The Barrier command blocks all jobs initiated by the Launch command until all processes have executed the Barrier command.

This is useful for synchronizing execution.  It can be used to force node 0 to wait for all other nodes to finish computing.

This function is currently not available in "hpc" mode.

dosome := proc()
   uses Grid;
   local i, me;
   me := MyNode();
   for i from 1 to 10^(me+3) do
       if i mod 10^5 = 0 then
           print(me,i);
       end if;
   end do;
   print(me,"done");
end proc:

$\mathrm{Grid}\left[\mathrm{Launch}\right]\left(\mathrm{dosome}\,\mathrm{numnodes}=4\right)$

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               0, "done"

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               1, "done"

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               2, 100000

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               2, "done"

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               3, 100000

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               3, 200000

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               3, 300000

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               3, 400000

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               3, 500000

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               3, 600000

doall:= proc()
   uses Grid;
   local i, me;
   me := MyNode();
   for i from 1 to 10^(me+3) do
       if i mod 10^5 = 0 then
           print(me,i);
       end if;
   end do;
   print(me,"done");
   Barrier();
end proc:

$\mathrm{Grid}\left[\mathrm{Launch}\right]\left(\mathrm{doall}\,\mathrm{numnodes}=4\right)$

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               1, "done"

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               0, "done"

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               3, 100000

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               2, 100000

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               2, "done"

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               3, 200000

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               3, 300000

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               3, 400000

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               3, 500000

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               3, 600000

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               3, 700000

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               3, 800000

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               3, 900000

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              3, 1000000

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               3, "done"

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

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