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00001 #include "cs.h" 00002 /* C = A(p,q) where p and q are permutations of 0..m-1 and 0..n-1. */ 00003 cs *cs_permute (const cs *A, const int *pinv, const int *q, int values) 00004 { 00005 int t, j, k, nz = 0, m, n, *Ap, *Ai, *Cp, *Ci ; 00006 double *Cx, *Ax ; 00007 cs *C ; 00008 if (!CS_CSC (A)) return (NULL) ; /* check inputs */ 00009 m = A->m ; n = A->n ; Ap = A->p ; Ai = A->i ; Ax = A->x ; 00010 C = cs_spalloc (m, n, Ap [n], values && Ax != NULL, 0) ; /* alloc result */ 00011 if (!C) return (cs_done (C, NULL, NULL, 0)) ; /* out of memory */ 00012 Cp = C->p ; Ci = C->i ; Cx = C->x ; 00013 for (k = 0 ; k < n ; k++) 00014 { 00015 Cp [k] = nz ; /* column k of C is column q[k] of A */ 00016 j = q ? (q [k]) : k ; 00017 for (t = Ap [j] ; t < Ap [j+1] ; t++) 00018 { 00019 if (Cx) Cx [nz] = Ax [t] ; /* row i of A is row pinv[i] of C */ 00020 Ci [nz++] = pinv ? (pinv [Ai [t]]) : Ai [t] ; 00021 } 00022 } 00023 Cp [n] = nz ; /* finalize the last column of C */ 00024 return (cs_done (C, NULL, NULL, 1)) ; 00025 }