digamma

fun digamma(argX: Double): Double

Computes the digamma function Mark Johnson, 2nd September 2007

Computes the Ψ(x) or digamma function, i.e., the derivative of the log gamma function, using a series expansion.

http://www.cog.brown.edu/~mj/code/digamma.c

Return

the function value

Parameters

argX

the value to evaluate