Programming the C8051F020 Using C Language Professor Yasser Kadah – .
Logic Programming Dr. Yasser Nada Fall 2010/2011 Lecture 1 1 Logic Programming.
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Transcript of Logic Programming Dr. Yasser Nada Fall 2010/2011 Lecture 1 1 Logic Programming.
Logic Programming
Dr. Yasser Nada Fall 2010/2011
Lecture 1
1Logic Programming
Text Book
• Prolog Programming, A First Course, by Paula Brna, 2001
• References:– Leon Starling and Ehud Shapiro, The art of
Prolog. 1989.– Ivan Brotko, Prolog Programming for Artificial
Intelligence. 1986.
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Course Description
• This course will introduce the theory and concepts of logic programming. Prolog will be studied as a logic programming approach for declarative logic programming.
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Course Objectives
• Upon completion of the course, student should:– Knowledge of concepts and theories of logic
programming.– Become familiar with Prolog language syntax.– Be able to solve problems in Prolog.– Be able to use knowledge in a suitable form to
be used in Prolog language..
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Course Policy• Students are expected to participate and attend the class
in time. Students are responsible to submit assignments in time. Exams will be a combination of lectures in class and homework assignments. Late homework submission will be subject to penalties. If an assignment is submitted late, a penalty of 10 percent of that assignment's grade will be assessed for each day it is late. A homework paper will not be accepted after graded papers have been returned, after a solution has been distributed, or after the final examination.
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Absence Policy
• Students absent that exceeds (25% lectures) are being considered dropped from the course. After 3 lectures absent a warning is issued for the student. After another 3 lectures absent student will be dropped from the class.
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Examination
• There will be no makeup exams except under emergencies. If a student cannot attend the exam, then student must make arrangement with the instructor prior to the planned absence. The emergency makeup exam will be either written or oral.
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Grading
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Assignment 10%
Attendance 10%
Midterm 30%
Final 50%
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What is Logic Programming
• Two types of programming languages:– Imperative languages (C, C++, VB, C#, Java, …).– Declarative languages (prolog, lisp, …).
• Logic programming is a type of programming called declarative programming.
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Imperative Languages
• They are also called procedural languages.• Programmer gives all steps to solve a problem. He
must know an algorithm to solve a problem.• Example: find average of list of numbers:
• Input total• Input number• Average = total/number• Print Average
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Declarative Languages• Programmer describe the problem without the
control flow, then the system will solve the problem.
• Programmer must know the relations between objects to solve the problem.
• Programmer does not need to know an algorithm to solve the problem.
• Declarative languages consists of:– Program or theory.– Computation which is deduction.
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First Order Predicate • Represent relation between objects:
• own(ahmed, car).• friend(ali, ahmed).• father(sami, ali).• brother(kareem, ali).
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• It is a declarative language (not completely declarative) based on first order logic.
• Prolog means Programming in Logic.• It consists of:
– Facts.– Rules.– Goal
• Used in AI: NLP, expert systems, games, automated answering system, ….
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Prolog
Logic Programming
• Prolog Program consist of:– Facts: asserts a property to an object, or relation
between two or more objects:• parent(ali, salem).• own(ali, car).
– Rules: allow to infer a relationship or a property based on a precondition:
• parent(X,Y) :- father(F,X), father(P,Y).– Goal: Query or questions asked by user.
• parent(ali, Y).
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Prolog
Logic Programming
• Atom is – a sequence of alphanumeric characters– usually starting with lower case letter– or, a string enclosed in single quotes– They represent constants.
• Examples:– ali, salem, a, b, c, a1, a2, b3, c5, …– ‘Mr. Ali’, ’Dr. Sultan’
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Atoms
Logic Programming
• A variable is • a sequence of alphanumeric characters• usually starting with an uppercase letter
• Examples:• X, Y, Z, Parent, Child, Foo, X1, Y1, X2, X5, X6,
….
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Variables
Logic Programming
• A predicate has the form– p(t1,...,tn)– where p is an atom and t1...tn are variables or
atoms.– n is the number of arguments of predicate p (written
as p/n which represents the signature of predicate).– Predicates can be of 0-arg, 1-arg, 2-arg, …
• Examples:– father(ali, ahmed).
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Predicates
Logic Programming
like(ali, car).like(ahmed, car).father(salem, ali).father(salem, ahmed).brother(X,Y) :- father(P,X), father(P,Y).friend(X,Y) :- like(X,C), like(Y,C).
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Prolog Program Example
Logic Programming
Predicate name
Predicate arguments
Predicate End
if
and
• A goal is a conjunction of predicates– p(X,Y),q(Y,Z),t(Z,W).
– A goal is the question or query asked by the user. Prolog will try to find an answer for the goal.
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Goals
Logic Programming
• Given a goal, Prolog searches for answer(s):– “yes” (possibly with answer substitution)– “no” (if no answer or no more answer found).– Substitutions are bindings of variables that
make goal true.
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Answers
Logic Programming
• ?- father(X,ali).– X = salem ? ;– no
• ?- father(X,Y), brother(Y,Z).– X = salem, Y = ali, Z = ahmed – yes– ? ;– X = salem, Y=ahmed, Z=ali– Yes– ? ;– no
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Examples
Logic Programming
male(ali).male(ahmed).male(salem).father(salem, ali).father(salem, ahmed).brother(X,Y) :- father(P,X),
father(P,Y), male(X), male(Y).
• A rule is an assertion of the form– p(ts) :- q(ts’), ..., r(ts’’).– where ts, ts’, ts’’ are atoms or variables
• “p(ts) holds if q(ts’) holds and ... And r(ts’’) holds”
• Example:– brother(X,Y) :- father(Z,X), father(Z,Y).
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Rules
Logic Programming
• You can try prolog by downloading prolog compiler:– Ciao:
http://clip.dia.fi.upm.es/Software/Ciao/Latest/download.html
– Choose Windows version, • For Windows Vista: current version 1.13.0.• For Windows XP: select version Ciao-
1.10p5Win32.zip
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Prolog
Logic Programming
• After downloading ciao-1.10pWin32.zip, extract it in C:\• Then goto C:\Ciao-1.10p5Win32• Double click on the file: install.bat• Then type ciaosh at the DOS prompt, the prolog prompt
appears: ?-
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Ciao installation under Windows XP
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• After downloading CiaoDE-1.13.0-XXXX.exe, double click on it to run.
• At the desktop you will find a file: ciaosh shortcut. Double click on it and the Prolog prompt appears:
• ?-
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Ciao installation under Windows Vista
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• Comments– % single line comment– /* multiple line
comment */• To quit Ciao, type
– ?- exit.– (or just control-D)
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Miscellaneous
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