PPAI/L2

From WikiZMSI

Spis treści 1 Part 2 - Data objects, operators, matching 1.1 Data objects, operators 1.2 Matching 1.3 Exercises 1.3.1 To do 2 Recursion

Part 2 - Data objects, operators, matching

Data objects, operators

1. Three types of data objects: atoms and numbers, variables, structures
2. Operator notation:
   • +
   • -
   • /
   • // integer division
   • *
   • ** power
   • mod modulo
   • is arithmetic equal np. ( X is 1 mod 3. )
   • =:= comparing if two values are equal
   • =\= comparing if two values are not equal
   • >
   • <
   • >=
   • =<
3. Task 1: Check on Family.pro:

parent(X,_).  
mother(_,_). 
mother(X,X).

1. Task 2: Define the relation hasachild/1 and isgrandparent/0
2. Task 3: Define the relation that gives the distance between two points in two and three dimensional space. Use: p2(X,Y) and p3(X,Y,Z) structure.

distance(p2( X1, Y1), p2(X2, Y2), D) :-
D is ((X2-X1)**2 + (Y2-Y1)**2))**(1/2).

distance(p3( X1, Y1, Z1), p3(X2, Y2, Z2), D) :-
D is ????.

Matching

1. Task 1: Try each command in the question mode. What is the meaning?:

X = alice. 

X = Y.

alice = malice.

X = date(1, may, 2014).

date(D, may, 2013) = date(1, may, 2014).

date(D, may, 2013) = date(1, may, R).

fun(X) = fun(fun(X)).

3 = 3.

1+2 = 3.

1+2 =:= 3.

alice == alice.

X == Y.

X == X.

2+1 == 1+2.

alice \== malice.

horizontal( p( 1, 2), p( A)) = horizontal( B, p( 1, 2)).

horizontal( p( 1, 2), p( A,B)) = horizontal( B, p( 1, C)).

Exercises

1. Ex 1: Define the relation max(X,Y,Max) so that Max is the greater of two numbers X and Y.
2. Ex 2:
3. Ex 3: Define the relation gcd/3. For example gcd(5,10,5) is satisfied. Use the three following rules:
   1. If X and Y are equal then D is equal to X
   2. If X <Y than D is equal to the greatest common divisor of X and the Difference Y-X
   3. If Y<X is the same as in case (2) with X and Y interchanged.
4. Ex 4: Look at and consult the prolog source code sentence.pro
   1. How to ask questions to this code?
   2. What is the order of generated sentences.

To do

1. Reading: chapter 2 "Syntax and Meaning of Prolog Programs", chapter 3.3 "Operator notation" and 3.4 "Arithmetic"

Recursion

1. slides