1

In The Name Of Allah

Lab 03

Tahani Aldweesh

Tahani Aldweesh 2

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

Tahani Aldweesh 3

Searching for the solution’s

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

Tahani Aldweesh 4

cont

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

The solution are found through searching, matching and backtracking.

Tahani Aldweesh 5

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.

Tahani Aldweesh 6

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.

Tahani Aldweesh 7

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

Tahani Aldweesh 8

Examples

Tahani Aldweesh 9

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).

Tahani Aldweesh 10

Comments

Tahani Aldweesh 11

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.

Tahani Aldweesh 12

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.

Tahani Aldweesh 13

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).

Tahani Aldweesh 14

Unification Examples

Tahani Aldweesh 15

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).

Tahani Aldweesh 16

Disjunction “or”;“ – ”

Tahani Aldweesh 17

Conjunction “and”,“ – ”

Tahani Aldweesh 18

Steps for create new project

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

Tahani Aldweesh 19

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.

Tahani Aldweesh 20

Doubleclick

Class FactsClass Predicates

Run Statement

Tahani Aldweesh 21

Application in this lecture

Tahani Aldweesh 22

Execute the program

Tahani Aldweesh 23

Any Question

Tahani Aldweesh 24

ا�ال�ب�ت�س�ا�م�ة� ل�غ���������ة

ت�ح�ت�ا�ج� ال�إ�ل���������ى�

ت�ر�ج�م�����������ة� ...