title: In MPI_Gather(), MPI_Scatter() what is the difference between send count and receive count?
body: <p>In MPI gather and scatter there is two counts for send and receive. I checked the docs and found out that both should have the same value. </p>
  
  <p>Ex:- In <code>MPI_Gather()</code> both <code>send_count</code> and <code>receive_count</code> should have the size of the send buffer size. <a href="https://www.mpich.org/static/docs/v3.1/www3/MPI_Gather.html" rel="noreferrer">https://www.mpich.org/static/docs/v3.1/www3/MPI_Gather.html</a></p>
  
  <p>Can someone explain what is the purpose of this redundant parameters?</p>