expert_system's Introduction

Expert System

École 42 assignment - an expert system for propositional calculus using backward-chaining algorithm

About the project

This is a group project of École 42.
My teammate is keatchut.
The objective of this project is to create a program that can take logical statements, their initial value and use backward chaining algorithm to find the value of the queried facts.

Ubuntu 18.04

sudo apt update
sudo apt install cmake
sudo apt install libboost-all-dev

mkdir build
cd build
cmake ..
cmake -build .
cd ..

The executable will be at bin/expert_system.

To run in normal mode

./bin/expert_system [filename]

Shorthand	Full	Mode	Description
-h	--help		show help message
-f	--facts	interactive facts mode	user can change initial facts without having to rerun the program
-q	--query	interactive query mode	user can change query without having to rerun the program
-v	--visualisation	reasoning visualisation mode	display step-by-step backward chaining reasoning process
-d	--debug	debug mode	display all values after evaluation
-c	--color	color mode	display with color
-p	--print	print mode	print input file

Below is an example of an input.

A + B => C
C => D

=AB

?D

The input are seperated into 3 sequential parts:

rules

Format: condition => conclusion.

A condition contains one or more facts and operators on the list below (ordered by priority of execution).
- NOT !
- AND +
- OR |
- XOR ^
A conclusion has one or more facts and can have only operator AND +
initial facts

Format: =[facts]

All fact values are default to FALSE. The initial facts declaration will change the fact values to TRUE.
query

Format: ?[facts] The program will do backward chaining on the facts and print the result.

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