Systolic array: Difference between revisions

Revision as of 19:54, 24 October 2019

Revision as of 03:18, 8 February 2020

Line 1:

{{Use dmy dates|date=October 2019}}

In [[parallel computing|parallel]] [[computer architectures]], a '''systolic array''' is a homogeneous [[Graph (discrete mathematics)|network]] of tightly coupled [[data processing unit]]s (DPUs) called cells or [[Node (computer science)|node]]s. Each node or DPU independently computes a partial result as a function of the data received from its upstream neighbors, stores the result within itself and passes it downstream. Systolic arrays were invented by [[H. T. Kung]] and [[Charles Leiserson]] who described arrays for many dense linear algebra computations (matrix product, solving systems of [[linear equation]]s, [[LU decomposition]], etc.) for banded matrices. Early applications include computing [[greatest common divisor]]s of integers and polynomials.<ref>http://www.eecs.harvard.edu/~htk/publication/1984-ieeetoc-brent-kung.pdf</ref>{{Failed verification|date=February 2017}} They are sometimes classified as [[MISD|multiple-instruction single-data]] (MISD) architectures under [[Flynn's taxonomy]], but this classification is questionable because a strong argument can be made to distinguish systolic arrays from any of Flynn's four categories: [[SISD]], [[SIMD]], [[MISD]], [[MIMD]], as discussed later in this article.

The parallel input [[data]] flows through a network of hard-wired [[Microprocessor|processor]] nodes, which combine, process, [[merge algorithm|merge]] or [[sorting algorithm|sort]] the input data into a derived result. Because the [[wave]]-like propagation of data through a systolic array resembles the [[pulse]] of the human circulatory system, the name ''systolic'' was coined from medical terminology. The name is derived from [[systole]] as an analogy to the regular pumping of blood by the heart.