Need LU Factorization code in MMA

*To*: mathgroup at yoda.physics.unc.edu*Subject*: Need LU Factorization code in MMA*From*: Jack K. Cohen <jkc at dix.mines.colorado.edu>*Date*: Thu, 19 May 94 09:44:55 -0600

I need an LU code for the NON-SQUARE case in MMA. I am losing sleep over this, so I am interested in anything you have that really works. (I've made quite a few attempts that _almost_ work :-) However, my real need is a student level code, so I prefer: 1. Calculations NOT be in place, i.e., given a rectangular matrix A, the code returns the 3 matrices P, L, U such that P . A = L . U 2. Pivoting only be done to avoid zeros, i.e., don't hunt for the max abs pivot, just take the next one that's available. 3. In general, clarity is much more important than efficiency and stability, we'll only be using the code to check hand calculations on small matrices with small integer coefficients. E-mail me directly please and thanks much in advance, Jack