Hello, when moving from PETSc 2.3.2-p10 to 2.3.3-p13, I recently encountered a strange behaviour (segmentation fault) of the new version concerning the usage of MatPtAP. I tried to pull everything down to a simple test case. For square matrices (A as well as P), everything seems to work fine.
But when I set up a simple non-square example (A being the 3x3-identity, P being a 3x5 matrix, see attached file PETScLibTest.cpp), I encounter severe problems: As soon as P gets entries outside its 3x3 block (an entry P(0,3), e.g.), PETSc is telling me about Memory corruption while using MatPtAP (see part of command line output in the attached file output.txt, run with -info). I used valgrind to check if sth. weird happens, but it is giving nothing until the PETSc error message. Using the same test case with PETSc 2.3.2-p10 (with identic configuring options on the same machine) does not show any problems at all. So I am a bit confused. Is it not allowed any longer to use MatPtAP with non-square matrices? I checked the online documentation but did not find anything ... Next idea was to use MatMatMult directly to see if that works. So I used MatMatMultTranspose(P, A, MAT_INITIAL_MATRIX, 1.0, &C1) and then MatMatMult(C1, P, MAT_INITIAL_MATRIX, 1.0, &C) to get C=C1*P=P^T*A*P in two steps. This time, everything works fine for the small test case from above, also with the new version 2.3.3-p13. Best regards Tobias Neckel -- Dipl.-Tech. Math. Tobias Neckel Institut f?r Informatik V, TU M?nchen Boltzmannstr. 3, 85748 Garching Tel.: 089/289-18602 Email: neckel at in.tum.de URL: http://www5.in.tum.de/persons/neckel.html -------------- next part -------------- A non-text attachment was scrubbed... Name: PETScLibTest.cpp Type: text/x-c++src Size: 3257 bytes Desc: not available URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20080701/690fe1b8/attachment.cpp> -------------- next part -------------- An embedded and charset-unspecified text was scrubbed... Name: output.txt URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20080701/690fe1b8/attachment.txt>
