[petsc-users] [PETSc-Users] The MatSetValues takes too much time

[Dongyu Liu via petsc-users]

Hi,

I am using PETSc sparse matrix ('aij') for a FEM program, when the 
matrix is really big, let's say 1million by 1million, we use setValues 
based on the index vector I and J, but the whole process takes around 2 
hours.

I don't know why it is like that, or is there any option that I should 
set to make this faster?


Best,

Dongyu