matrix assembling time

[Yixun Liu]

Hi,
Using PETSc the assembling time for a mesh with 6000 vertices  is about
14 second parallelized on 4 processors, but another sequential program
based on gmm lib is about 0.6 second. PETSc's solver is much faster than
gmm, but I don't know why its assembling is so slow although I have
preallocate an enough space for the matrix.

MatMPIAIJSetPreallocation(sparseMeshMechanicalStiffnessMatrix, 1000,
PETSC_NULL, 1000, PETSC_NULL);

Yixun