Petsc Wrong Results

Arwa_Wadhane · April 13, 2022, 04:16

I m calling Petsc (conjugate gradient algorithm) in my code, when I run it with mpiexec -n 8 ,it gives wrong results. and when I run it with mpiexec -n 1 it gives good results .can someone help me please?

dlahaye · April 18, 2022, 12:18

I imagine PETSc (beware of spelling) solver setting to be the culprit here.

With increase in subdomains, the preconditioned becomes less effective.

Run with output of PETSc convergence history on and increase accuracy of linear solver.

Get in touch here in case you would like more input.

April 13, 2022, 04:16	Petsc Wrong Results	#1
Arwa_Wadhane New Member Arwa wadhane Join Date: Apr 2022 Posts: 1 Rep Power: 0	I m calling Petsc (conjugate gradient algorithm) in my code, when I run it with mpiexec -n 8 ,it gives wrong results. and when I run it with mpiexec -n 1 it gives good results .can someone help me please?

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April 18, 2022, 12:18		#2
dlahaye Senior Member Domenico Lahaye Join Date: Dec 2013 Posts: 723 Blog Entries: 1 Rep Power: 17	I imagine PETSc (beware of spelling) solver setting to be the culprit here. With increase in subdomains, the preconditioned becomes less effective. Run with output of PETSc convergence history on and increase accuracy of linear solver. Get in touch here in case you would like more input.