jburkardt

ASA121\ The Trigamma Function {#asa121-the-trigamma-function align=”center”} =====================

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ASA121 is a C++ library which evaluates the trigamma function, by BE Schneider.

ASA121 is Applied Statistics Algorithm 121. Source code for many Applied Statistics Algorithms is available through STATLIB.

Licensing: {#licensing align=”center”}

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

Languages: {#languages align=”center”}

ASA121 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: {#related-data-and-programs align=”center”}

ASA103, a C++ library which evaluates the digamma function.

TEST_VALUES, a C++ library which contains sample values for a number of special functions.

Author: {#author align=”center”}

Original FORTRAN77 version by BE Schneider; C++ version by John Burkardt.

Reference: {#reference align=”center”}

1. BE Schneider,\ Algorithm AS 121: Trigamma Function,\ Applied Statistics,\ Volume 27, Number 1, 1978, pages 97-99.

Source Code: {#source-code align=”center”}

• asa121.cpp, the source code.
• asa121.hpp, the include file.

Examples and Tests: {#examples-and-tests align=”center”}

• asa121_prb.cpp, a sample calling program.
• asa121_prb_output.txt, the output file.

List of Routines: {#list-of-routines align=”center”}

• TIMESTAMP prints out the current YMDHMS date as a timestamp.
• TRIGAM calculates trigamma(x) = d**2 log(gamma(x)) / dx**2
• TRIGAMMA_VALUES returns some values of the TriGamma function.

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

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Last revised on 19 January 2008.