public BigComplex Sqrt(MathContext mc)
{
BigDecimal half = new BigDecimal(2);
/* compute l=sqrt(re^2+im^2), then u=sqrt((l+re)/2)
* and v= +- sqrt((l-re)/2 as the new real and imaginary parts.
*/
BigDecimal l = Abs(mc);
if (l.CompareTo(BigDecimal.Zero) == 0)
{
return(new BigComplex(BigMath.ScalePrecision(BigDecimal.Zero, mc),
BigMath.ScalePrecision(BigDecimal.Zero, mc)));
}
BigDecimal u = BigMath.Sqrt(l.Add(Real).Divide(half, mc), mc);
BigDecimal v = BigMath.Sqrt(l.Subtract(Real).Divide(half, mc), mc);
if (Imaginary.CompareTo(BigDecimal.Zero) >= 0)
{
return(new BigComplex(u, v));
}
else
{
return(new BigComplex(u, v.Negate()));
}
}
public BigComplex Multiply(BigComplex oth, MathContext mc)
{
BigDecimal a = Real.Add(Imaginary).Multiply(oth.Real);
BigDecimal b = oth.Real.Add(oth.Imaginary).Multiply(Imaginary);
BigDecimal c = oth.Imaginary.Subtract(oth.Real).Multiply(Real);
BigDecimal x = a.Subtract(b, mc);
BigDecimal y = a.Add(c, mc);
return(new BigComplex(x, y));
}
public void SubtractBigDecimal()
{
BigDecimal sub1 = BigDecimal.Parse("13948");
BigDecimal sub2 = BigDecimal.Parse("2839.489");
BigDecimal result = sub1.Subtract(sub2);
Assert.IsTrue(result.ToString().Equals("11108.511") && result.Scale == 3, "13948 - 2839.489 is wrong: " + result);
BigDecimal result2 = sub2.Subtract(sub1);
Assert.IsTrue(result2.ToString().Equals("-11108.511") && result2.Scale == 3, "2839.489 - 13948 is wrong");
Assert.IsTrue(result.Equals(result2.Negate()), "13948 - 2839.489 is not the negative of 2839.489 - 13948");
sub1 = new BigDecimal(value, 1);
sub2 = BigDecimal.Parse("0");
result = sub1.Subtract(sub2);
Assert.IsTrue(result.Equals(sub1), "1234590.8 - 0 is wrong");
sub1 = new BigDecimal(1.234E-03);
sub2 = new BigDecimal(3.423E-10);
result = sub1.Subtract(sub2);
Assert.IsTrue(result.ToDouble() == 0.0012339996577, "1.234E-03 - 3.423E-10 is wrong, " + result.ToDouble());
sub1 = new BigDecimal(1234.0123);
sub2 = new BigDecimal(1234.0123000);
result = sub1.Subtract(sub2);
Assert.IsTrue(result.ToDouble() == 0.0, "1234.0123 - 1234.0123000 is wrong, " + result.ToDouble());
}
