The fix consists of three parts:
1. Rewriting `inline-matrix*'. The material change here is that the
expansion now contains only direct applications of `+' and `*'.
TR's optimizer replaces them with `unsafe-fx+' and `unsafe-fx*',
which keeps intermediate flonum values from being boxed.
2. Making the types of all functions that operate on (Matrix Number)
values more precise. Now TR can prove that matrix operations preserve
inexactness. For example, matrix-conjugate : (Matrix Flonum) ->
(Matrix Flonum) and three other cases for Real, Float-Complex, and
Number.
3. Changing the return types of some functions that used to return
things like (Matrix (U A 0)). Now that we worry about preserving
inexactness, we can't have `matrix-upper-triangle' always return a
matrix that contains exact zeros. It now accepts an optional `zero'
argument of type A.
* Narrowed type of `submatrix' to only sensible argument types
* `matrix-invertible?' now returns #f when given a non-square matrix
instead of raising an error
* Allowed `matrix-diagonal' to operate on non-square matrices
* At least stubbed out all (or almost all) `math/matrix' exports; many
have complete documentation (e.g. types, predicates, accessors,
constructors, for loops, conversion, much of "Comparing Matrices")
* Moved `matrix-zero?' and fixed to use (matrix-error-norm) as its norm
* Added `matrix-basis-cos-angle' (currently a stub; should return smallest
singular value of a certain matrix multiplication)
