On Mar 20, 2014, at 11:06 AM, Thomas Barkar <[email protected]> wrote:
> I have a question about the setting of coefficients.
> We are currently trying to solve a diffusion problem with variable
> coefficients. Is there a way to set a new value for the coefficients in every
> time step? See schematic example below:
>
>
> eq = TransientTerm() == DiffusionTerm(coeff=myCoeff1) -
> DiffusionTerm((coeff=myCoeff2,myCoeff3))
> while t < duration:
> myCoeff1 = someNewValue
> myCoeff2 = someNewValue
> myCoeff3 = someNewValue
> eq.solve(var=phi, dt=dt)
Simplest case:
myCoeff1 = Variable(value=someValue)
myCoeff2 = Variable(value=someValue)
myCoeff3 = Variable(value=someValue)
eq = TransientTerm() == DiffusionTerm(coeff=myCoeff1) -
DiffusionTerm((coeff=myCoeff2,myCoeff3))
while t < duration:
myCoeff1.value = someNewValue
myCoeff2.value = someNewValue
myCoeff3.value = someNewValue
eq.solve(var=phi, dt=dt)
If your coefficients are functions of solution variables or time, then you
should just write myCoeff1 et al. as the appropriate expressions and let FiPy's
lazy evaluation take care of things for you. See examples/diffusion/mesh1D.py
for examples of a time-dependent boundary condition (a time-dependent
coefficient would work the same) and of a coefficient that is a function of the
solution variable.
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