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// CXSparse/Source/cs_usolve: 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 Ux=b where x and b are dense. x=b on input, solution on output. */
CS_INT cs_usolve (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 = n-1 ; j >= 0 ; j--)
{
x [j] /= Ux [Up [j+1]-1] ;
for (p = Up [j] ; p < Up [j+1]-1 ; p++)
{
x [Ui [p]] -= Ux [p] * x [j] ;
}
}
return (1) ;
}
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