This is documentation for an old release of SciPy (version 0.10.0). Read this page Search for this page in the documentation of the latest stable release (version 1.15.1).

scipy.special.gammainc

scipy.special.gammainc(x1, x2[, out]) = <ufunc 'gammainc'>

y=gammainc(a,x) returns the incomplete gamma integral defined as 1 / gamma(a) * integral(exp(-t) * t**(a-1), t=0..x). a must be positive and x must be >= 0.