>>>>> "Ether" == Ether Jones <maxima at etherjones.us> writes:
Ether> Does Maxima have QR factorization built in?
Ether> i.e.? A = Q*R
Ether> where A has more rows than columns, Q is orthogonal, and R is upper triangular?
Ether> Also, does? Maxima have a backsubstitution method, so that
Ether> the overdetermined linear system? Ax~b can be solved using QR factorization by solving
Ether> Rx=Q'b by backsubstitution?
Did you ever get lapack to compile on your system?
I poked around a bit and see that lapack has a dgels routine that
solves overdetermined or underdetermined real linear systems involving
an M-by-N matrix A, or its transpose, using a QR or LQ factorization
of A. It is assumed that A has full rank.
Would that be of use to you? It doesn't give you Q or R, but does
give you the solution.
There's no interface to it in maxima (and dgels isn't in maxima), but
it shouldn't be hard to add dgels and a rudimentary interface for it.
Ray