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// CXSparse/Source/cs_cumsum: cumulative sum
// CXSparse, Copyright (c) 2006-2022, Timothy A. Davis. All Rights Reserved.
// SPDX-License-Identifier: LGPL-2.1+
#include "cs.h"
/* p [0..n] = cumulative sum of c [0..n-1], and then copy p [0..n-1] into c */
double cs_cumsum (CS_INT *p, CS_INT *c, CS_INT n)
{
CS_INT i, nz = 0 ;
double nz2 = 0 ;
if (!p || !c) return (-1) ; /* check inputs */
for (i = 0 ; i < n ; i++)
{
p [i] = nz ;
nz += c [i] ;
nz2 += c [i] ; /* also in double to avoid CS_INT overflow */
c [i] = p [i] ; /* also copy p[0..n-1] back into c[0..n-1]*/
}
p [n] = nz ;
return (nz2) ; /* return sum (c [0..n-1]) */
}
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