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Interpolation from vector expression to vector function
6 years 11 months ago #295
by Karatza
Interpolation from vector expression to vector function was created by Karatza
Dear NGSolve users and developers,
I read the section "Interpolate a CoefficientFunction" of
ngsolve.org/docu/nightly/i-tutorials/uni...ficientfunction.html
and I would like to interpolate a vector expression to a vector function following the same
snippet. How should I do that?
Below you can find a code where I try to
a) interpolate from scalar expression to scalar space: this is working correctly
b) interpolate from scalar expression to each component of vector space: this is working correctly
c) my case, interpolate from vector expression to vector function, and two ways I tried, and the corresponding errors
Thanks,
best regards,
Makis
I read the section "Interpolate a CoefficientFunction" of
ngsolve.org/docu/nightly/i-tutorials/uni...ficientfunction.html
and I would like to interpolate a vector expression to a vector function following the same
snippet. How should I do that?
Below you can find a code where I try to
a) interpolate from scalar expression to scalar space: this is working correctly
b) interpolate from scalar expression to each component of vector space: this is working correctly
c) my case, interpolate from vector expression to vector function, and two ways I tried, and the corresponding errors
Thanks,
best regards,
Makis
Code:
from ngsolve import *
from netgen.geom2d import unit_square
ngsglobals.msg_level = 0
mesh = Mesh (unit_square.GenerateMesh(maxh=0.2))
myfunc = x*(1-x)
# a) Interpolate from scalar expression to scalar space: working
V1 = H1(mesh, order=1)
u1 = GridFunction(V1)
u1.Set(myfunc)
print(u1.vec.Norm())
# b) Interpolate from scalar expression to each component of vector space: working
V2 = FESpace([V1, V1])
u2 = GridFunction(V2)
u20 = 2*u1
u21 = 3*u1
u2.components[0].Set(u20)
u2.components[1].Set(u21)
print(u2.vec.Norm(), u1.vec.Norm()*sqrt(13))
# c) Interpolate from vector expression to vector function
u3 = GridFunction(V2)
u2_double = 2*u2
# c1)
u3.Set(u2_double) # Segmentation fault
# c2)
u3.components[0].Set(u2_double[0]) # RuntimeError: don't know my dimension, space is N6ngcomp15CompoundFESpaceE
u3.components[1].Set(u2_double[1])
print(u3.vec.Norm(), u1.vec.Norm()*2)
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6 years 11 months ago #299
by christopher
Replied by christopher on topic Interpolation from vector expression to vector function
This should work:
This creates a vector valued CoefficientFunction.
The problem here is, that set would require a vectorized space to be set with a vectorized coefficient function, but you have a vector of spaces (the internal layout of the dofs is different)
If you use a vectorized space then you can do that:
Best
Christopher
Code:
u2_double = CoefficientFunction((2*u2.components[0],2*u2.components[1]))
u3.components[0].Set(u2_double[0])
u3.components[1].Set(u2_double[1])
The problem here is, that set would require a vectorized space to be set with a vectorized coefficient function, but you have a vector of spaces (the internal layout of the dofs is different)
If you use a vectorized space then you can do that:
Code:
V2 = H1(mesh,order=1,dim=2)
u3 = GridFunction(V2)
u1_double = CoefficientFunction((2*u1, 2*u1))
u3.Set(u1_double)
Best
Christopher
The following user(s) said Thank You: Karatza
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