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5.2.2 Global Router Communications

The global router allows any PE to communicate with any other PE in the array. To use the router the programmer must specify the address of the PE(s) with which communication is desired and a variable name on the accessed PEs.

If the statement

is executed, then each processor will set its variable x to the value of y on the processor. One advantage is that the programmer does not need to know how the communicating processors are located relative to one another. However, there is only one router channel for each set of 16 processors, and this can slow things down if a program calls for a lot of communications within a set. Typically Xnet is a more efficient means of communication if it can be used. However, keep in mind that Xnet and router communication are useful for different purposes.