I think I understand the purpose of that routine. I seems to be an
approximation to the following form:
[J] x_weighted = - sum_i ( w_i {partial R / partial p_i} )
and is only called from the routines dealing with the Hessian in
ImplicitSystem.
-Manav
On Fri, Nov 1, 2013 at 11:49 AM, Manav Bhatia <[email protected]> wrote:
> Hi,
>
> I am currently working on adding support for use supplied sensitivity.
>
> In the process, I looked at the code in
> ImplicitSystem::weighted_sensitivity_solve(), and now want to make sure I
> understand what is going on inside it.
>
> The header file describes the idea to be
>
> [J] x_weighted = - sum_i ( w_i {partial R / partial p_i} )
>
> but what seems implemented is
>
> [J] x_weighted = - partial R / partial p_weighted
>
> where p_weighted = sum_i w_i * p_i .
>
> I would appreciate if someone could clarify.
>
> Thanks,
> Manav
>
> On Fri, Nov 1, 2013 at 12:11 AM, Manav Bhatia <[email protected]>wrote:
>
>> Thanks Paul!
>>
>> I need this soon and will start hacking tomorrow morning.
>>
>> Will keep you in the loop.
>>
>> Manav
>>
>> On Oct 31, 2013, at 11:09 PM, "Paul T. Bauman" <[email protected]>
>> wrote:
>>
>> On Thu, Oct 31, 2013 at 5:00 PM, Roy Stogner
>> <[email protected]>wrote:
>>
>>>
>>> On Thu, 31 Oct 2013, Manav Bhatia wrote:
>>>
>>> > My applications provide analytical sensitivity of RHS for
>>> sensitivity
>>> > analysis. The current code structure seems to assumed finite
>>> differencing
>>> > for this, and I am hoping to use my routines instead.
>>> >
>>> > Perhaps it would be best to provide for a
>>> user_sensitivity_function, or
>>> > user_sensitivity_object like the assembly_object in system.
>>> >
>>> > I this seems relevant (?), I can take a dig at it and share a patch.
>>>
>>> Paul Bauman had some plans along these lines, so let me double-check
>>> that he saw this post; he may already have something partly done or he
>>> may have some suggestions about the API.
>>>
>>
>> Yeah, sorry, been slow to reply today. Been a fun day in TX if you live
>> near the Blanco river…
>>
>> So I had hacked together what I needed for a project I was working on and
>> haven't ported back to libMesh yet (in particular, FEMSystem), but here's
>> the general idea. All the code I've written thus far is here (in GRINS):
>> https://github.com/pbauman/grins/compare/sensitivity_hacking
>>
>> IIRC, the higher level part of the residual derivatives was done
>> correctly. That is, default is finite difference, but the user can override
>> with analytical without having to recode the global loop. And that's what I
>> did here. I took it further and added
>> element_residual_parameter_derivative, etc. for FEMSystem style
>> computation. However, IIRC (and apologies if I'm not), the QoI derivative
>> wasn't as completely separated. Again, want to finite difference by default
>> and let the user override for analytical. In the GRINS branch I linked to,
>> I hadn't ported the finite difference, I just set up what I need. If I had
>> 2 days, I could finish this off. Alas.
>>
>> Manav, if you're up for it, you're more than welcome to take any of that
>> code and create a libMesh patch. I could at least make time to answer
>> questions, look at some of your code, and steer you in the right direction.
>>
>> Best,
>>
>> Paul
>>
>>
>
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