  <span class="keyword">typedef</span> <span class="identifier">vector_type</span><span class="special">::</span><span class="identifier">reference</span>                          <a name="boost.compute.flat_map.reference"></a><span class="identifier">reference</span><span class="special">;</span>             
  <span class="keyword">typedef</span> <span class="identifier">vector_type</span><span class="special">::</span><span class="identifier">const_reference</span>                    <a name="boost.compu