
+     * @param real
+     * @param imag
+     */
+    public JComplex(double real, double imag) {
+        re = real;
+        im = imag;
+    }
+
+    /**
+     * @return a string representation of the invoking Complex object
+     */
+    @Override
+    public String toString() {
+        return "JComplex(" + re + ", " + im + "i)";
+    }
+
+    /**
+     *
+     * @return abs/modulus/magnitude
+     */
+    public final double abs() {
+        return Math.hypot(re, im);
+    }
+
+    /**
+     *
+     * @return square of abs/modulus/magnitude
+     */
+    public final double abs2() {
+        return re * re + im * im;
+    }
+
+    /**
+     *
+     * @return angle/phase/argument, normalized to be between -pi and pi
+     */
+    public final double phase() {
+        return Math.atan2(im, re);
+    }
+
+    /**
+     *
+     * @param b
+     * @return a new Complex object whose value is (this + b)
+     */
+    public final JComplex add(JComplex b) {
+        JComplex a = this;             // invoking object
+        double real = a.re + b.re;
+        double imag = a.im + b.im;
+        return new JComplex(real, imag);
+    }
+
+    /**
+     *
+     * @param scalar
+     * @return a new Complex object whose value is (this + scalar)
+     */
+    public final JComplex add(double scalar) {
+        return new JComplex(re + scalar, im);
+    }
+
+    public final boolean zero() {
+        return this.equals(ZERO);
+    }
+
+    /**
+     *
+     * @param b
+     * @return a new Complex object whose value is (this - b)
+     */
+    public final JComplex sub(JComplex b) {
+        JComplex a = this;
+        double real = a.re - b.re;
+        double imag = a.im - b.im;
+        return new JComplex(real, imag);
+    }
+
+    /**
+     *
+     * @param scalar
+     * @return a new Complex object whose value is (this - scalar)
+     */
+    public final JComplex sub(double scalar) {
+        return new JComplex(re - scalar, im);
+    }
+
+    /**
+     *
+     * @param b
+     * @return a new Complex object whose value is (this * b)
+     */
+    public final JComplex mul(JComplex b) {
+        JComplex a = this;
+        double real = a.re * b.re - a.im * b.im;
+        double imag = a.re * b.im + a.im * b.re;
+        return new JComplex(real, imag);
+    }
+
+    /**
+     * Also known as scale
+     *
+     * @param b
+     * @return a new Complex object whose value is (this * b)
+     */
+    public final JComplex mul(double b) {
+        return new JComplex(re * b, im * b);
+    }
+
+    /**
+     *
+     * @return a new Complex object whose value is the conjugate of this
+     */
+    public final JComplex conjugate() {
+        return new JComplex(re, -im);
+    }
+
+    /**
+     *
+     * @return a new Complex object whose value is the reciprocal of this
+     */
+    private JComplex reciprocal() {
+        double scale = re * re + im * im; // self dot product
+        return new JComplex(re / scale, -im / scale);
+    }
+
+    /**
+     *
+     * @param other
+     * @return this^other
+     */
+    public final JComplex pow(JComplex other) {
+        if (this.zero()) {
+            if (other.zero()) {
+                return ZERO;
+            }
+            return NAN;
+        }
+        return (this).log().mul(other).exp();
+    }
+
+    /**
+     *
+     * @param scalar
+     * @return this^scalar
+     */
+    public final JComplex pow(double scalar) {
+        if (this.zero()) {
+            if (scalar == 0) {
+                return ZERO;
+            }
+            return NAN;
+        }
+        return (this).log().mul(scalar).exp();
+    }
+
+    /**
+     *
+     * @return log
+     */
+    private JComplex log() {
+        return new JComplex(Math.log(abs()), Math.atan2(im, re));
+    }
+
+    /**
+     *
+     * @return real part
+     */
+    public final double re() {
+        return re;
+    }
+
+    /**
+     *
+     * @return imaginary part
+     */
+    public final double im() {
+        return im;
+    }
+
+    /**
+     *
+     * @param b
+     * @return a / b
+     */
+    public final JComplex div(JComplex b) {
+        JComplex a = this;
+        return a.mul(b.reciprocal());
+    }
+
+    /**
+     *
+     * @param b
+     * @return a / b
+     */
+    public final JComplex div(double b) {
+        if (b == 0) {
+            return NAN;
+        }
+        return new JComplex(re / b, im / b);
+    }
+
+    /**
+     *
+     * @return a new Complex object whose value is the complex exponential of
+     * this
+     */
+    public final JComplex exp() {
+        return new JComplex(Math.exp(re) * Math.cos(im), Math.exp(re) * Math.sin(im));
+    }
+
+    @Override
+    public final int hashCode() {
+        return Objects.hash(re, im);
+    }
+
+    @Override
+    public final boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null) {
+            return false;
+        }
+        if (getClass() != obj.getClass()) {
+            return false;
+        }
+        final JComplex other = (JComplex) obj;
+        if (Double.doubleToLongBits(this.re) != Double.doubleToLongBits(other.re)) {
+            return false;
+        }
+        return Double.doubleToLongBits(this.im) == Double.doubleToLongBits(other.im);
+    }
+}