QR FACTORIZATION
QR factorization, also known as the QR decomposition, is a matrix factorization technique that decomposes a matrix into a product of an orthogonal matrix and an upper triangular matrix. Given an m × n matrix A, QR factorization finds an orthogonal matrix Q and an upper triangular matrix R such that A = QR, where Q is an m × m orthogonal matrix and R is an m × n upper triangular matrix.