Paul : Is your matrix A dense or sparse? Petsc is a powerful tool for solving Ax=b with sparse matrix A. When A is dense, petsc supports wrapper to LAPACK (sequential) and PLAPACK (parallel).
I would suggest read petsc user manual, and test ~petsc/src/ksp/ksp/examples/tutorials/ex1.c, ex2.c ... then replace matrix and rhs vector with yours. Hong > > I am attempting to solve a large, dense equation system. I would like to try > using the BiCGSTAB algorithm, and specifically, the petsc library, as it is > open source and seems to be well supported. I take it petsc is primarily > aimed at people solving partial differential equations by 'brute force' type > methods. In my case, I would like to either > 1) supply my A and b in Ax = b, and have a library solve it (LU factorization > from LAPACK works, but it's slow) or > 2) supply matrix products A times a vector (this is what is used internally > in BiCGSTAB), the right hand side > If necessary, I have a decent idea for a solution guess for the first > iteration. > > So my questions are: > 1) Is it feasible, and reasonably convenient, to use petsc for this purpose? > 2) If so, is there a good example/tutorial/pseudocode somewhere online, or on > the mailinglist, for my use case? I have been reading the petsc examples, but > they are somewhat tough to follow for a complete petsc beginner. Also, they > seem to apply primarily to PDE solving. > > I am using the Fortran 90/95 language. > > Best regards > Paul > >
