[petsc-dev] -snes_check_jacobian

[Peter Brune]

Reaction after looking at Barry's changeset -- yeah this is great.  Jed,
does -compare_explicit_* do anything that's missing here?

- Peter


On Thu, Dec 13, 2012 at 5:22 PM, Peter Brune <prbrune at gmail.com> wrote:

>
>
>
> On Thu, Dec 13, 2012 at 5:10 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:
>
>>
>> On Dec 13, 2012, at 5:04 PM, Peter Brune <prbrune at gmail.com> wrote:
>>
>> > Dangit Barry!  I already started a patch moving all Jed's
>> -snes_compare_* garbage in SNESComputeJacobian() over to a
>> SNESJacobianMonitor registration type deal where it has functions you can
>> register to run after computing the Jacobian.  This will allow you to do
>> all sorts of nice comparisons.
>>
>>   Dang it we don't need yet another registration thingy, I used the
>> SNESSetUpdate() hook.
>>
>>
>   Actually I don't mind if you do something better and remove mine (it is
>> the story of my life) but don't remove mine until yours produces as pretty
>> an output and has good names for the options and yes
>> snes_compare_explicit is a terrible name. At least put jacobian in the
>> option so I have some clue that it has something to do with the jacobian!
>>
>>
> I agree, and this seems like a fine place for it to happen.  I'll have to
> look at exactly what you did, but you could save a Jacobian computation if
> you put it after the user Jacobian has been computed, which is why I was
> putting it as hooks to be run at the end of SNESComputeJacobian().
>
> I want similar facilities for the objectives as well.   There's already an
> FD test objective in place (used by SNESTEST to verify if you have written
> a proper objective -> function -> jacobian set).  If we had it so you could
> register multiple tests (even in the update slot) we could provide a whole
> suite of potential useful output without much work.
>
> - Peter
>
>   Barry
>>
>> >
>> > Dangit Jed!  -snes_compare_* is a seeerious mess and shouldn't be in
>> SNESComputeJacobian().  Barry's recent holy war against string comparisons
>> will find this some day and there will be a lot of explaining to do.
>> >
>> > - Peter
>> >
>> >
>> > On Thu, Dec 13, 2012 at 4:59 PM, Jed Brown <jedbrown at mcs.anl.gov>
>> wrote:
>> > Surely you were aware of the -snes_compare_* options that can be
>> activated in SNESComputeJacobian().
>> >
>> > Can we settle on one common way to do this testing and perhaps remove
>> -snes_type test.
>> >
>> >
>> > On Thu, Dec 13, 2012 at 2:55 PM, Barry Smith <bsmith at mcs.anl.gov>
>> wrote:
>> >
>> >    I got sick of -snes_type test only checking the Jacobian at the
>> initial solution and not being able to test later Jacobians so I added
>> -snes_check_jacobian that allows the regular running of SNESSolve() (also
>> inside TS) and compares every Jacobian computed with a finite difference
>> version.
>> >
>> >   For example, (already found one bug in one example :-(). This may be
>> the best thing I've added to PETSc in a decade.
>> >
>> >    Barry
>> >
>> >
>> > Barrys-MacBook-Pro:advection-diffusion-reaction barrysmith$ ./ex1
>> -snes_check_jacobian -snes_monitor  -ts_type arkimex | more
>> >     0 SNES Function norm 2.182384017537e+00
>> >         Testing hand-coded Jacobian, if the ratio is O(1.e-8), the
>> hand-coded Jacobian is probably correct.
>> >         Run with -snes_check_jacobian_display to show difference of
>> hand-coded and finite difference Jacobian.
>> >       1.68322e-09 = ||J - Jfd||//J|| 6.69028e-06  = ||J - Jfd||
>> >     1 SNES Function norm 4.695397453383e-07
>> >         Testing hand-coded Jacobian, if the ratio is O(1.e-8), the
>> hand-coded Jacobian is probably correct.
>> >         Run with -snes_check_jacobian_display to show difference of
>> hand-coded and finite difference Jacobian.
>> >       2.45109e-09 = ||J - Jfd||//J|| 9.74235e-06  = ||J - Jfd||
>> >     2 SNES Function norm 4.020379099215e-13
>> >     0 SNES Function norm 6.799718390407e-01
>> >         Testing hand-coded Jacobian, if the ratio is O(1.e-8), the
>> hand-coded Jacobian is probably correct.
>> >         Run with -snes_check_jacobian_display to show difference of
>> hand-coded and finite difference Jacobian.
>> >       1.65487e-09 = ||J - Jfd||//J|| 6.5776e-06  = ||J - Jfd||
>> >     1 SNES Function norm 4.558192078678e-08
>> >         Testing hand-coded Jacobian, if the ratio is O(1.e-8), the
>> hand-coded Jacobian is probably correct.
>> >         Run with -snes_check_jacobian_display to show difference of
>> hand-coded and finite difference Jacobian.
>> >       2.93714e-09 = ||J - Jfd||//J|| 1.16742e-05  = ||J - Jfd||
>> >     2 SNES Function norm 9.907308296870e-14
>> >     0 SNES Function norm 1.000842117652e+00
>> >         Testing hand-coded Jacobian, if the ratio is O(1.e-8), the
>> hand-coded Jacobian is probably correct.
>> >         Run with -snes_check_jacobian_display to show difference of
>> hand-coded and finite difference Jacobian.
>> >       1.24476e-09 = ||J - Jfd||//J|| 4.94755e-06  = ||J - Jfd||
>> >     1 SNES Function norm 9.875108391772e-08
>> >         Testing hand-coded Jacobian, if the ratio is O(1.e-8), the
>> hand-coded Jacobian is probably correct.
>> >         Run with -snes_check_jacobian_display to show difference of
>> hand-coded and finite difference Jacobian.
>> >       1.10818e-10 = ||J - Jfd||//J|| 4.40468e-07  = ||J - Jfd||
>> >     2 SNES Function norm 7.677760150017e-14
>> >     0 SNES Function norm 2.179048757949e+00
>> >         Testing hand-coded Jacobian, if the ratio is O(1.e-8), the
>> hand-coded Jacobian is probably correct.
>> >         Run with -snes_check_jacobian_display to show difference of
>> hand-coded and finite difference Jacobian.
>> >       1.32338e-09 = ||J - Jfd||//J|| 5.27058e-07  = ||J - Jfd||
>> >     1 SNES Function norm 4.625448863612e-05
>> >         Testing hand-coded Jacobian, if the ratio is O(1.e-8), the
>> hand-coded Jacobian is probably correct.
>> >         Run with -snes_check_jacobian_display to show difference of
>> hand-coded and finite difference Jacobian.
>> >       1.57582e-09 = ||J - Jfd||//J|| 6.27588e-07  = ||J - Jfd||
>> >     2 SNES Function norm 4.391784647745e-14
>> >     0 SNES Function norm 6.761591873515e-01
>> >         Testing hand-coded Jacobian, if the ratio is O(1.e-8), the
>> hand-coded Jacobian is probably correct.
>> >
>> >
>> >
>> >
>>
>>
>
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