The Set command sets variables in remote parallel compute nodes.  

The Grid package provides routines for multiprocess parallelism. Each compute node runs a separate Maple process that does not share state with the main interactive Maple session. That means that a variable assigned in the main interactive session, say, a:=1 will not be automatically propagated to the remote compute nodes. The Set command provides a way to assign variables copying state from the current session to the remote session.  

Calling Set(0,'a'=42) will assign the variable a the value 42 on node 0.  If a is already assigned 42 in the local session, this command can be shortened to Set(0,'a'). Leaving the node number off, Set('a') will cause the same value of a to be assigned on all compute nodes.

The Set command is only available in local Grid mode.

$f≔x\mapsto x^2$

$f≔x\mapsto x^2$

$\mathrm{anames}\left('\mathrm{user}'\right)$

$\mathrm{defaultScreenWidth},f$

$\mathrm{Grid}:-\mathrm{Run}\left(\mathrm{anames}\,\left['\mathrm{user}'\right]\right)$

$\mathrm{Grid}:-\mathrm{Set}\left('f'\right)$

$\mathrm{Grid}:-\mathrm{Run}\left(\mathrm{anames}\,\left['\mathrm{user}'\right]\right)$

$\mathrm{Grid}:-\mathrm{Set}\left(0\,'r'=1..5\right)$

$\mathrm{Grid}:-\mathrm{Set}\left(1\,'r'=6..10\right)$

$\mathrm{Grid}:-\mathrm{Run}\left(0..1\,\mathrm{add}\,\left['i'\,'i'='r'\right]\right)$

$\mathrm{Grid}:-\mathrm{Run}\left(0\,\mathrm{print}\,\left['r'\right]\,'\mathrm{wait}'\right)$

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                1 .. 5

$\mathrm{Grid}:-\mathrm{Run}\left(1\,\mathrm{print}\,\left['r'\right]\,'\mathrm{wait}'\right)$

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                6 .. 10

p := proc()
  local loc;
  Grid:-Set(1,loc=4);
  Grid:-Run(1,print,["the local variable",loc],'wait');
  Grid:-Run(1,print,["the global variable",:-loc],'wait');
end;

$p≔\mathbf{proc}\left(\right)\mathbf{local}\mathrm{loc}\;\mathrm{Grid}:-\mathrm{Set}\left(1\,\mathrm{loc}\=4\right)\;\mathrm{Grid}:-\mathrm{Run}\left(1\,\mathrm{print}\,\left[''the\; local\; variable''\,\mathrm{loc}\right]\,\'\mathrm{wait}\'\right)\;\mathrm{Grid}:-\mathrm{Run}\left(1\,\mathrm{print}\,\left[''the\; global\; variable''\,:-\mathrm{loc}\right]\,\'\mathrm{wait}\'\right)\mathbf{end\; proc}$

$p\left(\right)$

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        "the local variable", 4

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      "the global variable", loc

$\mathrm{Grid}:-\mathrm{Set}\left(1\,v=4\right)$

$\mathrm{Grid}:-\mathrm{Run}\left(1\,\mathrm{print}\,\left['v'\right]\,'\mathrm{wait}'\right)$

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   4

$\mathrm{Grid}:-\mathrm{Set}\left(1\,v=''v''\right)$

$\mathrm{Grid}:-\mathrm{Run}\left(1\,\mathrm{print}\,\left['v'\right]\,'\mathrm{wait}'\right)$

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   v

The Grid[Set] command was introduced in Maple 2015.

For more information on Maple 2015 changes, see Updates in Maple 2015.