in the name of allah lab 03 1tahani aldweesh. objectives searching for the solution’s....

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In The Name Of Allah

Lab 03

Tahani Aldweesh

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objectivesSearching for the solution’s.Declaration.Query.Comments.Prolog Concepts.Unification.Disjunction.Conjunction.

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Searching for the solution’s

Consider the query : is there a person who likes both reading and swimming?

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cont

Likes(Person , reading) likes(Person , Swimming).

The solution are found through searching, matching and backtracking.

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Declaration in visual prologPredicate and their argument must be declared.They are declared in predicate section.Clauses for the predicate are given in clauses section.Dynamic facts can be given in the facts section.Execution starts in the Goal section.

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Query: true / falseIn natural language we ask you :

Does Bill Like Cindy?

In prolog syntax, we ask prolog: Likes(bill, cindy).

Given this query , prolog would answer: Yes.

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Queries : getting answersWe could ask you in natural language: What does bill like?

In prolog syntax , we ask prolog : Likes ( bill, What).

Prolog will return: What=cindyWhat=dog

2 Solutions

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Examples

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Using Underscore as a variable

The anonymous can be used in place of any other variable. The difference is that the anonymous

variable will never get set to value :GOAL Parent(Parent, _ ).But it can also be used in facts!

owns(_ , shoes).GOAL owns(bill,shoes).GOAL owns(gane,shoes).

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Comments

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Prolog ConceptsUnification :

passing parameter ,dealing with assignment , Case selection ,etc.

Search principle:Searching for success (or failure).Top-down, right to left.

Backtracking: Providing multiple solutions.Non-determisme, determinism and cut.

Recursion.

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UnificationUnification is performed when a goal or sub-goal

Is matched against a suitable fact or left hand side of rule.

Unification is made between : The 1st parameter in the goal (sub-goal).And 1st parameter in fact/rule-head.

“=“means Unification.

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Unification and matchingIdentical values match each other:Parent(joe,tammy)matches parent(joe,tammy).A free variable can match with any value:Parent(joe, X)matches parent(joe,tammy).A bound variable matched only with it is bound to:

X=tammy, Parent(joe,X)matches parent(joe,tammy).Two free variable s unifies each other:Parent(joe,X)matches parent(joe,Y).

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Unification Examples

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Unification and calculation

Visual Prolog support the most know used mathematical functions. They can be tried out

by : Unifying a free variable with various calculation ,for example:

GOAL X=sqrt(4)*7+1Visual Prolog support logical expressions like:GOAL not(2<=4).

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Disjunction “or”;“ – ”

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Conjunction “and”,“ – ”

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Steps for create new project

1 -)Open prolog program. 2 -)project new

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3 -)Build Build .4 -)Build Execute.

5 -)Look at the project tree a file is created named “same name your proj.pro”, double click on it and put your code.

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Doubleclick

Class FactsClass Predicates

Run Statement

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Application in this lecture

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Execute the program

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Any Question

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