#include "cs.h" /* pinv = p', or p = pinv' */ int *cs_pinv (int const *p, int n) { int k, *pinv ; if (!p) return (NULL) ; /* p = NULL denotes identity */ pinv = cs_malloc (n, sizeof (int)) ; /* allocate result */ if (!pinv) return (NULL) ; /* out of memory */ for (k = 0 ; k < n ; k++) pinv [p [k]] = k ;/* invert the permutation */ return (pinv) ; /* return result */ }