http://dev.clojure.org/jira This file is an XML representation of an issue en-us 4.4 649 25-07-2011 http://dev.clojure.org/jira/browse/CLJ-1082 Clojure <p>I could reproduce on current 10/05 git.</p> <p>Reduce doesn't work on subvecs of primitive vectors.<br/> Root cause seems to be that RT/subvec and APersistentVector$SubVector make assumptions about implementation</p> <p>If reduce on a subvec doesn't work then neither will nice ops like fold.</p> <p>How to cause: </p> <p>(let <span class="error">&#91;prim-vec (into (vector-of :long) (range 10000))&#93;</span><br/> (reduce + (subvec prim-vec 1 500)))</p> <p>-&gt;&gt; ClassCastException clojure.core.Vec cannot be cast to clojure.lang.PersistentVector clojure.lang.APersistentVector$SubVector.iterator (APersistentVector.java:523)</p> 1.7.0-08, OS X 10.8 CLJ-1082

Subvecs of primitive vectors cannot be reduced

Defect Minor Open Unresolved Unassigned Ghadi Shayban Fri, 5 Oct 2012 18:49:21 -0500 Sat, 26 Jan 2013 07:29:55 -0600 0 2 <p>Confirmed to be broken on master. Vetting. Not sure what it's going to take to fix this, however. If this is of intrest for you, you might want to help push it along by providing a patch. </p> <p>There is no code or ticket for this yet, but I wanted to mention that I've begun working on an implementation of RRB-Tree (Relaxed Radix Balanced Tree) vectors for Clojure (see discussion at <a href="https://groups.google.com/forum/?fromgroups=#!topic/clojure-dev/xnbtzTVEK9A">https://groups.google.com/forum/?fromgroups=#!topic/clojure-dev/xnbtzTVEK9A</a>). Assuming it is no big deal to get reducers to work on such vectors, subvec could be implemented in O(log n) time in such a way that the result was the same concrete type of vector as you started with, and thus reducers would work on them, too.</p> <p>It would mean O(log n) time for subvec instead of today's O(1), but this would likely fix other limitations that exist today with subvec's, e.g. <a href="http://dev.clojure.org/jira/browse/CLJ-761" title="print-dup generates call to nonexistent method for APersistentVector$SubVector">CLJ-761</a>.</p> <p>I have a fix for this and a regression test in the tree below:</p> <p><a href="https://github.com/mikera/clojure/tree/winfix">https://github.com/mikera/clojure/tree/winfix</a></p> <p>Not sure how best to make this into a patch though - I also have the pprint fix in here (<a href="http://dev.clojure.org/jira/browse/CLJ-1076" title="pprint tests fail on Windows, expecting \n">CLJ-1076</a>)</p> <p>Attached a patch that I created with: </p> <p>git format-patch winfix --stdout HEAD~3..HEAD &gt; clj-1082.patch</p> <p>Does this do the trick? I had to use the HEAD~3..HEAD to just get the most recent 3 commits and exclude the pprint changes that I needed in order to build on Windows.</p> <p>Patch for <a href="http://dev.clojure.org/jira/browse/CLJ-1082" title="Subvecs of primitive vectors cannot be reduced">CLJ-1082</a>, containing 3 commits</p> <p>Mike, your patch clj-1082.patch applies cleanly to latest master for me, so looks like you found one way to do it.</p> <p>Another would be as follows, and closer to the directions on the JIRA workflow page: <a href="http://dev.clojure.org/display/design/JIRA+workflow">http://dev.clojure.org/display/design/JIRA+workflow</a> (but not identical). Note that these commands would work on Mac OS X or Linux. I'm not sure what the correct corresponding command would be on Windows for the "git am" step below, unless that just happens to work because Windows and/or git implement the input redirection with "&lt;" somehow.</p> <ol> <li>Check out a fresh repo<br/> $ git clone git://github.com/clojure/clojure.git<br/> $ cd clojure</li> </ol> <ol> <li>Apply the patch for <a href="http://dev.clojure.org/jira/browse/CLJ-1076" title="pprint tests fail on Windows, expecting \n">CLJ-1076</a> to the master branch. This step isn't on the JIRA workflow page.<br/> $ git am --keep-cr -s &lt; clj-1076-fix-tests-on-windows-patch-v1.txt</li> </ol> <ol> <li>Create a branch for yourself<br/> $ git checkout -b fix-clj-1082</li> </ol> <ol> <li>After editing to make your changes, commit them to the current fix-clj-1082 branch<br/> $ git commit -a -m "fixed annoying bug, refs #42"</li> </ol> <p>From there on down it is the same as the instructions on the JIRA workflow page. The "git format-patch master --stdout &gt; file.patch" will create a patch for the changes you have made in the current branch fix-clj-1082 starting from the master branch, which has the <a href="http://dev.clojure.org/jira/browse/CLJ-1076" title="pprint tests fail on Windows, expecting \n">CLJ-1076</a> fix because of the 'git am' command above.</p> Approval Vetted Global Rank Patch Code and Test