Matt, Thanks for your explanation. I guess we are using different compilers (I'm using the intel 10.1) which may explain why I get a SEGV and you don't. I didn't change anything else in src/ksp/ksp/examples/tutorials/ex2f.F. To help me understand, could you please tell me where exactly the dummy is passed in?
Chris ---------------------------------------------------------------------- Message: 1 Date: Mon, 7 Sep 2009 07:03:01 -0500 From: Matthew Knepley <[email protected]> Subject: Re: dummy in MyKSPConverged To: PETSc users list <petsc-users at mcs.anl.gov> Message-ID: <a9f269830909070503g684e2197yc43a7232aa9b88da at mail.gmail.com> Content-Type: text/plain; charset="iso-8859-1" On Mon, Sep 7, 2009 at 2:01 AM, Klaij, Christiaan <C.Klaij at marin.nl> wrote: > 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? > dummy is something *you passed in* earlier in the code, and you passed in something that should not change. I do not know why you are getting an SEGV (I do not get one), but I do know you should not change this for the code to function correctly. Matt > Chris > > > > Message: 5 > Date: Fri, 4 Sep 2009 10:49:25 -0500 > From: Matthew Knepley <knepley at gmail.com> > 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<http://www.mcs.anl.gov/petsc/petsc-as/documentation/troubleshooting.html#Signal%5B0%5DPETSC> > > 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.htmR&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: 4940 bytes Desc: not available URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20090908/e90b0d34/attachment.bin>
