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-1087 Clojure <p><tt>clojure.data/diff</tt>, on line 118, defines:</p> <div class="code panel" style="border-width: 1px;"><div class="codeContent panelContent"> <pre class="code-java">java.util.Map (diff-similar [a b] (diff-associative a b (set/union (keys a) (keys b))))</pre> </div></div> <p>Since <tt>keys</tt> returns a key seq, this seems like an error. <tt>clojure.set/union</tt> has strange and inconsistent behavior with regard to non-sets, and in this case the two key seqs are concatenated. Based on a cursory benchmark, it seems that this bug <img class="emoticon" src="http://dev.clojure.org/jira/images/icons/emoticons/help_16.gif" height="16" width="16" align="absmiddle" alt="" border="0"/> is a slight performance gain when the maps have no common keys, and a significant performance loss when the maps have the same keys. The results are still correct because of the merging reduce in <tt>diff-associative</tt>.</p> <p>The patch is easy (just call set on each key seq).</p> CLJ-1087

clojure.data/diff uses set union on key seqs

Enhancement Minor Open Unresolved Unassigned Tom Jack bug performance Mon, 15 Oct 2012 03:59:52 -0500 Mon, 15 Oct 2012 14:52:42 -0500 0 1 <p>clj-1087-diff-perf-enhance-patch-v1.txt dated Oct 15 2012 implements Tom's suggested performance enhancement, although not exactly in the way he suggested. It does calculate the union of the two key sequences.</p> Global Rank Patch Code