# LogP machine

The **LogP machine** is a model for parallel computation.^{[1]}
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 , , and .

The LogP machine consists of arbitrarily many processing units with distributed memory. 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:

- , the latency of the communication medium.
- , the overhead of sending and receiving a message.
- , the gap required between two send/receive operations. A more common interpretation of this quantity is as the inverse of the bandwidth of a processor-processor communication channel.
- , 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 , and are measured in multiples of processor cycles.

## See also

## Notes

- ↑ Culler et al. 1993

## References

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