Hi everyone, I have developed a code for thrombosis modeling, which involves a lot of Advection-Diffusion-Reaction (ADR) equations under influence of flow. For the Navier-Stokes calculations I use the Oasis solver, the rest of the model is implemented in a problem specific function. For solving the…

Maybe take a look at this tread: [image] Mumps in parallel slower than in serial Hey, I had a similar problem which is due to petsc (or in particular its mumps solver) using thread parallelism via OpenMP. Let us say your PC has n threads available. Then, when you run y…

I added the ‘export OMP_NUM_THREADS = 1’ line to my .bashrc. Indeed the parallel simulations are not that much slower anymore, but certainly not much faster. Any idea what the reason for this might be?

Hi, Consider using an iterative solver+preconditioner when running at parallel for better results if you are not doing it already. You can change the default direct lu solver inside NonlinearVariationalSolver like this: solver = NonlinearVariationalSolver(problem) solver.parameters["newton_solve…

I already defined my solver as following: # Define jacobian J_P = derivative(F_P, cp, dcp) # Create the Newton solver problem = NonlinearVariationalProblem(F_P, cp, bccp, J_P) pap_solver = NonlinearVariationalSolver(problem) solverType = 'newton' #solverType = 'snes' # PETSc SNES has some more op…

Try locating the part of the problem that consumes the most computational time using: list_timings() You can also solve a simpler benchmark nonlinear problem (like nonlinear poisson) just to be sure that this is not a problem caused by available cores/threads (although @kamensky covered this).

Running in parallel slower than serial?

kamensky October 3, 2019, 1:47pm 2

Maybe take a look at this tread:

Topic		Replies	Views
Mumps in parallel slower than in serial	1	3608	April 24, 2019
Assembling in Parallel and Solving in Serial Linear Algebra	4	1664	October 16, 2019
Parallel Solver is Slow Linear Algebra	5	1474	August 25, 2019
How can I run my code in parallel? General mpi	1	102	June 18, 2024
Conspicuous speed ups in parallel computing General	1	449	September 12, 2023

Running in parallel slower than serial?

Related topics