A function that processes a set of inputs and results in a set of outputs, or associates arguments (inputs) with values (outputs).|Special cases are: a) An operation that consumes no input (has no input arguments). Such operation is either a constant function, or an operation depending only on the underlying state. b) An operation that may modify the underlying state but has no output. c) The singular-case operation with no input or output, that still may modify the underlying state.

Computational procedure
Computational subroutine
Computational operation
Function (programming)
Lambda abstraction
Mathematical function
Mathematical operation
Computational method
Computational tool