scipy.special.gammaln

scipy.special.gammaln(x)

Logarithm of the absolute value of the Gamma function for real inputs.

Parameters:

x : array-like

Values on the real line at which to compute gammaln

Returns:

gammaln : ndarray

Values of gammaln at x.

See also

gammasgn

sign of the gamma function

loggamma

principal branch of the logarithm of the gamma function

Notes

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.

For complex-valued log-gamma, use loggamma instead of gammaln.