Arc consistency, Computer Engineering

Assignment Help:

Arc Consistency:

There have been many advances in how constraint solvers search for solutions (remember this means an assignment of a value to each variable in such a way thatno constraint is broken). We look first at a pre-processing step which can greatly improve efficiency by pruning the search space, namely arc-consistency. Following this, we'll look at two search methods, backtracking and forward checking which keep assigning values to variables until a solution is found. Finally, we'll look at some heuristics for improving the efficiency of the solver, namely how to order the choosing of the variables, and how to order the assigning of the values to variables. 

The pre-processing routine for bianry constraints known as  arc-consistency involves calling a pair (xi, xj) an arc and noting that this is an ordered pair, i.e., it is not the same as (xj, xi). Each arc is associated with a single constraint Cij, which constrains variables xi  and xj. We say that the arc (xi, xj) is  consistent  if, for all values a in Di, there is a value b in Dj  such that the assignment xi=a and xj=b satisfies constraint Cij. Note that (xi, xj) being consistent doesn't necessarily mean that (xj,xi) is also consistent. To use this in a pre-processing way, we take every pair of variables and make it arc-consistent. That is, we take each pair (xi,xj) and remove variables from Di  which make it inconsistent, until it becomes consistent. This effectively removes values from the domain of variables, hence prunes the search space and makes it likely that the solver will succeed (or fail to find a solution) more quickly.


Related Discussions:- Arc consistency

Java, A string S is said to be "Super ASCII", if it contains the character ...

A string S is said to be "Super ASCII", if it contains the character frequency equal to their ascii values. String will contain only lower case alphabets (''a''-''z'') and the asci

Social media strategy design, For this phase of the project you are require...

For this phase of the project you are required to formulate a social media strategy for a product/service/business/concept/charity...etc. the strategy can include technologies such

Fact finding techniques on banking system, what are the questionnaries and ...

what are the questionnaries and observation of work site for banking system?

Illustrate when are intermolecular forces the strongest, Q. Illustrate when...

Q. Illustrate when are intermolecular forces the strongest? Answer:- Intermolecular forces dispersion and dipole-dipole and hydrogen bonds. These forces are feeble than ch

Explain about microsoft access, Microsoft access name has been transformed ...

Microsoft access name has been transformed to Microsoft office access. This software incorporates relational database management system which joins GUI (graphical user interface) w

Explain shift register with diagram and waveform, Q. Explain Shift register...

Q. Explain Shift register with diagram and waveform.   Q. Write a short note on Decoder.

What are the uses of router, What are the uses of Router? Router: ...

What are the uses of Router? Router: A router is used to transfer or route data among two or more similar networks. This determines the next network point to that a data

Predicates, Fred, Barney and Ralph belong to the La Trobe Mountain Club. Ev...

Fred, Barney and Ralph belong to the La Trobe Mountain Club. Every member of the Club is either a skier or a hiker. Anyone that doesn't like snow does not like skiing. No hikers li

Evaluate bandwidth of disk drive, Q. Evaluate Bandwidth of disk drive? ...

Q. Evaluate Bandwidth of disk drive? Bandwidth:  Bandwidth can be measured in bytes per second. Sustained bandwidth is the average data rate at the time of a large transfer w

Advantages of edi (electronic data interchange), Advantages of EDI 1.  ...

Advantages of EDI 1.  EDI replaces paper transactions with electronic transactions therefore it saves times and speeds up transactions. 2.  It gives a legal record of busine

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd