asa007

asa007, a Fortran90 code which computes the inverse of a symmetric positive definite (SPD) matrix, by Michael Healy.

The code is a version of Applied Statistics Algorithm 7.

The algorithm implemented here uses a compressed storage for both the matrix A and the factor U. This saves some storage, but can make computations a little awkward.

Licensing:

The information on this web page is distributed under the MIT license.

Languages:

asa007 is available in a C version and a C++ version and a Fortran90 version and a MATLAB version and an Octave version and a Python version.

Related Data and Programs:

asa007_test

asa006, a Fortran90 code which computes the Cholesky factorization of a symmetric positive definite (SPD) matrix. A version of this routine is used by ASA007.

asa047, a Fortran90 code which implements the Nelder-Mead minimization algorithm, and uses a version of asa007() for the computation.

lapack_test, a Fortran90 code which demonstrates the use of the lapack() linear algebra library.

Author:

Original Fortran77 version by Michael Healy. This version by John Burkardt.

Reference:

1. Michael Healy,
   Algorithm AS 7: Inversion of a Positive Semi-Definite Symmetric Matrix,
   Applied Statistics,
   Volume 17, Number 2, 1968, pages 198-199.

Source Code:

• asa007.f90, the source code.
• asa007.sh, compiles the source code.