Vortex radius square use in linear functions

[ngoiz]

The parameter vortex_radius_sq is calculated from the input for the vortex_radius. However, when the vortex_radius gets small, the square can lead to numerical issues.

In the linear functions it is used solely as a reference of up to where to compute (i.e. the actual value of the square of the vortex_radius is not required) thus vortex_radius_sq could be any number such that it doesn't cause these inaccuracies.

Using: 4a4a1fe

[ArturoMS13]

i have set "vortex_radius_sq = vortex_radius". We have found accuracy issues when "vortex_radius_sq = vortex_radius*vortex_radius". We believe "vortex_radius_sq" is a limit for numerical accuracy so the changes makes sense.

[ngoiz]

Works, thanks!