New answers tagged numerical-value
4
I am not sure I understand your question 100%, do you mean something like this:
r = RegionDifference[
RegionDifference[Cuboid[{-1, -1, -1}, {1, 1, 1}],
Cylinder[{{0, 0, -1/4}, {0, 0, -1/2}}, 1/2]],
Cylinder[{{0, 0, 1/4}, {0, 0, 1/2}}, 1/2]];
Needs["NDSolve`FEM`"]
(mesh = ToElementMesh[r,
"RegionHoles" -> {{0, 0, 3/8}, {0, 0, -3/8}}])["...
1
I think something is not quite right with way you process the equations. If you use this you get what you expect:
b = 1;
c = 1;
h[x_] = -b x + c Cos[2 x]/2;
Lh[l_, x_] := D[l[x], x, x] - (1/4) (D[h[x], x])^2 l[x]
{vals, funs} =
NDEigensystem[{-Lh[l, x], l[0] == l[Pi]}, l, {x, 0, Pi}, 6,
Method -> {"PDEDiscretization" -> {"FiniteElement", {"...
2
For NDEigensystem[], only homogeneous boundary conditions can be set. In this case, we have
b = 1;
c = 1;
h[x_] := -b x + c Cos[2 x]/2
eq = -(D[l[z], z, z] - (1/4) (D[h[z], z])^2 l[z]);
{vals, funs} =
NDEigensystem[{eq, DirichletCondition[l[z] == 0, z == 0 || z == Pi]},
l[z], {z, 0, Pi}, 5]
Table[Plot[{eq /. l[z] -> funs[[i]], vals[[i]] funs[[i]]...
Top 50 recent answers are included
