Thank you Stefano for the help. I added the lines you indicated, but the
error remains the same, here goes snes.view() + error
> SNES Object: 1 MPI processes
> type: qn
> SNES has not been set up so information may be incomplete
> type is BROYDEN, restart type is DEFAULT, scale type is JACOBIAN
> Stored subspace size: 10
> Using the single reduction variant.
> maximum iterations=10000, maximum function evaluations=30000
> tolerances: relative=1e-08, absolute=1e-50, solution=1e-08
> total number of function evaluations=0
> norm schedule ALWAYS
> SNESLineSearch Object: 1 MPI processes
> type: basic
> maxstep=1.000000e+08, minlambda=1.000000e-12
> tolerances: relative=1.000000e-08, absolute=1.000000e-15,
lambda=1.000000e-08
> maximum iterations=1
> Traceback (most recent call last):
> File "Twist.py", line 234, in <module>
> snes.setUp()
> File "PETSc/SNES.pyx", line 530, in petsc4py.PETSc.SNES.setUp
> petsc4py.PETSc.Error: error code 83
On Tue, Oct 12, 2021 at 2:07 PM Stefano Zampini <stefano.zamp...@gmail.com>
wrote:
>
>
> Il giorno mar 12 ott 2021 alle ore 13:56 Nicolás Barnafi <nab...@gmail.com>
> ha scritto:
>
>> Hello PETSc users,
>>
>> first email sent!
>> I am creating a SNES solver using fenics, my example runs smoothly with
>> 'newtonls', but gives a strange missing function error (error 83):
>>
>>
> Dolphin swallows any useful error information returned from PETSc. You can
> try using the below code snippet at the beginning of your script
>
> from petsc4py import PETSc
> from dolfin import *
> # Remove the dolfin error handler
> PETSc.Sys.pushErrorHandler('python')
>
>
>
>>
>> these are the relevant lines of code where I setup the solver:
>>
>> > problem = SNESProblem(Res, sol, bcs)
>> > b = PETScVector() # same as b = PETSc.Vec()
>> > J_mat = PETScMatrix()
>> > snes = PETSc.SNES().create(MPI.COMM_WORLD)
>> > snes.setFunction(problem.F, b.vec())
>> > snes.setJacobian(problem.J, J_mat.mat())
>> > # Set up fieldsplit
>> > ksp = snes.ksp
>> > ksp.setOperators(J_mat.mat())
>> > pc = ksp.pc
>> > pc.setType('fieldsplit')
>> > dofmap_s = V.sub(0).dofmap().dofs()
>> > dofmap_p = V.sub(1).dofmap().dofs()
>> > is_s = PETSc.IS().createGeneral(dofmap_s)
>> > is_p = PETSc.IS().createGeneral(dofmap_p)
>> > pc.setFieldSplitIS((None, is_s), (None, is_p))
>> > pc.setFromOptions()
>> > snes.setFromOptions()
>> > snes.setUp()
>>
>>
> If it can be useful, this are the outputs of snes.view(), ksp.view() and
>> pc.view():
>>
>> > type: qn
>> > SNES has not been set up so information may be incomplete
>> > type is BROYDEN, restart type is DEFAULT, scale type is JACOBIAN
>> > Stored subspace size: 10
>> > Using the single reduction variant.
>> > maximum iterations=10000, maximum function evaluations=30000
>> > tolerances: relative=1e-08, absolute=1e-50, solution=1e-08
>> > total number of function evaluations=0
>> > norm schedule ALWAYS
>> > SNESLineSearch Object: 4 MPI processes
>> > type: basic
>> > maxstep=1.000000e+08, minlambda=1.000000e-12
>> > tolerances: relative=1.000000e-08, absolute=1.000000e-15,
>> lambda=1.000000e-08
>> > maximum iterations=1
>> > KSP Object: 4 MPI processes
>> > type: gmres
>> > restart=1000, using Modified Gram-Schmidt Orthogonalization
>> > happy breakdown tolerance 1e-30
>> > maximum iterations=1000, initial guess is zero
>> > tolerances: relative=1e-05, absolute=1e-50, divergence=10000.
>> > left preconditioning
>> > using UNPRECONDITIONED norm type for convergence test
>> > PC Object: 4 MPI processes
>> > type: fieldsplit
>> > PC has not been set up so information may be incomplete
>> > FieldSplit with Schur preconditioner, factorization FULL
>>
>> I know that PC is not setup, but if I do it before setting up the SNES,
>> the error persists. Thanks in advance for your help.
>>
>> Best,
>> Nicolas
>> --
>> Nicolás Alejandro Barnafi Wittwer
>>
>
>
> --
> Stefano
>
--
Nicolás Alejandro Barnafi Wittwer
