[petsc-users] checking jacobian

[Barry Smith]

  You also have to KEEP the -snes_check_jacobian option

  Barry

> On Aug 11, 2015, at 1:09 PM, Gideon Simpson <gideon.simpson at gmail.com> wrote:
> 
> I don’t see it listed in -help, but I do get
> 
> ./blowup -xmax 50 -nx 1000 -snes_check_jacobian
>       Testing hand-coded Jacobian, if the ratio is O(1.e-8), the hand-coded Jacobian is probably correct.
>       Run with -snes_check_jacobian_view [viewer][:filename][:format] to show difference of hand-coded and finite difference Jacobian.
>     63386.1 = ||J - Jfd||//J|| 63386.1  = ||J - Jfd||
> 
> -gideon
> 
>> On Aug 11, 2015, at 2:07 PM, Matthew Knepley <knepley at gmail.com> wrote:
>> 
>> On Tue, Aug 11, 2015 at 1:04 PM, Gideon Simpson <gideon.simpson at gmail.com> wrote:
>> Macports installation of 3.5.3.
>> 
>> Use -help to find the option name. Maybe its -snes_test.
>> 
>>   Thanks,
>> 
>>     Matt
>>  
>> -gideon
>> 
>>> On Aug 11, 2015, at 2:03 PM, Matthew Knepley <knepley at gmail.com> wrote:
>>> 
>>> On Tue, Aug 11, 2015 at 12:51 PM, Gideon Simpson <gideon.simpson at gmail.com> wrote:
>>> #End of PETSc Option Table entries
>>> There is one unused database option. It is:
>>> Option left: name:-snes_check_jacobian_view (no value)
>>> 
>>> This is the option for the newest release. What are you using?
>>> 
>>>    Matt
>>>  
>>> -gideon
>>> 
>>>> On Aug 11, 2015, at 1:50 PM, Matthew Knepley <knepley at gmail.com> wrote:
>>>> 
>>>> On Tue, Aug 11, 2015 at 12:49 PM, Gideon Simpson <gideon.simpson at gmail.com> wrote:
>>>> Maybe it’s a quirk of the macports installation of petsc, but nothing seems to be getting generated.
>>>> 
>>>> Run with -options_left. Is it reading the option?
>>>> 
>>>>   Matt
>>>>  
>>>> -gideon
>>>> 
>>>>> On Aug 11, 2015, at 1:40 PM, Jed Brown <jed at jedbrown.org> wrote:
>>>>> 
>>>>> Gideon Simpson <gideon.simpson at gmail.com> writes:
>>>>> 
>>>>>> I’m a bit confused by the following options:
>>>>>> 
>>>>>> Run with -snes_check_jacobian_view [viewer][:filename][:format] to show difference of hand-coded and finite difference Jacobian.
>>>>>> 
>>>>>> What flags do I pass it to get some output to diagnose my Jacobian error?
>>>>> 
>>>>> Nothing to display ASCII to the screen.  You might use
>>>>> "binary:thematrix" if you want to read it in with Python or MATLAB, for
>>>>> example.
>>>> 
>>>> 
>>>> 
>>>> 
>>>> -- 
>>>> What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.
>>>> -- Norbert Wiener
>>> 
>>> 
>>> 
>>> 
>>> -- 
>>> What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.
>>> -- Norbert Wiener
>> 
>> 
>> 
>> 
>> -- 
>> What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.
>> -- Norbert Wiener
>