// CXSparse/Source/cs_utsolve: x=U'\b where x and b are dense // CXSparse, Copyright (c) 2006-2022, Timothy A. Davis. All Rights Reserved. // SPDX-License-Identifier: LGPL-2.1+ #include "cs.h" /* solve U'x=b where x and b are dense. x=b on input, solution on output. */ CS_INT cs_utsolve (const cs *U, CS_ENTRY *x) { CS_INT p, j, n, *Up, *Ui ; CS_ENTRY *Ux ; if (!CS_CSC (U) || !x) return (0) ; /* check inputs */ n = U->n ; Up = U->p ; Ui = U->i ; Ux = U->x ; for (j = 0 ; j < n ; j++) { for (p = Up [j] ; p < Up [j+1]-1 ; p++) { x [j] -= CS_CONJ (Ux [p]) * x [Ui [p]] ; } x [j] /= CS_CONJ (Ux [Up [j+1]-1]) ; } return (1) ; }