I have a problem using the FF package.
In[]:=
FEMAddOnsInstall[];
In[]:=
Needs["FEMAddOns`"]
In[]:=
Needs["NDSolve`FEM`"]
Mesh:
In[]:=
bmesh1=ToBoundaryMesh
,MaxCellMeasureInfinity;
In[]:=
bmesh2=ToBoundaryMesh
,MaxCellMeasureInfinity;
In[]:=
bmesh3=ToBoundaryMesh
,MaxCellMeasureInfinity;
In[]:=
bmesh=BoundaryElementMeshJoin[bmesh1,bmesh2,bmesh3]
Out[]=
ElementMesh[{{-1.,1.},{-1.,1.}},Automatic]
In[]:=
mesh=ToElementMesh[bmesh,"RegionMarker"{{{0,0.5},10},{{0,-0.5},20}},"MaxCellMeasure"0.005]
Out[]=
ElementMesh[{{-1.,1.},{-1.,1.}},{TriangleElement[<983>]}]
Material Properties:
In[]:=
kk=Piecewise[{{0.079,ElementMarker10},{0.235,ElementMarker20}}];
In[]:=
ρρ=Piecewise[{{7.87,ElementMarker10},{2.7,ElementMarker20}}];
In[]:=
cc=Piecewise[{{0.44,ElementMarker10},{0.9,ElementMarker20}}];
Initial and Boundary Condition:
In[]:=
in={u[x,y,0]==0,​​DirichletCondition[u[x,y,t]100Sin[2πAbs[x]],{x,y}∈bmesh1],DirichletCondition[u[x,y,t]10,{x,y}∈bmesh2]};
In[]:=
neu=NeumannValue[1000,{x,y}∈bmesh3];
Solution:
In[]:=
eq=Div[kkGrad[u[x,y,t],{x,y}],{x,y}]+

e
ger
==ρρccD[u[x,y,t],t]+neu/.

e
ger
->50//Simplify
Out[]=
50+
0.079
ElementMarker10
0.235
ElementMarker20
0
True

(0,2,0)
u
[x,y,t]+
(2,0,0)
u
[x,y,t]NeumannValue[1000,{x,y}∈ElementMesh[{{-1.,1.},{0.,0.}},Automatic]]+
0.44
ElementMarker10
0.9
ElementMarker20
0
True
7.87
ElementMarker10
2.7
ElementMarker20
0
True
(0,0,1)
u
[x,y,t]
In[]:=
dsol=NDSolve[Join[{eq},in],u,{t,0,20},{x,y}∈mesh]//Flatten
CompiledFunction
:Argument {Boole[{1.,0.}∈ElementMesh[{{1.,0.},{-1.,0.},{0.,0.}},Automatic,{LineElement[{{2},{2}},{1,1}]},{PointElement[{{1},{1},{1}},{1,1,1}]}]],9,83} at position 1 should be a rank 1 tensor of machine-size integers.
Out[]=
uInterpolatingFunction
Domain: {{-1.,1.},{-1.,1.},{0.,20.}}
Output: scalar
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
The above message appears. Does anyone know how to solve this?