A using Gaussian elimination with partial pivoting. On Return a is the n by n transformed matrix A , containing the results of the factorization. U is an upper triangular matrix.
P is the permutation matrix.
If n is 0, no computation is performed. Error Conditions Resource Errors Unable to allocate internal work area. Computational Errors Matrix A is singular. The return code is set to 1. This example shows a factorization of a real general matrix A of order 9.