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 practical disciplines (includi ...

, also known as factoring, is breaking a complex problem or system 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 breaks down a software system from the system context level to system functions and data entities as described by

Tom DeMarco Tom DeMarco (born August 20, 1940) is an American software engineer, author, and consultant on software engineering topics. He was an early developer of structured analysis in the 1970s. Early life and education Tom DeMarco was born in Hazle ...

. * ''

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 p ...

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 Grady Booch (born February 27, 1955) is an American software engineer, best known for developing the Unified Modeling Language (UML) with Ivar Jacobson and James Rumbaugh. He is recognized internationally for his innovative work in software archi ...

(1994). ''Object-oriented Analysis and Design'' (2nd ed.). Redwood Cita, CA: Benjamin/Cummings. pp.16-20. More generally,

functional decomposition In mathematics, functional decomposition is the process of resolving a functional relationship into its constituent parts in such a way that the original function can be reconstructed (i.e., recomposed) from those parts by function composition. ...

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 Jean Leonardus Gerardus (Jan) Dietz (born 20 June 1945) is a Dutch Information systems researcher, Emeritus Professor of Information Systems Design, and part-time Professor of Enterprise Engineering at the Delft University of Technology, known for ...

(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 In computer science, an abstract data type (ADT) is a mathematical model for data types. An abstract data type is defined by its behavior (semantics) from the point of view of a ''user'', of the data, specifically in terms of possible values, pos ...

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 of p ...

ones. The concept of decomposition paradigm is entirely independent and different from that of

model of computation In computer science, and more specifically in computability theory and computational complexity theory, a model of computation is a model which describes how an output of a mathematical function is computed given an input. A model describes how ...

, 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 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