SubVec anomaly
user= (nth (subvec [:??? 1 2] 1) -1) :??? This could be a bug, not sure. Only the upper bound of the internal SubVec is being checked. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: SubVec anomaly
On Thu, Mar 29, 2012 at 5:15 AM, stirfoo stir...@gmail.com wrote: user= (nth (subvec [:??? 1 2] 1) -1) :??? This could be a bug, not sure. Only the upper bound of the internal SubVec is being checked. Hmm. This also raises the specter of (let [a (some-very-large-vector-with-millions-of-elements) b (subvec a n (+ n 2))] (swap! something assoc :somekey b)) holding onto the entirety of a via the subvec. One would hope that b would only hold onto the minimal subtree of a needed to span b, i.e. the tree root for b would be the deepest node of a that has all the elements of b as children. With b only a couple of elements long that would usually mean holding onto only 32 elements of a and occasionally 1024 elements (when b was split across two of a's 32-element leaf nodes). That hope would be dashed: user= (def a (vec (range 64))) #'user/a user= (let [b (subvec a 33 35)] (nth b -17)) 16 user= (let [x (vec (range 64)) b (subvec x 33 35)] (nth b -17)) 16 user= (def b (subvec a 33 35)) #'user/b user= (def a nil) #'user/a user= (System/gc) nil user= (nth b -17) 16 The bs in this instance would not have access to the first half of a/x with that implementation, certainly not after the a vector was completely purged by setting a to nil and doing a full GC. And yet they do. Subvec should be modified to hold onto the deepest node of the parent that holds all of the subvec's elements. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: SubVec anomaly
Thanks for the catch. Bug report with patch created: http://dev.clojure.org/jira/browse/CLJ-962 Andy On Mar 29, 2012, at 2:15 AM, stirfoo wrote: user= (nth (subvec [:??? 1 2] 1) -1) :??? This could be a bug, not sure. Only the upper bound of the internal SubVec is being checked. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
