A computer/processor that has an architecture especially designed for processing arrays (e.g. matrices) of numbers. The architecture includes a number of processors (say 64 by 64) working simultaneously, each handling one element of the array, so that a single operation can apply to all elements of the array in parallel. To obtain the same effect in a conventional processor, the operation must be applied to each element of the array sequentially, and so consequently much more slowly.

An array processor may be built as a self-contained unit attached to a main computer via an I/O port or internal bus; alternatively, it may be a distributed array processor where the processing elements are distributed throughout, and closely linked to, a section of the computer’s memory.

Array processors are very powerful tools for handling problems with a high degree of parallelism. They do however demand a modified approach to programming. The conversion of conventional (sequential) programs to serve array processors is not a trivial task, and it is sometimes necessary to select different (parallel) algorithms to suit the parallel approach.

See also parallel processing, vector processing.