int_ex6.sparc

sorts definition

boolean(true). 
boolean(false).
fluent_type(defined).
fluent_type(inertial).
agent(b).
agent(j).

agent_action(X) :- physical_action(X).				     
agent_action(X) :- mental_action(X).
possible_action(X) :- agent_action(X).      
possible_action(X) :- exogenous_action(X).
room(1..4).
step(0..16).
//We need a sort to range over possible activity components.
comp(1..10).
comp(X):-physical_action(X).

index(0..11).//I use index(max_length+1) insted of index(-1),since negative numbers are not supported by dlv
created_activity(1..10).
activity(X) :- created_activity(X).
activity(d).
physical_action(move(b,R1,R2)) :- connected(R1,R2).
exogenous_action(move(j,R1,R2)) :- connected(R1,R2).
possible_fluent(in(A,R)):-agent(A),room(R).
possible_fluent(meet(A1,A2)) :- agent(A1),agent(A2),A1 != A2.
possible_fluent(meet(A1,A2)) :- agent(A1),agent(A2),A1 != A2.
possible_fluent(minor_goal(G)):-possible_goal(G).
possible_fluent(minor_activity(M)):-activity(M).
possible_fluent(active_activity(M)):-activity(M).
possible_fluent(active_goal(G)):-possible_goal(G).
possible_fluent(status(M,K)):-activity(M),index(K).
possible_fluent(curr_subact(M1,M)):- activity(M),activity(M1), M1!= M.
possible_fluent(failure(M)):- activity(M).
possible_fluent(success(M)):- activity(M).
possible_fluent(cancelled(M)):- activity(M).
possible_fluent(irrelevant(M)):- activity(M).
possible_fluent(in_progress_activity(M)):- activity(M).
possible_fluent(in_progress_goal(G)):- possible_goal(G).
possible_fluent(name(X)):-created_activity(X).
possible_fluent(intended_action(M,AA)):-activity(M),agent_action(AA).
possible_fluent(form_activity(M,G)):-activity(M),possible_goal(G).
possible_action(stop(M)):-activity(M).
possible_action(start(M)):-activity(M).
possible_action(select(G)):-possible_goal(G).
possible_action(abandon(G)):-possible_goal(G).
possible_action(make_explanation).
created_activity(1..10).
activity(X) :- created_activity(X).

possible_goal(meet(b,j)).
is_agentAction(X):-agent_action(X).
is_exogenousAction(X):-exogenous_action(X).
possible_action(delay(A)):-agent(A).


predicates declaration

connected(room,room)
fluent(possible_fluent,fluent_type)
hpd(possible_action,step)
h(possible_fluent,step)
o(possible_action,step)
occurs(possible_action,step)
neg_occ(possible_action,step)
currstep(step)
in_history(step)
after(step)
obs(possible_fluent,boolean,step)
inconsistent_obs(possible_fluent,boolean,step)
mental_action(possible_action)
component(activity,index,comp)
goal(activity,possible_goal)
exogenous_action(possible_action)
physical_action(possible_action)
length(activity,index)
intended(agent_action,step) 
unobserved(exogenous_action,step)
projected_success(activity)
has_comp(activity,index)
is_agentAction(agent_action)
is_exogenousAction(exogenousAction)
holds(possible_fluent,step)
status(activity,index,step)
success(activity,step)
failure(activity,step)
cancelled(activity,step)
intended_index(activity,possible_action,step)
in_progress_activity(activity,step)
neg_ip(possible_goal)
act_formed(activity,possible_goal,step)
active_activity(activity,step)
active_goal(possible_goal,step)
inc_fluent(possible_fluent,step)
inc_action(possible_action,step)
meeting(step)
neg_minor_goal(possible_goal,step)
neg_minor_activity(activity,step)
cur_sub(activity,activity,step)
trigger(possible_fluent,possible_action)
program rules

o(A,I+1):-trigger(F,A),h(F,I),not -o(A,I+1).

// Room connectivity
connected(1,2).
connected(2,3).
connected(3,4).
connected(R1,R2) :-  connected(R2,R1).
//Fluents
fluent(in(A,R),inertial).
fluent(meet(A1,A2),defined) :- A1 != A2.

//Law of inertia:
h(F,I+1) :- h(F,I),
            not -h(F,I+1),
            I < 16,
            fluent(F,inertial).

-h(F,I+1) :- -h(F,I),
             not h(F,I+1),
             I < 16,
             fluent(F,inertial).
			 
h(meet(A1,A2),I) :- A1 != A2,
                    h(in(A1,R),I),
                    h(in(A2,R),I).
 
h(meet(A2,A1),I) :- h(meet(A1,A2),I).


// CWA for defined positive fluent:
-h(F,I) :- fluent(F,defined),
           not h(F,I).


h(in(A,R2),I+1) :- o(move(A,R1,R2),I).

-h(in(A,R2),I) :- h(in(A,R1),I),
                  R1 != R2.


-o(move(A,R1,R2),I) :- -h(in(A,R1),I).

-o(move(A1,R1,R2),I) :- o(move(A2,R1,R2),I),
                        A1 != A2.

-o(move(A1,R1,R2),I) :- o(move(A2,R2,R1),I).



exogenous_action(delay(b)).

-o(move(A,R1,R2),I) :- o(delay(A),I).

// reality check for the past, we handle the present separately.
:-  obs(F,false,I),
     h(F,I), 
    currstep(I1),
    I < I1.
    
:-  obs(F,true,I),
    -h(F,I),
     currstep(I1),
     I < I1.
inconsistent_obs(F,false,I):-  obs(F,false,I),
  						       h(F,I).
    					
inconsistent_obs(F,true,I):-  obs(F,true,I),
   						      -h(F,I).
							  
							  
// observations of action occurrences and fluent are correct
o(E,I) :- hpd(E,I).
// observations at 0 define the initial status
h(F,0) :- obs(F,true,0).
-h(F,0) :- obs(F,false,0).

//////// PAGE 9 %%%%%%%%

////////////////////////////////////////////////////////////
//////////////// Theory of Intentions  %%%%%%%%%%%%%%%%%% 
///  To reason with the theory using ASP solvers we will need to
///  restrict the possible length of its activities. We'll denote
///  this limit by max_len.

fluent(active_activity(M), defined).
fluent(status(M,K),inertial).
//The fluent holds when -1 < K < L is the index of the component of activity
// M that has most recently been executed; K = L+1(11) is used to indicate
// that activity M is dormant. 

// The fluent is a function of M. This is indicated by the rule

-h(status(M,K1),I) :- h(status(M,K2),I), 
                      K1 != K2.

// Initially the agent's activities are normally inactive. 

h(status(M,11),0) :- not -h(status(M,11),0).

//when a mental action occurs no other physical, exogenous, or mental action occurs

-o(E,I) :- o(Ma,I), E != Ma,mental_action(Ma).


// Activities are moved into and out of the mental state of the agent 
// by mental actions start and stop.

mental_action(start(M)). 
mental_action(stop(M)). 

// PAGE 10 %%%%%%%%


// Action start which sets the value of status to 0, 
// and action stop returns the activity to a status of -1.

h(status(M,0),I+1) :- o(start(M),I).
h(status(M,11),I+1) :- o(stop(M),I).

// There are also natural executability conditions for these actions:
// an agent can neither start an ongoing activity,
// nor stop a dormant activity. 

-o(start(M),I) :- h(active_activity(M),I). 
-o(stop(M),I) :- -h(active_activity(M),I).

// defines active in terms of status   

h(active_activity(M),I) :- -h(status(M,11),I).
fluent(curr_subact(M1,M), defined).
// An activity M1 that is the current component of an activity M is a 
// current sub-activity of M. It is recursively defined in terms of status.
h(curr_subact(M1,M),I) :- component(M,K+1,M1), 
                          h(status(M,K),I).

h(curr_subact(M1,M),I) :- h(curr_subact(M2,M),I),
                          h(curr_subact(M1,M2),I).
// An activity M1 that is a current sub-activity and its goal are said to
// be minor.

fluent(minor_activity(M), defined).
fluent(minor_goal(G), defined).

h(minor_activity(M1),I) :- h(curr_subact(M1,M),I).

h(minor_goal(G),I) :- h(minor_activity(M),I),
                 goal(M,G).          
// the stopping of an activity returns its current sub-activities and
// their goals to an inactive state.

h(status(M1,11),I+1) :- o(stop(M),I),
                        h(curr_subact(M1,M),I). 

-h(active_goal(G1),I+1) :- o(stop(M),I),
                      h(curr_subact(M1,M),I), 
                      goal(M1,G1).
//The next inertial fluent from the mental state of the agent is active(G).

fluent(active_goal(G),inertial).  

// PAGE 11 %%%%%%%%                     
             
// Initially the agent has no active goals.
-h(active_goal(G),0) :- not h(active_goal(G),0).

// There are two actions, select and abandon a goal G which in this paper, are
// viewed as usually performed by agent's controllers. In a sense they are
// viewed as input to out theory.  Action select activates the goal and
// action abandon returns the goal to an inactive state.

exogenous_action(select(G)).
exogenous_action(abandon(G)).

h(active_goal(G),I+1) :- o(select(G),I).
-h(active_goal(G),I+1) :- o(abandon(G),I).
//There are also two natural executability conditions. 
// An active goal cannot be selected and an inactive goal cannot be abandoned.
// To prevent micromanaging of our agents's activities, we do not allow
// abandoning of minor goals.

-o(select(G1),I) :- h(active_goal(G),I), G1 != G.
-o(abandon(G),I) :- -h(active_goal(G),I). 
-o(abandon(G),I) :- h(minor_goal(G),I).

// The active/inactive state of a goal G of an activity M propagates
// to the goals of M's current sub-activities.

h(active_goal(G1),I) :- h(active_goal(G),I),
                   goal(M,G),
                   h(curr_subact(M1,M),I),
                   goal(M1,G1).
 
-h(active_goal(G1),I) :- -h(active_goal(G),I),
                    goal(M,G),
                    h(curr_subact(M1,M),I),
                    goal(M1,G1). 
                    
// To further describe the mental state of the agent executing activity M
// to achieve goal G it will be convienent to introduce several other 
// fluents defined in terms of fluents status(M) and active(G).

// Execution of an active activity M is cancelled at step I if
// M's goal is no longer active.

fluent(cancelled(M), defined).

h(cancelled(M),I) :- h(active_action(M),I),
                     -h(active_goal(G),I),
                     goal(M,G).
                
//Execution of an active an uncancelled activity M achieves success
// at step I if M's goal becomes true at .

fluent(success(M), defined).              

//%%%% PAGE 12 %%%%%%%% 

h(success(M),I) :- h(active_activity(M),I),  
                   goal(M,G), 
                   h(G,I),
                   -h(cancelled(M),I).
             
// The next axiom returns goal G to an inactive state after being achieved.
-h(active_goal(G),I+1) :- o(stop(M),I),
                     goal(M,G),
                     h(success(M),I).

//The execution of an activity M is completed at I but M's goal
// remains unfulfilled we say that M is a failure at I.

fluent(failure(M), defined).

h(failure(M),I) :- length(M,K),
                   h(status(M,K),I),
                   -h(success(M),I),
                   -h(cancelled(M),I).  


//Our definition of plans naturally lead to the assumption that 
//the failure of part of the plan indirectly causes the failure of the 
//entire plan.

h(failure(M),I) :- h(status(M,K),I),
                   component(M,K+1,M1),
                   h(failure(M1),I),
	               -h(success(M),I),
	               -h(cancelled(M),I).

//If an awakened activity neither failed nor succeeded it
//is said to be in progress.

fluent(in_progress_activity(M), defined).

h(in_progress_activity(M),I) :- h(active_activity(M),I),  
                       -h(cancelled(M),I),
                       -h(success(M),I),
                       -h(failure(M),I).
             
//A current sub-activity is irrelevant if one of its ancestors is a success,
//failure, or is cancelled.

fluent(irrelevant(M), defined).

// PAGE 13 %%%%%%%%

h(irrelevant(M1),I) :- h(curr_subact(M1,M),I),  
                       h(success(M),I).

h(irrelevant(M1),I) :- h(curr_subact(M1,M),I),  
                       h(failure(M),I).
                       
h(irrelevant(M1),I) :- h(curr_subact(M1,M),I),  
                       h(cancelled(M),I).

             
//The next fluent defines the action of activity M which is intended
// for execution. Variable Aa ranges over physical and mental agent actions.
	
fluent(intended_action(M,Aa), defined). 	    

// If the first not yet executed component of an active activity
// is an action then it is intended for execution.

h(intended_action(M,PA),I) :- h(status(M,K),I),
                              component(M,K+1,PA),
                              h(in_progress_activity(M),I),
                              -h(irrelevant(M),I),
							  physical_action(PA).
    
//If the first not yet executed component of an active activity is a
// sub-activity the agent will intend to start this sub-activity.

h(intended_action(M,start(M1)),I) :- h(status(M,K),I),
                                     component(M,K+1,M1),
                                     h(in_progress_activity(M),I),
                                     -h(active_activity(M1),I),
                                     -h(irrelevant(M1),I).  
									 
//// Relevant activities that are a success, failure or cancelled should be stopped.

h(intended_action(M,stop(M)),I) :- h(failure(M),I),
                                   -h(irrelevant(M),I).  
                 
h(intended_action(M,stop(M)),I) :- h(success(M),I), 
                                   -h(irrelevant(M),I).
                                   
h(intended_action(M,stop(M)),I) :- h(cancelled(M),I),
                                   -h(irrelevant(M),I).
               
//// Intended actions propagate up from current sub-activities.

h(intended_action(M,Aa),I) :- h(intended_action(M1,Aa),I),
                              h(curr_subact(M1,M),I), 
                              h(in_progress_activity(M),I).   

//// PAGE 14 %%%%%%%%

/// Execution of an intended action that is a physical action increments 
/// the status.

h(status(M,K+1),I+1) :- o(PA,I),
		                h(intended_action(M,PA),I),
                        h(status(M,K),I),
                        component(M,K+1,PA),
						 physical_action(PA).

/// Ending a sub-activity increments the status.

h(status(M,K+1),I+1) :- o(stop(M1),I),
                        h(intended_action(M1,stop(M1)),I),
	                    h(status(M,K),I),
                        component(M,K+1,M1).  //h(curr_subact(M1,M),I).  
               

////// non procrastination axiom %%%%
/// An agent tends to execute an intended action as soon as possible.

o(Aa,I) :- h(intended_action(M,Aa),I),
           is_agentAction(Aa),
           not -o(Aa,I),
           I < 16.

/// Action abandon interrupts the execution of an intended activity

-o(E,I) :- o(abandon(G),I),
           h(intended_action(M,E),I).
//NOT DONE 
//While executing an intended activity an agent should only execute
// physical actions that are intended.

intended(PA,I) :- h(intended_action(M,PA),I),physical_action(PA). 

-o(PA,I) :- h(active_activity(M),I),    
            not intended(PA,I),physical_action(PA).     


//%%%%%%%%%%% Diagnosis  %%%%%%%%%%%%%%%

//%%%% PAGE 17 %%%%%%%%
  
// When an agent discovers an inconsistent observations, it must make them 
// find an explanation that resolves the inconsistency between observations
// and expectations. Mental action make explanation is executed whenever
// the agent has an inconsistent observation.

mental_action(make_explanation).

o(make_explanation,I) :- inconsistent_obs(F,B,I).

//The cr rule below says taht the agent looking for an explanation of an
// inconsistent observation may assume that any exogenous action could have
// occurred in the past.

diag: o(EA,I2) :+ hpd(make_explanation,I1),
                             I2 < I1,exogenous_action(EA). 

//Note -- the specific exogenous action and the step in which it 
// hypothetically occurred are not parameters of the action, so the
// exact explanation is not recorded in the history as a paramenter,
// all that is recorded is that an explanation was made
 
//Then next two axioms encode the requirement that an explanation resolve all
// inconsistent observations. An inconsistent observation of fluent F having
// truth value V at I is resolved if the expected value of F at I+1 is V.

:- inconsistent_obs(F,true,I),  
   currstep(I+1),              
   -h(F,I+1).

:- inconsistent_obs(F,false,I),  
   currstep(I+1),
   h(F,I+1).   

// We limit possible explanations of the discrepency between observations 
// and expectations to a single unobserved occurrence of an exogenous action.

unobserved(EA,I) :- o(EA,I),
                    not hpd(EA,I),exogenous_action(EA).
:- unobserved(EA1,I1), exogenous_action(EA1),
   unobserved(EA2,I2), exogenous_action(EA2),
   EA1 != EA2.
   
//          
/// Planning %%%%%%%%%%
/// PAGE 18 %%%%%%%%

// we name activities generated by the agent by integers from set.



fluent(name(X),inertial).
                   
h(name(1),0).

h(name(X+1),I+1) :- o(start(X),I),
                    h(name(X),I).   

-h(name(M),I) :- h(name(M1),I),
                 M != M1.  
                 
// A goal is in progress if the agent is executing an activity M with goal G.                 
fluent(in_progress_goal(G),defined).

h(in_progress_goal(G),I) :- h(active_activity(M),I), 
                       goal(M,G).
 
// An activity M is formed to achieve goal G when the goal is active but no
// activity with this goal is currently in progress.

fluent(form_activity(M,G), defined).

h(form_activity(M,G),I) :- h(active_goal(G),I),
                           -h(minor_goal(G),I),  // yes so activating of subgoal doesnt cause planning 
                           h(name(M),I),
                           -h(in_progress_goal(G),I),
                           currstep(I1),
                           I <= I1.

// The goal for the activity which needs to be formed is given by the rule.
goal(M,G) :-  h(form_activity(M,G),I).



// The activity's components are generated by cr-rule
// which says that any possible component can be used to form the activity.

plan : component(M,K,C) :+ h(form_activity(M,G),I),
                                    currstep(I),
                                    0 < K.  

//%%%% PAGE 19 %%%%%%%%

// natural constraints on relations component(C,K,M)
:- component(M,K,M).  

:- component(M,K,C),
   component(M,K,C1),
   C1 != C.
   
:- component(M,K,C),
   length(M,K1),
   K > K1.     

// We only want to generate activities which are expected to succeed in 
// achieving the goal. This constraint is given by:

:- currstep(I),
   h(form_activity(M,G),I),
   not projected_success(M).
                  
projected_success(M) :- currstep(I),
                        h(form_activity(M,G),I),
                        h(success(M),I2),
                        I < I2.

// Finally we describe the length of the activty.

has_comp(M,K) :- component(M,K,C).

length(M,K) :- has_comp(M,K),
               not has_comp(M,K+1).

// The newly formed activity should be executed. 

h(intended_action(M,start(M)),I) :- h(form_activity(M,G),I).
                        

//Axioms about the history (not described explicitly in paper) 

currstep(I) :- in_history(I),
               not after(I).
in_history(I+1) :- hpd(E,I).  
in_history(I) :- obs(F,B,I).

after(I) :- in_history(I),
            in_history(I1),
            I < I1.

/// end axioms about the history %%%%%%%%%%%%%%%%%%

/// Assumptions on occurences of actions

// The agents recorded history of his own actions is correct
-o(Aa,I) :- currstep(I1),
            I < I1,
			is_agentAction(Aa),
            not hpd(Aa,I).
            

// The agent normally observes the occurence of exogenous actions            
-o(EA,I) :- currstep(I1),
            I < I1,
            not hpd(EA,I),
			is_exogenousAction(EA),
            not o(EA,I).
            
            


// DISPLAY: %%%%%%%%%%%%%%%%%%%%

occurs(E,I) :-
         o(E,I).
neg_occ(E,I) :- -o(E,I).         

holds(Fl,I) :-
        h(Fl,I).

status(M,K,I) :-
        h(status(M,K),I).
success(M,I) :-
        h(success(M),I).
failure(M,I) :-
        h(failure(M),I).
cancelled(M,I) :-
        h(cancelled(M),I).

intended_index(M,E,I) :-
        h(intended_action(M,E),I).
intended_index(d,E,I) :-
        h(intended_action(d,E),I).  
in_progress_activity(M,I) :-
            h(in_progress_activity(M),I).
neg_ip(G) :- -h(in_progress_goal(G),I).            

act_formed(M,G,I) :-
            h(form_activity(M,G),I).           
            

active_activity(M,I) :-
            h(active_activity(M),I).
active_goal(G,I) :-
            h(active_goal(G),I).
inc_fluent(F,I) :-
       h(F,I),
       -h(F,I).

inc_action(E,I) :-
       o(E,I),
       -o(E,I).



meeting(I) :-
    h(in(b,R),I),
    h(in(j,R),I).


neg_minor_goal(G,I) :- -h(minor_goal(G),I).
neg_minor_activity(M,I) :- -h(minor_activity(M),I).
cur_sub(M1,M,I) :- h(curr_subact(M1,M),I).
////SCENARIO::::::::::::::::::::::::::::::::::::::::::::::;

////SCENARIO::::::::::::::::::::::::::::::::::::::::::::::;

obs(in(b,1),true,0).
obs(in(j,3),true,0).

trigger(in(b,1),move(j,3,4)).

//hpd(select(in(b,2)),0).

hpd(select(meet(b,j)),0).