[petsc-users] -snes_type test

[Gianluca Meneghello]

Thanks Jed.

One more thing: what does the three lines stand for then? I was
thinking it was three Newton steps, but I understand it's not...

The output I sent was actually the output of one of your examples. The
one from my own code is

Testing hand-coded Jacobian, if the ratio is
O(1.e-8), the hand-coded Jacobian is probably correct.
Run with -snes_test_display to show difference
of hand-coded and finite difference Jacobian.
Norm of matrix ratio 9.17257e-08 difference 2.58876e-05
Norm of matrix ratio 1.45865e-06 difference 0.000430034
Norm of matrix ratio 1.47148e-06 difference 0.000429436
[0]PETSC ERROR: SNESSolve() line 2361 in src/snes/interface/snes.c
[0]PETSC ERROR: main() line 71 in jactest.cpp
application called MPI_Abort(MPI_COMM_WORLD, 73) - process 0
[unset]: aborting job:
application called MPI_Abort(MPI_COMM_WORLD, 73) - process 0

so I guess I have to look for an error somewhere!

Thanks again

Gianluca


On 18 March 2011 12:12, Jed Brown <jed at 59a2.org> wrote:
> On Fri, Mar 18, 2011 at 12:07, Gianluca Meneghello <gianmail at gmail.com>
> wrote:
>>
>> esting hand-coded Jacobian, if the ratio is
>> O(1.e-8), the hand-coded Jacobian is probably correct.
>> Run with -snes_test_display to show difference
>> of hand-coded and finite difference Jacobian.
>> Norm of matrix ratio 1.08967e-07 difference 2.43658e-07
>> Norm of matrix ratio 7.6194e-08 difference 3.4075e-07
>> Norm of matrix ratio 7.6211e-08 difference 3.40826e-07
>
> Your Jacobian looks good so you don't need to use TEST.
>
>>
>> [0]PETSC ERROR: SNESSolve() line 2360 in src/snes/interface/snes.c
>> [0]PETSC ERROR: main() line 144 in src/snes/examples/tutorials/ex1.c
>> application called MPI_Abort(MPI_COMM_WORLD, 73) - process 0
>> [unset]: aborting job:
>> application called MPI_Abort(MPI_COMM_WORLD, 73) - process 0
>
> This is intentional, the end of SNESSolve_Test() has
>   /*
>          Return error code cause Jacobian not good
>   */
>   PetscFunctionReturn(PETSC_ERR_ARG_WRONGSTATE);
> Perhaps it should be done differently, maybe even solve the Newton step and
> continue, but that's not the current behavior.



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