# Re: Compute total free energy of a system

Thanks to both of you, I will try it!


Regards,

Anders

________________________________
From: fipy-boun...@nist.gov <fipy-boun...@nist.gov> on behalf of Guyer,
Jonathan E. Dr. (Fed) <jonathan.gu...@nist.gov>
Sent: Thursday, January 4, 2018 6:01:05 PM
To: FIPY
Subject: Re: Compute total free energy of a system

I believe (...).cellVolumeAverage * mesh.cellVolumes.sum() is what you want.

> On Jan 4, 2018, at 10:49 AM, Daniel Wheeler <daniel.wheel...@gmail.com> wrote:
>
> You might want to multiply by the cell volumes, "mesh.cellVolumes".
>
> On Thu, Jan 4, 2018 at 10:22 AM, Anders Ericsson
> <anders.erics...@solid.lth.se> wrote:
>> Hi,
>>
>>
>> I wonder if there is a simple way to compute the total free energy of a
>> system (Phase-field modeling) in FiPy?
>>
>>
>> That is e.g.:
>>
>>
>> $$>> F = \int_V f(\phi, c, T) + \frac{\epsilon_{\phi}^2}{2}\nabla \phi^2 dV >>$$
>>
>> I figured that it would be something in accordance with:
>>
>> def freeEnergyVolume(phi_, c_, T, epsSq):
>>    return (0.5 * epsSq * (phi_.grad.mag)**2 +
>> f(phi_,c_,T)).cellVolumeAverage
>>
>> But cellVolumeAverage wouldn't give me the full energy of the domain if I'm
>> not mistaken?
>
>
> --
> Daniel Wheeler
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