[petsc-users] Iterative solver behavior with increasing number of mpi

[Marian Greg]

Hi All,

I am facing strange behavior of the ksp solvers with increasing number of
MPI. The solver is taking more and more iterations with increase in number
of MPIs. Is that a normal situation? I was expecting to get the same number
of iteration with whatever number of MPIs I use.

E.g.
My matrix has about 2 million dofs
Solving with np 1 takes about 3500 iteration while solving with np 4 takes
6500 iterations for the same convergence criteria.

Thanks
Mari
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