[petsc-users] Problem with SNES

[Milan Mitrovic]

call MatCreateMPIAIJ(PETSC_COMM_WORLD, Np, Np, Ng, Ng, &
        nmax, PETSC_NULL_INTEGER, nmax, PETSC_NULL_INTEGER, Jac, info)

well, now I get:

[1]PETSC ERROR: --------------------- Error Message
------------------------------------
[1]PETSC ERROR: Null argument, when expecting valid pointer!
[1]PETSC ERROR: Null Object: Parameter # 2!


how can I create the matrix without d_nnz and o_nnz?