First of all: Thank you so much for your help!
> I would use .getFaceGrad() here, not .getFaceGradAverage(). I didn't realize
> we even had such a function (for five years!), and contrary to its
> documentation, I think it has to be 1st order accurate, not 2nd. For what
> it's worth, it doesn't appear that we use it anywhere.
Thanks for the tip, but it didn't seem to change much...
>> So here's my question: Am I on the right track here? Is this the right
>> way to solve my PDE? Is manually updating the variables for each
>> timestep the way to go?
>
> Manually updating phi as a result of your renormalization is probably
> necessary, although it's possible that you're not doing what you intend. If
> you show me the code for your update, I can check that it has the effect you
> want.
I am updating the function H in the following way:
newHValues = [0.0] * len(centers)
for i in range(len(centers)):
alpha = centers[i]
newHValues[i] = h(alpha, t)
H.setValue(newHValues)
The normalization is performed the same way:
for value in values:
normalization += value * dAlpha
for i in range(length):
newValues[i] = values[i] / normalization
phi.setValue(value=newValues)
Is this slover than using variables?
> Since you are renormalizing \phi, you should sweep the solution at each
> timestep, as you are effectively introducing a non-linearity, even though
> your equation is not explicitly non-linear.
How would I combine the renormalization and the sweeping? I tried
something along the lines of:
for step in range(timeSteps):
#update the H function variable
for i in range(sweepSteps):
eq.sweep(var=phi, boundaryConditions=BCs, dt=timeStepDuration)
normalize(phi, dAlpha)
phi.updateOld()
Where normalize directly sets the value of phi (as can be seen in the
code I posted earlier). Is this the right way? It doesn't seem to make
any difference...
When compared to a solution that I get from Mathematica, my solution
tends to evolve slower. When convoluting the probability distribution
phi for each timestep with an almost linear weight-function, I always
get a value that is lower than the one Mathematica calculates (see
http://imgur.com/SCzVT ).
Any ideas what the reason could be?
Cheers,
Matej
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