Matt, Thanks for your answer!
dummy is defined as a PETSc integer inside MyKSPConverged, so why can't I set it to 0? I know it's not useful because it's just a dummy and nothing happens with it, but setting it shouldn't crash the code, right? Also, if setting it changes the basic definition of PETSC_NULL_OBJECT shouldn't you get a SEGV as well, or at least some kind of trouble? Chris Message: 5 Date: Fri, 4 Sep 2009 10:49:25 -0500 From: Matthew Knepley <[email protected]> Subject: Re: dummy in MyKSPConverged To: PETSc users list <petsc-users at mcs.anl.gov> Message-ID: <a9f269830909040849t7a8dd52dwc7fa33c6a0d313f7 at mail.gmail.com> Content-Type: text/plain; charset="iso-8859-1" On Fri, Sep 4, 2009 at 10:35 AM, Klaij, Christiaan <C.Klaij at marin.nl> wrote: > Hello, > > With the new version 3.0.0-p8, if I assign a value to the dummy in > MyKSPConverged at the end of src/ksp/ksp/examples/tutorials/ex2f.F, I get a > segmentation fault (this didn't happen with version 2.3.3-p13). Any idea > why? > 1) I do not get a SEGV 2) You should not be setting this at all. You pass in PETSC_NULL_OBJECT, which means you are changing the definition of that basic thing in PETSc. This can produce undefined results. Matt > $ tail ex2f.F > else > flag = 0 > endif > ierr = 0 > dummy = 0 > > end > $ ./ex2f -my_ksp_convergence > [0]PETSC ERROR: > ------------------------------------------------------------------------ > [0]PETSC ERROR: Caught signal number 11 SEGV: Segmentation Violation, > probably memory access out of range > [0]PETSC ERROR: Try option -start_in_debugger or -on_error_attach_debugger > [0]PETSC ERROR: or see > http://www.mcs.anl.gov/petsc/petsc-as/documentation/troubleshooting.html#Signal[0]PETSC > ERROR: or try http://valgrind.org on linux or man libgmalloc on Apple to > find memory corruption errors > [0]PETSC ERROR: likely location of problem given in stack below > [0]PETSC ERROR: --------------------- Stack Frames > ------------------------------------ > [0]PETSC ERROR: Note: The EXACT line numbers in the stack are not > available, > [0]PETSC ERROR: INSTEAD the line number of the start of the function > [0]PETSC ERROR: is given. > [0]PETSC ERROR: [0] GMREScycle line 133 src/ksp/ksp/impls/gmres/gmres.c > [0]PETSC ERROR: [0] KSPSolve_GMRES line 228 src/ksp/ksp/impls/gmres/gmres.c > [0]PETSC ERROR: [0] KSPSolve line 308 src/ksp/ksp/interface/itfunc.c > [0]PETSC ERROR: --------------------- Error Message > ------------------------------------ > [0]PETSC ERROR: Signal received! > [0]PETSC ERROR: > ------------------------------------------------------------------------ > [0]PETSC ERROR: Petsc Release Version 3.0.0, Patch 8, Fri Aug 21 14:02:12 > CDT 2009 > [0]PETSC ERROR: See docs/changes/index.html for recent updates. > [0]PETSC ERROR: See docs/faq.html for hints about trouble shooting. > [0]PETSC ERROR: See docs/index.html for manual pages. > [0]PETSC ERROR: > ------------------------------------------------------------------------ dr. ir. Christiaan Klaij CFD Researcher Research & Development mailto:C.Klaij at marin.nl T +31 317 49 33 44 MARIN 2, Haagsteeg, P.O. Box 28, 6700 AA Wageningen, The Netherlands T +31 317 49 39 11, F +31 317 49 32 45, I http://www.marin.nl/ http://www.marin.nl/web/News/News-items/RD-seminar-on-September-22-few-places-left.htm R&D seminar on September 22: few places left This e-mail may be confidential, privileged and/or protected by copyright. If you are not the intended recipient, you should return it to the sender immediately and delete your copy from your system. -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/ms-tnef Size: 4396 bytes Desc: not available URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20090907/4f3b9528/attachment-0001.bin>
