Hello, I'm trying to solve a 2*2 block matrix system. I managed to form a 2*2 MatNest and a 21 VecNest. However when I try to make use of ksp solve, I encounter the following error. There is only one or two examples on MatNest and VecNest. I could not figure out what could be the trouble.
[0]PETSC ERROR: --------------------- Error Message -------------------------------------------------------------- [0]PETSC ERROR: Invalid argument [0]PETSC ERROR: Nest vector argument 2 not setup. [0]PETSC ERROR: See https://www.mcs.anl.gov/petsc/documentation/faq.html for trouble shooting. [0]PETSC ERROR: Petsc Release Version 3.12.5, Mar, 29, 2020 [0]PETSC ERROR: ./testSolve on a arch-linux2-c-debug named f601294ac804 by Unknown Thu Jul 16 01:56:11 2020 [0]PETSC ERROR: Configure options --with-cc=gcc --with-cxx=g++ --with-fc=gfortran --download-mpich --download-fblaslapack --with-cuda [0]PETSC ERROR: #1 VecCopy_Nest() line 68 in /usr/local/petsc/petsc-3.12.5/src/vec/vec/impls/nest/vecnest.c [0]PETSC ERROR: #2 VecCopy() line 1577 in /usr/local/petsc/petsc-3.12.5/src/vec/vec/interface/vector.c [0]PETSC ERROR: #3 KSPInitialResidual() line 61 in /usr/local/petsc/petsc-3.12.5/src/ksp/ksp/interface/itres.c [0]PETSC ERROR: #4 KSPSolve_GMRES() line 236 in /usr/local/petsc/petsc-3.12.5/src/ksp/ksp/impls/gmres/gmres.c [0]PETSC ERROR: #5 KSPSolve() line 760 in /usr/local/petsc/petsc-3.12.5/src/ksp/ksp/interface/itfunc.c Regards JT
