<span class="identifier">OutputValueIterator</span> values_result<span class="special">,</span>
<span class="identifier">command_queue</span> <span class="special">&</span> queue <span class="special">=</span> <span class="identifier">system</span><span class="special">::</span><span class="identifier">default_queue</span><span class="special">(</span><span class="special">)</span><span class="special">)</span><span class="special">;</span></pre></div>
<div class="refsect1">
-<a name="idm46094050537632"></a><h2>Description</h2>
+<a name="idm46113331652080"></a><h2>Description</h2>
<p>The <code class="computeroutput">reduce_by_key()</code> algorithm performs reduction for each contiguous subsequence of values determinate by equivalent keys.</p>
<p>Returns a pair of iterators at the end of the ranges [<code class="computeroutput">keys_result</code>, keys_result_last) and [<code class="computeroutput">values_result</code>, <code class="computeroutput">values_result_last</code>).</p>
<p>If no function is specified, <code class="computeroutput">plus</code> will be used. If no predicate is specified, <code class="computeroutput">equal_to</code> will be used.</p>