factors a N+1-by-N matrix using LU factorization with row
partial pivoting. The main algorithm is the "right looking" variant
with or without look-ahead. The lower triangular factor is left
unpivoted and the pivots are not returned. The right hand side is the
N+1 column of the coefficient matrix.
GRID (local input) HPL_T_grid *
On entry, GRID points to the data structure containing the
process grid information.
ALGO (global input) HPL_T_palg *
On entry, ALGO points to the data structure containing the
A (local input/output) HPL_T_pmat *
On entry, A points to the data structure containing the local