> On 10 May 2016, at 11:02, Onno Bokhove <O.Bokhove@leeds.ac.uk> wrote:
>
> I did do the updates and all went through well it seems, but
> both with the codes of Fryderyk and Will matters crash at the solve stage; I also attache d F's code he just send me.
> I run on an macbook and they run under linux.
> The code runs for Fryderyk, he said.
>
> mtob$ python ns_plane_poiseuille.py
> ...
> Traceback (most recent call last):
>   File "ns_plane_poiseuille.py", line 104, in <module>
>     solve(F_u == 0, u, bcs = [bc0,bc1,bc2],solver_parameters={'pc_type': 'lu', 'pc_factor_mat_solver_package': 'mumps'} ) #
>   File "/Users/amtob/werk/firedrake/lib/python2.7/site-packages/firedrake/solving.py", line 120, in solve
>     _solve_varproblem(*args, **kwargs)
>   File "/Users/amtob/werk/firedrake/lib/python2.7/site-packages/firedrake/solving.py", line 164, in _solve_varproblem
>     solver.solve()
>   File "<decorator-gen-295>", line 2, in solve
>   File "/Users/amtob/werk/firedrake/lib/python2.7/site-packages/pyop2/profiling.py", line 203, in wrapper
>     return f(*args, **kwargs)
>   File "/Users/amtob/werk/firedrake/lib/python2.7/site-packages/firedrake/variational_solver.py", line 190, in solve
>     solving_utils.check_snes_convergence(self.snes)
>   File "/Users/amtob/werk/firedrake/lib/python2.7/site-packages/firedrake/solving_utils.py", line 62, in check_snes_convergence
>     %s""" % (snes.getIterationNumber(), msg))
> RuntimeError: Nonlinear solve failed to converge after 0 nonlinear iterations.
> Reason:
>    Inner linear solve failed to converge after 0 iterations with reason: unknown reason (petsc4py enum incomplete?

This looks like the jacobian is singular, please follow the advice here: http://firedrakeproject.org/solving-interface.html#debugging-convergence-failures

To try and get an idea as to what is going on.

I get:
Linear  solve did not converge due to DIVERGED_PCSETUP_FAILED iterations 0
                 PCSETUP_FAILED due to FACTOR_NUMERIC_ZEROPIVOT



> Similar problem for Will's code:
>     ast_handler.plan_cpu(self._opts)
>   File "/Users/amtob/werk/firedrake/lib/python2.7/site-packages/coffee/plan.py", line 184, in plan_cpu
>     _generate_cpu_code(self, kernel, **params)
>   File "/Users/amtob/werk/firedrake/lib/python2.7/site-packages/coffee/plan.py", line 110, in _generate_cpu_code
>     loop_opt.eliminate_zeros()
>   File "/Users/amtob/werk/firedrake/lib/python2.7/site-packages/coffee/optimizer.py", line 163, in eliminate_zeros
>     self.nz_syms = zls.reschedule(self.header)
>   File "/Users/amtob/werk/firedrake/lib/python2.7/site-packages/coffee/scheduler.py", line 844, in reschedule
>     self.exprs.update(elf.fission(stmt, expr_info))
>   File "/Users/amtob/werk/firedrake/lib/python2.7/site-packages/coffee/scheduler.py", line 463, in fission
>     split, splittable = self.cutter.cut(*splittable)
>   File "/Users/amtob/werk/firedrake/lib/python2.7/site-packages/coffee/scheduler.py", line 300, in cut
>     index = expr_info.parent.children.index(node)
> ValueError: <coffee.base.Incr object at 0x10e4186d0> is not in list

This may be a bug in coffee, but it runs for Will?  Please try running firedrake-clean and then try again if so.  Otherwise, please provide a failing test case and report it as a github issue (https://github.com/firedrakeproject/firedrake/issues)

Thanks,

Lawrence