[petsc-users] Performance of mumps vs. Intel Pardiso

[Faraz Hussain]

>Mumps uses parmetis or scotch for parallel symbolic factorization. For sequential symbolic >factorization, it has several matrix orderings, which you can experiment with the option >'-mat_mumps_icntl_7 <>'.
> I doubt any of these ordering would match the performance of Pardiso.


Thanks, I have been experimenting with the different ordering options in Mumps. So far I have not seen any speed difference among them. Do you feel Pardiso ordering is so superior to result in 2X increase in speed? I find this hard to believe since my problem is fairly classic and can't imagine why a 10+ year old algorithm would be so much better than what's available today.


> Again, how large is your matrix? How do you run Pardiso in parallel? Can you use Pardiso on large matrices as mumps?



My matrix is 3million^2 with max 1000 non-zeroes per line. Pardiso supports multi-thread, so I just do export OMP_NUM_THREADS=24 to use all available cpus . When running Petsc/Mumps I have to do export OMP_NUM_THREADS=1, otherwise I get very weird cpu utilization. Perhaps that has something to do with the speed difference?