Programming Distributed Memory Machines
The key issue in programming distributed memory systems is how to distribute the data over the memories. Depending on the problem solved, the data can be distributed statically, or it can be moved through the nodes. Data can be moved on demand, or data can be pushed to the new nodes in advance.
As an example, if a problem can be described as a pipeline where data X is processed subsequently through functions F, G, H, etc. (the result is H(G(F(X)))), then this can be expressed as a distributed memory problem where the data is transmitted first to the node that performs F that passes the result onto the second node that computes G, and finally to the third node that computes H. This is also known as systolic computation.
Data can be kept statically in nodes if most computations happen locally, and only changes on edges have to be reported to other nodes. An example of this is simulation where data is modeled using a grid, and each node simulates a small part of the larger grid. On every iteration, nodes inform all neighboring nodes of the new edge data.
Read more about this topic: Distributed Memory
Famous quotes containing the words programming, distributed, memory and/or machines:
“If there is a price to pay for the privilege of spending the early years of child rearing in the driver’s seat, it is our reluctance, our inability, to tolerate being demoted to the backseat. Spurred by our success in programming our children during the preschool years, we may find it difficult to forgo in later states the level of control that once afforded us so much satisfaction.”
—Melinda M. Marshall (20th century)
“Indiana was really, I suppose, a Democratic State. It has always been put down in the book as a state that might be carried by a close and careful and perfect organization and a great deal of—[from audience: “soap”Ma reference to purchased votes, the word being followed by laughter].
I see reporters here, and therefore I will simply say that everybody showed a great deal of interest in the occasion, and distributed tracts and political documents all through the country.”
—Chester A. Arthur (1829–1886)
“Those who believe in their truth—the only ones whose imprint is retained by the memory of men—leave the earth behind them strewn with corpses. Religions number in their ledgers more murders than the bloodiest tyrannies account for, and those whom humanity has called divine far surpass the most conscientious murderers in their thirst for slaughter.”
—E.M. Cioran (b. 1911)
“The machine has had a pernicious effect upon virtue, pity, and love, and young men used to machines which induce inertia, and fear, are near impotents.”
—Edward Dahlberg (1900–1977)