scipy.special.gdtr

scipy.special.gdtr(x1, x2, x3[, out]) = <ufunc 'gdtr'>

y=gdtr(a,b,x) returns the integral from zero to x of the gamma probability density function: a**b / gamma(b) * integral(t**(b-1) exp(-at),t=0..x). The arguments a and b are used differently here than in other definitions.