(note: this question was closed on math stack exchange before it was answered, so I'm asking it here)
Suppose one wishes to test if a given surface f(x,y,z,w) = 0 in projective 3 space has singular points (i.e. df/dx = df/dy = df/dz = 0), and one also wishes to calculate these singular points explicitly. Is there a general algorithm for doing this, and does there exist an implementation of this algorithm in a modern programming language?
I've looked into the programming language Magma which seems to have a function "SingularPoints(C) : Sch -> SetIndx" which claims to return "The singular points of the curve C which are defined over the base field of C." But beyond this, the documentation is a bit sparse, and doesn't say if this function works for curves of more than two variables. Here's the link to the documentation:
http://magma.maths.usyd.edu.au/magma/handbook/text/1415#15982
I found the above documentation after looking at the following paper on arxiv:
https://arxiv.org/pdf/2206.05492 (page 109)
I have written my own script in MatLab which does find singular points, but it doesn't find all of them. It takes the naive approach and simply calculates the partial derivatives and attempts to solve for the system. For a quintic polynomial which is known to have 31 singularities, my algorithm only finds 20 singularities. I've looked at the Magma documentation, but I am unfamiliar with that language.