Dirac delta distribution (dolfinx)

3

If you want the point source to not align with the grid, you could use
x = ufl.SpatialCoordinate(mesh)
to defined the Dirac delta as the limit distribution:

delta_a = 1/(np.abs(a)*np.sqrt(pi))*ufl.exp(-(x[0]/a)**2).
If the point of interest aligns with the mesh, you should use

dofs = dolfinx.fem.locate_dofs_geometrical(V,  lambda x: np.isclose(x.T, [px, py,pz]).all(axis=1))
u.x.array[dofs] = 1

(if V is a scalar space).

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