20 lines
650 B
C
20 lines
650 B
C
#include "cs.h"
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/* xi [top...n-1] = nodes reachable from graph of G*P' via nodes in B(:,k).
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* xi [n...2n-1] used as workspace */
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int cs_reach (cs *G, const cs *B, int k, int *xi, const int *pinv)
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{
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int p, n, top, *Bp, *Bi, *Gp ;
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if (!CS_CSC (G) || !CS_CSC (B) || !xi) return (-1) ; /* check inputs */
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n = G->n ; Bp = B->p ; Bi = B->i ; Gp = G->p ;
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top = n ;
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for (p = Bp [k] ; p < Bp [k+1] ; p++)
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{
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if (!CS_MARKED (Gp, Bi [p])) /* start a dfs at unmarked node i */
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{
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top = cs_dfs (Bi [p], G, top, xi, xi+n, pinv) ;
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}
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}
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for (p = top ; p < n ; p++) CS_MARK (Gp, xi [p]) ; /* restore G */
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return (top) ;
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}
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