Spurious calculation with body at X=[0,0,0]

[EdoAlvarezR]

I ran into an odd case where a vortex particle initiated at X=[0,0,0] was getting spurious calculations from the FMM. After shifting all the particles by a small amount, the spurious calculation at that center particle went away.

Is there anything in the calculation of spherical harmonics that would break if there is an element located exactly at X=[0,0,0]?

In case it matters, my particle field was initiated from a uniform Cartesian grid, so it was symmetric about the global origin.

[rymanderson]

Interesting- can you share a minimal working example? Nothing immediately comes to mind that would cause that- certainly not in the definition of the spherical harmonics- but I'm happy to look into it.