[petsc-users] Error with MatSchurComplement

[Barry Smith]

> On Feb 17, 2016, at 11:06 AM, Griffith, Boyce Eugene <boyceg at email.unc.edu> wrote:
> 
>> 
>> On Feb 17, 2016, at 12:57 AM, Barry Smith <bsmith at mcs.anl.gov> wrote:
>> 
>> 
>> Hmm, it seems this should never happen. It is like inconsistent (and in correct) IS are being generated. 
>> 
>>  1 is an odd number of processes, does it happen then?
>> 
>>  Are you providing the IS yourself to the PCFIELDSPLIT or using the default? If you are providing them is it possible that you have a bug in generating them for certain configurations? Of course it could also be a bug in PETSc. 
> 
> We are doing this ourselves.  Could this happen if we accidentally duplicated entries in one of the IS'es on different processors?

   I don't know could be. Likely there is some wrong with your IS.
> 
> -- Boyce
> 
>>  I recommend trying to produce the crash on a small a problem as possible then run in the debugger to check the IS at each stage to see why one of them becomes bonkers.
>> 
>>  It could be we should have more asserts in PETSc to insure that input IS are compatible.
>> 
>> Barry
>> 
>>> On Feb 16, 2016, at 10:37 PM, Bhalla, Amneet Pal S <amneetb at live.unc.edu> wrote:
>>> 
>>> Hi Folks,
>>> 
>>> I am getting error with odd number of processors with PCFIELDSPLIT. The error log is attached. Any hints where to start digging?
>>> 
>>> 
>>> +++++++++++++++++++++++++++++++++++++++++++++++++++
>>> At beginning of timestep # 0
>>> Simulation time is 0
>>>   Residual norms for ib_ solve.
>>>   0 KSP unpreconditioned resid norm 5.093934451651e+05 true resid norm 5.093934451651e+05 ||r(i)||/||b|| 1.000000000000e+00
>>> [2]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------
>>> [2]PETSC ERROR: Nonconforming object sizes
>>> [2]PETSC ERROR: Local columns of A10 1072 do not equal local rows of A00 1104
>>> [2]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble shooting.
>>> [2]PETSC ERROR: Petsc Release Version 3.6.1, unknown 
>>> [2]PETSC ERROR: ./main2d on a darwin-dbg named Amneets-MBP.attlocal.net by Taylor Tue Feb 16 20:30:45 2016
>>> [2]PETSC ERROR: Configure options --CC=mpicc --CXX=mpicxx --FC=mpif90 --PETSC_ARCH=darwin-dbg --with-debugging=1 --with-c++-support=1 --with-hypre=1 --download-hypre=1 --with-hdf5=yes --with-hdf5-dir=/Users/Taylor/Documents/SOFTWARES/HDF5/
>>> [2]PETSC ERROR: #1 MatSchurComplementSetSubMatrices() line 261 in /Users/Taylor/Documents/SOFTWARES/PETSc-BitBucket/PETSc/src/ksp/ksp/utils/schurm.c
>>> [2]PETSC ERROR: #2 PCSetUp_FieldSplit() line 714 in /Users/Taylor/Documents/SOFTWARES/PETSc-BitBucket/PETSc/src/ksp/pc/impls/fieldsplit/fieldsplit.c
>>> [2]PETSC ERROR: #3 PCSetUp() line 983 in /Users/Taylor/Documents/SOFTWARES/PETSc-BitBucket/PETSc/src/ksp/pc/interface/precon.c
>>> [2]PETSC ERROR: #4 KSPSetUp() line 332 in /Users/Taylor/Documents/SOFTWARES/PETSc-BitBucket/PETSc/src/ksp/ksp/interface/itfunc.c
>>> [2]PETSC ERROR: #5 KSPSolve() line 546 in /Users/Taylor/Documents/SOFTWARES/PETSc-BitBucket/PETSc/src/ksp/ksp/interface/itfunc.c
>>> [2]PETSC ERROR: #6 solveSystem() line 229 in ../../../IBAMR/ibtk/lib/../src/solvers/impls/PETScLevelSolver.cpp
>>> P=00002:Program abort called in file ``../../../IBAMR/ibtk/lib/../src/solvers/impls/PETScLevelSolver.cpp'' at line 229
>>> P=00002:ERROR MESSAGE: 
>>> P=00002:
>>> application called MPI_Abort(MPI_COMM_WORLD, -1) - process 2
>>> *** Warning, AutoPtr is deprecated and will be removed in a future library version! ./include/libmesh/auto_ptr.h, line 271, compiled Feb  3 2016 at 10:29:17 ***
>>> 
>>> 
>>> — Amneet