public static ScalarValue Psi(int n, ScalarValue z)
{
if (n < 0)
{
throw new YAMPArgumentRangeException("n", 0.0);
}
if (z.Re <= 0.0 && z.Im == 0)
{
return(ScalarValue.RealInfinity);
}
if (n == 0)
{
return(Psi0(z));
}
else if (n == 1)
{
return(Psi1(z));
}
var hzeta = HzetaFunction.HurwitzZeta(n + 1.0, z);
var ln_nf = Helpers.Factorial(n);
var result = hzeta * ln_nf;
if (n % 2 == 0)
{
result = -result;
}
Helpers.Factorial(1);
return(result);
}
public static double Psi(int n, double x)
{
if (n < 0)
{
throw new YAMPArgumentRangeException("n", 0.0);
}
if (x <= 0.0)
{
throw new YAMPArgumentRangeException("x", 0.0);
}
if (n == 0)
{
return(Gamma.Psi(x));
}
else if (n == 1)
{
return(Psi1(x));
}
var hzeta = HzetaFunction.HurwitzZeta(n + 1.0, x);
var ln_nf = Helpers.Factorial(n);
var result = hzeta * ln_nf;
if (n % 2 == 0)
{
result = -result;
}
Helpers.Factorial(1);
return(result);
}
static ScalarValue PsiXgt0(int n, ScalarValue z)
{
if (n == 0)
{
return(Psi0(z));
}
/* Abramowitz + Stegun 6.4.10 */
var hzeta = HzetaFunction.HurwitzZeta(n + 1.0, z);
var ln_nf = Helpers.Factorial(n);
var result = hzeta * ln_nf;
if (n % 2 == 0)
{
result = -result;
}
return(result);
}
static double PsiXgt0(int n, double x)
{
if (n == 0)
{
return(Gamma.Psi(x));
}
/* Abramowitz + Stegun 6.4.10 */
var hzeta = HzetaFunction.HurwitzZeta(n + 1.0, x);
var ln_nf = Helpers.Factorial(n);
var result = hzeta * ln_nf;
if (n % 2 == 0)
{
result = -result;
}
return(result);
}