ASA032
the Incomplete Gamma Function

ASA032 is a MATLAB program, using double precision arithmetic, which evaluates the incomplete Gamma function.

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

Related Data and Programs:

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

ASA147 is a FORTRAN77 library which evaluates the incomplete Gamma function.

ASA239 is a FORTRAN77 library which evaluates the incomplete Gamma function.

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

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

PROB is a FORTRAN90 library which evaluates and inverts a number of probabilistic distributions.

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

TOMS435 is 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.