The MyNode command is for use as part of a parallel computation.

When a parallel job is started on a specified number of servers, say N, each server will be given an integer identifier between 0 and N-1 for the duration of this computation. MyNode() returns the integer identifier for the node that it is called on.

who := proc()
   uses Grid;
   local me,i;

   me := MyNode();
   if me = 0 then
       return [0, seq(Receive(),i=1..NumNodes()-1)];
   else
       Send(0,me);
   end if;
end proc;

$\mathrm{who}≔\mathbf{proc}\left(\right)\mathbf{local}\mathrm{me}\,i\;\mathrm{me}≔\mathrm{Grid}:-\mathrm{MyNode}\left(\right)\;\mathbf{if}\mathrm{me}\=0\mathbf{then}\mathbf{return}\left[0\,\mathrm{seq}\left(\mathrm{Grid}:-\mathrm{Receive}\left(\right)\,i\=1..\mathrm{Grid}:-\mathrm{NumNodes}\left(\right)-1\right)\right]\mathbf{else}\mathrm{Grid}:-\mathrm{Send}\left(0\,\mathrm{me}\right)\mathbf{end\; if}\mathbf{end\; proc}$

$r≔\mathrm{Grid}:-\mathrm{Launch}\left(\mathrm{who}\,\mathrm{numnodes}=8\right)$

$r≔\left[0\,2\,1\,3\,4\,5\,6\,7\right]$

$\mathrm{sort}\left(r\right)$

$\left[0\,1\,2\,3\,4\,5\,6\,7\right]$

The Grid[MyNode] command was introduced in Maple 15.

For more information on Maple 15 changes, see Updates in Maple 15.