Ada matrix package

Question

Hi, I'm in search for a free package that do most matrix/vector operations. I can write some basic functions myself but for advanced ones like computing eigenvalues and eigenvectors I would prefer robust code and I would like to know if such packages are freely available. If I understand correctly Ada 2005 have more matrix operations facilities but it has a function to calculate the eigenvalues for a symmetric and hermitian matrices only. I'll need a more general packages which can handle any kind of matrix.

An Ada95 matrix package (54KB tar.gz file) from Drexel Fusion Laboratory had the link: http://dflwww.ece.drexel.edu/research/ada/ but the page for this ink is non-existent today.

Thanks a lot...

Answer 1

I think that the Ada95 package you mean is here -- but it's only 35k, and it seems to have less functionality than the Ada2005 standard library does.

Not sure how this Ada95 binding to BLAS came to be in my browser cache! I see that for general matrix solving you need LAPACK too, I wonder whether the bindings already in GNAT will help? Package System.Generic_Real_LAPACK in file s-gerela.ad[bs]. The comments say

--  LAPACK Computational Routines

--  gerfs  Refines the solution of a system of linear equations with
--         a general matrix and estimates its error
--  getrf  Computes LU factorization of a general m-by-n matrix
--  getri  Computes inverse of an LU-factored general matrix
--         square matrix, with multiple right-hand sides
--  getrs  Solves a system of linear equations with an LU-factored
--         square matrix, with multiple right-hand sides
--  orgtr  Generates the Float orthogonal matrix Q determined by sytrd
--  steqr  Computes all eigenvalues and eigenvectors of a symmetric or
--         Hermitian matrix reduced to tridiagonal form (QR algorithm)
--  sterf  Computes all eigenvalues of a Float symmetric
--         tridiagonal matrix using QR algorithm
--  sytrd  Reduces a Float symmetric matrix to tridiagonal form

which I suspect is a small subset of the full library. Still, could act as a useful springboard for more extensive bindings.

Answer 2

As suggested in John Barnes Rationale for Ada 2005, Ada's Annex G: Numerics is not intended "as a substitute for professional libraries such as the renowned BLAS," but nothing precludes an implementation from using BLAS internally. As a concrete example, the GNAT compiler implements both G.3.1 Real Vectors and Matrices and G.3.2 Complex Vectors and Matrices using BLAS and LAPACK. To see the details, you can examine the relevant package bodies:

$ export ADA_INC = /your/path/to/adinclude
$ view $ADA_INC/$(gnatkr Ada.Numerics.Generic_Real_Arrays.adb)
$ view $ADA_INC/$(gnatkr Ada.Numerics.Generic_Complex_Arrays.adb)