[petsc-users] Problem with SNES

[Milan Mitrovic]

Ok... I had a problem with indexing (-1 offset) in the local to global
mapping and now I get the following:

Testing hand-coded Jacobian, if the ratio is
O(1.e-8), the hand-coded Jacobian is probably correct.
Run with -snes_test_display to show difference
of hand-coded and finite difference Jacobian.
Norm of matrix ratio 3.24883e-07 difference 3.24883e-05
Norm of matrix ratio 3.25662e-07 difference 3.25662e-05
Norm of matrix ratio 3.26517e-07 difference 3.26517e-05
[0]PETSC ERROR: SNESSolve() line 2255 in src/snes/interface/snes.c

so I guess this means that it is slightly wrong :)

can you explain now what it is doing here (and why I get this
error)... can I make it try to solve the equation with the
approximated fd jacobian (is it doing that already?)