ASA147
the Incomplete Gamma Function

ASA147 is a C++ library which evaluates the incomplete Gamma function.

ASA147 is Applied Statistics Algorithm 147. 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:

ASA147 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:

ASA032, a C++ library which evaluates the incomplete Gamma function.

ASA239, a C++ library which evaluates the incomplete Gamma function.

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

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

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

TEST_VALUES, a C++ 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. Chi Leung Lau,
   Algorithm AS 147: A Simple Series for the Incomplete Gamma Integral,
   Applied Statistics,
   Volume 29, Number 1, 1980, pages 113-114.

Source Code:

• asa147.cpp, the source code.
• asa147.hpp, the include file.
• asa147.sh, commands to compile the source code.

Examples and Tests:

• asa147_prb.cpp, a sample calling program.
• asa147_prb.sh, commands to compile and run the sample program.
• asa147_prb_output.txt, the output file.

List of Routines:

• ALNGAM computes the logarithm of the gamma function.
• GAMMA_INC_VALUES returns some values of the incomplete Gamma function.
• GAMMDS computes the incomplete Gamma integral.
• TIMESTAMP prints out the current YMDHMS date as a timestamp.

You can go up one level to the C++ source codes.