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/*
* 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 = -6195664516687396620L;
/** The imaginary part. */
private final double imaginary;
/** The real part. */
private final double real;
/**
* 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;
}
/**
* Creates a Complex from its polar representation.
* <p>
* If either {@code r} or {@code theta} is NaN, or {@code theta} is
* infinite, {@link Complex#NaN} is returned.
* <p>
* If {@code r} is infinite and {@code 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, \(\pi\)) = INFINITY + INFINITY i
* polar2Complex(INFINITY, 0) = INFINITY + NaN i
* polar2Complex(INFINITY, \(-\frac{\pi}{4}\)) = INFINITY - INFINITY i
* polar2Complex(INFINITY, \(5\frac{\pi}{4}\)) = -INFINITY - INFINITY i }
* </pre>
*
* @param r the modulus of the complex number to create
* @param theta the argument of the complex number to create
* @return {@code Complex}
* @since 1.1
*/
public Complex polar(double r, double theta) {
checkNotNegative(r);
return new Complex(r * Math.cos(theta), r * Math.sin(theta));
}
/**
* For a real constructor argument x, returns a new Complex object c
* where {@code c = cos(x) + i sin (x)}
*
* @param x {@code double} to build the cis number
* @return {@code Complex}
*/
public Complex cis(double x) {
return new Complex(Math.cos(x), Math.sin(x));
}
/**
* Returns true if either real or imaginary component of the Complex
* is NaN
*
* @return {@code boolean}
*/
public boolean isNaN() {
if (Double.isNaN(real) || Double.isNaN(imaginary)) {
return true;
} else {
return false;
}
}
/**
* Returns true if either real or imaginary component of the Complex
* is Infinite
*
* @return {@code boolean}
*/
public boolean isInfinite() {
if (Double.isInfinite(real) || Double.isInfinite(imaginary)) {
return true;
} else {
return false;
}
}
/**
* Returns projection of this complex number onto the Riemann sphere,
* i.e. all infinities (including those with an NaN component)
* project onto real infinity, as described in the
* <a href="http://pubs.opengroup.org/onlinepubs/9699919799/functions/cproj.html">
* IEEE and ISO C standards</a>.
* <p>
*
*
* @return {@code Complex} projected onto the Riemann sphere.
*/
public Complex proj() {
if (Double.isInfinite(real) || Double.isInfinite(imaginary)) {
return new Complex(Double.POSITIVE_INFINITY);
} else {
return this;
}
}
/**
* 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 (Math.abs(real) < Math.abs(imaginary)) {
if (imaginary == 0.0) {
return Math.abs(real);
}
final double q = real / imaginary;
return Math.abs(imaginary) * Math.sqrt(1 + q * q);
} else {
if (real == 0.0) {
return Math.abs(imaginary);
}
final double q = imaginary / real;
return Math.abs(real) * Math.sqrt(1 + q * q);
}
}
/**
* Return the norm of this complex number, defined as the square of the magnitude
in the
* <a href="http://pubs.opengroup.org/onlinepubs/9699919799/functions/cproj.html">
* IEEE and ISO C standards</a>.
*
* @return the norm.
*/
public double norm() {
return abs()*abs();
}
/**
* 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>
*
* @param addend Value to be added to this {@code Complex}.
* @return {@code this + addend}.
* @if {@code addend} is {@code null}.
*/
public Complex add(Complex addend) {
checkNotNull(addend);
return new Complex(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) {
return new Complex(real + addend, imaginary);
}
/**
* Returns the conjugate of this complex number.
* The conjugate of {@code a + bi} is {@code a - bi}.
*
* @return the conjugate of this complex object.
*/
public Complex conjugate() {
return new Complex(real, -imaginary);
}
/**
* Returns the conjugate of this complex number.
* C++11 grammar.
* </p>
* @return the conjugate of this complex object.
*/
public Complex conj() {
return conjugate();
}
/**
* 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 {@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}.
* @if {@code divisor} is {@code null}.
*/
public Complex divide(Complex divisor) {
checkNotNull(divisor);
final double c = divisor.getReal();
final double d = divisor.getImaginary();
if (c == 0.0 && d == 0.0) {
return NaN;
}
if ( (Double.isInfinite(c) || Double.isInfinite(d))&& (Double.isInfinite(real) || Double.isInfinite(imaginary))) {
return ZERO;
}
if (Math.abs(c) < Math.abs(d)) {
final double q = c / d;
final double denominator = c * q + d;
return new Complex((real * q + imaginary) / denominator,
(imaginary * q - real) / denominator);
} else {
final double q = d / c;
final double denominator = d * q + c;
return new Complex((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 (divisor == 0d) {
return NaN;
}
if (Double.isInfinite(divisor)) {
return !(Double.isInfinite(real) || Double.isInfinite(imaginary)) ? ZERO : NaN;
}
return new Complex(real / divisor,
imaginary / divisor);
}
/**
* Returns the multiplicative inverse of this instance.
*
* @return {@code 1 / this}.
* @see #divide(Complex)
*/
public Complex reciprocal() {
if (Math.abs(real) < Math.abs(imaginary)) {
final double q = real / imaginary;
final double scale = 1. / (real * q + imaginary);
double scaleQ = 0;
if (q != 0 && scale != 0) {
scaleQ = scale * q;
}
return new Complex(scaleQ, -scale);
} else {
final double q = imaginary / real;
final double scale = 1. / (imaginary * q + real);
double scaleQ = 0;
if (q != 0 && scale != 0) {
scaleQ = scale * q;
}
return new Complex(scale, -scaleQ);
}
}
/**
* 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;
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 (Double.isNaN(real) || Double.isNaN(imaginary)) {
return 7;
}
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();
}
/**
* Access the imaginary part.
*
* @return the imaginary part.
*/
public double getImaginary() {
return imaginary;
}
/**
* Access the imaginary part (C++ grammar)
*
* @return the imaginary part.
*/
public double imag() {
return imaginary;
}
/**
* Access the real part.
*
* @return the real part.
*/
public double getReal() {
return real;
}
/**
* Access the real part (C++ grammar)
*
* @return the real part.
*/
public double real() {
return real;
}
/**
* 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}.
* @if {@code factor} is {@code null}.
*/
public Complex multiply(Complex factor) {
checkNotNull(factor);
return new Complex(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) {
return new Complex(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) {
return new Complex(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() {
return new Complex(-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>
*
* @param subtrahend value to be subtracted from this {@code Complex}.
* @return {@code this - subtrahend}.
*/
public Complex subtract(Complex subtrahend) {
checkNotNull(subtrahend);
return new Complex(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) {
return new Complex(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>
*
* @return the inverse cosine of this complex number.
*/
public Complex acos() {
if (real == 0.0&& Double.isNaN(imaginary)) {
return new Complex(Math.PI * 0.5, Double.NaN);
} else if (neitherInfiniteNorZeroNorNaN(real) && imaginary == Double.POSITIVE_INFINITY) {
return new Complex(Math.PI * 0.5, Double.NEGATIVE_INFINITY);
} else if (real == Double.NEGATIVE_INFINITY && imaginary == 1) {
return new Complex(Math.PI, Double.NEGATIVE_INFINITY);
} else if (real == Double.POSITIVE_INFINITY && imaginary == 1) {
return new Complex(0, Double.NEGATIVE_INFINITY);
} else if (real == Double.NEGATIVE_INFINITY && imaginary == Double.POSITIVE_INFINITY) {
return new Complex(Math.PI * 0.75, Double.NEGATIVE_INFINITY);
} else if (real == Double.POSITIVE_INFINITY && imaginary == Double.POSITIVE_INFINITY) {
return new Complex(Math.PI * 0.25, Double.NEGATIVE_INFINITY);
} else if (real == Double.POSITIVE_INFINITY && Double.isNaN(imaginary)) {
return new Complex(Double.NaN , Double.POSITIVE_INFINITY);
} else if (real == Double.NEGATIVE_INFINITY && Double.isNaN(imaginary)) {
return new Complex(Double.NaN, Double.NEGATIVE_INFINITY);
} else if (Double.isNaN(real) && imaginary == Double.POSITIVE_INFINITY) {
return new Complex(Double.NaN, Double.NEGATIVE_INFINITY);
}
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.
* <p>
* {@code asin(z) = -i (log(sqrt(1 - z<sup>2</sup>) + iz))}
* </p><p>
* @return the inverse sine of this complex number
*/
public Complex asin() {
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>
* @return the inverse tangent of this complex number
*/
public Complex atan() {
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/InverseHyperbolicSine.html" TARGET="_top">
* inverse hyperbolic sine</a> of this complex number.
* Implements the formula:
* <p>
* {@code asinh(z) = log(z+sqrt(z^2+1))}
* </p><p>
* @return the inverse hyperbolic cosine of this complex number
* @since 1.2
*/
public Complex asinh(){
if (neitherInfiniteNorZeroNorNaN(real) && imaginary == Double.POSITIVE_INFINITY) {
return new Complex(Double.POSITIVE_INFINITY, Math.PI * 0.5);
} else if (real == Double.POSITIVE_INFINITY && !Double.isInfinite(imaginary) && !Double.isNaN(imaginary)) {
return new Complex(Double.POSITIVE_INFINITY, 0.0);
} else if (real == Double.POSITIVE_INFINITY && imaginary == Double.POSITIVE_INFINITY) {
return new Complex(Double.POSITIVE_INFINITY, Math.PI * 0.25);
} else if (real == Double.POSITIVE_INFINITY && Double.isNaN(imaginary)) {
return new Complex(Double.POSITIVE_INFINITY, Double.NaN);
} else if (Double.isNaN(real) && imaginary == 0.0) {
return new Complex(Double.NaN, 0.0);
} else if (Double.isNaN(real) && imaginary == Double.POSITIVE_INFINITY) {
return new Complex(Double.POSITIVE_INFINITY, Double.NaN);
}
return square().add(Complex.ONE).sqrt().add(this).log();
}
/**
* Compute the
* <a href="http://mathworld.wolfram.com/InverseHyperbolicTangent.html" TARGET="_top">
* inverse hyperbolic tangent</a> of this complex number.
* Implements the formula:
* <p>
* {@code atanh(z) = log((1+z)/(1-z))/2}
* </p><p>
* @return the inverse hyperbolic cosine of this complex number
* @since 1.2
*/
public Complex atanh(){
if (real == 0.0 && Double.isNaN(imaginary)) {
return new Complex(0, Double.NaN);
} else if (neitherInfiniteNorZeroNorNaN(real) && imaginary == 0.0) {
return new Complex(Double.POSITIVE_INFINITY, 0.0);
} else if (neitherInfiniteNorZeroNorNaN(real) && imaginary == Double.POSITIVE_INFINITY) {
return new Complex(0, Math.PI*0.5);
} else if (real == Double.POSITIVE_INFINITY && neitherInfiniteNorZeroNorNaN(imaginary)) {
return new Complex(0, Math.PI*0.5);
} else if (real == Double.POSITIVE_INFINITY && imaginary == Double.POSITIVE_INFINITY) {
return new Complex(0, Math.PI*0.5);
} else if (real == Double.POSITIVE_INFINITY && Double.isNaN(imaginary)) {
return new Complex(0, Double.NaN);
} else if (Double.isNaN(real) && imaginary == Double.POSITIVE_INFINITY) {
return new Complex(0, Math.PI*0.5);
}
return this.add(Complex.ONE).divide(Complex.ONE.subtract(this)).log().divide(new Complex(2));
}
/**
* Compute the
* <a href="http://mathworld.wolfram.com/InverseHyperbolicCosine.html" TARGET="_top">
* inverse hyperbolic cosine</a> of this complex number.
* Implements the formula:
* <p>
* {@code acosh(z) = log(z+sqrt(z^2-1))}
* </p><p>
* @return the inverse hyperbolic cosine of this complex number
* @since 1.2
*/
public Complex acosh() {
return square().subtract(Complex.ONE).sqrt().add(this).log();
}
/**
* Compute the square of this complex number.
*
* @return square of this complex number
*/
public Complex square(){
return this.multiply(this);
}
/**
* 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>
*
* @return the cosine of this complex number.
*/
public Complex cos() {
return new Complex(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>
*
* @return the hyperbolic cosine of this complex number.
*/
public Complex cosh() {
if (real == 0.0&& imaginary == Double.POSITIVE_INFINITY) {
return new Complex(Double.NaN, 0.0);
} else if (real == 0.0&& Double.isNaN(imaginary)) {
return new Complex(Double.NaN, 0.0);
} else if (real == Double.POSITIVE_INFINITY && imaginary == 0.0) {
return new Complex(Double.POSITIVE_INFINITY, 0.0);
} else if (real == Double.POSITIVE_INFINITY && imaginary == Double.POSITIVE_INFINITY) {
return new Complex(Double.POSITIVE_INFINITY, Double.NaN);
} else if (real == Double.POSITIVE_INFINITY && Double.isNaN(imaginary)) {
return new Complex(Double.POSITIVE_INFINITY, Double.NaN);
} else if (Double.isNaN(real) && imaginary == 0.0) {
return new Complex(Double.NaN, 0.0);
}
return new Complex(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}.
*
* @return <code><i>e</i><sup>this</sup></code>.
*/
public Complex exp() {
if (real == Double.POSITIVE_INFINITY && imaginary == 0.0) {
return new Complex(Double.POSITIVE_INFINITY, 0.0);
} else if (real == Double.NEGATIVE_INFINITY && imaginary == Double.POSITIVE_INFINITY) {
return Complex.ZERO;
} else if (real == Double.POSITIVE_INFINITY && imaginary == Double.POSITIVE_INFINITY) {
return new Complex(Double.POSITIVE_INFINITY, Double.NaN);
} else if (real == Double.NEGATIVE_INFINITY && Double.isNaN(imaginary)) {
return Complex.ZERO;
} else if (real == Double.POSITIVE_INFINITY && Double.isNaN(imaginary)) {
return new Complex(Double.POSITIVE_INFINITY, Double.NaN);
} else if (Double.isNaN(real) && imaginary == 0.0) {
return new Complex(Double.NaN, 0.0);
}
double expReal = Math.exp(real);
return new Complex(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).
*
* @return the value <code>ln &nbsp; this</code>, the natural logarithm
* of {@code this}.
*/
public Complex log() {
if (real == Double.POSITIVE_INFINITY && imaginary == Double.POSITIVE_INFINITY) {
return new Complex(Double.POSITIVE_INFINITY, Math.PI * 0.25);
} else if (real == Double.POSITIVE_INFINITY && Double.isNaN(imaginary)) {
return new Complex(Double.POSITIVE_INFINITY, Double.NaN);
} else if (Double.isNaN(real) && imaginary == Double.POSITIVE_INFINITY) {
return new Complex(Double.POSITIVE_INFINITY, Double.NaN);
}
return new Complex(Math.log(abs()),
Math.atan2(imaginary, real));
}
/**
* Compute the base 10 or
* <a href="http://mathworld.wolfram.com/CommonLogarithm.html" TARGET="_top">
* common logarithm</a> of this complex number.
*
* @return the base 10 logarithm of <code>this</code>.
*/
public Complex log10() {
return new Complex(Math.log(abs())/Math.log(10),
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.
*
* @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 == 0.0&& imaginary == 0.0) {
if (x.real > 0 && x.imaginary == 0.0) {
// 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 == 0.0&& imaginary == 0.0) {
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}.
*
* @return the sine of this complex number.
*/
public Complex sin() {
return new Complex(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}.
*
* @return the hyperbolic sine of {@code this}.
*/
public Complex sinh() {
if (real == 0.0&& imaginary == 0.0) {
return Complex.ZERO;
} else if (real == 0.0&& imaginary == Double.POSITIVE_INFINITY) {
return new Complex(0, Double.NaN);
} else if (real == 0.0&& Double.isNaN(imaginary)) {
return new Complex(0, Double.NaN);
} else if (real == Double.POSITIVE_INFINITY && imaginary == 0.0) {
return new Complex(Double.POSITIVE_INFINITY, 0.0);
} else if (real == Double.POSITIVE_INFINITY && imaginary == Double.POSITIVE_INFINITY) {
return new Complex(Double.POSITIVE_INFINITY, Double.NaN);
} else if (real == Double.POSITIVE_INFINITY && Double.isNaN(imaginary)) {
return new Complex(Double.POSITIVE_INFINITY, Double.NaN);
} else if (Double.isNaN(real) && imaginary == 0.0) {
return new Complex(Double.NaN, 0.0);
}
return new Complex(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>
*
* @return the square root of {@code this}.
*/
public Complex sqrt() {
if (real == 0.0 && imaginary == 0.0) {
return new Complex(0.0, 0.0);
} else if (neitherInfiniteNorZeroNorNaN(real) && imaginary == Double.POSITIVE_INFINITY) {
return new Complex(Double.POSITIVE_INFINITY, Double.POSITIVE_INFINITY);
} else if (real == Double.NEGATIVE_INFINITY && neitherInfiniteNorZeroNorNaN(imaginary)) {
return new Complex(0.0, Double.NaN);
} else if (real == Double.NEGATIVE_INFINITY && Double.isNaN(imaginary)) {
return new Complex(Double.NaN, Double.POSITIVE_INFINITY);
} else if (real == Double.POSITIVE_INFINITY && Double.isNaN(imaginary)) {
return new Complex(Double.POSITIVE_INFINITY, Double.NaN);
}
final double t = Math.sqrt((Math.abs(real) + abs()) / 2.0);
if (real >= 0.0) {
return new Complex(t, imaginary / (2.0 * t));
} else {
return new Complex(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)))}.
*
* @return the square root of <code>1 - this<sup>2</sup></code>.
*/
public Complex sqrt1z() {
return new Complex(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}.
*
* @return the tangent of {@code this}.
*/
public Complex tan() {
if (imaginary > 20.0) {
return new Complex(0.0, 1.0);
}
if (imaginary < -20.0) {
return new Complex(0.0, -1.0);
}
final double real2 = 2.0 * real;
final double imaginary2 = 2.0 * imaginary;
final double d = Math.cos(real2) + Math.cosh(imaginary2);
return new Complex(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}.
*
* @return the hyperbolic tangent of {@code this}.
*/
public Complex tanh() {
if (real == Double.POSITIVE_INFINITY && imaginary == Double.POSITIVE_INFINITY) {
return new Complex(1.0, 0.0);
} else if (real == Double.POSITIVE_INFINITY && Double.isNaN(imaginary)) {
return new Complex(1.0, 0.0);
} else if (Double.isNaN(real) && imaginary == 0) {
return new Complex(Double.NaN, 0);
}
final double real2 = 2.0 * real;
final double imaginary2 = 2.0 * imaginary;
final double d = Math.cosh(real2) + Math.cos(imaginary2);
return new Complex(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());
}
/**
* Compute the argument of this complex number.
* C++11 syntax
*
* @return the argument of {@code this}.
*/
public double arg() {
return getArgument();
}
/**
* 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>();
// 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) {
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) {
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 new Complex(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");
}
}
/**
* Check that the argument is positive and throw a RuntimeException
* if it is not.
* @param arg {@code int} to check
*/
private static void checkNotNegative(int arg) {
if (arg <= 0) {
throw new RuntimeException("Complex: Non-positive argument");
}
}
/**
* Check that the argument is positive and throw a RuntimeException
* if it is not.
* @param arg {@code double} to check
*/
private static void checkNotNegative(double arg) {
if (arg <= 0) {
throw new RuntimeException("Complex: Non-positive argument");
}
}
/**
* 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));
}
private static boolean neitherInfiniteNorZeroNorNaN(double d) {
if (!Double.isNaN(d) && !Double.isInfinite(d) && d != 0) {
return true;
} else return false;
}
}