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 on this subject. Your advice will be welcome. > > *---------------------------------------------------------------------------* > > * 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 | * *---------------------------------------------------------------------------*