How can I set the linear solver to MUMPS in dolfin 1.5?

Question

Hello

I need to set the linear solver to MUMPS. I try to use

prm = solver.parameters
prm['linear_solver']='mumps'

but I received the error

*** Error:   Unable to solve linear system.
*** Reason:  Unknown solver method "mumps". Use list_linear_solver_methods() to list available methods.

How is the right way to set it? I'm using DOLFIN 1.5.

Best regard
Valentina

johannr · Answer 1 · Jun 16, 2015

This should work:

solver.parameters["linear_solver"] = "mumps"

Are you sure mumps is available on your installation of FEniCS? Try list_linear_solver_methods() to see what is available.

>>> list_linear_solver_methods()
Solver method  |  Description                                                 
------------------------------------------------------------------------------
default        |  default linear solver                                       
umfpack        |  UMFPACK (Unsymmetric MultiFrontal sparse LU factorization)  
mumps          |  MUMPS (MUltifrontal Massively Parallel Sparse direct Solver)
superlu_dist   |  Parallel SuperLU                                            
petsc          |  PETSc built in LU solver                                    
cg             |  Conjugate gradient method                                   
gmres          |  Generalized minimal residual method                         
minres         |  Minimal residual method                                     
tfqmr          |  Transpose-free quasi-minimal residual method                
richardson     |  Richardson method                                           
bicgstab       |  Biconjugate gradient stabilized method

answered Jun 16, 2015 by johannr FEniCS Expert (17,350 points)

I try list_linear_solver_methods() and I discover that mumps is not available on my installation. What have I to do to solve this problem?
I've Dolfin 1.5 on mac os 10.10 (yosemite).

Thank you for the answer!

commented Jun 16, 2015 by ValeS FEniCS Novice (330 points)

The problem is that OS X does not come with a Fortran compiler, which is needed to build PETSc with MUMPS. If you installed FEniCS using the fenics-install.sh script, then you can try the superlu_dist as an alternative to mumps. The FEniCS binary package does not have superlu_dist.

commented Jun 16, 2015 by johannr FEniCS Expert (17,350 points)

Thank you but I didn't install fenics with the fenics-install.sh so i can't try the superlu_dist.

commented Jun 16, 2015 by ValeS FEniCS Novice (330 points)

Is there a way to set the solver to MUMPS in C++? I cannot find any reference to this...

commented Jun 17, 2015 by senseiwa FEniCS User (2,620 points)

@senseiwa:

solver.parameters["linear_solver"] = "mumps";

commented Jun 18, 2015 by johannr FEniCS Expert (17,350 points)

Unfortunately, it won't work. This is the C++ code:

// Solver
PETScLUSolver solver;
solver.parameters["linear_solver"] = "mumps";

and the error says I cannot use that:

*** Error:   Unable to access parameter.
*** Reason:  Parameter "petsc_lu_solver.linear_solver" not defined.
*** Where:   This error was encountered inside Parameters.cpp.

commented Jun 25, 2015 by senseiwa FEniCS User (2,620 points)

How can I set the linear solver to MUMPS in dolfin 1.5?

1 Answer