The LogP machine is a model for parallel computation.Culler et al. 1993 It aims at being more practical than the PRAM model while still allowing for easy analysis of computation. The name is not related to the mathematical logarithmic function: Instead, the machine is described by the four parameters

L

o

g

and

P

. The LogP machine consists of arbitrarily many processing units with

distributed memory In computer science, distributed memory refers to a Multiprocessing, multiprocessor computer system in which each Central processing unit, processor has its own private Computer memory, memory. Computational tasks can only operate on local data ...

. The processing units are connected through an abstract communication medium which allows point-to-point communication. This model is pair-wise synchronous and overall asynchronous. The machine is described by the four parameters: *

L

, the latency of the communication medium. *

o

, the overhead of sending and receiving a message. *

g

, the gap required between two send/receive operations. A more common interpretation of this quantity is as the inverse of the

bandwidth Bandwidth commonly refers to: * Bandwidth (signal processing) or ''analog bandwidth'', ''frequency bandwidth'', or ''radio bandwidth'', a measure of the width of a frequency range * Bandwidth (computing), the rate of data transfer, bit rate or thr ...

of a processor-processor communication channel. *

P

, the number of processing units. Each local operation on each machine takes the same time ('unit time'). This time is called a processor cycle. The units of the parameters

L

o

and

g

are measured in multiples of processor cycles.

Notes

References

Educational abstract machines Theoretical computer science Models of computation Parallel computing {{Comp-sci-stub

See also

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References