[petsc-dev] -snes_check_jacobian

[Barry Smith]

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!

  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.
> 
> 
> 
>