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

[Anthony Paul Haas]

Hi Barry,

Thanks for you message. I will do the sequence of problems as you
suggested. In the meantime I want also to get started with iterative solver
for SLEPc. I have tried GMRES with bjacobi preconditioner but the
convergence is rather poor. Should I install hypre? Which preconditioner
would you recommend for a generalized EVP?

Thanks

Anthony

On Tue, Jul 7, 2015 at 1:27 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:

>
>    I would suggest running a sequence of problems, 101 by 101 111 by 111
> etc and get the memory usage in each case (when you run out of memory you
> can get NO useful information out about memory needs). You can then plot
> memory usage as a function of problem size to get a handle on how much
> memory it is using.  You can also run on more and more processes (which
> have a total of more memory) to see how large a problem you may be able to
> reach.
>
>    MUMPS also has an "out of core" version (which we have never used) that
> could in theory anyways let you get to large problems if you have lots of
> disk space, but you are on your own figuring out how to use it.
>
>   Barry
>
> > On Jul 7, 2015, at 2:37 PM, Anthony Paul Haas <aph at email.arizona.edu>
> wrote:
> >
> > 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
> >
> >
> >
> <module_petsc.F90><test.out-mumps-151x151><test.out_superlu_dist-101x101><test.out-superlu_dist-151x151>
>
>
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