** Factors from Gaussian elimination. **

** [L,U] = LU(X) stores a upper triangular matrix in U and a **

** "psychologically lower triangular matrix", i.e. a product **

** of lower triangular and permutation matrices, in L , so **

** that X = L*U. **

** **

** **

** [L,U,P] = LU(X) returns lower triangular matrix L, upper **

** triangular matrix U, and permutation matrix P so that **

** P*X = L*U. **

** **

** **

** By itself, LU(X) returns the output from LINPACK'S ZGEFA routine. **

** **