1 #include "cs.h" 2 /* pinv = p', or p = pinv' */ cs_pinv(CS_INT const * p,CS_INT n)3CS_INT *cs_pinv (CS_INT const *p, CS_INT n) 4 { 5 CS_INT k, *pinv ; 6 if (!p) return (NULL) ; /* p = NULL denotes identity */ 7 pinv = cs_malloc (n, sizeof (CS_INT)) ; /* allocate result */ 8 if (!pinv) return (NULL) ; /* out of memory */ 9 for (k = 0 ; k < n ; k++) pinv [p [k]] = k ;/* invert the permutation */ 10 return (pinv) ; /* return result */ 11 } 12