ASA103 The Digamma or Psi Function

ASA103 is a Python library which evaluates the digamma or psi function, by Jose Bernardo.

ASA103 is Applied Statistics Algorithm 103. Source code for many Applied Statistics Algorithms is available through STATLIB.

Languages:

ASA103 is available in a C version and a C++ version and a FORTRAN90 version and a MATLAB version and a Python version.

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Author:

Original FORTRAN77 version by Jose Bernardo; Python version by John Burkardt.

Reference:

1. Jose Bernardo,
Algorithm AS 103: Psi ( Digamma ) Function,
Applied Statistics,
Volume 25, Number 3, 1976, pages 315-317.

Source Code:

• digamma.py calculates DIGAMMA ( X ) = d ( LOG ( GAMMA ( X ) ) ) / dX
• psi_values.py returns some values of the Psi or Digamma function for testing.
• timestamp.py prints out the current YMDHMS date as a timestamp.

Examples and Tests:

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

Last revised on 17 March 2016.