[petsc-users] Can't expand MemType 1: jcol 16104

[Anthony Paul Haas]

Hi Jose,

In my code, I use once PETSc to solve a linear system to get the baseflow
(without using SLEPc) and then I use SLEPc to do the stability analysis of
that baseflow. This is why, there are some SLEPc options that are not used
in test.out-superlu_dist-151x151 (when I am solving for the baseflow with
PETSc only). I have attached a 101x101 case for which I get the
eigenvalues. That case works fine. However If i increase to 151x151, I get
the error that you can see in test.out-superlu_dist-151x151 (similar error
with mumps: see test.out-mumps-151x151 line 2918 ). If you look a the very
end of the files test.out-superlu_dist-151x151 and test.out-mumps-151x151,
you will see that the last info message printed is:

On Processor (after EPSSetFromOptions)  0    memory:
0.65073152000E+08          =====>  (see line 807 of module_petsc.F90)

This means that the memory error probably occurs in the call to EPSSolve
(see module_petsc.F90 line 810). I would like to evaluate how much memory
is required by the most memory intensive operation within EPSSolve. Since I
am solving a generalized EVP, I would imagine that it would be the LU
decomposition. But is there an accurate way of doing it?

Before starting with iterative solvers, I would like to exploit as much as
I can direct solvers. I tried GMRES with default preconditioner at some
point but I had convergence problem. What solver/preconditioner would you
recommend for a generalized non-Hermitian (EPS_GNHEP) EVP?

Thanks,

Anthony

On Tue, Jul 7, 2015 at 12:17 AM, Jose E. Roman <jroman at dsic.upv.es> wrote:

>
> El 07/07/2015, a las 02:33, Anthony Haas escribió:
>
> > Hi,
> >
> > I am computing eigenvalues using PETSc/SLEPc and superlu_dist for the LU
> decomposition (my problem is a generalized eigenvalue problem). The code
> runs fine for a grid with 101x101 but when I increase to 151x151, I get the
> following error:
> >
> > Can't expand MemType 1: jcol 16104   (and then [NID 00037] 2015-07-06
> 19:19:17 Apid 31025976: OOM killer terminated this process.)
> >
> > It seems to be a memory problem. I monitor the memory usage as far as I
> can and it seems that memory usage is pretty low. The most memory intensive
> part of the program is probably the LU decomposition in the context of the
> generalized EVP. Is there a way to evaluate how much memory will be
> required for that step? I am currently running the debug version of the
> code which I would assume would use more memory?
> >
> > I have attached the output of the job. Note that the program uses twice
> PETSc: 1) to solve a linear system for which no problem occurs, and, 2) to
> solve the Generalized EVP with SLEPc, where I get the error.
> >
> > Thanks
> >
> > Anthony
> > <test.out-superlu_dist-151x151>
>
> In the output you are attaching there are no SLEPc objects in the report
> and SLEPc options are not used. It seems that SLEPc calls are skipped?
>
> Do you get the same error with MUMPS? Have you tried to solve linear
> systems with a preconditioned iterative solver?
>
> Jose
>
>
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