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

What is enhanced ide, Q. What is Enhanced IDE? The principle behind EID...

Q. What is Enhanced IDE? The principle behind EIDE interface is the same as in IDE interface however this drive has capacities varying from 10.2GB to 20.5GB. The rotation speed

Assembly language programming, write an assembly language program for fibon...

write an assembly language program for fibonacci series?

Explain transformational analogy, Question 1 Why is it important that a...

Question 1 Why is it important that an expert system be able to explain why and how questions related to a problem solving session. 2 Give the architecture of an Expert syst

Adding layers to the timeline, ADDING LAYERS TO THE TIMELINE AND GIVING MOT...

ADDING LAYERS TO THE TIMELINE AND GIVING MOTION TO THE LAYER Step 1:  Choose Layer from Common toolbar after that draw a layer. Step 2:  Write the text inside Layer. Step

Define the term intranet, Define the term Intranet. Intranet: An...

Define the term Intranet. Intranet: An Intranet is a type of information system that facilitates communication within the organizations among widely dispersed department

Bi polar junction transistor, draw input and output charectoristics of BJT ...

draw input and output charectoristics of BJT and justify CE configuration provides large current amplification

8085 programs, what is the theory used to check whether a number is negativ...

what is the theory used to check whether a number is negative or positive?

What is write miss, What is write miss? During the write operation if t...

What is write miss? During the write operation if the addressed word is not in cache then said to be write miss.

Write down the basic performance equation, Write down the basic performance...

Write down the basic performance equation? T=N*S/R T=processor time N=no.of instructions S=no of steps R=clock rate

What is boot manager, An EFI boot manager is also used to select and load t...

An EFI boot manager is also used to select and load the operating system, removing the require for a dedicated boot loader mechanism

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