I'm having problems using mat_view in petsc 3.4.3 in combination with a prefix. For example in ../snes/examples/tutorials/ex70:
mpiexec -n 2 ./ex70 -nx 16 -ny 24 -ksp_type fgmres -pc_type fieldsplit -pc_fieldsplit_type schur -pc_fieldsplit_schur_fact_type lower -user_ksp -a00_mat_view does not print the matrix a00 to screen. This used to work in 3.3 versions before the single consistent -xxx_view scheme. Similarly, if I add this at line 105 of ../ksp/ksp/examples/tutorials/ex1f.F: call MatSetOptionsPrefix(A,"a_",ierr) then running with -mat_view still prints the matrix to screen but running with -a_mat_view doesn't. I expected the opposite. The problem only occurs with mat, not with ksp. For example, if I add this at line 184 of ../ksp/ksp/examples/tutorials/ex1f.F: call KSPSetOptionsPrefix(ksp,"a_",ierr) then running with -a_ksp_monitor does print the residuals to screen and -ksp_monitor doesn't, as expected. dr. ir. Christiaan Klaij CFD Researcher Research & Development E mailto:c.kl...@marin.nl T +31 317 49 33 44 MARIN 2, Haagsteeg, P.O. Box 28, 6700 AA Wageningen, The Netherlands T +31 317 49 39 11, F +31 317 49 32 45, I www.marin.nl