iFEM is a MATLAB software package containing robust, efficient, and easy-following codes for the main building blocks of adaptive finite element methods on unstructured simplicial grids in both two and three dimensions.
Home Page: https://lyc102.github.io/ifem/
License: GNU General Public License v3.0
@lyc102 just using ifem to produce an adaptive shallow water equation solver. But ran into a strange problem with eleminterpolate when interpolating from a fine mesh to a coarse mesh.
For some reason the last command in eleminterpolate.m
newp(tree(:,3)) = [];
doesn't seem to be applied (at least in some cases).
I have attached an example where the error turns up (at least when using matlab R2017a)
I can get around the problem by explicitly adding the command newp(tree(:,3)) = []; after the call to eleminterpolate.
By the way, ifem is an impressive package, well done.
Professor Chen,
Sorry to disturb you. There's some bug in my codes and it took a lot of effort and time to get nothing. I was coding the adaptive Wilson element to solve the Poisson equation. Since it is the rectangle element, I can rarely refer to you ifem package. I write the square bisect codes (bisectQuad.m). In the solving step (PoissonWilson.m), things go right when dealing with the uniform refinement (compSolFig_nohang.m). While with hangnodes, it goes wrong (compSolFig_hang.m).
I am hoping if you can have a look on my codes when you are spare. Thanks a lot!
The theoretical results refer to the following pdf.
Have a nice day!
Xuemei ZHou
A Ph.D. student of Chinese Academy of Sciences
One data m file is missing, which is just the Lshapedata.m in your ifem package.
Hello!
so far it seems that the periodic boundary conditions are not applied for CahnHillard Benchmark?
Best regards!
HodgeLaplacianE(node,elem,pde,bdFlag,option) <---> HodgeLaplacianE(node,elem,bdFlag, pde, option)
mfemHodgeLap(node,elem,bdFlag,pde,option) <-----> mfemHodgeLap(mesh,pde,option,varargin)
In 842ba40 commit, the loop ordering of the cubemesh is changed such that the elem generated by it will have a nice ascending ordering in both rows and columns. For example
[node, elem] = cubemesh([-1,1,-1,1,-1,1],1);gives
elem =
1 4 5 14
1 2 5 14
1 10 13 14
1 10 11 14
1 4 13 14
1 2 11 14
2 5 6 15
2 3 6 15
2 11 14 15
2 11 12 15
2 5 14 15
2 3 12 15
4 7 8 17
4 5 8 17
4 13 16 17
4 13 14 17
4 7 16 17
4 5 14 17
5 8 9 18
5 6 9 18
5 14 17 18
5 14 15 18
5 8 17 18
5 6 15 18
10 13 14 23
10 11 14 23
10 19 22 23
10 19 20 23
10 13 22 23
10 11 20 23
11 14 15 24
11 12 15 24
11 20 23 24
11 20 21 24
11 14 23 24
11 12 21 24
13 16 17 26
13 14 17 26
13 22 25 26
13 22 23 26
13 16 25 26
13 14 23 26
14 17 18 27
14 15 18 27
14 23 26 27
14 23 24 27
14 17 26 27
14 15 24 27
Visualizing the elements by a six-element group we will have
However, if we do from cubemesh then uniformrefine3, the ascending ordering is gone.
[node,elem] = cubemesh([-1,1,-1,1,-1,1],2);
[node,elem] = uniformrefine3(node,elem);gives
elem =
1 10 11 15
1 9 11 15
1 12 14 15
1 12 13 15
1 10 14 15
1 9 13 15
10 3 19 21
9 2 16 18
12 5 24 25
12 5 23 25
10 3 20 21
9 2 17 18
11 19 4 22
11 16 4 22
14 24 7 27
13 23 6 26
14 20 7 27
13 17 6 26
15 21 22 8
15 18 22 8
15 25 27 8
15 25 26 8
15 21 27 8
15 18 26 8
10 11 15 21
9 11 15 18
12 14 15 25
12 13 15 25
10 14 15 21
9 13 15 18
10 11 19 21
9 11 16 18
12 14 24 25
12 13 23 25
10 14 20 21
9 13 17 18
11 15 21 22
11 15 18 22
14 15 25 27
13 15 25 26
14 15 21 27
13 15 18 26
11 19 21 22
11 16 18 22
14 24 25 27
13 23 25 26
14 20 21 27
13 17 18 26
and visualizing the refined elements by 6-element groups yields something like the following:
uniformrefine3, this is somewhat unwanted from a development pov.Does "ifem" support VEM elements with the adaptive solver?
when I run the example\fem\Maxwell\Maxwell3ND0femrate.m, the fellowing error will appear
Output argument "isBdNode" (and possibly others) not assigned a value in
the execution with "gradmatrix" function.
Error in mgMaxwell (line 79)
[grad,isBdNode] = gradmatrix(edge,isBdEdge);
Error in Maxwell (line 393)
[u,info] = mgMaxwell(bigAD,f,AP,node,elemold,edge,HB,option);
Error in femMaxwell3 (line 60)
[u,edge,eqn,info] = Maxwell(node,elem,bdFlag,pde,option);
Error in Maxwell3ND0femrate (line 39)
femMaxwell3(mesh,pde,option);
this error will be resolved when I make the following changes to the file solver/gradmatrix.m
@@ -28,5 +28,6 @@ if any(isBdEdge) % no grad on boundary edges
idx = ~(isBdEdge(i) | isBdNode(j));
else
idx = 1:length(i);
isBdNode = false(N,1);
end
grad = sparse(i(idx),j(idx),s(idx),NE,N);
is the modification reasonable? thank you.
Is there 3D VEM code?
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