Goals and strategies

[olufjen]

A list of opponent pieces to capture based on rank. A list of own pieces and their priority to move A list of Positions to capture or protect.

[olufjen]

Rules to follow:

1. Capture opponent KIng
2. Capture opponent pieces (without loss)
3. Activate officers
4. Conquer the centre squares.

[olufjen]

Procedure:

Construct a KB consisting of Percepts and Sentences A ChessState is a Percept? Construct a KB Agent which implements

• makePerceptSntence(Precept p, int t) returning a Sentence
• makeActionQuery(int t) returning a Sentence
• makeActionSentence(Action action,int t) returning a Sentence
• ask(KB kb,Sentence sentence) returning an Action

[olufjen]

Examples of how to write rules to the knowledgebase: // We can connect stench and breeze percepts directly // to the properties of the squares where they are experienced // through the location fluent as follows. For any time step t // and any square [x,y], we assert tell(new ComplexSentence( newSymbol(LOCATION, t, agentPosition.getX(), agentPosition.getY()), Connective.IMPLICATION, new ComplexSentence(newSymbol(PERCEPT_BREEZE, t), Connective.BICONDITIONAL, newSymbol(BREEZE, agentPosition.getX(), agentPosition.getY()))));

From AIMA book p. 247 R4, and R5: A location (x,y) precepts a breeze, then there must be a breeze at this location. How to express this precepts of breeze at a given location: : We want to establish the fact that there is a breeze in a certain location: newSymbol(BREEZE, agentPosition.getX(), agentPosition.getY())))); This is the head. This is the case iff: new ComplexSentence( newSymbol(LOCATION, t, agentPosition.getX(), agentPosition.getY()), Connective.IMPLICATION, new ComplexSentence(newSymbol(PERCEPT_BREEZE, t), .....

In chess: We want to establish the fact that a position is protected and safe to move to.

[olufjen]

An example of how to create rules of a knowledge base:

/**
 * TELL the KB the atemporal "physics" sentences (used to initialize the KB).
 */
protected void tellAtemporalPhysicsSentences() {
    //
    // 7.7.1 - The current state of the World
    // The agent knows that the starting square contains no pit
    tell(new ComplexSentence(Connective.NOT, newSymbol(PIT, start.getX(), start.getY())));
    // and no wumpus.
    tell(new ComplexSentence(Connective.NOT, newSymbol(WUMPUS, start.getX(), start.getY())));

    // Atemporal rules about breeze and stench
    // For each square, the agent knows that the square is breezy
    // if and only if a neighboring square has a pit; and a square
    // is smelly if and only if a neighboring square has a wumpus.
    for (int y = 1; y <= caveYDimension; y++) {
        for (int x = 1; x <= caveXDimension; x++) {

            List<PropositionSymbol> pitsIn = new ArrayList<>();
            List<PropositionSymbol> wumpsIn = new ArrayList<>();

            if (x > 1) { // West room exists
                pitsIn.add(newSymbol(PIT, x - 1, y));
                wumpsIn.add(newSymbol(WUMPUS, x - 1, y));
            }
            if (y < caveYDimension) { // North room exists
                pitsIn.add(newSymbol(PIT, x, y + 1));
                wumpsIn.add(newSymbol(WUMPUS, x, y + 1));
            }
            if (x < caveXDimension) { // East room exists
                pitsIn.add(newSymbol(PIT, x + 1, y));
                wumpsIn.add(newSymbol(WUMPUS, x + 1, y));
            }
            if (y > 1) { // South room exists
                pitsIn.add(newSymbol(PIT, x, y - 1));
                wumpsIn.add(newSymbol(WUMPUS, x, y - 1));
            }

            tell(new ComplexSentence
                    (newSymbol(BREEZE, x, y), Connective.BICONDITIONAL, Sentence.newDisjunction(pitsIn)));
            tell(new ComplexSentence
                    (newSymbol(STENCH, x, y), Connective.BICONDITIONAL, Sentence.newDisjunction(wumpsIn)));
        }
    }

    // The agent also knows there is exactly one wumpus. This is represented
    // in two parts. First, we have to say that there is at least one wumpus
    List<PropositionSymbol> wumpsAtLeast = new ArrayList<>();
    for (int x = 1; x <= caveXDimension; x++)
        for (int y = 1; y <= caveYDimension; y++)
            wumpsAtLeast.add(newSymbol(WUMPUS, x, y));

    tell(Sentence.newDisjunction(wumpsAtLeast));

    // Then, we have to say that there is at most one wumpus.
    // For each pair of locations, we add a sentence saying
    // that at least one of them must be wumpus-free.
    int numRooms = (caveXDimension * caveYDimension);
    for (int i = 0; i < numRooms; i++) {
        for (int j = i + 1; j < numRooms; j++) {
            tell(new ComplexSentence(Connective.OR,
                    new ComplexSentence
                            (Connective.NOT, newSymbol(WUMPUS, (i / caveXDimension) + 1, (i % caveYDimension) + 1)),
                    new ComplexSentence
                            (Connective.NOT, newSymbol(WUMPUS, (j / caveXDimension) + 1, (j % caveYDimension) + 1))));
        }
    }
}