Package Bio :: Package CodonAlign :: Module chisq
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Module chisq

source code

Python implementation of chisqprob, to avoid SciPy dependency.

Adapted from SciPy: scipy/special/cephes/{chdtr,igam}.c

Functions [hide private]
 
chisqprob(x, df)
Probability value (1-tail) for the Chi^2 probability distribution.
source code
 
_igamc(a, x)
Complemented incomplete Gamma integral.
source code
 
_igam(a, x)
Left tail of incomplete Gamma function:
source code
Variables [hide private]
  MACHEP = 1e-07
  BIG = 4.50359962737e+15
  BIGINV = 2.22044604925e-16
  __package__ = 'Bio.CodonAlign'
Function Details [hide private]

chisqprob(x, df)

source code 

Probability value (1-tail) for the Chi^2 probability distribution.

Broadcasting rules apply.

Parameters
----------
x : array_like or float > 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`.

_igamc(a, x)

source code 
Complemented incomplete Gamma integral.

SYNOPSIS:

double a, x, y, igamc();

y = igamc( a, x );

DESCRIPTION:

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.

_igam(a, x)

source code 
Left tail of incomplete Gamma function:

        inf.      k
 a  -x   -       x
x  e     >   ----------
         -     -
        k=0   | (a+k+1)