The TOPOLOGY statement (TOP, TOPO)
A TOPOLOGY statement looking like this
TOPOLOGY 5,17:12:31,45:36,27; 8,18:12:24
declares that node 5 is to be able to transmit and receive data to and from nodes 17, 12, and 31, and to send data to nodes 45 and 36, and to receive data from node 27, and that node 8 can send data to, or recieve data from, nodes 18 and 12 and 24, in as direct a manner as possible.
This statement can be used, in parallel processing environments, either to dynamically reconfigure the processor, or to control the assignment of virtual nodes to actual processors. In the latter case, any TOPOLOGY statements required must be executed prior to the commencement of explicit parallel processing, as a TOPOLOGY statement may change the connections between nodes, but not their identity whenever that may be relevant.