System model where there are many processing elements, but they are designed to execute the same instruction at the same time; that is, one program counter is used to sequence through a single copy of the program. SIMD is especially useful for solving problems that have lots of data that needs to be updated on a wholesale basis; such as numerical calculations that are regular. Many scientific and engineering applications (such as, image processing, particle simulation, and finite element methods) naturally fall into the SIMD paradigm. See also array processing, pipeline, vector processing.