Wumpus World Code

There is extra information stored to facilitate modification

main.pro

Clear the data base

% Write a string and a list, followed by a newline.format(S,L):- write(S), write(L), nl.

% GAME begins here.play :-initialize_general,format("the game is begun.",[]),description_total,retractall(is_situation(_,_,_,_,_)),time(T),agent_location(L),agent_orientation(O),assert(is_situation(T,L,O,[],i_know_nothing)),write("I'm conquering the World Ah!Ah!..."),nl,step.

Clear the data base

Fairly crude IO

step :- % One move for healthy agent who is in caveagent_healthy,agent_in_cave, is_nb_visited,% count the number of rooms visited agent_location(L),retractall(is_visited(L)),assert(is_visited(L)),description,% display a short summary of my statemake_percept_sentence(Percept),% I perceive...format("I feel ",[Percept]),tell_KB(Percept),% I learn...(infer)ask_KB(Action),format("I'm doing : ",[Action]),apply(Action),% I do...short_goal(SG),% the goal of my current action time(T),% Time update New_T is T+1,retractall(time(_)),assert(time(New_T)),agent_orientation(O),assert(is_situation(New_T,L,O,Percept,SG)),% we keep in memory to check :% time, agent_location, agent_Orientation,perception, short_goal.step,!.

Looks up what you aretrying to do

Ask knowledge base whatit should do AND do it.

% Final move if dead or out of the cave% NOTE: we get here if the first version of step cannot be

satisfied.step :-format("the game is finished.~n",[]), % either dead or out the caveagent_score(S),time(T),New_S is S - T,retractall(agent_score(_)),assert(agent_score(New_S)),description_total,the_end(MARK),display(MARK).

Note how we update global variables.

Prints summary

decl.proinitialize_land(map0):-retractall(land_extent(_)),retractall(wumpus_location(_)),retractall(wumpus_healthy),retractall(gold_location(_)),retractall(pit_location(_)),assert(land_extent(5)),assert(wumpus_location([3,2])),assert(wumpus_healthy),assert(gold_location([2,3])),assert(pit_location([3,3])),assert(pit_location([4,4])),assert(pit_location([3,1])).

initialize agent

initialize_agent(agent0):-retractall(agent_location(_)), …assert(agent_location([1,1])),assert(agent_orientation(0)),assert(agent_healthy),assert(agent_arrows(1)),assert(agent_goal(find_out)),assert(agent_score(0)),assert(agent_in_cave).

other initializationinitialize_general :-initialize_land(map0),% NOTE: Which map you wishinitialize_agent(agent0),retractall(time(_)),assert(time(0)),retractall(nb_visited(_)),assert(nb_visited(0)),retractall(score_agent_dead(_)),assert(score_agent_dead(10000)),retractall(score_climb_with_gold(_)),assert(score_climb_with_gold(1000)),retractall(score_grab(_)),assert(score_grab(0)),retractall(score_wumpus_dead(_)),assert(score_wumpus_dead(0)),retractall(is_situation(_,_,_,_,_)),retractall(short_goal(_)).

perc.promake_percept_sentence([Stench,Breeze,Glitter,Bump,Scream]) :-stenchy(Stench),breezy(Breeze),glittering(Glitter),bumped(Bump),heardscream(Scream).

stenchy(yes) :-wumpus_location(L1),agent_location(L2),adjacent(L1,L2),!.stenchy(no).

The system knows the wumpuslocation. It had BETTER beadjacent to where you are,or you will fail. KB check.

Similar KB check for glittering

glittering(yes) :-

agent_location(L),

gold_location(L),

!.

glittering(no).

Looking up agent_location

disp.pro (display)

• Displays state infoagent_healthy_state(perfect_health) :- agent_healthy,agent_courage,!.

agent_healthy_state(a_little_tired_but_alive) :- agent_healthy,!.agent_healthy_state(dead).

Performs a series of actions

the_end('=) Pfftt too easy') :-no(agent_in_cave),agent_hold,no(is_dead),!.Called by:the_end(MARK),display(MARK).

display does ioCan convert from infix to prefix

% A location is estimated thanks to ... good, medium, risky, deadly.

good(L) :- % a wall can be a good room !!!is_wumpus(no,L),is_pit(no,L),no(is_visited(L)).

medium(L) :- % Obviously if is_visited(L) ->is_visited(L). % is_wumpus(no,L) and is_pit(no,L)

risky(L) :- no(deadly(L)).

deadly(L) :-is_wumpus(yes,L),is_pit(yes,L),no(is_visited(L)).

More.pro – I’m not sure if want a wall to be a good room – or it just happens

agent_courage seems to reflect on time spent searching

agent_courage :- % we could compute nb_visited / max_room_to_visit

time(T), % time

nb_visited(N), % number of visted room

land_extent(LE), % size of the land

E is LE * LE, % maximum of room to visit

NPLUSE is E * 2,

less_equal(T,NPLUSE).

Computes next location based on orientation

location_toward([X,Y],0,[New_X,Y]) :- New_X is X+1.

location_toward([X,Y],90,[X,New_Y]) :- New_Y is Y+1.

location_toward([X,Y],180,[New_X,Y]) :- New_X is X-1.

location_toward([X,Y],270,[X,New_Y]) :- New_Y is Y-1

Note the use of !, fail to prohibit trying other choices.

no(P) :-

P,

!,

fail.

no(P)

tell.pro – updates KB

tell_KB([Stench,Breeze,Glitter,yes,Scream]) :- add_wall_KB(yes),!.

tell_KB([Stench,Breeze,Glitter,Bump,Scream]) :-% agent_location(L), % update only if unknown could be

great% no(is_visited(L)), % but the wumpus dead changes :

perceptadd_wumpus_KB(Stench),add_pit_KB(Breeze),add_gold_KB(Glitter),add_scream_KB(Scream).

Allows options of having walls otherthan at borders

There was no stenchadd_wumpus_KB(no) :-

agent_location(L1),assume_wumpus(no,L1), % I'm not in a wumpus placelocation_toward(L1,0,L2), % I'm sure there are no Wumpus inassume_wumpus(no,L2), % each adjacent room. >=Plocation_toward(L1,90,L3),assume_wumpus(no,L3),location_toward(L1,180,L4),assume_wumpus(no,L4),location_toward(L1,270,L5),assume_wumpus(no,L5),!.

There was a stenchadd_wumpus_KB(yes) :-

agent_location(L1), % I don't know if I'm in a wumpus placelocation_toward(L1,0,L2),% And It's possible there is a Wumpus in assume_wumpus(yes,L2), % each adjacent room. <=|location_toward(L1,90,L3),assume_wumpus(yes,L3),location_toward(L1,180,L4),assume_wumpus(yes,L4),location_toward(L1,270,L5),assume_wumpus(yes,L5).

But you came from one direction, so howdoes knowing no wumpus compare with possible wumpus?

• % Don't allow a "possible" wumpus to override a "no wumpus"• assume_wumpus(yes,L) :- % before I knew there is no Wumpus,• is_wumpus(no,L), % so Wumpus can't be now ... =)• !.• assume_wumpus(yes,L) :- • wall(L), % Wumpus can't be in a wall• retractall(is_wumpus(_,L)),• assert(is_wumpus(no,L)),• !.•• assume_wumpus(yes,L) :- • wumpus_healthy, % so...• retractall(is_wumpus(_,L)),• assert(is_wumpus(yes,L)),• !.•• assume_wumpus(yes,L) :-• retractall(is_wumpus(_,L)),• assert(is_wumpus(no,L)). % because Wumpus is dead >=]•

We think there is a wumpus.We treat is as truth until proven otherwise

exec.pro – carry out result of action

apply(grab) :-agent_score(S), % get my current scorescore_grab(SG), % get value of grabbingNew_S is S + SG,retractall(agent_score(S)),assert(agent_score(New_S)), % reset scoreretractall(gold_location(_)), % no more gold at this placeretractall(is_gold(_)), % The gold is with me!assert(agent_hold), % money, money, :P retractall(agent_goal(_)),assert(agent_goal(go_out)), % Now I want to go homeformat("Give me the money >=}...",[]),

• !.

If miss wumpus, update facts…% Wumpus is missed % there are several shoot options. % this one occurs after we know we didn’t hitapply(shoot) :-

format("Ouchh, I fail Grrrr >=}...",[]),retractall(agent_arrows(_)), % I can infer some information !!! assert(agent_arrows(0)),agent_location([X,Y]), % I can assume that Wumpus...location_ahead([X,NY]),is_wumpus(yes,[X,WY]),retractall(is_wumpus(yes,[X,WY])),assert(is_wumpus(no,[X,WY])),% ...is not in the supposed room.

• !

ask.pro – ask KB for adviceask_KB(Action) :- make_action_query(Strategy,Action).make_action_query(Strategy,Action) :- act(strategy_reflex,Action),!.make_action_query(Strategy,Action) :- act(strategy_find_out,Action),!.make_action_query(Strategy,Action) :- act(strategy_go_out,Action),!

act(strategy_reflex,die) :- agent_healthy,wumpus_healthy,agent_location(L),wumpus_location(L),is_short_goal(die_wumpus),!.

act(strategy_reflex,die) :- agent_healthy,agent_location(L),pit_location(L),is_short_goal(die_pit),!.

Notice our order for actions, first reflex,then find goal, then get out

act(strategy_reflex,shoot) :- % I shoot Wumpus only if I think agent_arrows(1), % that we are in the same Xagent_location([X,Y]), % it means I assume Wumpus and melocation_ahead([X,NY]),is_wumpus(yes,[X,WY]), % are in the same columndist(NY,WY,R1), % And If I don't give him my back...dist(Y,WY,R2), % <=> If I'm in the good orientationless_equal(R1,R2), % to shoot him... HE!HE!is_short_goal(shoot_forward_in_the_same_X),!.

act(strategy_find_out,forward) :-agent_goal(find_out),agent_courage,good(_), % I'm interested by a good room somewherelocation_ahead(L),good(L), % the room in front of me.no(is_wall(L)),is_short_goal(find_out_forward_good_good),!.

act(strategy_find_out,turnleft) :-agent_goal(find_out),agent_courage,good(_), % I'm interested,...agent_orientation(O),Planned_O is (O+90) mod 360,agent_location(L),location_toward(L,Planned_O,Planned_L),good(Planned_L), % directly by my left side.no(is_wall(Planned_L)),is_short_goal(find_out_turnleft_good_good),!

find_out means find out where the gold is.Thus, you proceed if finding the gold is yourgoal and you have enough time to do it.

Are there any good rooms known?

more.pro shows what is_short_goal is

// Here you set a short goal//The short_goal is stored so planning steps// know what the next goal is.// It doesn’t appear it is used at// this point.is_short_goal(X) :-

retractall(short_goal(_)),assert(short_goal(X)).