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Posted to commits@commons.apache.org by er...@apache.org on 2018/02/02 13:28:59 UTC

[04/50] commons-numbers git commit: Small cleanup

Small cleanup


Project: http://git-wip-us.apache.org/repos/asf/commons-numbers/repo
Commit: http://git-wip-us.apache.org/repos/asf/commons-numbers/commit/8830e479
Tree: http://git-wip-us.apache.org/repos/asf/commons-numbers/tree/8830e479
Diff: http://git-wip-us.apache.org/repos/asf/commons-numbers/diff/8830e479

Branch: refs/heads/feature__NUMBERS-51__field
Commit: 8830e47976f109bda6cf9a763d7276c814a37b22
Parents: fc70d93
Author: Eric Barnhill <er...@apache.org>
Authored: Fri Jan 26 15:35:59 2018 +0100
Committer: Eric Barnhill <er...@apache.org>
Committed: Fri Jan 26 15:35:59 2018 +0100

----------------------------------------------------------------------
 .../commons/numbers/complex/Complex.java.orig   | 1320 ------------------
 1 file changed, 1320 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/commons-numbers/blob/8830e479/commons-numbers-complex/src/main/java/org/apache/commons/numbers/complex/Complex.java.orig
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diff --git a/commons-numbers-complex/src/main/java/org/apache/commons/numbers/complex/Complex.java.orig b/commons-numbers-complex/src/main/java/org/apache/commons/numbers/complex/Complex.java.orig
deleted file mode 100644
index d3c7ce0..0000000
--- a/commons-numbers-complex/src/main/java/org/apache/commons/numbers/complex/Complex.java.orig
+++ /dev/null
@@ -1,1320 +0,0 @@
-/*
- * 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.numbers.complex;
-
-import java.io.Serializable;
-import java.util.ArrayList;
-import java.util.List;
-import org.apache.commons.numbers.core.Precision;
-/**
- * Representation of a Complex number, i.e., a number which has both a
- * real and imaginary part.
- * <p>
- * Implementations of arithmetic operations handle {@code NaN} and
- * infinite values according to the rules for {@link java.lang.Double}, i.e.
- * {@link #equals} is an equivalence relation for all instances that have
- * a {@code NaN} in either real or imaginary part, e.g. the following are
- * considered equal:
- * <ul>
- *  <li>{@code 1 + NaNi}</li>
- *  <li>{@code NaN + i}</li>
- *  <li>{@code NaN + NaNi}</li>
- * </ul><p>
- * Note that this contradicts the IEEE-754 standard for floating
- * point numbers (according to which the test {@code x == x} must fail if
- * {@code x} is {@code NaN}). The method
- * {@link org.apache.commons.numbers.core.Precision#equals(double,double,int)
- * equals for primitive double} in class {@code Precision} conforms with
- * IEEE-754 while this class conforms with the standard behavior for Java
- * object types.</p>
- *
- */
-public class Complex implements Serializable  {
-    /** The square root of -1. A number representing "0.0 + 1.0i" */
-    public static final Complex I = new Complex(0.0, 1.0);
-    // CHECKSTYLE: stop ConstantName
-    /** A complex number representing "NaN + NaNi" */
-    public static final Complex NaN = new Complex(Double.NaN, Double.NaN);
-    // CHECKSTYLE: resume ConstantName
-    /** A complex number representing "+INF + INFi" */
-    public static final Complex INF = new Complex(Double.POSITIVE_INFINITY, Double.POSITIVE_INFINITY);
-    /** A complex number representing "1.0 + 0.0i" */
-    public static final Complex ONE = new Complex(1.0, 0.0);
-    /** A complex number representing "0.0 + 0.0i" */
-    public static final Complex ZERO = new Complex(0.0, 0.0);
-
-    /** Serializable version identifier */
-    private static final long serialVersionUID = 201701120L;
-
-    /** The imaginary part. */
-    private final double imaginary;
-    /** The real part. */
-    private final double real;
-    /** Record whether this complex number is equal to NaN. */
-    private final transient boolean isNaN;
-    /** Record whether this complex number is infinite. */
-    private final transient boolean isInfinite;
-
-    /**
-     * Create a complex number given only the real part.
-     *
-     * @param real Real part.
-     */
-    public Complex(double real) {
-        this(real, 0.0);
-    }
-
-    /**
-     * Create a complex number given the real and imaginary parts.
-     *
-     * @param real Real part.
-     * @param imaginary Imaginary part.
-     */
-    public Complex(double real, double imaginary) {
-        this.real = real;
-        this.imaginary = imaginary;
-
-        isNaN = Double.isNaN(real) || Double.isNaN(imaginary);
-        isInfinite = !isNaN &&
-            (Double.isInfinite(real) || Double.isInfinite(imaginary));
-    }
-
-    /**
-     * Return the absolute value of this complex number.
-     * Returns {@code NaN} if either real or imaginary part is {@code NaN}
-     * and {@code Double.POSITIVE_INFINITY} if neither part is {@code NaN},
-     * but at least one part is infinite.
-     * This code follows the <a href="http://www.iso-9899.info/wiki/The_Standard">ISO C Standard</a>, Annex G, in calculating the returned value (i.e. the hypot(x,y) method)
-     *
-     * @return the absolute value.
-     */
-    public double abs() {
-        if (isNaN) {
-            return Double.NaN;
-        }
-        if (isInfinite()) {
-            return Double.POSITIVE_INFINITY;
-        }
-        if (Math.abs(real) < Math.abs(imaginary)) {
-            if (imaginary == 0.0) {
-                return Math.abs(real);
-            }
-            double q = real / imaginary;
-            return Math.abs(imaginary) * Math.sqrt(1 + q * q);
-        } else {
-            if (real == 0.0) {
-                return Math.abs(imaginary);
-            }
-            double q = imaginary / real;
-            return Math.abs(real) * Math.sqrt(1 + q * q);
-        }
-    }
-
-    /**
-     * Returns a {@code Complex} whose value is
-     * {@code (this + addend)}.
-     * Uses the definitional formula
-     * <p>
-     *   {@code (a + bi) + (c + di) = (a+c) + (b+d)i}
-     * </p>
-     * If either {@code this} or {@code addend} has a {@code NaN} value in
-     * either part, {@link #NaN} is returned; otherwise {@code Infinite}
-     * and {@code NaN} values are returned in the parts of the result
-     * according to the rules for {@link java.lang.Double} arithmetic.
-     *
-     * @param  addend Value to be added to this {@code Complex}.
-     * @return {@code this + addend}.
-     */
-    public Complex add(Complex addend) {
-        checkNotNull(addend);
-        if (isNaN || addend.isNaN) {
-            return NaN;
-        }
-
-        return createComplex(real + addend.getReal(),
-                             imaginary + addend.getImaginary());
-    }
-
-    /**
-     * Returns a {@code Complex} whose value is {@code (this + addend)},
-     * with {@code addend} interpreted as a real number.
-     *
-     * @param addend Value to be added to this {@code Complex}.
-     * @return {@code this + addend}.
-     * @see #add(Complex)
-     */
-    public Complex add(double addend) {
-        if (isNaN || Double.isNaN(addend)) {
-            return NaN;
-        }
-
-        return createComplex(real + addend, imaginary);
-    }
-
-     /**
-     * Returns the conjugate of this complex number.
-     * The conjugate of {@code a + bi} is {@code a - bi}.
-     * <p>
-     * {@link #NaN} is returned if either the real or imaginary
-     * part of this Complex number equals {@code Double.NaN}.
-     * </p><p>
-     * If the imaginary part is infinite, and the real part is not
-     * {@code NaN}, the returned value has infinite imaginary part
-     * of the opposite sign, e.g. the conjugate of
-     * {@code 1 + POSITIVE_INFINITY i} is {@code 1 - NEGATIVE_INFINITY i}.
-     * </p>
-     * @return the conjugate of this Complex object.
-     */
-    public Complex conjugate() {
-        if (isNaN) {
-            return NaN;
-        }
-
-        return createComplex(real, -imaginary);
-    }
-
-    /**
-     * Returns a {@code Complex} whose value is
-     * {@code (this / divisor)}.
-     * Implements the definitional formula
-     * <pre>
-     *  <code>
-     *    a + bi          ac + bd + (bc - ad)i
-     *    ----------- = -------------------------
-     *    c + di         c<sup>2</sup> + d<sup>2</sup>
-     *  </code>
-     * </pre>
-     * but uses
-     * <a href="http://doi.acm.org/10.1145/1039813.1039814">
-     * prescaling of operands</a> to limit the effects of overflows and
-     * underflows in the computation.
-     * <p>
-     * {@code Infinite} and {@code NaN} values are handled according to the
-     * following rules, applied in the order presented:
-     * <ul>
-     *  <li>If either {@code this} or {@code divisor} has a {@code NaN} value
-     *   in either part, {@link #NaN} is returned.
-     *  </li>
-     *  <li>If {@code divisor} equals {@link #ZERO}, {@link #NaN} is returned.
-     *  </li>
-     *  <li>If {@code this} and {@code divisor} are both infinite,
-     *   {@link #NaN} is returned.
-     *  </li>
-     *  <li>If {@code this} is finite (i.e., has no {@code Infinite} or
-     *   {@code NaN} parts) and {@code divisor} is infinite (one or both parts
-     *   infinite), {@link #ZERO} is returned.
-     *  </li>
-     *  <li>If {@code this} is infinite and {@code divisor} is finite,
-     *   {@code NaN} values are returned in the parts of the result if the
-     *   {@link java.lang.Double} rules applied to the definitional formula
-     *   force {@code NaN} results.
-     *  </li>
-     * </ul>
-     *
-     * @param divisor Value by which this {@code Complex} is to be divided.
-     * @return {@code this / divisor}.
-     */
-    public Complex divide(Complex divisor) {
-        checkNotNull(divisor);
-        if (isNaN || divisor.isNaN) {
-            return NaN;
-        }
-
-        final double c = divisor.getReal();
-        final double d = divisor.getImaginary();
-        if (c == 0.0 && d == 0.0) {
-            return NaN;
-        }
-
-        if (divisor.isInfinite() && !isInfinite()) {
-            return ZERO;
-        }
-
-        if (Math.abs(c) < Math.abs(d)) {
-            double q = c / d;
-            double denominator = c * q + d;
-            return createComplex((real * q + imaginary) / denominator,
-                (imaginary * q - real) / denominator);
-        } else {
-            double q = d / c;
-            double denominator = d * q + c;
-            return createComplex((imaginary * q + real) / denominator,
-                (imaginary - real * q) / denominator);
-        }
-    }
-
-    /**
-     * Returns a {@code Complex} whose value is {@code (this / divisor)},
-     * with {@code divisor} interpreted as a real number.
-     *
-     * @param  divisor Value by which this {@code Complex} is to be divided.
-     * @return {@code this / divisor}.
-     * @see #divide(Complex)
-     */
-    public Complex divide(double divisor) {
-        if (isNaN || Double.isNaN(divisor)) {
-            return NaN;
-        }
-        if (divisor == 0d) {
-            return NaN;
-        }
-        if (Double.isInfinite(divisor)) {
-            return !isInfinite() ? ZERO : NaN;
-        }
-        return createComplex(real / divisor,
-                             imaginary  / divisor);
-    }
-
-    /**
-     * Returns the multiplicative inverse this instance.
-     *
-     * @return {@code 1 / this}.
-     * @see #divide(Complex)
-     */
-    public Complex reciprocal() {
-        if (isNaN) {
-            return NaN;
-        }
-
-        if (real == 0.0 && imaginary == 0.0) {
-            return INF;
-        }
-
-        if (isInfinite) {
-            return ZERO;
-        }
-
-        if (Math.abs(real) < Math.abs(imaginary)) {
-            double q = real / imaginary;
-            double scale = 1. / (real * q + imaginary);
-            return createComplex(scale * q, -scale);
-        } else {
-            double q = imaginary / real;
-            double scale = 1. / (imaginary * q + real);
-            return createComplex(scale, -scale * q);
-        }
-    }
-
-    /**
-     * Test for equality with another object.
-     * If both the real and imaginary parts of two complex numbers
-     * are exactly the same, and neither is {@code Double.NaN}, the two
-     * Complex objects are considered to be equal.
-     * The behavior is the same as for JDK's {@link Double#equals(Object)
-     * Double}:
-     * <ul>
-     *  <li>All {@code NaN} values are considered to be equal,
-     *   i.e, if either (or both) real and imaginary parts of the complex
-     *   number are equal to {@code Double.NaN}, the complex number is equal
-     *   to {@code NaN}.
-     *  </li>
-     *  <li>
-     *   Instances constructed with different representations of zero (i.e.
-     *   either "0" or "-0") are <em>not</em> considered to be equal.
-     *  </li>
-     * </ul>
-     *
-     * @param other Object to test for equality with this instance.
-     * @return {@code true} if the objects are equal, {@code false} if object
-     * is {@code null}, not an instance of {@code Complex}, or not equal to
-     * this instance.
-     */
-    @Override
-    public boolean equals(Object other) {
-        if (this == other) {
-            return true;
-        }
-        if (other instanceof Complex){
-            Complex c = (Complex) other;
-            if (c.isNaN) {
-                return isNaN;
-            } else {
-                return equals(real, c.real) &&
-                    equals(imaginary, c.imaginary);
-            }
-        }
-        return false;
-    }
-
-    /**
-     * Test for the floating-point equality between Complex objects.
-     * It returns {@code true} if both arguments are equal or within the
-     * range of allowed error (inclusive).
-     *
-     * @param x First value (cannot be {@code null}).
-     * @param y Second value (cannot be {@code null}).
-     * @param maxUlps {@code (maxUlps - 1)} is the number of floating point
-     * values between the real (resp. imaginary) parts of {@code x} and
-     * {@code y}.
-     * @return {@code true} if there are fewer than {@code maxUlps} floating
-     * point values between the real (resp. imaginary) parts of {@code x}
-     * and {@code y}.
-     *
-     * @see Precision#equals(double,double,int)
-     */
-    public static boolean equals(Complex x, Complex y, int maxUlps) {
-        return Precision.equals(x.real, y.real, maxUlps) &&
-            Precision.equals(x.imaginary, y.imaginary, maxUlps);
-    }
-
-    /**
-     * Returns {@code true} iff the values are equal as defined by
-     * {@link #equals(Complex,Complex,int) equals(x, y, 1)}.
-     *
-     * @param x First value (cannot be {@code null}).
-     * @param y Second value (cannot be {@code null}).
-     * @return {@code true} if the values are equal.
-     */
-    public static boolean equals(Complex x, Complex y) {
-        return equals(x, y, 1);
-    }
-
-    /**
-     * Returns {@code true} if, both for the real part and for the imaginary
-     * part, there is no double value strictly between the arguments or the
-     * difference between them is within the range of allowed error
-     * (inclusive).  Returns {@code false} if either of the arguments is NaN.
-     *
-     * @param x First value (cannot be {@code null}).
-     * @param y Second value (cannot be {@code null}).
-     * @param eps Amount of allowed absolute error.
-     * @return {@code true} if the values are two adjacent floating point
-     * numbers or they are within range of each other.
-     *
-     * @see Precision#equals(double,double,double)
-     */
-    public static boolean equals(Complex x, Complex y, double eps) {
-        return Precision.equals(x.real, y.real, eps) &&
-            Precision.equals(x.imaginary, y.imaginary, eps);
-    }
-
-    /**
-     * Returns {@code true} if, both for the real part and for the imaginary
-     * part, there is no double value strictly between the arguments or the
-     * relative difference between them is smaller or equal to the given
-     * tolerance. Returns {@code false} if either of the arguments is NaN.
-     *
-     * @param x First value (cannot be {@code null}).
-     * @param y Second value (cannot be {@code null}).
-     * @param eps Amount of allowed relative error.
-     * @return {@code true} if the values are two adjacent floating point
-     * numbers or they are within range of each other.
-     *
-     * @see Precision#equalsWithRelativeTolerance(double,double,double)
-     */
-    public static boolean equalsWithRelativeTolerance(Complex x, Complex y,
-                                                      double eps) {
-        return Precision.equalsWithRelativeTolerance(x.real, y.real, eps) &&
-            Precision.equalsWithRelativeTolerance(x.imaginary, y.imaginary, eps);
-    }
-
-    /**
-     * Get a hashCode for the complex number.
-     * Any {@code Double.NaN} value in real or imaginary part produces
-     * the same hash code {@code 7}.
-     *
-     * @return a hash code value for this object.
-     */
-    @Override
-    public int hashCode() {
-        if (isNaN) {
-            return 7;
-        }
-<<<<<<< HEAD
-        return 37 * 17 * (hash(imaginary) +
-            hash(real));
-    }
-
-    private int hash(double d) {
-        final long v = Double.doubleToLongBits(d);
-        return (int)(v^(v>>>32));
-        //return new Double(d).hashCode();
-=======
-        return 37 * (17 * hash(imaginary) +
-            hash(real));
->>>>>>> eb-test
-    }
-
-    /**
-     * Access the imaginary part.
-     *
-     * @return the imaginary part.
-     */
-    public double getImaginary() {
-        return imaginary;
-    }
-
-    /**
-     * Access the real part.
-     *
-     * @return the real part.
-     */
-    public double getReal() {
-        return real;
-    }
-
-    /**
-     * Checks whether either or both parts of this complex number is
-     * {@code NaN}.
-     *
-     * @return true if either or both parts of this complex number is
-     * {@code NaN}; false otherwise.
-     */
-    public boolean isNaN() {
-        return isNaN;
-    }
-
-    /**
-     * Checks whether either the real or imaginary part of this complex number
-     * takes an infinite value (either {@code Double.POSITIVE_INFINITY} or
-     * {@code Double.NEGATIVE_INFINITY}) and neither part
-     * is {@code NaN}.
-     *
-     * @return true if one or both parts of this complex number are infinite
-     * and neither part is {@code NaN}.
-     */
-    public boolean isInfinite() {
-        return isInfinite;
-    }
-
-    /**
-     * Returns a {@code Complex} whose value is {@code this * factor}.
-     * Implements preliminary checks for {@code NaN} and infinity followed by
-     * the definitional formula:
-     * <p>
-     *   {@code (a + bi)(c + di) = (ac - bd) + (ad + bc)i}
-     * </p>
-     * Returns {@link #NaN} if either {@code this} or {@code factor} has one or
-     * more {@code NaN} parts.
-     * <p>
-     * Returns {@link #INF} if neither {@code this} nor {@code factor} has one
-     * or more {@code NaN} parts and if either {@code this} or {@code factor}
-     * has one or more infinite parts (same result is returned regardless of
-     * the sign of the components).
-     * </p><p>
-     * Returns finite values in components of the result per the definitional
-     * formula in all remaining cases.</p>
-     *
-     * @param  factor value to be multiplied by this {@code Complex}.
-     * @return {@code this * factor}.
-     */
-    public Complex multiply(Complex factor) {
-        checkNotNull(factor);
-        if (isNaN || factor.isNaN) {
-            return NaN;
-        }
-        if (Double.isInfinite(real) ||
-            Double.isInfinite(imaginary) ||
-            Double.isInfinite(factor.real) ||
-            Double.isInfinite(factor.imaginary)) {
-            // we don't use isInfinite() to avoid testing for NaN again
-            return INF;
-        }
-        return createComplex(real * factor.real - imaginary * factor.imaginary,
-                             real * factor.imaginary + imaginary * factor.real);
-    }
-
-    /**
-     * Returns a {@code Complex} whose value is {@code this * factor}, with {@code factor}
-     * interpreted as a integer number.
-     *
-     * @param  factor value to be multiplied by this {@code Complex}.
-     * @return {@code this * factor}.
-     * @see #multiply(Complex)
-     */
-    public Complex multiply(final int factor) {
-        if (isNaN) {
-            return NaN;
-        }
-        if (Double.isInfinite(real) ||
-            Double.isInfinite(imaginary)) {
-            return INF;
-        }
-        return createComplex(real * factor, imaginary * factor);
-    }
-
-    /**
-     * Returns a {@code Complex} whose value is {@code this * factor}, with {@code factor}
-     * interpreted as a real number.
-     *
-     * @param  factor value to be multiplied by this {@code Complex}.
-     * @return {@code this * factor}.
-     * @see #multiply(Complex)
-     */
-    public Complex multiply(double factor) {
-        if (isNaN || Double.isNaN(factor)) {
-            return NaN;
-        }
-        if (Double.isInfinite(real) ||
-            Double.isInfinite(imaginary) ||
-            Double.isInfinite(factor)) {
-            // we don't use isInfinite() to avoid testing for NaN again
-            return INF;
-        }
-        return createComplex(real * factor, imaginary * factor);
-    }
-
-    /**
-     * Returns a {@code Complex} whose value is {@code (-this)}.
-     * Returns {@code NaN} if either real or imaginary
-     * part of this Complex number is {@code Double.NaN}.
-     *
-     * @return {@code -this}.
-     */
-    public Complex negate() {
-        if (isNaN) {
-            return NaN;
-        }
-
-        return createComplex(-real, -imaginary);
-    }
-
-    /**
-     * Returns a {@code Complex} whose value is
-     * {@code (this - subtrahend)}.
-     * Uses the definitional formula
-     * <p>
-     *  {@code (a + bi) - (c + di) = (a-c) + (b-d)i}
-     * </p>
-     * If either {@code this} or {@code subtrahend} has a {@code NaN]} value in either part,
-     * {@link #NaN} is returned; otherwise infinite and {@code NaN} values are
-     * returned in the parts of the result according to the rules for
-     * {@link java.lang.Double} arithmetic.
-     *
-     * @param  subtrahend value to be subtracted from this {@code Complex}.
-     * @return {@code this - subtrahend}.
-     */
-    public Complex subtract(Complex subtrahend) {
-        checkNotNull(subtrahend);
-        if (isNaN || subtrahend.isNaN) {
-            return NaN;
-        }
-
-        return createComplex(real - subtrahend.getReal(),
-                             imaginary - subtrahend.getImaginary());
-    }
-
-    /**
-     * Returns a {@code Complex} whose value is
-     * {@code (this - subtrahend)}.
-     *
-     * @param  subtrahend value to be subtracted from this {@code Complex}.
-     * @return {@code this - subtrahend}.
-     * @see #subtract(Complex)
-     */
-    public Complex subtract(double subtrahend) {
-        if (isNaN || Double.isNaN(subtrahend)) {
-            return NaN;
-        }
-        return createComplex(real - subtrahend, imaginary);
-    }
-
-    /**
-     * Compute the
-     * <a href="http://mathworld.wolfram.com/InverseCosine.html" TARGET="_top">
-     * inverse cosine</a> of this complex number.
-     * Implements the formula:
-     * <p>
-     *  {@code acos(z) = -i (log(z + i (sqrt(1 - z<sup>2</sup>))))}
-     * </p>
-     * Returns {@link Complex#NaN} if either real or imaginary part of the
-     * input argument is {@code NaN} or infinite.
-     *
-     * @return the inverse cosine of this complex number.
-     */
-    public Complex acos() {
-        if (isNaN) {
-            return NaN;
-        }
-
-        return this.add(this.sqrt1z().multiply(I)).log().multiply(I.negate());
-    }
-
-    /**
-     * Compute the
-     * <a href="http://mathworld.wolfram.com/InverseSine.html" TARGET="_top">
-     * inverse sine</a> of this complex number.
-     * Implements the formula:
-     * <p>
-     *  {@code asin(z) = -i (log(sqrt(1 - z<sup>2</sup>) + iz))}
-     * </p><p>
-     * Returns {@link Complex#NaN} if either real or imaginary part of the
-     * input argument is {@code NaN} or infinite.</p>
-     *
-     * @return the inverse sine of this complex number.
-     */
-    public Complex asin() {
-        if (isNaN) {
-            return NaN;
-        }
-
-        return sqrt1z().add(this.multiply(I)).log().multiply(I.negate());
-    }
-
-    /**
-     * Compute the
-     * <a href="http://mathworld.wolfram.com/InverseTangent.html" TARGET="_top">
-     * inverse tangent</a> of this complex number.
-     * Implements the formula:
-     * <p>
-     * {@code atan(z) = (i/2) log((i + z)/(i - z))}
-     * </p><p>
-     * Returns {@link Complex#NaN} if either real or imaginary part of the
-     * input argument is {@code NaN} or infinite.</p>
-     *
-     * @return the inverse tangent of this complex number
-     */
-    public Complex atan() {
-        if (isNaN) {
-            return NaN;
-        }
-
-        return this.add(I).divide(I.subtract(this)).log()
-                .multiply(I.divide(createComplex(2.0, 0.0)));
-    }
-
-    /**
-     * Compute the
-     * <a href="http://mathworld.wolfram.com/Cosine.html" TARGET="_top">
-     * cosine</a> of this complex number.
-     * Implements the formula:
-     * <p>
-     *  {@code cos(a + bi) = cos(a)cosh(b) - sin(a)sinh(b)i}
-     * </p><p>
-     * where the (real) functions on the right-hand side are
-     * {@link Math#sin}, {@link Math#cos},
-     * {@link Math#cosh} and {@link Math#sinh}.
-     * </p><p>
-     * Returns {@link Complex#NaN} if either real or imaginary part of the
-     * input argument is {@code NaN}.
-     * </p><p>
-     * Infinite values in real or imaginary parts of the input may result in
-     * infinite or NaN values returned in parts of the result.</p>
-     * <pre>
-     *  Examples:
-     *  <code>
-     *   cos(1 &plusmn; INFINITY i) = 1 \u2213 INFINITY i
-     *   cos(&plusmn;INFINITY + i) = NaN + NaN i
-     *   cos(&plusmn;INFINITY &plusmn; INFINITY i) = NaN + NaN i
-     *  </code>
-     * </pre>
-     *
-     * @return the cosine of this complex number.
-     */
-    public Complex cos() {
-        if (isNaN) {
-            return NaN;
-        }
-
-        return createComplex(Math.cos(real) * Math.cosh(imaginary),
-                             -Math.sin(real) * Math.sinh(imaginary));
-    }
-
-    /**
-     * Compute the
-     * <a href="http://mathworld.wolfram.com/HyperbolicCosine.html" TARGET="_top">
-     * hyperbolic cosine</a> of this complex number.
-     * Implements the formula:
-     * <pre>
-     *  <code>
-     *   cosh(a + bi) = cosh(a)cos(b) + sinh(a)sin(b)i
-     *  </code>
-     * </pre>
-     * where the (real) functions on the right-hand side are
-     * {@link Math#sin}, {@link Math#cos},
-     * {@link Math#cosh} and {@link Math#sinh}.
-     * <p>
-     * Returns {@link Complex#NaN} if either real or imaginary part of the
-     * input argument is {@code NaN}.
-     * </p>
-     * Infinite values in real or imaginary parts of the input may result in
-     * infinite or NaN values returned in parts of the result.
-     * <pre>
-     *  Examples:
-     *  <code>
-     *   cosh(1 &plusmn; INFINITY i) = NaN + NaN i
-     *   cosh(&plusmn;INFINITY + i) = INFINITY &plusmn; INFINITY i
-     *   cosh(&plusmn;INFINITY &plusmn; INFINITY i) = NaN + NaN i
-     *  </code>
-     * </pre>
-     *
-     * @return the hyperbolic cosine of this complex number.
-     */
-    public Complex cosh() {
-        if (isNaN) {
-            return NaN;
-        }
-
-        return createComplex(Math.cosh(real) * Math.cos(imaginary),
-                             Math.sinh(real) * Math.sin(imaginary));
-    }
-
-    /**
-     * Compute the
-     * <a href="http://mathworld.wolfram.com/ExponentialFunction.html" TARGET="_top">
-     * exponential function</a> of this complex number.
-     * Implements the formula:
-     * <pre>
-     *  <code>
-     *   exp(a + bi) = exp(a)cos(b) + exp(a)sin(b)i
-     *  </code>
-     * </pre>
-     * where the (real) functions on the right-hand side are
-     * {@link Math#exp}, {@link Math#cos}, and
-     * {@link Math#sin}.
-     * <p>
-     * Returns {@link Complex#NaN} if either real or imaginary part of the
-     * input argument is {@code NaN}.
-     * </p>
-     * Infinite values in real or imaginary parts of the input may result in
-     * infinite or NaN values returned in parts of the result.
-     * <pre>
-     *  Examples:
-     *  <code>
-     *   exp(1 &plusmn; INFINITY i) = NaN + NaN i
-     *   exp(INFINITY + i) = INFINITY + INFINITY i
-     *   exp(-INFINITY + i) = 0 + 0i
-     *   exp(&plusmn;INFINITY &plusmn; INFINITY i) = NaN + NaN i
-     *  </code>
-     * </pre>
-     *
-     * @return <code><i>e</i><sup>this</sup></code>.
-     */
-    public Complex exp() {
-        if (isNaN) {
-            return NaN;
-        }
-
-        double expReal = Math.exp(real);
-        return createComplex(expReal *  Math.cos(imaginary),
-                             expReal * Math.sin(imaginary));
-    }
-
-    /**
-     * Compute the
-     * <a href="http://mathworld.wolfram.com/NaturalLogarithm.html" TARGET="_top">
-     * natural logarithm</a> of this complex number.
-     * Implements the formula:
-     * <pre>
-     *  <code>
-     *   log(a + bi) = ln(|a + bi|) + arg(a + bi)i
-     *  </code>
-     * </pre>
-     * where ln on the right hand side is {@link Math#log},
-     * {@code |a + bi|} is the modulus, {@link Complex#abs},  and
-     * {@code arg(a + bi) = }{@link Math#atan2}(b, a).
-     * <p>
-     * Returns {@link Complex#NaN} if either real or imaginary part of the
-     * input argument is {@code NaN}.
-     * </p>
-     * Infinite (or critical) values in real or imaginary parts of the input may
-     * result in infinite or NaN values returned in parts of the result.
-     * <pre>
-     *  Examples:
-     *  <code>
-     *   log(1 &plusmn; INFINITY i) = INFINITY &plusmn; (&pi;/2)i
-     *   log(INFINITY + i) = INFINITY + 0i
-     *   log(-INFINITY + i) = INFINITY + &pi;i
-     *   log(INFINITY &plusmn; INFINITY i) = INFINITY &plusmn; (&pi;/4)i
-     *   log(-INFINITY &plusmn; INFINITY i) = INFINITY &plusmn; (3&pi;/4)i
-     *   log(0 + 0i) = -INFINITY + 0i
-     *  </code>
-     * </pre>
-     *
-     * @return the value <code>ln &nbsp; this</code>, the natural logarithm
-     * of {@code this}.
-     */
-    public Complex log() {
-        if (isNaN) {
-            return NaN;
-        }
-        return createComplex(Math.log(abs()),
-                             Math.atan2(imaginary, real));
-    }
-
-    /**
-     * Returns of value of this complex number raised to the power of {@code x}.
-     * Implements the formula:
-     * <pre>
-     *  <code>
-     *   y<sup>x</sup> = exp(x&middot;log(y))
-     *  </code>
-     * </pre>
-     * where {@code exp} and {@code log} are {@link #exp} and
-     * {@link #log}, respectively.
-     * <p>
-     * Returns {@link Complex#NaN} if either real or imaginary part of the
-     * input argument is {@code NaN} or infinite, or if {@code y}
-     * equals {@link Complex#ZERO}.</p>
-     *
-     * @param  x exponent to which this {@code Complex} is to be raised.
-     * @return <code> this<sup>x</sup></code>.
-     */
-    public Complex pow(Complex x) {
-        checkNotNull(x);
-        if (real == 0 && imaginary == 0) {
-            if (x.real > 0 && x.imaginary == 0) {
-                // 0 raised to positive number is 0
-                return ZERO;
-            } else {
-                // 0 raised to anything else is NaN
-                return NaN;
-            }
-        }
-        return this.log().multiply(x).exp();
-    }
-
-    /**
-     * Returns of value of this complex number raised to the power of {@code x}.
-     *
-     * @param  x exponent to which this {@code Complex} is to be raised.
-     * @return <code>this<sup>x</sup></code>.
-     * @see #pow(Complex)
-     */
-     public Complex pow(double x) {
-        if (real == 0 && imaginary == 0) {
-            if (x > 0) {
-                // 0 raised to positive number is 0
-                return ZERO;
-            } else {
-                // 0 raised to anything else is NaN
-                return NaN;
-            }
-        }
-        return this.log().multiply(x).exp();
-    }
-
-    /**
-     * Compute the
-     * <a href="http://mathworld.wolfram.com/Sine.html" TARGET="_top">
-     * sine</a>
-     * of this complex number.
-     * Implements the formula:
-     * <pre>
-     *  <code>
-     *   sin(a + bi) = sin(a)cosh(b) - cos(a)sinh(b)i
-     *  </code>
-     * </pre>
-     * where the (real) functions on the right-hand side are
-     * {@link Math#sin}, {@link Math#cos},
-     * {@link Math#cosh} and {@link Math#sinh}.
-     * <p>
-     * Returns {@link Complex#NaN} if either real or imaginary part of the
-     * input argument is {@code NaN}.
-     * </p><p>
-     * Infinite values in real or imaginary parts of the input may result in
-     * infinite or {@code NaN} values returned in parts of the result.
-     * <pre>
-     *  Examples:
-     *  <code>
-     *   sin(1 &plusmn; INFINITY i) = 1 &plusmn; INFINITY i
-     *   sin(&plusmn;INFINITY + i) = NaN + NaN i
-     *   sin(&plusmn;INFINITY &plusmn; INFINITY i) = NaN + NaN i
-     *  </code>
-     * </pre>
-     *
-     * @return the sine of this complex number.
-     */
-    public Complex sin() {
-        if (isNaN) {
-            return NaN;
-        }
-
-        return createComplex(Math.sin(real) * Math.cosh(imaginary),
-                             Math.cos(real) * Math.sinh(imaginary));
-    }
-
-    /**
-     * Compute the
-     * <a href="http://mathworld.wolfram.com/HyperbolicSine.html" TARGET="_top">
-     * hyperbolic sine</a> of this complex number.
-     * Implements the formula:
-     * <pre>
-     *  <code>
-     *   sinh(a + bi) = sinh(a)cos(b)) + cosh(a)sin(b)i
-     *  </code>
-     * </pre>
-     * where the (real) functions on the right-hand side are
-     * {@link Math#sin}, {@link Math#cos},
-     * {@link Math#cosh} and {@link Math#sinh}.
-     * <p>
-     * Returns {@link Complex#NaN} if either real or imaginary part of the
-     * input argument is {@code NaN}.
-     * </p><p>
-     * Infinite values in real or imaginary parts of the input may result in
-     * infinite or NaN values returned in parts of the result.
-     * <pre>
-     *  Examples:
-     *  <code>
-     *   sinh(1 &plusmn; INFINITY i) = NaN + NaN i
-     *   sinh(&plusmn;INFINITY + i) = &plusmn; INFINITY + INFINITY i
-     *   sinh(&plusmn;INFINITY &plusmn; INFINITY i) = NaN + NaN i
-     *  </code>
-     * </pre>
-     *
-     * @return the hyperbolic sine of {@code this}.
-     */
-    public Complex sinh() {
-        if (isNaN) {
-            return NaN;
-        }
-
-        return createComplex(Math.sinh(real) * Math.cos(imaginary),
-            Math.cosh(real) * Math.sin(imaginary));
-    }
-
-    /**
-     * Compute the
-     * <a href="http://mathworld.wolfram.com/SquareRoot.html" TARGET="_top">
-     * square root</a> of this complex number.
-     * Implements the following algorithm to compute {@code sqrt(a + bi)}:
-     * <ol><li>Let {@code t = sqrt((|a| + |a + bi|) / 2)}</li>
-     * <li><pre>if {@code  a &#8805; 0} return {@code t + (b/2t)i}
-     *  else return {@code |b|/2t + sign(b)t i }</pre></li>
-     * </ol>
-     * where <ul>
-     * <li>{@code |a| = }{@link Math#abs}(a)</li>
-     * <li>{@code |a + bi| = }{@link Complex#abs}(a + bi)</li>
-     * <li>{@code sign(b) =  }{@link Math#copySign(double,double) copySign(1d, b)}
-     * </ul>
-     * <p>
-     * Returns {@link Complex#NaN} if either real or imaginary part of the
-     * input argument is {@code NaN}.
-     * </p>
-     * Infinite values in real or imaginary parts of the input may result in
-     * infinite or NaN values returned in parts of the result.
-     * <pre>
-     *  Examples:
-     *  <code>
-     *   sqrt(1 &plusmn; INFINITY i) = INFINITY + NaN i
-     *   sqrt(INFINITY + i) = INFINITY + 0i
-     *   sqrt(-INFINITY + i) = 0 + INFINITY i
-     *   sqrt(INFINITY &plusmn; INFINITY i) = INFINITY + NaN i
-     *   sqrt(-INFINITY &plusmn; INFINITY i) = NaN &plusmn; INFINITY i
-     *  </code>
-     * </pre>
-     *
-     * @return the square root of {@code this}.
-     */
-    public Complex sqrt() {
-        if (isNaN) {
-            return NaN;
-        }
-
-        if (real == 0.0 && imaginary == 0.0) {
-            return createComplex(0.0, 0.0);
-        }
-
-        double t = Math.sqrt((Math.abs(real) + abs()) / 2.0);
-        if (real >= 0.0) {
-            return createComplex(t, imaginary / (2.0 * t));
-        } else {
-            return createComplex(Math.abs(imaginary) / (2.0 * t),
-                                 Math.copySign(1d, imaginary) * t);
-        }
-    }
-
-    /**
-     * Compute the
-     * <a href="http://mathworld.wolfram.com/SquareRoot.html" TARGET="_top">
-     * square root</a> of <code>1 - this<sup>2</sup></code> for this complex
-     * number.
-     * Computes the result directly as
-     * {@code sqrt(ONE.subtract(z.multiply(z)))}.
-     * <p>
-     * Returns {@link Complex#NaN} if either real or imaginary part of the
-     * input argument is {@code NaN}.
-     * </p>
-     * Infinite values in real or imaginary parts of the input may result in
-     * infinite or NaN values returned in parts of the result.
-     *
-     * @return the square root of <code>1 - this<sup>2</sup></code>.
-     */
-    public Complex sqrt1z() {
-        return createComplex(1.0, 0.0).subtract(this.multiply(this)).sqrt();
-    }
-
-    /**
-     * Compute the
-     * <a href="http://mathworld.wolfram.com/Tangent.html" TARGET="_top">
-     * tangent</a> of this complex number.
-     * Implements the formula:
-     * <pre>
-     *  <code>
-     *   tan(a + bi) = sin(2a)/(cos(2a)+cosh(2b)) + [sinh(2b)/(cos(2a)+cosh(2b))]i
-     *  </code>
-     * </pre>
-     * where the (real) functions on the right-hand side are
-     * {@link Math#sin}, {@link Math#cos}, {@link Math#cosh} and
-     * {@link Math#sinh}.
-     * <p>
-     * Returns {@link Complex#NaN} if either real or imaginary part of the
-     * input argument is {@code NaN}.
-     * </p>
-     * Infinite (or critical) values in real or imaginary parts of the input may
-     * result in infinite or NaN values returned in parts of the result.
-     * <pre>
-     *  Examples:
-     *  <code>
-     *   tan(a &plusmn; INFINITY i) = 0 &plusmn; i
-     *   tan(&plusmn;INFINITY + bi) = NaN + NaN i
-     *   tan(&plusmn;INFINITY &plusmn; INFINITY i) = NaN + NaN i
-     *   tan(&plusmn;&pi;/2 + 0 i) = &plusmn;INFINITY + NaN i
-     *  </code>
-     * </pre>
-     *
-     * @return the tangent of {@code this}.
-     */
-    public Complex tan() {
-        if (isNaN || Double.isInfinite(real)) {
-            return NaN;
-        }
-        if (imaginary > 20.0) {
-            return createComplex(0.0, 1.0);
-        }
-        if (imaginary < -20.0) {
-            return createComplex(0.0, -1.0);
-        }
-
-        double real2 = 2.0 * real;
-        double imaginary2 = 2.0 * imaginary;
-        double d = Math.cos(real2) + Math.cosh(imaginary2);
-
-        return createComplex(Math.sin(real2) / d,
-                             Math.sinh(imaginary2) / d);
-    }
-
-    /**
-     * Compute the
-     * <a href="http://mathworld.wolfram.com/HyperbolicTangent.html" TARGET="_top">
-     * hyperbolic tangent</a> of this complex number.
-     * Implements the formula:
-     * <pre>
-     *  <code>
-     *   tan(a + bi) = sinh(2a)/(cosh(2a)+cos(2b)) + [sin(2b)/(cosh(2a)+cos(2b))]i
-     *  </code>
-     * </pre>
-     * where the (real) functions on the right-hand side are
-     * {@link Math#sin}, {@link Math#cos}, {@link Math#cosh} and
-     * {@link Math#sinh}.
-     * <p>
-     * Returns {@link Complex#NaN} if either real or imaginary part of the
-     * input argument is {@code NaN}.
-     * </p>
-     * Infinite values in real or imaginary parts of the input may result in
-     * infinite or NaN values returned in parts of the result.
-     * <pre>
-     *  Examples:
-     *  <code>
-     *   tanh(a &plusmn; INFINITY i) = NaN + NaN i
-     *   tanh(&plusmn;INFINITY + bi) = &plusmn;1 + 0 i
-     *   tanh(&plusmn;INFINITY &plusmn; INFINITY i) = NaN + NaN i
-     *   tanh(0 + (&pi;/2)i) = NaN + INFINITY i
-     *  </code>
-     * </pre>
-     *
-     * @return the hyperbolic tangent of {@code this}.
-     */
-    public Complex tanh() {
-        if (isNaN || Double.isInfinite(imaginary)) {
-            return NaN;
-        }
-        if (real > 20.0) {
-            return createComplex(1.0, 0.0);
-        }
-        if (real < -20.0) {
-            return createComplex(-1.0, 0.0);
-        }
-        double real2 = 2.0 * real;
-        double imaginary2 = 2.0 * imaginary;
-        double d = Math.cosh(real2) + Math.cos(imaginary2);
-
-        return createComplex(Math.sinh(real2) / d,
-                             Math.sin(imaginary2) / d);
-    }
-
-
-
-    /**
-     * Compute the argument of this complex number.
-     * The argument is the angle phi between the positive real axis and
-     * the point representing this number in the complex plane.
-     * The value returned is between -PI (not inclusive)
-     * and PI (inclusive), with negative values returned for numbers with
-     * negative imaginary parts.
-     * <p>
-     * If either real or imaginary part (or both) is NaN, NaN is returned.
-     * Infinite parts are handled as {@code Math.atan2} handles them,
-     * essentially treating finite parts as zero in the presence of an
-     * infinite coordinate and returning a multiple of pi/4 depending on
-     * the signs of the infinite parts.
-     * See the javadoc for {@code Math.atan2} for full details.
-     *
-     * @return the argument of {@code this}.
-     */
-    public double getArgument() {
-        return Math.atan2(getImaginary(), getReal());
-    }
-
-    /**
-     * Computes the n-th roots of this complex number.
-     * The nth roots are defined by the formula:
-     * <pre>
-     *  <code>
-     *   z<sub>k</sub> = abs<sup>1/n</sup> (cos(phi + 2&pi;k/n) + i (sin(phi + 2&pi;k/n))
-     *  </code>
-     * </pre>
-     * for <i>{@code k=0, 1, ..., n-1}</i>, where {@code abs} and {@code phi}
-     * are respectively the {@link #abs() modulus} and
-     * {@link #getArgument() argument} of this complex number.
-     * <p>
-     * If one or both parts of this complex number is NaN, a list with just
-     * one element, {@link #NaN} is returned.
-     * if neither part is NaN, but at least one part is infinite, the result
-     * is a one-element list containing {@link #INF}.
-     *
-     * @param n Degree of root.
-     * @return a List of all {@code n}-th roots of {@code this}.
-     */
-    public List<Complex> nthRoot(int n) {
-
-        if (n <= 0) {
-            throw new RuntimeException("cannot compute nth root for null or negative n: {0}");
-        }
-
-        final List<Complex> result = new ArrayList<Complex>();
-
-        if (isNaN) {
-            result.add(NaN);
-            return result;
-        }
-        if (isInfinite()) {
-            result.add(INF);
-            return result;
-        }
-
-        // nth root of abs -- faster / more accurate to use a solver here?
-        final double nthRootOfAbs = Math.pow(abs(), 1.0 / n);
-
-        // Compute nth roots of complex number with k = 0, 1, ... n-1
-        final double nthPhi = getArgument() / n;
-        final double slice = 2 * Math.PI / n;
-        double innerPart = nthPhi;
-        for (int k = 0; k < n ; k++) {
-            // inner part
-            final double realPart = nthRootOfAbs *  Math.cos(innerPart);
-            final double imaginaryPart = nthRootOfAbs *  Math.sin(innerPart);
-            result.add(createComplex(realPart, imaginaryPart));
-            innerPart += slice;
-        }
-
-        return result;
-    }
-
-    /**
-     * Create a complex number given the real and imaginary parts.
-     *
-     * @param realPart Real part.
-     * @param imaginaryPart Imaginary part.
-     * @return a new complex number instance.
-     * @see #valueOf(double, double)
-     */
-    protected Complex createComplex(double realPart,
-                                    double imaginaryPart) {
-        return new Complex(realPart, imaginaryPart);
-    }
-
-    /**
-     * Create a complex number given the real and imaginary parts.
-     *
-     * @param realPart Real part.
-     * @param imaginaryPart Imaginary part.
-     * @return a Complex instance.
-     */
-    public static Complex valueOf(double realPart,
-                                  double imaginaryPart) {
-        if (Double.isNaN(realPart) ||
-            Double.isNaN(imaginaryPart)) {
-            return NaN;
-        }
-        return new Complex(realPart, imaginaryPart);
-    }
-
-    /**
-     * Create a complex number given only the real part.
-     *
-     * @param realPart Real part.
-     * @return a Complex instance.
-     */
-    public static Complex valueOf(double realPart) {
-        if (Double.isNaN(realPart)) {
-            return NaN;
-        }
-        return new Complex(realPart);
-    }
-
-    /**
-     * Resolve the transient fields in a deserialized Complex Object.
-     * Subclasses will need to override {@link #createComplex} to
-     * deserialize properly.
-     *
-     * @return A Complex instance with all fields resolved.
-     */
-    protected final Object readResolve() {
-        return createComplex(real, imaginary);
-    }
-
-    /** {@inheritDoc} */
-    @Override
-    public String toString() {
-        return "(" + real + ", " + imaginary + ")";
-    }
-
-    /**
-     * Checks that an object is not null.
-     *
-     * @param o Object to be checked.
-     */
-    private static void checkNotNull(Object o) {
-        if (o == null) {
-            throw new RuntimeException("Null Argument to Complex Method");
-        }
-    }
-
-    /**
-     * Returns {@code true} if the values are equal according to semantics of
-     * {@link Double#equals(Object)}.
-     *
-     * @param x Value
-     * @param y Value
-     * @return {@code new Double(x).equals(new Double(y))}
-     */
-    private static boolean equals(double x, double y) {
-        return new Double(x).equals(new Double(y));
-    }
-
-    /**
-     * Returns an integer hash code representing the given double value.
-     *
-     * @param value the value to be hashed
-     * @return the hash code
-     */
-    private static int hash(double value) {
-        return new Double(value).hashCode();
-    }
-}