Hi All, I am using GAMG to solve a group of coupled diffusion equations, but the resulting matrix is not symmetrical. I got the following error messages:
*[0]PETSC ERROR: Petsc has generated inconsistent data[0]PETSC ERROR: Have un-symmetric graph (apparently). Use '-pc_gamg_sym_graph true' to symetrize the graph or '-pc_gamg_threshold -1.0' if the matrix is structurally symmetric.[0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html <http://www.mcs.anl.gov/petsc/documentation/faq.html> for trouble shooting.[0]PETSC ERROR: Petsc Release Version 3.7.5, unknown [0]PETSC ERROR: /home/kongf/workhome/projects/yak/yak-opt on a arch-linux2-c-opt named r2i2n0 by kongf Mon Apr 3 16:19:59 2017[0]PETSC ERROR: /home/kongf/workhome/projects/yak/yak-opt on a arch-linux2-c-opt named r2i2n0 by kongf Mon Apr 3 16:19:59 2017[0]PETSC ERROR: #1 smoothAggs() line 462 in /home/kongf/workhome/projects/petsc/src/ksp/pc/impls/gamg/agg.c[0]PETSC ERROR: #2 PCGAMGCoarsen_AGG() line 998 in /home/kongf/workhome/projects/petsc/src/ksp/pc/impls/gamg/agg.c[0]PETSC ERROR: #3 PCSetUp_GAMG() line 571 in /home/kongf/workhome/projects/petsc/src/ksp/pc/impls/gamg/gamg.c[0]PETSC ERROR: #3 PCSetUp_GAMG() line 571 in /home/kongf/workhome/projects/petsc/src/ksp/pc/impls/gamg/gamg.c* Does this mean that GAMG works for the symmetrical matrix only? Fande,