ASA032
the Incomplete Gamma Function

ASA032 is a MATLAB library which evaluates the incomplete Gamma function.

ASA032 is Applied Statistics Algorithm 32. Source code for many Applied Statistics Algorithms is available through STATLIB.

Licensing:

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

Languages:

ASA032 is available in a C version and a C++ version and a FORTRAN77 version and a FORTRAN90 version and a MATLAB version.

Related Data and Programs:

ASA147, a MATLAB library which evaluates the incomplete Gamma function.

ASA239, a MATLAB library which evaluates the incomplete Gamma function.

DCDFLIB, a FORTRAN90 library which evaluates and inverts a number of statistical distributions.

GSL, a C++ library which includes many routines for evaluating probability distributions.

PROB, a MATLAB library which evaluates and inverts a number of probabilistic distributions.

TEST_VALUES, a MATLAB library which contains sample values for a number of distributions.

TOMS435, a FORTRAN77 library which evaluates the modified incomplete Gamma function.

TOMS708, a FORTRAN90 library which includes routines to evaluate the incomplete Gamma function.

Reference:

1. G Bhattacharjee,
   Algorithm AS 32: The Incomplete Gamma Integral,
   Applied Statistics,
   Volume 19, Number 3, 1970, pages 285-287.

Source Code:

• alngam.m computes the logarithm of the gamma function.
• gamain.m computes the incomplete gamma ratio.
• gamma_inc_values.m returns some values of the incomplete Gamma function.
• timestamp.m prints out the current YMDHMS date as a timestamp.

Examples and Tests:

• asa032_test.m, calls all the tests.
• asa032_test01.m, tests GAMAIN.
• asa032_test_output.txt, the output file.

You can go up one level to the MATLAB source codes.