On 2/8/07, Ben Tay <zonexo at gmail.com> wrote: > i'm trying to solve my cfd code using PETSc in parallel. Besides the linear > eqns for PETSc, other parts of the code has also been parallelized using > MPI.
Finite elements or finite differences, or what? > however i find that the parallel version of the code running on 4 processors > is even slower than the sequential version. Can you monitor the convergence and iteration count of momentum and poisson steps? > in order to find out why, i've used the -info option to print out the > details. there are 2 linear equations being solved - momentum and poisson. > the momentum one is twice the size of the poisson. it is shown below: Can you use -log_summary command line option and send the output attached? > i saw some statements stating "seq". am i running in sequential or parallel > mode? have i preallocated too much space? It seems you are running in parallel. The "Seq" are related to local, internal objects. In PETSc, parallel matrices have inner sequential matrices. > lastly, if Ax=b, A_sta and A_end from MatGetOwnershipRange and b_sta and > b_end from VecGetOwnershipRange should always be the same value, right? I should. If not, you are likely going to get an runtime error. Regards, -- Lisandro Dalc?n --------------- Centro Internacional de M?todos Computacionales en Ingenier?a (CIMEC) Instituto de Desarrollo Tecnol?gico para la Industria Qu?mica (INTEC) Consejo Nacional de Investigaciones Cient?ficas y T?cnicas (CONICET) PTLC - G?emes 3450, (3000) Santa Fe, Argentina Tel/Fax: +54-(0)342-451.1594
