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CoefficientFunction with spacial condition

4 years 2 weeks ago #2531 by NilsHM

CoefficientFunction with spacial condition was created by NilsHM

Hello everyone,

I would like to set a CoefficientFunction that is different on the y-axis than anywhere else.
I hoped to do this as follows:

Code:

cf1 = 2*x
cf2 = CoefficientFunction(1)
cf = CoefficientFunction([cf2 if X == 0.0 else cf1 for X in x])

but cf now is zero everwhere.

How can I make cf be cf1 but cf2 on the y-axis?

Best
Nils

4 years 2 weeks ago #2532 by mneunteufel

Replied by mneunteufel on topic CoefficientFunction with spacial condition

Hi Nils,

I think the IfPos-CoefficientFunction is what you are looking for.

Code:

IfPos(x,0,IfPos(-x,0,1))

Maybe you need to "regularize" it a bit

Code:

eps = 1e-8
IfPos(x-eps,0,IfPos(-x-eps,0,1))

Best
Michael

The following user(s) said Thank You: NilsHM

4 years 2 weeks ago #2533 by NilsHM

Replied by NilsHM on topic CoefficientFunction with spacial condition

Thanks!

That was exactly what I needed.

Best

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