backtracking

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backtracking

[′bak‚trak·iŋ]

(computer science)

A method of solving problems automatically by a systematic search of the possible solutions; the invalid solutions are eliminated and are not retried.

backtracking

(algorithm)

A scheme for solving a series of sub-problems each of which may have multiple possible solutions and where the solution chosen for one sub-problem may affect the possible solutions of later sub-problems.

To solve the overall problem, we find a solution to the first sub-problem and then attempt to recursively solve the other sub-problems based on this first solution. If we cannot, or we want all possible solutions, we backtrack and try the next possible solution to the first sub-problem and so on. Backtracking terminates when there are no more solutions to the first sub-problem.

This is the algorithm used by logic programming languages such as Prolog to find all possible ways of proving a goal. An optimisation known as "intelligent backtracking" keeps track of the dependencies between sub-problems and only re-solves those which depend on an earlier solution which has changed.

Backtracking is one algorithm which can be used to implement nondeterminism. It is effectively a depth-first search of a problem space.

This article is provided by FOLDOC - Free Online Dictionary of Computing (foldoc.org)

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'This seems like another piece of backtracking by the First Minister.

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Crisis idea is discarded

While Steinberg seems conversant with most of the recent research supporting his provocative analysis of national backtracking on commitment to civil rights and their enforcement, he does leave some holes in his analysis.

Turning Back: The Retreat from Racial Justice in American Thought and Policy

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