Samar: If you include the error message while crashing using superlu_dist, I probably know the reason. (better yet, include the printout before the crash. )
Sherry On Mon, Feb 24, 2014 at 9:56 AM, Hong Zhang <[email protected]> wrote: > Samar : > There are limitations for direct solvers. > Do not expect any solver can be used on arbitrarily large problems. > Since superlu_dist also crashes, direct solvers may not be able to work on > your application. > This is why I suggest to increase size incrementally. > You may have to experiment other type of solvers. > > Hong > > Hi Hong and Jed, >> >> Many thanks for replying. It would indeed be nice if the error messages >> from MUMPS were less cryptic! >> >> 1) I have tried smaller matrices although given how my problem is set >> up a jump is difficult to avoid. But a good idea >> that I will try. >> >> 2) I did try various ordering but not the one you suggested. >> >> 3) Tracing the error through the MUMPS code suggest a rather abrupt >> termination of the program (there should be more >> error messages if, for example, memory was a problem). I therefore >> thought it might be an interface problem rather than >> one with mumps and turned to the petsc-users group first. >> >> 4) I've tried superlu_dist but it also crashes (also unclear as to why) >> at which point I decided to try mumps. The fact that both >> crash would again indicate a common (memory?) problem. >> >> I'll try a few more things before asking the MUMPS developers. >> >> Thanks again for your help! >> >> Samar >> >> On Feb 24, 2014, at 11:47 AM, Hong Zhang <[email protected]> wrote: >> >> Samar: >> The crash occurs in >> >>> ... >>> [161]PETSC ERROR: Error in external library! >>> [161]PETSC ERROR: Error reported by MUMPS in numerical factorization >>> phase: INFO(1)=-1, INFO(2)=48 >> >> >> for very large matrix, likely memory problem as you suspected. >> I would suggest >> 1. run problems with increased sizes (not jump from a small one to a very >> large one) and observe memory usage using >> '-ksp_view'. >> I see you use '-mat_mumps_icntl_14 1000', i.e., percentage of >> estimated workspace increase. Is it too large? >> Anyway, this input should not cause the crash, I guess. >> 2. experimenting with different matrix ordering -mat_mumps_icntl_7 <> (I >> usually use sequential ordering 2) >> I see you use parallel ordering -mat_mumps_icntl_29 2. >> 3. send bug report to mumps developers for their suggestion. >> >> 4. try other direct solvers, e.g., superlu_dist. >> >> >>> ... >>> >>> etc etc. The above error I can tell has something to do with processor >>> 48 (INFO(2)) and so forth but not the previous one. >>> >>> The full output enabled with -mat_mumps_icntl_4 3 looks as in the >>> attached file. Any hints as to what could be giving this >>> error would be very much appreciated. >>> >> >> I do not know how to interpret this output file. mumps developer would >> give you better suggestion on it. >> I would appreciate to learn as well :-) >> >> Hong >> >> >> >
