[petsc-users] Problem with SNES

[Jed Brown]

On Sat, Aug 27, 2011 at 12:22, Milan Mitrovic <milan.v.mitrovic at gmail.com>wrote:

> [1]PETSC ERROR: Unknown Mat type given: same!


What kind of Mat were you assembling? Are you passing any other flags? What
does your code assemble for the Jacobian? I think the Jacobian you passed in
does not implement MatDuplicate(). I just changed MatConvert() to be more
robust in petsc-dev.

With 3.1, you can try -pc_type lu -snes_monitor -ksp_monitor_singular_value.
Also compare output with -snes_mf_operator. I think your Jacobian may be
singular and this should help figure that out.
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