Logarithm of the absolute value of the Gamma function for real inputs.
x : array-like
Values on the real line at which to compute gammaln
gammaln : ndarray
Values of gammaln at x.
When used in conjunction with gammasgn, this function is useful for working in logspace on the real axis without having to deal with complex numbers, via the relation exp(gammaln(x)) = gammasgn(x)*gamma(x).
Note that gammaln currently accepts complex-valued inputs, but it is not the same function as for real-valued inputs, and the branch is not well-defined — using gammaln with complex is deprecated and will be disallowed in future Scipy versions.