Yes, here is what I am getting francois. [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: [1]PETSC ERROR: ------------------------------------------------------------------------
[1]PETSC ERROR: or try http://valgrind.org on linux or man libgmalloc on Apple to find memory corruption errors Caught signal number 11 SEGV: Segmentation Violation, probably memory access out of range [0]PETSC ERROR: likely location of problem given in stack below [1]PETSC ERROR: Try option -start_in_debugger or -on_error_attach_debugger [1]PETSC ERROR: [0]PETSC ERROR: --------------------- Stack Frames ------------------------------------ or see http://www.mcs.anl.gov/petsc/petsc-as/documentation/troubleshooting.html#Signal[1]PETSC ERROR: or try http://valgrind.org on linux or man libgmalloc on Apple to find memory corruption errors [1]PETSC ERROR: likely location of problem given in stack below [1]PETSC ERROR: --------------------- Stack Frames ------------------------------------ [0]PETSC ERROR: Note: The EXACT line numbers in the stack are not available, [1]PETSC ERROR: Note: The EXACT line numbers in the stack are not available, [1]PETSC ERROR: [0]PETSC ERROR: INSTEAD the line number of the start of the function [0]PETSC ERROR: INSTEAD the line number of the start of the function [1]PETSC ERROR: is given. is given. [0]PETSC ERROR: [0] PCFieldSplitGetSubKSP_FieldSplit_Schur line 751 src/ksp/pc/impls/fieldsplit/fieldsplit.c [1]PETSC ERROR: [1] PCFieldSplitGetSubKSP_FieldSplit_Schur line 751 src/ksp/pc/impls/fieldsplit/fieldsplit.c [1]PETSC ERROR: [0]PETSC ERROR: [0] PCFieldSplitGetSubKSP line 951 src/ksp/pc/impls/fieldsplit/fieldsplit.c [1] PCFieldSplitGetSubKSP line 951 src/ksp/pc/impls/fieldsplit/fieldsplit.c [1]PETSC ERROR: --------------------- Error Message ------------------------------------ [0]PETSC ERROR: --------------------- Error Message ------------------------------------ [1]PETSC ERROR: Signal received! [1]PETSC ERROR: [0]PETSC ERROR: ------------------------------------------------------------------------ [1]PETSC ERROR: Petsc Release Version 3.0.0, Patch 7, Mon Jul 6 11:33:34 CDT 2009 Signal received! [1]PETSC ERROR: See docs/changes/index.html for recent updates. [1]PETSC ERROR: [0]PETSC ERROR: ------------------------------------------------------------------------ See docs/faq.html for hints about trouble shooting. [1]PETSC ERROR: See docs/index.html for manual pages. [0]PETSC ERROR: [1]PETSC ERROR: Petsc Release Version 3.0.0, Patch 7, Mon Jul 6 11:33:34 CDT 2009 ------------------------------------------------------------------------ ... Matthew Knepley a ?crit : > Can you use the debugger to get a stack trace? > > Matt > > On Tue, Nov 24, 2009 at 10:46 AM, francois pacull <fpacull at fluorem.com > <mailto:fpacull at fluorem.com>> wrote: > > Dear PETSc team, > > I am having a little bit of trouble with the Schur option of > PCFieldSplit: I would like to apply some special treatments > respectively to the five first and the two last equations over > seven for each grid node of a CFD linear system... > > In the present case, the KSP is "gmres" (or "fgmres" if the PC is > changing), the PC is "asm" (the subdomain IS is defined with > PCASMSetLocalSubdomains in order to always include all the fields > associated to the grid points of the overlap), the SUBKSP is > "preonly" and the SUBPC is "fieldsplit". > > So far the FieldSplit options PC_COMPOSITE_ADDITIVE and > PC_COMPOSITE_MULTIPLICATIVE work well with fieldsplit_0 and > fieldsplit_1 set to KSPPREONLY and PCILU in the following way: > > PCFieldSplitGetSubKSP(SubPC,number_of_split,&FieldSplitKSP); > ... [for the fields 0,1,2,3,4 (fieldsplit_0)] > KSPSetType(FieldSplitKSP[0],KSPPREONLY); > KSPGetPC(FieldSplitKSP[0],&FieldSplitPC0); > PCSetType(FieldSplitPC0,PCILU); > ... [for the fields 5 and 6 (fieldsplit_1)] > KSPSetType(FieldSplitKSP[1],KSPPREONLY); > KSPGetPC(FieldSplitKSP[1],&FieldSplitPC1); > PCSetType(FieldSplitPC1,PCILU); > ... > > They also work well when I set the FieldSplitKSP[0] and/or > FieldSplitKSP[1] to KSPGMRES. However, I always get a segmentation > violation when I try to use the FieldSplit option > PC_COMPOSITE_SCHUR... I guess that I am missing something: is > there more options to set in this Schur case? > So far I did not turn on the Schur complement preconditioner > option: PCFieldSplitSchurPrecondition(subpc,PETSC_FALSE); > Is there a book or article describing the methods implemented in > this FieldSplit option? > > The version is petsc-3.0.0-p7... > > Thank you for your help, > Regards, > francois pacull. > > > > > -- > What most experimenters take for granted before they begin their > experiments is infinitely more interesting than any results to which > their experiments lead. > -- Norbert Wiener
