Differential rotation equation in vgrid.py is different from Cegla+2016 Eq. 8

[Huang-CL]

To implement the stellar rotational velocity at lines 40-44 in vgrid.py, the code cites Cegla+2016 Eq. 8, which accounts for the effect of stellar differential rotation. In Cegla et al. Eq. 8, they assumed a differential rotation law derived from the Sun, expressed as (1 - \alpha y'_perp^2). However, in vgrid.py, the velocity appears linear to y', not y'^2. Is it a typo? Or does the code apply another differential rotation law?

[Hoeijmakers]

Dear Huang, thank you very much for your question and I am very sorry to have replied so late.
Your assessment is correct. I have actually discovered the same last week and I am working on a comprehensive update of this code. This is available in the refactor branch, but is not fully operational yet.