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

Application to calculate the diameter, Write an application to calculate th...

Write an application to calculate the diameter, circumference, and area of a circle with a radius input by the user. Assign the radius float variable and then output the radius wit

Dhcp, how to set up dhcp

how to set up dhcp

What is master clock signal in control unit, Q. What is Master Clock Signal...

Q. What is Master Clock Signal in Control Unit? The Master Clock Signal: This signal causes micro-operations to be executed in a square. In a single clock cycle either a single

Call a screen as dialog box, The Syntex used to call a screen as dialog box...

The Syntex used to call a screen as dialog box (pop up)is CALL SCREEN STARTING AT ENDING AT

Data alignment in arrays, Q. Data Alignment in Arrays? Arrays are align...

Q. Data Alignment in Arrays? Arrays are aligned to templates by ALIGN directive. ALIGN directive is used to align elements of various arrays with one another denoting that they

Convert number to hexadecimal and decimal, Perform the following calculatio...

Perform the following calculations assuming that all numbers are stored in 16-bit registers as 2's complement binary numbers with no overflow provision. Convert each of the numbers

Describe jmx concepts and architecture, MX is conceptually easy, yet bears ...

MX is conceptually easy, yet bears the fruit of years of domain experience and research. In a nutshell, JMX describes a standard means for applications to expose management functio

#title.linear programming, zmax=7.5x1-3x2 subject to constraints 3x1-x2-x3>...

zmax=7.5x1-3x2 subject to constraints 3x1-x2-x3>=3 x1-x2+x3>=2 x1,x2,x3>=0

Characteristics of extreme unencoded micro-instructions, Q. Characteristics...

Q. Characteristics of extreme unencoded micro-instructions? 1. Two sources can be attached by respective control signals to a single destination; though only one of these sourc

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