[petsc-users] A number of questions about DMDA with SNES and Quasi-Newton methods

[zakaryah .]

One piece of information that would be useful is what ordering PETSc uses
for the Jacobian in the snes_test_display.  Is it a natural ordering, or
the PETSc ordering?  For debugging the Jacobian manually, the natural
ordering is much easier to work with.  For -n 1, are the orderings the same?

If I use a MatStencil r to represent a field with 3 degrees of freedom, and
the dimensions of my 3D DMDA are MxNxP, which row of the Jacobian
corresponds to r.i=x, r.j=y, r.k=z, r.c=f?
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