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problem running demo in parallel

0 votes

I'm trying to understand how to run a FEniCS program in parallel. I tried running the Cahn-Hilliard demo with mpirun -np 2 demo_cahn-hilliard.py and obtained the error

Number of global vertices: 9409
Number of global cells: 18432
Traceback (most recent call last):
Traceback (most recent call last):
  File "demo_cahn-hilliard.py", line 115, in <module>
    solver.solve(problem, u.vector())
RuntimeError: 

*** -------------------------------------------------------------------------
*** DOLFIN encountered an error. If you are not able to resolve this issue
*** using the information listed below, you can ask for help at
***
***     fenics@fenicsproject.org
***
*** Remember to include the error message listed below and, if possible,
*** include a *minimal* running example to reproduce the error.
***
*** -------------------------------------------------------------------------
*** Error:   Unable to solve linear system using PETSc LU solver.
*** Reason:  No suitable solver for parallel LU found. Consider configuring PETSc with MUMPS or SuperLU_dist.
*** Where:   This error was encountered inside PETScLUSolver.cpp.
*** Process: unknown
*** 
*** DOLFIN version: 1.4.0
*** Git changeset:  3b6582dfb45139c906c13b9ad57395632a2090f4
*** -------------------------------------------------------------------------

  File "demo_cahn-hilliard.py", line 115, in <module>
    solver.solve(problem, u.vector())
RuntimeError: 

*** -------------------------------------------------------------------------
*** DOLFIN encountered an error. If you are not able to resolve this issue
*** using the information listed below, you can ask for help at
***
***     fenics@fenicsproject.org
***
*** Remember to include the error message listed below and, if possible,
*** include a *minimal* running example to reproduce the error.
***
*** -------------------------------------------------------------------------
*** Error:   Unable to solve linear system using PETSc LU solver.
*** Reason:  No suitable solver for parallel LU found. Consider configuring PETSc with MUMPS or SuperLU_dist.
*** Where:   This error was encountered inside PETScLUSolver.cpp.
*** Process: unknown
*** 
*** DOLFIN version: 1.4.0
*** Git changeset:  3b6582dfb45139c906c13b9ad57395632a2090f4
*** -------------------------------------------------------------------------

--------------------------------------------------------------------------
mpirun noticed that the job aborted, but has no info as to the process
that caused that situation.
--------------------------------------------------------------------------

I'm having trouble solving this error, though I'm guessing there is an easy fix. Let me add that if I run the demo with mpirun -np 1 demo_cahn-hilliard.py, it works fine.

asked Nov 21, 2014 by bseguin FEniCS Novice (650 points)

1 Answer

+1 vote

You are running it correctly, but you do not seem to have a parallel LU solver, like the message says. See your available solvers with list_lu_solver_methods()

answered Nov 21, 2014 by mikael-mortensen FEniCS Expert (29,340 points)

Thanks a lot. How do I go about installing a parallel solver? Even pointing me in the direction of a source I could look at would be great.

commented Nov 21, 2014 by bseguin FEniCS Novice (650 points)

http://fenicsproject.org/download/

commented Nov 21, 2014 by mikael-mortensen FEniCS Expert (29,340 points)

Thanks for your prompt reply, but it leaves me a little puzzled. I already have FEniCS installed (using a binary package). Do I need to install it from the source instead to obtain the parallel solvers?

commented Nov 21, 2014 by bseguin FEniCS Novice (650 points)
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