Dear Petsc-Users, The SNES only converges for a small problem. I did the jacobian check. The result is sensitive to the choice of differencing parameter.
With the option "-snes_type test": "Norm of matrix ratio 4.11569e-09 difference 7.64426e-07 (user-defined state) Norm of matrix ratio 2.05846e-08 difference 3.89655e-06 (constant state -1.0) Norm of matrix ratio 5.77446e-09 difference 1.09307e-06 (constant state 1.0)" with the option "-snes_type test -mat_fd_type ds" : "Norm of matrix ratio 1.05213e-07 difference 1.95418e-05 (user-defined state) Norm of matrix ratio 2.51463e-07 difference 4.76004e-05 (constant state -1.0) Norm of matrix ratio 2.81081e-08 difference 5.32071e-06 (constant state 1.0)". Could you give me any hint where should I check for the error? Khai
