The LU code in linearalgebra works for double floats, bigfloats, and ....
Actually, by defining a new 'mring' structure, it's possible to get
LU, Cholesky, and eigens_by_jacobi to work for data types that are
unknown to Maxima. The same LU function (and Cholesky,...) works for
all data types.
It seems that if I followed your suggestions, I'd need to write
a separate LU function for doubles, one for complex doubles, and one for
any other
type I'd like to speed up. I was trying to avoid doing that
(and I doubt that I would try to do that). I could extract the spendy
parts of the LU function and specialize that code for a few different
types.
Maybe there is no simple solution.
Barton