scipy.special.gdtrix#
- scipy.special.gdtrix(a, b, p, out=None) = <ufunc 'gdtrix'>#
- Inverse of - gdtrvs x.- Returns the inverse with respect to the parameter x of - p = gdtr(a, b, x), the cumulative distribution function of the gamma distribution. This is also known as the pth quantile of the distribution.- Parameters:
- aarray_like
- a parameter values of - gdtr(a, b, x).- 1/ais the “scale” parameter of the gamma distribution.
- barray_like
- b parameter values of - gdtr(a, b, x). b is the “shape” parameter of the gamma distribution.
- parray_like
- Probability values. 
- outndarray, optional
- If a fourth argument is given, it must be a numpy.ndarray whose size matches the broadcast result of a, b and x. out is then the array returned by the function. 
 
- Returns:
- xscalar or ndarray
- Values of the x parameter such that p = gdtr(a, b, x). 
 
 - See also - Notes - Wrapper for the CDFLIB [1] Fortran routine cdfgam. - The cumulative distribution function p is computed using a routine by DiDinato and Morris [2]. Computation of x involves a search for a value that produces the desired value of p. The search relies on the monotonicity of p with x. - References [1]- Barry Brown, James Lovato, and Kathy Russell, CDFLIB: Library of Fortran Routines for Cumulative Distribution Functions, Inverses, and Other Parameters. [2]- DiDinato, A. R. and Morris, A. H., Computation of the incomplete gamma function ratios and their inverse. ACM Trans. Math. Softw. 12 (1986), 377-393. - Examples - First evaluate - gdtr.- >>> from scipy.special import gdtr, gdtrix >>> p = gdtr(1.2, 3.4, 5.6) >>> print(p) 0.94378087442 - Verify the inverse. - >>> gdtrix(1.2, 3.4, p) 5.5999999999999996