Dirichlet Mixture Estimation

GETWGT is a FORTRAN90 library which handles Dirichlet Mixture estimation.

The main requirement in the design of this library was that there be a single routine with a simple interface through which the user interacts. This routine, called getwgt(), accepts a set of nucleic acid counts, updates an internal Dirichlet mixture model, and returns its current estimate for the pseudocounts. All other transactions and information are hidden from the user.

The program requires a data file, containing the parameters of the Dirichlet density distributions that make up the mixture. This file needs to be named weights.txt. Two files are provided here as possible sources of this data. These files were obtained from the UCSC computational biology page, where more information, papers, and data is available.


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


GETWGT is available in a FORTRAN90 version.

Related Data and Programs:

ASA266, a FORTRAN90 library which evaluates various properties of a Dirichlet distribution.

BDMLIB, a FORTRAN90 library which estimates the weights in a Dirichlet mixture based on sample data;


  1. William Cody, Kenneth Hillstrom,
    Chebyshev Approximations for the Natural Logarithm of the Gamma Function, Mathematics of Computation,
    Volume 21, Number 98, April 1967, pages 198-203.
  2. Brian Everitt, David Hand,
    Finite Mixture Distributions,
    Chapman and Hall, 1981.
  3. Kenneth Lange,
    Mathematical and Statistical Methods for Genetic Analysis,
    Springer, 1997,
    ISBN: 0387953892,
    LC: QH438.4.M33.L36.
  4. AFM Smith, Udi Makov,
    A Quasi-Bayes Sequential Procedure for Mixtures,
    Journal of the Royal Statistical Society,
    Volume 40, Number 1, B, 1978, pages 106-112.

Source code:

Examples and Tests:

List of Routines:

You can go up one level to the FORTRAN90 source codes.

Last revised on 16 July 2013.