function [L,U,P] = lu_rightp (A) %LU_RIGHTP right-looking LU factorization, with partial pivoting. % % Example: % [L,U,P] = lu_rightp (A) % See also: cs_demo % CXSparse, Copyright (c) 2006-2022, Timothy A. Davis. All Rights Reserved. % SPDX-License-Identifier: LGPL-2.1+ n = size (A,1) ; P = eye (n) ; for k = 1:n [x,i] = max (abs (A (k:n,k))) ; % partial pivoting i = i+k-1 ; P ([k i],:) = P ([i k], :) ; A ([k i],:) = A ([i k], :) ; % (6.10), (6.11) A (k+1:n,k) = A (k+1:n,k) / A (k,k) ; % (6.12) A (k+1:n,k+1:n) = A (k+1:n,k+1:n) - A (k+1:n,k) * A (k,k+1:n) ; % (6.9) end L = tril (A,-1) + eye (n) ; U = triu (A) ;