B b @s4dZddlZdZdZdZddZdd Zd d ZdS) zwPython implementation of chisqprob, to avoid SciPy dependency. Adapted from SciPy: scipy/special/cephes/{chdtr,igam}. NgHz>g0Cg 0 df : array_like or float, probably int >= 1 Returns ------- chisqprob : ndarray The area from ``chisq`` to infinity under the Chi^2 probability distribution with degrees of freedom ``df``. rg?gz Domain error.g?) ValueError_igam_igamc)xZdfr3lib/python3.7/site-packages/Bio/codonalign/chisq.py chisqprobsrcCst|t||t|}d|}||d}d}d}|}|d}||} || } x|d7}|d7}|d7}||} |||| } | ||| } | dkr| | }t| ||}|} nd}|}| }| }| } t| tkr|t9}|t9}|t9}| t9} |tkr\| |Sq\WdS)aComplemented incomplete Gamma integral (PRIVATE). Parameters ---------- a: float x: float Returns ------- float Notes ----- The function is defined by:: igamc(a,x) = 1 - igam(a,x) inf. - 1 | | -t a-1 = ----- | e t dt. - | | | (a) - x In this implementation both arguments must be positive. The integral is evaluated by either a power series or continued fraction expansion, depending on the relative values of a and x. g?gg@rN)mathexploglgammaabsBIGBIGINVMACHEP)araxyzcZpkm2Zqkm2Zpkm1Zqkm1ansZycZpkZqkrtrrrr-s@!" rcCslt|t||t|}|}d}d}x8|d7}|||9}||7}||tkr0|||Sq0WdS)zLeft tail of incomplete Gamma function (PRIVATE). Computes this formula:: inf. k a -x - x x e > ---------- - - k=0 | (a+k+1) g?N)r r r r r)rrrrrrrrrrss "  r)__doc__r rrrrrrrrrrsF