Decomposition in

computer science Computer science is the study of computation, automation, and information. Computer science spans theoretical disciplines (such as algorithms, theory of computation, information theory, and automation) to Applied science, practical discipli ...

, also known as factoring, is breaking a complex problem or

system A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment, is described by its boundaries, structure and purpose and express ...

into parts that are easier to conceive, understand, program, and maintain.

Overview

There are different types of decomposition defined in computer sciences: * In structured programming, ''algorithmic decomposition'' breaks a process down into well-defined steps. *

Structured analysis In software engineering, structured analysis (SA) and structured design (SD) are methods for analyzing business requirements and developing specifications for converting practices into computer programs, hardware configurations, and related man ...

breaks down a software system from the system context level to system functions and data entities as described by Tom DeMarco. * ''

Object-oriented Object-oriented programming (OOP) is a programming paradigm based on the concept of "objects", which can contain data and code. The data is in the form of fields (often known as attributes or ''properties''), and the code is in the form of ...

decomposition'', on the other hand, breaks a large system down into progressively smaller classes or objects that are responsible for some part of the problem domain. * According to Booch, algorithmic decomposition is a necessary part of object-oriented analysis and design, but object-oriented systems start with and emphasize decomposition into objects. Grady Booch (1994). ''Object-oriented Analysis and Design'' (2nd ed.). Redwood Cita, CA: Benjamin/Cummings. pp.16-20. More generally, functional decomposition in computer science is a technique for mastering the complexity of the function of a model. A

functional model In systems engineering, software engineering, and computer science, a function model or functional model is a structured representation of the functions ( activities, actions, processes, operations) within the modeled system or subject area.

of a system is thereby replaced by a series of functional models of subsystems. Jan Dietz (2006). ''Enterprise Ontology - Theory and Methodology''. Springer-Verlag Berlin Heidelberg.

Decomposition topics

Decomposition paradigm

A decomposition paradigm in computer programming is a strategy for organizing a program as a number of parts, and it usually implies a specific way to organize a program text. Usually the aim of using a decomposition paradigm is to optimize some metric related to program complexity, for example the modularity of the program or its maintainability. Most decomposition paradigms suggest breaking down a program into parts so as to minimize the static dependencies among those parts, and to maximize the

cohesiveness Group cohesiveness (also called group cohesion and social cohesion) arises when bonds link members of a social group to one another and to the group as a whole. Although cohesion is a multi-faceted process, it can be broken down into four main co ...

of each part. Some popular decomposition paradigms are the procedural, modules, abstract data type and

object oriented Object-oriented programming (OOP) is a programming paradigm based on the concept of "objects", which can contain data and code. The data is in the form of fields (often known as attributes or ''properties''), and the code is in the form o ...

ones. The concept of decomposition paradigm is entirely independent and different from that of model of computation, but the two are often confused, most often in the cases of the

of computation being confused with procedural decomposition, and of the

actor model The actor model in computer science is a mathematical model of concurrent computation that treats ''actor'' as the universal primitive of concurrent computation. In response to a message it receives, an actor can: make local decisions, create mor ...

of computation being confused with

decomposition.

Decomposition diagram

Image:6 Decomposition Structure.svg, Decomposition Structure Image:21 Negative Node-Numbered Context.svg, Negative Node-Numbered Context Image:Static, Dynamic, and Requirements Models for Sys Partition.jpg, Static, Dynamic, and Requirements Models for Systems Partition Image:Functions and Use Scenarios Mapping to Requirements and Goals.jpg, Functions and Use Scenarios Mapping to Requirements and Goals A decomposition diagram shows a complex, process, organization, data subject area, or other type of object broken down into lower level, more detailed components. For example, decomposition diagrams may represent organizational structure or functional decomposition into processes. Decomposition diagrams provide a logical hierarchical decomposition of a system.

References

External links