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Compound space on different meshes
3 years 2 months ago #3966
by janfp
Compound space on different meshes was created by janfp
Dear all,
to simulate a PDE-ODE-System, I was trying to use a compound FE-Space on two different mesh, one with only one DOF (for the ODE). However, it seems that assembling in such a space does not work properly.
Is this a bug or am I using it in an unintended way?
Minimal example:
to simulate a PDE-ODE-System, I was trying to use a compound FE-Space on two different mesh, one with only one DOF (for the ODE). However, it seems that assembling in such a space does not work properly.
Is this a bug or am I using it in an unintended way?
Minimal example:
Code:
from ngsolve.meshes import Make1DMesh
from ngsolve.meshes import Mesh as NgMesh
from netgen.meshing import *
from ngsolve import *
nx = 10
ngsmesh = Make1DMesh(nx)
ngsmesh_ODE = Make1DMesh(1) # For the ODE, thus only one DOF
fes1 = L2(ngsmesh_ODE, order=0)
fes2 = L2(ngsmesh, order=1, dgjumps=True)
fes = FESpace([fes1,fes2])
u,v = fes.TnT()
m = BilinearForm(fes)
m.components[0] += BFI("mass", coef=1) #u[0]*v[0]*dx
m.components[1] += BFI("mass", coef=1) #u[1]*v[1]*dx
m.Assemble()
print(m.mat)
3 years 2 months ago #3967
by joachim
Replied by joachim on topic Compound space on different meshes
The component-spaces of a compound space have to live on the same mesh.
You can use NumberFESpace instead. It is one constant function on the whole domain.
Joachim
You can use NumberFESpace instead. It is one constant function on the whole domain.
Joachim
The following user(s) said Thank You: janfp
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3 years 2 months ago - 3 years 2 months ago #3968
by christopher
Replied by christopher on topic Compound space on different meshes
Compound spaces expect the same mesh to be defined on. But you can use a global space with one dof by using the NumberSpace:
Code:
fes1 = NumberSpace(ngsmesh)
fes2 = L2(ngsmesh, order=1, dgjumps=True)
fes = fes1 * fes2
(uO, u), (vO, v) = fes.TnT()
m = BilinearForm(fes)
m += uO * vO * dx
m += u * v * dx
m.Assemble()
print(m.mat)
Last edit: 3 years 2 months ago by christopher.
The following user(s) said Thank You: janfp
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