Yeah, that's how I have it now. It seemed better to have it all in one function, for distributing it to the parallel workers and loading and unloading, but what do I know.

@xzczd I have a compiled version of LinearSolve borrowed from here, which is somewhat faster. And I get a good speed up from all of the complex building up of each matrix (i.e. all the manipulations on what I call arg1.) I could really use some help writing code that isn't ToExpression[string] though!

@MichaelE2 Maybe I'm mistaken, but I'm solving the same polynomial with different parameter values and I want to save that structure and feed in (typed) parameter values. I thought that Compile would help. And NSolve seems to take forever for sure. I've been trying to switch to Root with a few different starting points.

Thanks, I don't know how I could have figured that out on my own.