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Divergence of inverse square

asked 2021-02-07 00:15:43 +0100

curios_mind gravatar image

Hello,

I tried to calculate the divergence of 1/r^2e_r, but I got zero, where it should have been 4pidirac_delta(re_r)

E.<r,th,ph>=EuclideanSpace(coordinates="spherical")
v=E.vector_field([1/r^2,0,0])
v.div().display()

Results is

E^3 --> R
(r, th, ph) |--> 0

Can this be considered as a bug?

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answered 2021-02-07 14:24:51 +0100

eric_g gravatar image

In the current implementation, vector fields are assumed to be smooth functions on their domain. The vector field that you have defined is not (actually, it is not even defined at $r=0$), so I would say this is not a bug.

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It would have been great, if it had given the dirac solution.

curios_mind gravatar imagecurios_mind ( 2021-02-08 14:54:22 +0100 )edit

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Asked: 2021-02-07 00:15:43 +0100

Seen: 210 times

Last updated: Feb 07 '21