sympy.vector Divergence() gives wrong answers in Cylindrical Coordinates

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Oct 31, 2021, 8:42:13 PM10/31/21

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Hello,

I discovered that the divergence() function from sympy.vector gives incorrect answers sometimes when using Cylindrical coordinates. For example:

divergence( 1 * rhat )

# returns 0 when it should give 1/R

I found that this issue was raised last year, and a patch offered, but it was never integrated into the sympy release.

I went into sympy/vector/operators.py and commented out lines 366-368 by hand. That seems to have fixed the problem.

I also found this library, called "symfields" which does div, grad, curl properly in cylindrical, spherical, or any curvilinear coordinate system

it does not use CoordSys3D.

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Nov 5, 2021, 1:32:00 AM11/5/21

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Could you please either show the code that gave that result or else add it as a test for #20047

/c

unread,

Nov 5, 2021, 2:53:45 AM11/5/21

to sympy

nevermind - a test was added. If you would like to see more added, please see https://github.com/sympy/sympy/pull/22427

/c

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