       Re: Q: Exponential or inversion of sparse matrices

• To: mathgroup at christensen.cybernetics.net
• Subject: [mg1929] Re: Q: Exponential or inversion of sparse matrices
• From: galand at cephag.observ-gr.fr (Marina Galand)
• Date: Wed, 23 Aug 1995 22:31:20 -0400

```I am looking for a mathematica fortran or C library corresponding
to my problem, that is concerning operations on sparse matrices.

I need help on the calculation of the exponential
of sparse matrices or at least on the inversion of sparse
matrices. I am looking for fortran or C library dealing with
sparse matrices and that computes the exponential or the inversion.

Recently I developed a method calculate the exponential
of a sparse matrix. I wrote it in a m-file under Matlab.
Now that I have validated it under Matlab, I would like to
use it on hudge sparse matrix. Matlab is not adapted to this,
being much too slow and restricted for memory. Therefore I want to
translate my m-file into a language which can be compiled
such as C or Fortran. The problem is that my algorithm performs
the inversion of a sparse matrix and I do not find a routine
in a fortran or C library to invert a sparse matrix.
In the libraries for sparse matrices I have just found routines
for the solution of a linear system :
routine resolving a linear system A.bj=cj, vector bj being the unknown
and c being a vector of zeros except at row j. Then the result bj
represents the column j of A^(-1). But you must apply the routine
a large number of times, the number of column of A... Is it realistic ?

I will be very pleased if you could answer me and help me

> > *---------------------------------------------------------------------------*
> > *    Marina Galand                      |                                   *
> > *    CEPHAG - ENSIEG                    |   Tel (33) 76 82 62 66            *
> > *    Rue de la Houille Blanche - BP 46  |   				    *
> > *    38402  Saint Martin d'Heres Cedex  |   Fax (33) 76 82 63 84            *
> > *    FRANCE                             | 				    *
> > *---------------------------------------------------------------------------*
> >
>

--

*---------------------------------------------------------------------------*
*    Marina Galand                      |                                   *
*    CEPHAG - ENSIEG                    |   Tel (33) 76 82 62 66            *
*    Rue de la Houille Blanche - BP 46  |   				    *
*    38402  Saint Martin d'Heres Cedex  |   Fax (33) 76 82 63 84            *
*    FRANCE                             | 				    *
*---------------------------------------------------------------------------*

```

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