ASA239
the Incomplete Gamma Function

ASA239 is a MATLAB program, using double precision arithmetic, which evaluates the incomplete Gamma function.

ASA239 is Applied Statistics Algorithm 239. Source code for many Applied Statistics Algorithms is available through STATLIB.

Related Data and Programs:

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

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

ASA239 is also available in a C++ version and a FORTRAN77 version and a FORTRAN90 version.

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. B Shea,
   Algorithm AS 239: Chi-squared and Incomplete Gamma Integral,
   Applied Statistics,
   Volume 37, Number 3, 1988, pages 466-473.

Source Code:

• alngam.m computes the logarithm of the gamma function.
• alnorm.m computes the cumulative density of the standard normal distribution.
• gammad.m computes the Incomplete Gamma Integral
• 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:

• asa239_test.m, a sample calling program.
• asa239_test01.m, tests GAMMAD.
• asa239_test_output.txt, the output file.

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