@User the old "gate matrix" technique might be interesting for you: https://open.library.ubc.ca/cIRcle/collections/ubctheses/831/items/1.0064932

The ASTRAN paper is a bit more state of the art.

Spice is from 1973, Magic from 1983. A technique from 1989 is actually more modern

And the paper I linked is from 2008.

Yes, I read it. Thanks for the reference