[petsc-users] Problem with SNES

[Milan Mitrovic]

for the jacobian i use:

    call MatCreateShell(PETSC_COMM_WORLD, Np, Np, Ng, Ng, 0, Jac, info)
    call MatShellSetOperation(Jac, MATOP_MULT, &
         jacobian_multiplication, info)

and do the multiplication myself because it is much faster. I tried
using parallel AIJ format but constructing the matrix took more than a
minute for my problem with only ~150 nonzero entries per row... (maybe
I was doing something very wrong)

should I return to the AIJ version to see if the jacobian is correct?