Hello, yes, I am sorry, there was a bug in the patch. The problem occurred when the number of preallocated vectors was bigger than the max number of old directions to store - as in the options in runex60. It hadn’t checked this case. Again, sorry for that. I prepared a new patch which also replaces a PetscMin for a PetscMax but also swaps argument positions. I ran ex2, ex43 and ex60 with appropriate options in valgrind and got no errors. BTW: valgrind is available for Mac through MacPorts again. Sascha On 20 Dec 2014, at 18:17, Barry Smith <[email protected]> wrote:

When I added this change src/ksp/ksp/examples/tutorials/ex60 make runex60 failed with valgrind errors.

bsmith@es:/sandbox/bsmith/petsc/src/ksp/ksp/examples/tutorials$ /sandbox/bsmith/petsc/bin/petscmpiexec -valgrind -n 1 ./ex60 -ksp_monitor_short -ksp_rtol 1e-6 -diagfunc 1 -ksp_type fcg -ksp_fcg_mmax 1 -eta 0.1 ==14854== Invalid write of size 8 ==14854== at 0x5C32987: KSPAllocateVectors_FCG (fcg.c:37) ==14854== by 0x5C32FE2: KSPSetUp_FCG (fcg.c:77) ==14854== by 0x5BEBD69: KSPSetUp (itfunc.c:267) ==14854== by 0x5BED3E3: KSPSolve (itfunc.c:419) ==14854== by 0x403599: main (ex60.c:219) ==14854== Address 0xa49f720 is 0 bytes after a block of size 16 alloc'd ==14854== at 0x4C29BE8: memalign (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so) ==14854== by 0x4F33A45: PetscMallocAlign (mal.c:27) ==14854== by 0x5C32D96: KSPSetUp_FCG (fcg.c:63) ==14854== by 0x5BEBD69: KSPSetUp (itfunc.c:267) ==14854== by 0x5BED3E3: KSPSolve (itfunc.c:419) ==14854== by 0x403599: main (ex60.c:219) ==14854==

Thus I have removed this change.

Barry

...

On Dec 19, 2014, at 8:18 AM, Sascha Schnepp <[email protected]> wrote:

Hello developers,

I prepared a patch to fix the allocation of direction vectors in KSPAllocateVectors_FCG within ksp-fcg.

The fix consists only of replacing a PetscMin with a PetscMax. This prevents vectors being allocated one-by-one instead of chunksize of them once the preallocated ones (nprealloc) are exhausted.

Let me know if you prefer a PR.

Best, Sascha

-------------------------------------- ETH Zurich Sascha Schnepp Institute of Geophysics - Geophysical Fluid Dynamics NO H23, Sonneggstrasse 5, 8092 Zurich, Switzerland

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