/**
* Calculates {@link BigComplex} x to the power of <code>long</code> y (x<sup>y</sup>).
*
* <p>The implementation tries to minimize the number of multiplications of {@link BigComplex x} (using squares whenever possible).</p>
*
* <p>See: <a href="https://en.wikipedia.org/wiki/Exponentiation#Efficient_computation_with_integer_exponents">Wikipedia: Exponentiation - efficient computation</a></p>
*
* @param x the {@link BigComplex} value to take to the power
* @param y the <code>long</code> value to serve as exponent
* @param mathContext the {@link MathContext} used for the result
* @return the calculated x to the power of y with the precision specified in the <code>mathContext</code>
*/
public static BigComplex pow(this BigComplex x, long y, MathContext mathContext)
{
MathContext mc = new MathContext(mathContext.getPrecision() + 10, mathContext.getRoundingMode());
if (y < 0)
{
return(BigComplex.ONE.divide(pow(x, -y, mc), mc).round(mathContext));
}
BigComplex result = BigComplex.ONE;
while (y > 0)
{
if ((y & 1) == 1)
{
// odd exponent -> multiply result with x
result = result.multiply(x, mc);
y -= 1;
}
if (y > 0)
{
// even exponent -> square x
x = x.multiply(x, mc);
}
y >>= 1;
}
return(result.round(mathContext));
}
public void Parse()
{
string expected = "3 + 4i";
string expected004 = "3";
string test001 = "(3, 4)";
string test002 = "3 + 4i";
string test003 = "(3 + 4i) ";
string test004 = "3";
BigComplex bc001 = BigComplex.Parse(test001);
BigComplex bc002 = BigComplex.Parse(test002);
BigComplex bc003 = BigComplex.Parse(test003);
BigComplex bc004 = BigComplex.Parse(test004);
string actual001 = bc001.ToString();
string actual002 = bc002.ToString();
string actual003 = bc003.ToString();
string actual004 = bc004.ToString();
Assert.AreEqual(expected, actual001, $"{test001} => {actual001}");
Assert.AreEqual(expected, actual002, $"{test002} => {actual002}");
Assert.AreEqual(expected, actual003, $"{test003} => {actual003}");
Assert.AreEqual(expected004, actual004, $"{test004} => {actual004}");
}
/**
* Calculates the cosine (cosinus) of {@link BigComplex} x in the complex domain.
*
* @param x the {@link BigComplex} to calculate the cosine for
* @param mathContext the {@link MathContext} used for the result
* @return the calculated cosine {@link BigComplex} with the precision specified in the <code>mathContext</code>
*/
public static BigComplex cos(this BigComplex x, MathContext mathContext)
{
MathContext mc = new MathContext(mathContext.getPrecision() + 4, mathContext.getRoundingMode());
return(BigComplex.valueOf(
BigDecimalMath.cos(x.re, mc).multiply(BigDecimalMath.cosh(x.im, mc), mc).round(mathContext),
BigDecimalMath.sin(x.re, mc).multiply(BigDecimalMath.sinh(x.im, mc), mc).negate().round(mathContext)));
}
/**
* Calculates the natural exponent of {@link BigComplex} x (e<sup>x</sup>) in the complex domain.
*
* <p>See: <a href="https://en.wikipedia.org/wiki/Exponential_function#Complex_plane">Wikipedia: Exponent (Complex plane)</a></p>
*
* @param x the {@link BigComplex} to calculate the exponent for
* @param mathContext the {@link MathContext} used for the result
* @return the calculated exponent {@link BigComplex} with the precision specified in the <code>mathContext</code>
*/
public static BigComplex exp(this BigComplex x, MathContext mathContext)
{
MathContext mc = new MathContext(mathContext.getPrecision() + 4, mathContext.getRoundingMode());
BigDecimal expRe = BigDecimalMath.exp(x.re, mc);
return(BigComplex.valueOf(
expRe.multiply(BigDecimalMath.cos(x.im, mc), mc).round(mathContext),
expRe.multiply(BigDecimalMath.sin(x.im, mc), mc)).round(mathContext));
}
/**
* Calculates the natural logarithm of {@link BigComplex} x in the complex domain.
*
* <p>See: <a href="https://en.wikipedia.org/wiki/Complex_logarithm">Wikipedia: Complex logarithm</a></p>
*
* @param x the {@link BigComplex} to calculate the natural logarithm for
* @param mathContext the {@link MathContext} used for the result
* @return the calculated natural logarithm {@link BigComplex} with the precision specified in the <code>mathContext</code>
*/
public static BigComplex log(this BigComplex x, MathContext mathContext)
{
// https://en.wikipedia.org/wiki/Complex_logarithm
MathContext mc1 = new MathContext(mathContext.getPrecision() + 20, mathContext.getRoundingMode());
MathContext mc2 = new MathContext(mathContext.getPrecision() + 5, mathContext.getRoundingMode());
return(BigComplex.valueOf(
BigDecimalMath.log(x.abs(mc1), mc1).round(mathContext),
x.angle(mc2)).round(mathContext));
}
/**
* Calculates {@link BigComplex} x to the power of {@link BigDecimal} y (x<sup>y</sup>).
*
* @param x the {@link BigComplex} value to take to the power
* @param y the {@link BigDecimal} value to serve as exponent
* @param mathContext the {@link MathContext} used for the result
* @return the calculated x to the power of y with the precision specified in the <code>mathContext</code>
*/
public static BigComplex pow(this BigComplex x, BigDecimal y, MathContext mathContext)
{
MathContext mc = new MathContext(mathContext.getPrecision() + 4, mathContext.getRoundingMode());
BigDecimal angleTimesN = x.angle(mc).multiply(y, mc);
return(BigComplex.valueOf(
BigDecimalMath.cos(angleTimesN, mc),
BigDecimalMath.sin(angleTimesN, mc)).multiply(BigDecimalMath.pow(x.abs(mc), y, mc), mc).round(mathContext));
}
/**
* Calculates the square root of {@link BigComplex} x in the complex domain (√x).
*
* <p>See <a href="https://en.wikipedia.org/wiki/Square_root#Square_root_of_an_imaginary_number">Wikipedia: Square root (Square root of an imaginary number)</a></p>
*
* @param x the {@link BigComplex} to calculate the square root for
* @param mathContext the {@link MathContext} used for the result
* @return the calculated square root {@link BigComplex} with the precision specified in the <code>mathContext</code>
*/
public static BigComplex sqrt(this BigComplex x, MathContext mathContext)
{
// https://math.stackexchange.com/questions/44406/how-do-i-get-the-square-root-of-a-complex-number
MathContext mc = new MathContext(mathContext.getPrecision() + 4, mathContext.getRoundingMode());
BigDecimal magnitude = x.abs(mc);
BigComplex a = x.add(magnitude, mc);
return(a.divide(a.abs(mc), mc).multiply(BigDecimalMath.sqrt(magnitude, mc), mc).round(mathContext));
}
public void TestReciprocal()
{
var expected = "0 - 1i";
BigComplex low = BigComplex.Parse("0 + 1i");
var result = BigComplex.Reciprocal(low);
var actual = result.ToString();
string description = $"{low} => {expected}";
TestContext.WriteLine(description);
Assert.AreEqual(expected, actual, description);
}
public void TestAbs001()
{
var expected = "5";
BigComplex low = BigComplex.Parse("4 + 3i");
var result = BigComplex.Abs(low);
var actual = result.ToString();
string description = $"{low} => {expected}";
TestContext.WriteLine(description);
Assert.AreEqual(expected, actual, description);
}
public void TestMultiply()
{
var expected = "-44 + 106i";
BigComplex low = BigComplex.Parse("3 + 13i");
BigComplex high = BigComplex.Parse("7 + 5i");
var result = high * low;
var actual = result.ToString();
string description = $"{low} * {high} => {expected}";
TestContext.WriteLine(description);
Assert.AreEqual(expected, actual, description);
}
public void TestDivide()
{
var expected = "2";
BigComplex low = BigComplex.Parse("3 + 2i");
BigComplex high = BigComplex.Parse("6 + 4i");
var result = high / low;
var actual = result.ToString();
string description = $"{high} / {low} => {expected}";
TestContext.WriteLine(description);
Assert.AreEqual(expected, actual, description);
}
/**
* Calculates the arc cosine (inverted cosine) of {@link BigComplex} x in the complex domain.
*
* <p>See: <a href="https://en.wikipedia.org/wiki/Inverse_trigonometric_functions#Extension_to_complex_plane">Wikipedia: Inverse trigonometric functions (Extension to complex plane)</a></p>
*
* @param x the {@link BigComplex} to calculate the arc cosine for
* @param mathContext the {@link MathContext} used for the result
* @return the calculated arc cosine {@link BigComplex} with the precision specified in the <code>mathContext</code>
*/
public static BigComplex acos(this BigComplex x, MathContext mathContext)
{
MathContext mc = new MathContext(mathContext.getPrecision() + 4, mathContext.getRoundingMode());
return(I.negate().multiply(log(x.add(sqrt(x.multiply(x, mc).subtract(BigComplex.ONE, mc), mc), mc), mc), mc).round(mathContext));
}
/**
* Calculates the angle in radians of the given complex number using the specified {@link MathContext}.
*
* @param x the complex number to calculate the angle
* @param mathContext the {@link MathContext} used to calculate the result
* @return the calculated {@link BigComplex} angle in radians
* @see BigComplex#angle(MathContext)
*/
public static BigDecimal angle(this BigComplex x, MathContext mathContext)
{
return(x.angle(mathContext));
}
/**
* Calculates the {@link BigComplex} n'th root of {@link BigComplex} x (<sup>n</sup>√x).
*
* <p>See <a href="http://en.wikipedia.org/wiki/Square_root">Wikipedia: Square root</a></p>
* @param x the {@link BigComplex} value to calculate the n'th root
* @param n the {@link BigComplex} defining the root
* @param mathContext the {@link MathContext} used for the result
*
* @return the calculated n'th root of x with the precision specified in the <code>mathContext</code>
*/
public static BigComplex root(this BigComplex x, BigComplex n, MathContext mathContext)
{
MathContext mc = new MathContext(mathContext.getPrecision() + 4, mathContext.getRoundingMode());
return(pow(x, BigComplex.ONE.divide(n, mc), mc).round(mathContext));
}
/**
* Calculates {@link BigComplex} x to the power of {@link BigComplex} y (x<sup>y</sup>).
*
* @param x the {@link BigComplex} value to take to the power
* @param y the {@link BigComplex} value to serve as exponent
* @param mathContext the {@link MathContext} used for the result
* @return the calculated x to the power of y with the precision specified in the <code>mathContext</code>
*/
public static BigComplex pow(this BigComplex x, BigComplex y, MathContext mathContext)
{
MathContext mc = new MathContext(mathContext.getPrecision() + 4, mathContext.getRoundingMode());
return(exp(y.multiply(log(x, mc), mc), mc).round(mathContext));
}
/**
* Calculates the conjugate of the given complex number using the specified {@link MathContext}.
*
* @param x the complex number to calculate the conjugate
* @return the calculated {@link BigComplex} result
* @see BigComplex#conjugate()
*/
public static BigComplex conjugate(this BigComplex x)
{
return(x.conjugate());
}
/**
* Calculates the arc cotangens (inverted cotangens) of {@link BigComplex} x in the complex domain.
*
* <p>See: <a href="https://en.wikipedia.org/wiki/Inverse_trigonometric_functions#Extension_to_complex_plane">Wikipedia: Inverse trigonometric functions (Extension to complex plane)</a></p>
*
* @param x the {@link BigComplex} to calculate the arc cotangens for
* @param mathContext the {@link MathContext} used for the result
* @return the calculated arc cotangens {@link BigComplex} with the precision specified in the <code>mathContext</code>
*/
public static BigComplex acot(this BigComplex x, MathContext mathContext)
{
MathContext mc = new MathContext(mathContext.getPrecision() + 4, mathContext.getRoundingMode());
return(log(x.add(I, mc).divide(x.subtract(I, mc), mc), mc).divide(I, mc).divide(TWO, mc).round(mathContext));
}
/**
* Calculates the reciprocal of the given complex number using the specified {@link MathContext}.
*
* @param x the complex number to calculate the reciprocal
* @param mathContext the {@link MathContext} used to calculate the result
* @return the calculated {@link BigComplex} result
* @see BigComplex#reciprocal(MathContext)
*/
public static BigComplex reciprocal(this BigComplex x, MathContext mathContext)
{
return(x.reciprocal(mathContext));
}
//
// http://scipp.ucsc.edu/~haber/archives/physics116A10/arc_10.pdf
/**
* Calculates the tangens of {@link BigComplex} x in the complex domain.
*
* @param x the {@link BigComplex} to calculate the tangens for
* @param mathContext the {@link MathContext} used for the result
* @return the calculated tangens {@link BigComplex} with the precision specified in the <code>mathContext</code>
*/
public static BigComplex tan(this BigComplex x, MathContext mathContext)
{
MathContext mc = new MathContext(mathContext.getPrecision() + 4, mathContext.getRoundingMode());
return(sin(x, mc).divide(cos(x, mc), mc).round(mathContext));
}
