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using functions for CoefficientFunction
4 years 2 months ago #2972
by sm22
using functions for CoefficientFunction was created by sm22
Hello NGSolve,
I need to use a coefficient function that depends on the spatial coordinates. I tried the following:
But the class can not be an argument for the CoefficientFunction. How to incorporate slightly involved functions such as the one above to be used in bilinear form? Thank you!!
I need to use a coefficient function that depends on the spatial coordinates. I tried the following:
Code:
#!/usr/bin/env python
# coding: utf-8
#
import netgen.gui
from ngsolve import *
from netgen.csg import *
from netgen.geom2d import unit_square
# initialise mpi
comm = mpi_world
rank = comm.rank
nproc= comm.size
mesh = Mesh(unit_square.GenerateMesh(maxh=0.2))
#
fes = H1(mesh, complex=True, order=2)
u = fes.TrialFunction()
v = fes.TestFunction()
R=0.8
class myCoeff:
def __init__(self):
self.R = R
def eval(self, value, x):
outside = ( x >= R )
coeff = 1. / (x - R)
value = outside * coeff
C = CoefficientFunction(myCoeff)
# want to use a coefficient in the bilinear form:
# a = BilinearForm (fes, symmetric=True)
# a += SymbolicBFI (C*grad(u)*grad(v))
But the class can not be an argument for the CoefficientFunction. How to incorporate slightly involved functions such as the one above to be used in bilinear form? Thank you!!
- mneunteufel
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4 years 2 months ago #2974
by mneunteufel
Replied by mneunteufel on topic using functions for CoefficientFunction
Hi sm22,
the IfPos CoefficientFunction should work
see also the documentation for CoefficientFunctions . If you need a fancy CoefficientFunction which is not available there is the possibility to define your own CoefficientFunction in C++ and then to export it to Python, see this link .
Best
Michael
the IfPos CoefficientFunction should work
Code:
IfPos(x-R,1/(x-R),0)
see also the documentation for CoefficientFunctions . If you need a fancy CoefficientFunction which is not available there is the possibility to define your own CoefficientFunction in C++ and then to export it to Python, see this link .
Best
Michael
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