This is probably a standard path-finding algorithm, and possibly already implemented in J.
Given a boolean matrix, as shown in the first output, and an index with 0, e.g. (<1 1); return 1s for all 0s reachable with rectangular paths. "."0;._2 '111111 100101 100101 100011 101001 111111 ' 1 1 1 1 1 1 1 0 0 1 0 1 1 0 0 1 0 1 1 0 0 0 1 1 1 0 1 0 0 1 1 1 1 1 1 1 "."0;._2 '000000 011000 011000 011100 010110 000000 ' 0 0 0 0 0 0 0 1 1 0 0 0 0 1 1 0 0 0 0 1 1 1 0 0 0 1 0 1 1 0 0 0 0 0 0 0 __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
