MPI: Difference between revisions

MPI (view source)

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 There are two major models of computational parallelism: shared memory, and distributed memory.
+<!-- Probably we should used threads instead. As processes have there own memory space -->
+In shared memory parallelism (commonly and casually abbreviated SMP), all processors see the same memory image, or to put it another way, all memory is globally addressable and all the processes can ultimately access it. Communication between processes on an SMP machine is implicit --- any process can ultimately read and write values to memory that can be subsequently accessed an manipulated directly by others. The challenge in writing these kinds of programs is data consistency: one should take extra care to ensure data is not modified by more than one process at a time.
-In shared memory parallelism (commonly and casually abbreviated SMP), all processors see the same memory image, or to put it another way, all memory is globally addressable and all the processes can ultimately access it. Communication between processes on an SMP machine is implicit --- any process can read and write values to memory that can be subsequently accessed an manipulated directly by others. The challenge in writing these kinds of programs is data consistency: one should take extra care to ensure data is not modified by more than one process at a time.
 [[Image:Smp.png|frame|center|'''Figure 1''': ''A conceptual picture of a shared memory architecture'']]