ink of this operation as a <code class="computeroutput">gather</code> to some process, followed by an <code class="computeroutput">std::prefix_sum()</code> over the gathered values using the operation <code class="computeroutput">op</code>. The ith process returns the ith value emitted by <code class="computeroutput">std::prefix_sum()</code>.</p>
<p>When the type <code class="computeroutput">T</code> has an associated MPI data type, this routine invokes <code class="computeroutput">MPI_Scan</code> to perfor