1		% (c) 2009-2026 Lehrstuhl fuer Softwaretechnik und Programmiersprachen,
2		% Heinrich Heine Universitaet Duesseldorf
3		% This software is licenced under EPL 1.0 (http://www.eclipse.org/org/documents/epl-v10.html)
4
5		:- module(state_space,
6		[get_state_space_stats/3, get_state_space_stats/4,
7		gen_new_state_id/1,
8		history/1, forward_history/1,
9		get_action_trace/1, % old trace/1
10		get_action_trace_with_limit/2,
11		get_action_term_trace/1,
12		op_trace_ids/1, add_to_op_trace_ids/1, remove_from_op_trace_ids/1, reset_op_trace_ids/0,
13		get_state_id_trace/1,
14		current_state_id/1, current_expression/2,
15		set_current_state_id/1,
16		current_options/1, set_current_options/1,
17		get_current_predecessor_state_id/1,
18
19		add_id_at_front/1, add_id_at_end/1,
20		add_id_random/1, /* from state_space_open_nodes_c */
21		add_id_with_weight/2, add_id_to_process/3,
22		pop_id_from_front/1, pop_id_from_end/1, pop_id_oldest/1,
23		retract_open_node/1, open_ids_empty/0,
24		top_front_id/1, top_front_weight/1,
25
26		visited_expression/3, visited_expression/2, visited_expression_id/1,
27		find_hashed_packed_visited_expression/3,
28		retract_visited_expression/2,
29		not_all_transitions_added/1,
30		not_invariant_checked/1, set_invariant_checked/1,
31		invariant_not_yet_checked/1, invariant_still_to_be_checked/1,
32		not_interesting/1, % nodes ignored because they do not satisfy a user-provided scope predicate
33		mark_as_not_interesting/1,
34		max_reached_for_node/1,
35		max_reached_or_timeout_for_node/1,
36		use_no_timeout/1, time_out_for_node/1, time_out_for_node/3, virtual_time_out_for_node/1,
37		hash_to_id/2,id_to_marker/2, hash_to_nauty_id/2,
38		register_back_edge/2, try_compute_depth_of_state_id/2,
39		invariant_violated/1, time_out_for_invariant/1, time_out_for_assertions/1,
40		set_invariant_violated/1,
41
42		state_error_exists/0, state_error/3, store_state_error/3,
43		set_context_state/1, set_context_state/2,
44		update_context_state/1, clear_context_state/0, get_current_context_state/1,
45		store_error_for_context_state/2,
46		copy_current_errors_to_state/2,
47		store_abort_error_for_context_state_if_possible/4,
48		abort_error_exists_in_context_state/1,
49
50		transition/3,transition/4, any_transition/3,
51		store_transition/4,
52		deadlocked_state/1, % no outgoing edge
53		is_initial_state_id/1, is_concrete_constants_state_id/1,
54		multiple_concrete_constants_exist/0,
55		root_sufficiently_explored/0,
56		get_constants_state_for_id/2, get_constants_state_for_id/3,
57		get_constants_state_id_for_id/2,
58		try_get_unique_constants_state/1,
59		get_constants_id_for_state_id/2,
60		get_variables_state_for_id/2,
61		out_degree/2,
62		operation_not_yet_covered/1, operation_name_not_yet_covered/1,
63		get_operation_name_coverage_infos/4,
64		mark_operation_as_covered/1,
65		initialise_operation_not_yet_covered/0,
66
67		transition_info/2, store_transition_infos/2,
68		keep_transition_info/1, check_relevant_transition_info_stored/2,
69		compute_transitions_if_necessary/1,
70
71		state_space_initialise/0, state_space_initialise_with_stats/0,
72		state_space_reset/0,
73		state_space_add/2, state_space_packed_add/2,
74		delete_node/1,
75
76		current_state_corresponds_to_initialised_b_machine/0,
77		current_state_corresponds_to_fully_setup_b_machine/0,
78		current_state_corresponds_to_setup_constants_b_machine/0,
79		visited_state_corresponds_to_initialised_b_machine/1,
80		visited_state_corresponds_to_setup_constants_b_machine/1,
81
82		specialized_inv/2, %reuse_operation/4,
83		assert_max_reached_for_node/1, assert_time_out_for_node/3,
84		assert_time_out_for_invariant/1, assert_time_out_for_assertions/1,
85
86		set_max_nr_of_new_impl_trans_nodes/1,
87		get_max_nr_of_new_impl_trans_nodes/1,
88		impl_trans_term/3, impl_trans_term/4,
89		impl_trans_term_all/2,
90		impl_trans_id/4, impl_trans_not_complete/1,
91		compute_transitions_if_necessary_saved/1,
92		max_nr_of_new_nodes_limit_not_reached/0,
93
94		find_trace_to_initial_state/2, find_initialised_states/1,
95
96		tcltk_save_state_space/1, tcltk_load_state/1,
97		compute_full_state_space_hash/1,
98
99		execute_id_trace_from_current/1, execute_id_trace_from_current/3,
100		set_trace_by_transition_ids/1, try_set_trace_by_transition_ids/1,
101		extend_trace_by_transition_ids/1,
102		extract_term_trace_from_transition_ids/2,
103
104		add_counterexample_node/1, add_counterexample_op/1,
105		reset_counterexample/0, set_counterexample_by_transition_ids/1,
106		counterexample_node/1, counterexample_op/1 % specific predicates to register counter examples
107		]).
108
109		:- use_module(library(lists)).
110
111		:- use_module(self_check).
112		:- use_module(error_manager).
113		:- use_module(gensym).
114		:- use_module(preferences).
115		:- use_module(tools).
116		:- use_module(debug,[debug_println/1, debug_println/2]).
117		%:- use_module(state_space_exploration_modes,[compute_hash/3]).
118
119		:- use_module(extension('counter/counter'),
120		[counter_init/0, new_counter/1, get_counter/2, inc_counter/1, inc_counter/2, inc_counter_by/2, reset_counter/1, set_counter/2]).
121
122		:- use_module(module_information).
123		:- module_info(group,state_space).
124		:- module_info(description,'This module keeps track of the visited states by the animator/model checker.').
125
126		% ----------------------------------
127
128		:- load_files(library(system), [when(compile_time), imports([environ/2])]).
129		:- if((environ(prob_myheap,false) ; \+ predicate_property(load_foreign_resource(_), _))).
130		:- use_module(state_space_open_nodes). %% comment in to use only Prolog datastructures
131		:- else.
132		:- use_module(state_space_open_nodes_c). %% comment in to use C++ multimap queue; can make use of HEURISTIC_FUNCTION
133		:- endif.
134
135		% ----------------------------------
136
137		get_state_space_stats(NrNodes,NrTransitions,ProcessedNodes) :-
138		get_counter(states,N), NrNodes is N+1,
139		get_counter(transitions,NrTransitions),
140		get_counter(processed_nodes,ProcessedNodes).
141
142		get_state_space_stats(NrNodes,NrTransitions,ProcessedNodes,IgnoredNodes) :-
143		get_state_space_stats(NrNodes,NrTransitions,ProcessedNodes),
144		get_counter(not_interesting_nodes,IgnoredNodes).
145
146		gen_new_state_id(Nr) :-
147		inc_counter(states,N1), Nr is N1-1. % only one C call
148		%get_counter(states,Nr), inc_counter(states).
149		reset_state_counter :- reset_counter(states).
150		reset_state_counter(Nr) :- set_counter(states,Nr).
151
152		get_state_id_trace(StateIds) :-
153		history(History),
154		current_state_id(CurID),
155		reverse([CurID|History],StateIds).
156
157		get_current_predecessor_state_id(PriorID) :-
158		history([PriorID|_]).
159
160		:- dynamic history/1.
161		history([]).
162
163
164		:- dynamic forward_history/1.
165
166		:- dynamic current_state_id/1.
167		current_state_id(root).
168		/* INITIAL STATE, third arg: clp(fd) constraints as generated
169		by fd_copy_term */
170
171		current_expression(ID,State) :- current_state_id(ID),
172		visited_expression(ID,State).
173		current_packed_expression(ID,State) :- current_state_id(ID),
174		packed_visited_expression(ID,State).
175
176		:- use_module(specfile,[state_corresponds_to_initialised_b_machine/1,
177		state_corresponds_to_fully_setup_b_machine/1,
178		state_corresponds_to_set_up_constants/1]).
179		current_state_corresponds_to_initialised_b_machine :-
180		current_packed_expression(_,PS), unpack_state_top_level(PS,TLState),
181		state_corresponds_to_initialised_b_machine(TLState).
182		visited_state_corresponds_to_initialised_b_machine(ID) :-
183		packed_visited_expression(ID,PS), unpack_state_top_level(PS,TLState),
184		state_corresponds_to_initialised_b_machine(TLState).
185
186		current_state_corresponds_to_fully_setup_b_machine :-
187		current_packed_expression(_,PS), unpack_state_top_level(PS,TLState),
188		state_corresponds_to_fully_setup_b_machine(TLState).
189
190		current_state_corresponds_to_setup_constants_b_machine :-
191		current_packed_expression(_,PS), unpack_state_top_level(PS,TLState),
192		state_corresponds_to_set_up_constants(TLState).
193
194		visited_state_corresponds_to_setup_constants_b_machine(ID) :-
195		packed_visited_expression(ID,PS), unpack_state_top_level(PS,TLState),
196		state_corresponds_to_set_up_constants(TLState).
197
198		:- dynamic current_options/1.
199		current_options([]).
200
201		set_current_options(Options) :-
202		retractall( current_options(_) ),
203		assertz( current_options(Options) ).
204
205		:- dynamic packed_visited_expression/2.
206		%packed_visited_expression(v_0,true).
207
208		:- use_module(state_packing).
209
210		retract_visited_expression(ID,State) :- retract(packed_visited_expression(ID,PState)),
211		unpack_state(PState,State).
212
213		retractall_visited_expression(ID) :- retractall(packed_visited_expression(ID,_)).
214
215		state_space_packed_add(Id,PackedTerm) :- assertz(packed_visited_expression(Id,PackedTerm)).
216
217		state_space_add(Id,Term) :-
218		(pack_state(Term,PackedTerm) -> assertz(packed_visited_expression(Id,PackedTerm))
219		; add_internal_error('State packing failed: ',pack_state(Term,_)),
220		assertz(packed_visited_expression(Id,Term))).
221
222		% deprecated:
223		visited_expression(ID,State,true) :- visited_expression(ID,State).
224		% not call(CurBody); for the moment we always have true as last argument
225
226	?	visited_expression(A,B) :- packed_visited_expression(A,PB),
227		(unpack_state(PB,R) -> B=R ; add_internal_error('Unpacking state failed: ',unpack_state(PB,R)),R=A).
228
229		%visited_expression_id(A) :- packed_visited_expression(A,_). % avoid unpacking state
230		% even better: not to look up fact at all to avoid constructing state term, this is done below:
231		:- use_module(library(between),[between/3]).
232		visited_expression_id(ID) :- number(ID),!, ID>=0, get_counter(states,N), ID<N.
233		visited_expression_id(ID) :- ID==root,!.
234		visited_expression_id(root).
235	?	visited_expression_id(Nr) :- Nr \== root, get_counter(states,N), N1 is N-1, between(0,N1,Nr).
236
237		% given a hash and a packed state: find ID (fail if does not exist)
238		find_hashed_packed_visited_expression(Hash,PackedState,ID) :-
239	?	hash_to_id(Hash,ID),
240		(packed_visited_expression(ID,PackedState)
241		-> true /* warning: may instantiate State if not ground */
242		; functor(PackedState,concrete_constants,1),
243		preference(maxNrOfInitialisations,Max), Max =< 4
244		-> debug_println(19,hash_collision_for_constants(Hash,ID)),fail
245		% this is not too bad if maxNrOfInitialisations small;
246		% can happen due to depth limit in term_depth_hash in compute_hash
247		; write(hash_collision(Hash,ID)),nl,fail
248		).
249
250
251		:- dynamic not_invariant_checked/1.
252		set_invariant_checked(ID) :- %print(inv_checked(ID)),nl,
253	?	retract(not_invariant_checked(ID)).
254
255		invariant_not_yet_checked(ID) :-
256		not_all_transitions_added(ID) ; /* assumption: if not all transitions added then we haven't checked invariant yet */
257		not_invariant_checked(ID) ;
258		not_interesting(ID). % assumption: if a node is marked as not interesting it will not be examined
259
260		% difference with invariant_not_yet_checked: not interesting nodes not reported and cannot be backtracked
261		invariant_still_to_be_checked(ID) :-
262		(not_all_transitions_added(ID) -> true ; not_invariant_checked(ID) -> true).
263
264		:- dynamic not_interesting/1.
265		%not_interesting(v_0).
266
267		:- dynamic max_reached_for_node/1.
268		/* true if not all outgoing transistions were computed due to the limit
269		on the number of operations/initialisations computed */
270		:- dynamic time_out_for_node/3, use_no_timeout/1, time_out_for_invariant/1, time_out_for_assertions/1.
271
272		time_out_for_node(ID) :- (var(ID) -> visited_expression_id(ID) ; true),
273		(time_out_for_node(ID,_,_) -> true ; fail).
274
275		% only succeeds for virtual time_outs
276		virtual_time_out_for_node(ID) :- (var(ID) -> visited_expression_id(ID) ; true),
277		(time_out_for_node(ID,_,virtual_time_out) -> true ; fail).
278
279		:- dynamic transition/4.
280		%transition(v_0,a,1,v_1).
281
282		store_transition(Org,Action,Dest,Id) :-
283		%get_counter(transitions,Id), inc_counter(transitions),
284		inc_counter(transitions,Id1), Id is Id1-1, % only one C call
285		assertz(transition(Org,Action,Id,Dest)).
286
287	?	deadlocked_state(Origin) :- \+ any_transition(Origin,_,_).
288
289		is_concrete_constants_state_id(ID) :-
290	?	logical_transition_from_root(ID),
291		packed_visited_expression(ID,concrete_constants(_)).
292
293		% get the transition to the first logical successor to root, jumping over start_cspm_MAIN in CSP||B mode
294		logical_transition_from_root(ID) :-
295	?	transition(root,T,_TransId,ID1),
296		(T=start_cspm_MAIN, csp_with_bz_mode
297		-> transition(ID1,_,ID) % the first logical successor of root is a successor of ID1
298		; ID1=ID
299		).
300
301		% check if we have explored a successor of root node to find constants (or initial state if no constants exist)
302		% i.e., did we compute successors of root, and in case of CSP||B did we from there set up constants or initialise machine
303		root_sufficiently_explored :-
304		transition(root,T,_TransId,ID1),!,
305		(T=start_cspm_MAIN, csp_with_bz_mode
306		-> \+ not_all_transitions_added(ID1)
307		; true
308		).
309
310		% check if we have multiple constant setups
311		multiple_concrete_constants_exist :-
312	?	is_concrete_constants_state_id(ID),
313	?	is_concrete_constants_state_id(ID2), ID2 \= ID,!.
314
315
316		is_initial_state_id(InitialStateID) :-
317		logical_transition_from_root(State),
318		packed_visited_expression(State,P),
319		(P = concrete_constants(_) % also covers '$partial_setup_constants'
320		-> state_space:transition(State,_,InitialStateID)
321		; InitialStateID=State).
322
323		% get the constants for a state (if there are constants), avoid unpacking variables
324		get_constants_state_for_id(ID,CS) :- get_constants_state_for_id(ID,[],CS).
325		get_constants_state_for_id(ID,Opts,ConstantsState) :-
326		packed_visited_expression(ID,PState),
327		unpack_state_top_level(PState,TLState),
328		(TLState = const_and_vars(CID,_) -> get_constants_state_for_id(CID,[],ConstantsState)
329		; unpack_state(PState,UPState),
330		(UPState = concrete_constants(CS) -> ConstantsState=CS
331		; UPState = [_|_], member(allow_variable_list,Opts),
332		ConstantsState=UPState,
333		% could be that we have a state where constants and variables are mixed in a single list
334		% e.g., ProB2's FindStateCommand does currently not create new intermediate constant states
335		add_message(get_constants_state_for_id,'State is a list of bindings and has no reference to a constant valuation: ',ID)
336		)
337		).
338
339		% get the state id for associated constants state for a state (if there are constants)
340		get_constants_state_id_for_id(ID,CstID) :-
341		packed_visited_expression(ID,PState),
342		unpack_state_top_level(PState,TLState),
343		get_constants_id_for_id_aux(TLState,ID,CstID).
344		get_constants_id_for_id_aux(concrete_constants(_),ID,ID).
345		get_constants_id_for_id_aux(const_and_vars(ID,_),_,ID).
346
347		get_variables_state_for_id(ID,VarState) :-
348		visited_expression(ID,State),
349		get_vars_aux(State,VarState).
350		%get_vars_aux(concrete_constants(ConstantsState),[]).
351		get_vars_aux(const_and_vars(_,Vars),State) :- !, State=Vars.
352		get_vars_aux([],[]).
353		get_vars_aux([H|T],[H|T]).
354
355		% check if there is a unique constants state:
356		try_get_unique_constants_state(ConstantsState) :-
357		logical_transition_from_root(DestID),
358		\+ (logical_transition_from_root(DestID2), DestID2 \= DestID), % no other transition exists
359		\+ max_reached_or_timeout_for_node(root),
360		DestID \= root, % DestID=root should never happen
361		get_constants_state_for_id(DestID,ConstantsState).
362
363		% returns id of constants state for a state (if it exists)
364		get_constants_id_for_state_id(ID,ConstID) :-
365		packed_visited_expression(ID,'$cst_vars'(ConstID,_)).
366
367	?	any_transition(Origin,TransID,Destination) :- transition(Origin,_,TransID,Destination).
368
369	?	transition(Origin,Action,Destination) :- transition(Origin,Action,_TransID,Destination).
370
371		:- dynamic transition_info/2.
372		store_transition_infos([],_TransId).
373		store_transition_infos([Info|Irest],TransId) :-
374		store_transition_info(Info,TransId),
375		store_transition_infos(Irest,TransId).
376		store_transition_info(Info,TransId) :- %print(info(Info,TransId)),nl,
377		(keep_transition_info(Info)
378		-> assertz(transition_info(TransId,Info))
379		; true).
380
381		% Do not store path info by default
382		keep_transition_info(path(_)) :- !,
383		preference(eventtrace,true). % STORE_DETAILED_TRANSITION_INFOS
384		keep_transition_info(eventtrace(_)) :- !,preference(eventtrace,true).
385		keep_transition_info(event(_)) :- !,
386		preference(store_event_transinfo,true). % store info about parameters and abstract Rodin events
387		keep_transition_info(_). % store everything else
388
389		% check if all relevant transition infos have been stored for a transition
390		check_relevant_transition_info_stored([],_).
391		check_relevant_transition_info_stored([Info|Irest],TransId) :-
392		(keep_transition_info(Info) -> transition_info(TransId,Info) ; true),
393		check_relevant_transition_info_stored(Irest,TransId).
394
395
396		reset_transition_store :-
397		retractall(transition(_,_,_,_)),
398		retractall(transition_info(_,_)),
399		reset_counter(transitions),
400		reset_counterexample.
401
402		/*
403		Version with packing of transitions:
404		store_transition(Org,Action,Dest,Id) :-
405		retract(transition_counter(Id)),
406		NewId is Id+1,
407		assertz(transition_counter(NewId)),
408		Action =.. [ActionName|Parameters],
409		pack_values(Parameters,PackedParameters),
410		assertz(packed_transition(Org,ActionName,PackedParameters,Id,Dest)).
411
412		transition(Origin,Action,TransID,Destination) :- nonvar(Action),!,
413		Action =.. [ActionName|Parameters],
414		packed_transition(Origin,ActionName,PackedParameters,TransID,Destination),
415		unpack_values(PackedParameters,Parameters).
416		transition(Origin,Action,TransID,Destination) :-
417		packed_transition(Origin,ActionName,PackedParameters,TransID,Destination),
418		unpack_values(PackedParameters,Parameters),
419		Action =.. [ActionName|Parameters].
420		any_transition(Origin,TransID,Destination) :- packed_transition(Origin,_,_,TransID,Destination).
421		*/
422
423		% compute out-degree of a node
424		out_degree(ID,OutDegree) :- findall(0, transition(ID,_,_,_), L), length(L,OutDegree).
425
426	?	operation_name_not_yet_covered(OpName) :- operation_not_yet_covered(OpName).
427
428
429		get_operation_name_coverage_infos(PossibleNr,FeasibleNr,UncovNr,UncoveredList) :-
430		findall(ON, specfile:get_possible_event(ON), Possible), length(Possible,PossibleNr),
431		findall(OF, specfile:get_feasible_event(OF), Feasible), length(Feasible,FeasibleNr),
432		findall(OpName, state_space: operation_name_not_yet_covered(OpName), UncoveredList),
433		length(UncoveredList,UncovNr).
434
435
436		:- dynamic operation_not_yet_covered/1.
437		%operation_not_yet_covered(b).
438
439		:- use_module(probsrc(debug),[formatsilent/2]).
440		mark_operation_as_covered(OpName) :-
441		(operation_not_yet_covered(OpName), % small improvement in B/PerformanceTests/ModelChecking/EnumSetLookups.mch
442		retract(operation_not_yet_covered(OpName))
443		-> (preferences:get_preference(provide_trace_information,true)
444		-> formatsilent('Covered ~w~n',[OpName])
445		; true),
446	?	(operation_not_yet_covered(_) -> true ; formatsilent('~nALL OPERATIONS COVERED~n',[]))
447		; true
448		).
449
450		:- use_module(bmachine,[b_top_level_operation/1]).
451		:- use_module(probcspsrc(haskell_csp),[channel/2]).
452		initialise_operation_not_yet_covered :- retractall(operation_not_yet_covered(_)),
453		b_or_z_mode,
454	?	b_top_level_operation(Name),
455		% b_get_machine_operation(Name,_,Par,_), length(Par,Arity), functor(Op,Name,Arity),
456		% Note: no '-->' added
457		assertz(operation_not_yet_covered(Name)),
458		fail.
459		/* Missing: treat operations with return values */
460		initialise_operation_not_yet_covered :- csp_mode, \+ csp_with_bz_mode,
461	?	channel(Name,_),
462		assertz(operation_not_yet_covered(Name)),
463		fail.
464		initialise_operation_not_yet_covered.
465
466		state_error_exists :- state_error(_,_,_),!.
467		:- dynamic state_error/3.
468
469		%state_error([],invariant_violated).
470
471		reset_next_state_error_id_counter :- reset_counter(next_state_error_id).
472		:- use_module(tools_printing, [print_error/1, format_error_with_nl/2]).
473		:- use_module(error_manager,[print_error_span/1]).
474		store_state_error(State,Error,Id) :- state_error(State,Id,Error),!. % do not store identical error twice
475		store_state_error(State,Error,Id) :-
476		%retract( next_state_error_id(Id) ),
477		inc_counter(next_state_error_id,Id),
478		% tools_printing:print_term_summary(Error),nl, tools_printing:nested_print_term(Error),nl,
479		assertz( state_error(State,Id,Error) ).
480		store_error_for_context_state(Error,Id) :-
481		( context_state(State,Errs) ->
482		(Errs<25
483		-> store_state_error(State,Error,Id), E1 is Errs+1,
484		%assertz(context_state(State,E1))
485		set_context_number_of_errors(E1)
486		; store_state_error(State,max_state_errors_reached(25),Id)
487		)
488		;
489		add_internal_error('No known context when calling store_error_for_context_state: ',store_error_for_context_state(Error,Id)),
490		fail).
491
492		% check if we already have a certain type of error in the current context state
493		abort_error_exists_in_context_state(ErrType) :- get_current_context_state(State),
494		Error = abort_error(ErrType,_Msg,_Term,_Pos),
495		state_error(State,_Id,Error).
496
497		% copy current errors from error_manager to state errors
498		copy_current_errors_to_state(StateID,Context) :-
499		% error_manager:logged_error(Source,ErrMsg,_Context,Span), % will not retract
500		error_manager:get_error_with_span(Source,ErrMsg,Span), % will retract
501		store_state_error(StateID,abort_error(Source,ErrMsg,'',span_context(Span,Context)),SID),
502		% TO DO: use other error class
503		debug_println(4,stored_state_error(Source,SID,_Context,ErrMsg)),
504		fail.
505		copy_current_errors_to_state(_,_).
506
507		store_abort_error_for_context_state_if_possible(ErrType,Msg,Term,Span) :-
508		%print(store(Msg,Term,Span)),nl,
509		( get_current_context_state(State) ->
510		error_manager:get_error_context(Context),
511		(abort_error_for_same_location_exists(State,Id1,ErrType,Msg,Span),
512		abort_error_for_same_location_exists(State,Id2,ErrType,Msg,Span),
513		Id2>Id1
514		-> /* two errors of same type, for same state and same source location exists */
515		/* TO DO: maybe merge state errors */
516		simplify_span(Span,Span1),
517		compress_span(Span1,Span2),
518		store_state_error(State,abort_error(ErrType,'Further identical errors occurred (not stored !)',Term,span_context(Span2,Context)),_)
519		;
520		format_error_with_nl('! An error occurred in state ~w: ~w !',[State,ErrType]),
521		% usual errors: precondition_error, while_invariant_violation, while_variant_error,
522		% assert_error, well_definedness_error, card_overflow_error
523		print_error(Msg),
524		print_error_term(Term,Span),
525		% print_error(context_state_id(State)), % printed by print_error_context
526		print_error_context,
527		(debug_mode(on),visited_expression(State,S) -> translate:translate_bstate(S,O),print_error(O) ; true),
528		compress_span(Span,Span2),
529		print_error_span(Span2),
530		store_state_error(State,abort_error(ErrType,Msg,Term,span_context(Span2,Context)),_)
531		),
532		(add_new_event_in_error_scope(abort_error(ErrType)) -> true ; true), % should we use well_definedness_error?
533		assert_real_error_occurred(abort_error) % Note that in this case the error manager list of errors maybe empty even though real_error_occured is true. (see ProB2 kernel test de.prob.cli.integration.rules.RulesMachineTest > testReuseStateSpace)
534		; % no current context_state exists:
535		compress_span(Span,Span2),
536		add_error(ErrType,Msg,Term,Span2)
537		).
538
539
540		:- use_module(bsyntaxtree, [find_identifier_uses/3]).
541		compress_span(span_context(Span,C),span_context(CS,C)) :- !,
542		compress_span(Span,CS).
543		compress_span(pos_context(Span1,C,Span2),pos_context(CS1,C,CS2)) :- !,
544		compress_span(Span1,CS1),
545		compress_span(Span2,CS2).
546		compress_span(span_predicate(Pred,LS,S),Res) :- find_identifier_uses(Pred,[],Ids),
547		sort(Ids,SIds),
548		filter_state(LS,SIds,FLS),
549		filter_state(S,SIds,FS), % TODO: do we need to store the global state? we can reconstruct it ?
550		% format('Compressed span_predicate (~w)~n',[Ids]),
551		!,
552		Res = span_predicate(Pred,FLS,FS).
553		compress_span(S,S).
554		% avoid storing large useless values
555		% TO DO: probably we should stop storing spans when a certain threshold of number of errors is reached
556
557
558		:- use_module(library(ordsets),[ord_member/2]).
559		filter_state([],_,[]).
560		filter_state([bind(ID,L)|T],Vars,Res) :-
561		(ord_member(ID,Vars) -> Res = [bind(ID,L)|RT] ; Res=RT),
562		filter_state(T,Vars,RT).
563
564
565		:- use_module(translate, [translate_error_term/3]).
566		print_error_term(T,S) :- (var(T);var(S)),!,
567		print_error('### VARIABLE error term or span:'), print_error(print_error_term(T,S)).
568		print_error_term(Term,Span) :- translate_error_term(Term,Span,S),
569		(S='' -> true ; print_error(S)).
570
571		abort_error_for_same_location_exists(State,Id,ErrType,Msg,Span) :-
572	?	state_error(State,Id,abort_error(ErrType,Msg,_Term2,span_context(Span2,_Ctxt2))),
573		same_span_location(Span2,Span).
574		% should be moved to error_manager ?
575		same_span_location(span_context(Span1,C),span_context(Span2,C)) :- !, same_span_location(Span1,Span2).
576		same_span_location(pos_context(Span1,C,_),pos_context(Span2,C,_)) :- !,
577		same_span_location(Span1,Span2). % should we check second span?
578		same_span_location(span_predicate(Pred1,_,_),span_predicate(Pred2,_,_)) :- !,Pred1=Pred2.
579		same_span_location(X,X).
580
581		:- dynamic saved_nested_context_state/2.
582		save_nested_context_state(_S) :-
583		bb_get(state_space_context_state,ID),
584		bb_get(state_space_context_errors,Errs),!,
585		%print(saving_context_state(_S,ID,Errs)),nl,
586		asserta(saved_nested_context_state(ID,Errs)).
587		save_nested_context_state(_).
588
589		% actually pops context state
590		clear_context_state :-
591	?	retract(saved_nested_context_state(ID,Errs)),!, %print(restoring_nested(ID,Errs)),nl,
592		bb_put(state_space_context_state,ID),
593		bb_put(state_space_context_errors,Errs).
594		clear_context_state :-
595		(bb_delete(state_space_context_state,_) -> true ; true).
596		%(retract(context_state(_,_)) -> true ; true). % retractall seems to be slowing down with use
597
598		% Note: Each Prolog module maintains its own blackboard for bb_get/bb_put
599		context_state(ID,Errs) :-
600		bb_get(state_space_context_state,ID), bb_get(state_space_context_errors,Errs).
601
602		% sets a new context state; pushing the previous one if necessary
603		set_context_state(State) :- %print(set_id(State)),nl,
604		save_nested_context_state(State),
605		bb_put(state_space_context_state,State),
606		bb_put(state_space_context_errors,0).
607
608		set_context_state(State,_Context) :- % Context can be used for debugging later
609		set_context_state(State).
610
611		% update current context state, without storing nested states
612		update_context_state(State) :-
613		bb_put(state_space_context_state,State),
614		bb_put(state_space_context_errors,0).
615
616		get_current_context_state(ID) :- bb_get(state_space_context_state,ID).
617		%get_current_context_state(ID) :- context_state(ID,_).
618
619		set_context_number_of_errors(Errs) :- bb_put(state_space_context_errors,Errs).
620
621		retractall_invariant_violated(State) :-
622		retractall(state_error(State,_,invariant_violated)).
623		invariant_violated(State) :-
624	?	state_error(State,_,invariant_violated).
625		set_invariant_violated(State) :-
626		( invariant_violated(State) -> true
627		; time_out_for_invariant(ID) -> print('Timeout for node: '), print(ID),nl,
628		print('Not setting invariant violation status'),nl
629		; store_state_error(State,invariant_violated,_)
630		).
631
632		%:- set_invariant_violated([]). % why is this ??
633
634
635		:- dynamic hash_to_id/2.
636		:- dynamic id_to_marker/2.
637		:- dynamic id_back_edge/3. % optional facts to keep track where a state was constructed from
638
639		:- dynamic hash_to_nauty_id/2. % used in nauty mode to map nauty id's to hash values
640
641		:- dynamic specialized_inv/2. /* stores whether for a node a specialized invariant
642		version could be computed */
643
644		% :- dynamic reuse_operation/4. /* when for a state and given operation name we can reuse the operation computed for another state */
645		% used to be used for OPERATION_REUSE TRUE
646
647		:- use_module(hashing).
648		state_space_startup :- % call once at startup to ensure all counters exist
649		counter_init,
650		new_counter(states), new_counter(processed_nodes), new_counter(transitions),
651		new_counter(next_state_error_id),
652		new_counter(not_interesting_nodes),
653		reset_open_ids. % also calls myheap init
654		state_space_initialise :- counter_init, reset_gennum, reset_gensym,
655		new_counter(states), new_counter(processed_nodes), new_counter(transitions),
656		new_counter(next_state_error_id), new_counter(not_interesting_nodes),
657		reset_state_counter, reset_processed_nodes_counter, reset_next_state_error_id_counter,
658		retractall_visited_expression(_),
659		reset_open_ids,
660		reset_stored_values, % state_packing
661		retractall(not_invariant_checked(_)),
662		reset_not_interesting,
663		retractall(max_reached_for_node(_)),
664		retractall(time_out_for_node(_,_,_)),
665		retractall(time_out_for_invariant(_)),
666		retractall(time_out_for_assertions(_)),
667		retractall(use_no_timeout(_)),
668		retractall(state_error(_,_,_)),
669		clear_context_state,
670		reset_transition_store,
671		retractall(operation_not_yet_covered(_)),
672		retractall(hash_to_id(_,_)),
673		retractall(id_back_edge(_,_,_)),
674		retractall(hash_to_nauty_id(_,_)),
675		retractall(id_to_marker(_,_)),
676		retractall(specialized_inv(_,_)),
677		%retractall(reuse_operation(_,_,_,_)),
678		state_space_add(root,root),
679		add_id_at_front(root),
680		my_term_hash(root,RootHash),
681		assertz(hash_to_id(RootHash,root)),
682		%assertz(not_invariant_checked(root)),
683		state_space_reset.
684
685		:- use_module(eventhandling,[register_event_listener/3]).
686		:- register_event_listener(startup_prob,state_space_startup,
687		'Initialise Statespace Counters.').
688		:- register_event_listener(reset_specification,state_space_initialise,
689		'Reset Statespace.').
690		:- register_event_listener(change_of_animation_mode,state_space_initialise,
691		'Reset Statespace.').
692		:- register_event_listener(specification_initialised,initialise_operation_not_yet_covered,
693		'Init coverage info.').
694		:- register_event_listener(reset_prob,state_space_initialise,
695		'Reset Statespace.').
696
697		/* A version of reset which checks how much memory is used by each fact */
698		/* state_space:init_with_stats */
699		state_space_initialise_with_stats :-
700		reset_gennum, reset_gensym, reset_state_counter, reset_processed_nodes_counter,
701		reset_next_state_error_id_counter,
702	?	retract_open_ids_with_statistics,
703	?	retract_with_statistics(state_space,[packed_visited_expression(_,_),
704		not_invariant_checked(_),
705		not_interesting(_),
706		max_reached_for_node(_),
707		time_out_for_node(_,_,_),
708		time_out_for_invariant(_),
709		time_out_for_assertions(_),
710		use_no_timeout(_),
711		state_error(_,_,_),
712		transition(_,_,_,_),
713		transition_info(_,_),
714		operation_not_yet_covered(_),
715		hash_to_id(_,_),
716		hash_to_nauty_id(_,_),
717		id_to_marker(_,_),
718		specialized_inv(_,_),
719		%reuse_operation(_,_,_,_),
720		history(_), forward_history(_), op_trace_ids(_)]),
721		reset_not_interesting,
722	?	retract_stored_values_with_statistics,
723		clear_context_state,
724		reset_transition_store,
725		state_space_add(root,root),
726		add_id_at_front(root),
727		%assertz(not_invariant_checked(root)),
728		state_space_reset,
729		initialise_operation_not_yet_covered.
730
731
732
733		:- dynamic op_trace_ids/1.
734		reset_trace :- retractall(op_trace_ids(_)), assertz(op_trace_ids([])).
735		get_action_trace(T) :- trace(T).
736		get_action_term_trace(PT) :- get_action_trace_with_limit(0,T), project_on_action_term(T,PT).
737		trace(Trace) :- get_action_trace_with_limit(500,Trace).
738		get_action_trace_with_limit(Limit,Trace) :-
739		op_trace_ids(IDT), reverse(IDT,RIDT),
740		extract_trace_from_transition_ids(RIDT,root,Limit,[],Trace).
741
742		reset_op_trace_ids :- retractall(op_trace_ids(_)), assertz(op_trace_ids([])).
743		add_to_op_trace_ids(OpID) :- retract(op_trace_ids(OpIDS)), assertz(op_trace_ids([OpID|OpIDS])).
744		remove_from_op_trace_ids(OpID) :- retract(op_trace_ids(OpIDS)),
745		(OpIDS = [R|Rest]
746		-> assertz(op_trace_ids(Rest)), OpID = R
747		; assertz(op_trace_ids(OpIDS)), fail).
748
749		% translate a list of transition ids (from root) into a list of operation terms
750		extract_term_trace_from_transition_ids(TransIDListFromRoot,Trace) :-
751		extract_trace_from_transition_ids(TransIDListFromRoot,root,0,[],ActionTrace),
752		reverse_and_project_on_action_term(ActionTrace,[],Trace).
753
754		reverse_and_project_on_action_term([],A,A).
755		reverse_and_project_on_action_term([action(_,Term)|T],Acc,Res) :- !,
756		reverse_and_project_on_action_term(T,[Term|Acc],Res).
757		reverse_and_project_on_action_term([H|T],Acc,Res) :-
758		add_error(reverse_and_project_on_action_term,'Illegal action: ',H),
759		reverse_and_project_on_action_term(T,[H|Acc],Res).
760
761		project_on_action_term([],[]).
762		project_on_action_term([action(_,Term)|T],Res) :- !, Res=[Term|TR],
763		project_on_action_term(T,TR).
764		project_on_action_term([H|T],Res) :-
765		add_error(project_on_action_term,'Illegal action: ',H),
766		project_on_action_term(T,Res).
767
768		extract_trace_from_transition_ids([],_CurrentState,_,Trace,Trace).
769		extract_trace_from_transition_ids([TransId|Rest],CurrentState,Limit,AccTrace,Trace) :-
770		compute_op_string(TransId,CurrentState,Limit,OpTerm,OpString,DestState),!,
771		extract_trace_from_transition_ids(Rest,DestState,Limit,
772		[action(OpString,OpTerm)|AccTrace],Trace).
773		extract_trace_from_transition_ids([TransId|_],CurrentState,_,_,_Trace) :-
774		add_error(state_space,'Could not execute transition id: ', TransId:from(CurrentState)),fail.
775
776		:- use_module(translate,[translate_event_with_src_and_target_id/5]).
777		compute_op_string(jump(TO),_CurID,_,Term,String,DestID) :- !, Term=jump,String=jump,DestID=TO.
778		compute_op_string(TransId,CurID,Limit,Term,String,DestID) :- transition(CurID,Term,TransId,DestID),
779		translate_event_with_src_and_target_id(Term,CurID,DestID,Limit,String).
780
781		% reset history and forward history, but not state-space itself
782		state_space_reset :-
783		reset_trace,
784		retractall(history(_)),
785		retractall(forward_history(_)),
786		retractall(current_state_id(_)),
787		retractall(current_options(_)),
788		assertz(history([])),
789		assertz(current_state_id(root)).
790
791		reset_not_interesting :- retractall(not_interesting(_)), reset_counter(not_interesting_nodes).
792
793		mark_as_not_interesting(ID) :- assertz(not_interesting(ID)), inc_counter(not_interesting_nodes).
794
795		set_current_state_id(ID) :- (retract(current_state_id(_)) -> true ; true),
796		assertz(current_state_id(ID)).
797
798		state_space_clean_all :-
799		retractall(state_space_version_in_file(_)),
800		retractall_visited_expression(_),
801		reset_open_ids,
802		retractall(not_invariant_checked(_)),
803		reset_not_interesting,
804		retractall(max_reached_for_node(_)),
805		retractall(time_out_for_node(_,_,_)),
806		retractall(time_out_for_invariant(_)),
807		retractall(time_out_for_assertions(_)),
808		retractall(use_no_timeout(_)),
809		retractall(state_error(_,_,_)),
810		clear_context_state,
811		reset_transition_store,
812		retractall(operation_not_yet_covered(_)),
813		retractall(hash_to_id(_,_)),
814		retractall(id_back_edge(_,_,_)),
815		retractall(hash_to_nauty_id(_,_)),
816		retractall(id_to_marker(_,_)),
817		retractall(specialized_inv(_,_)),
818		%retractall(reuse_operation(_,_,_,_)),
819		retractall(history(_)),
820		retractall(forward_history(_)),
821		retractall(op_trace_ids(_)),
822		retractall(current_state_id(_)),
823		retractall(current_options(_)).
824
825		% this is only used from within the Tcl/Tk animator at the moment:
826		delete_node(ID) :- print(deleting(ID)),nl,
827		retractall_visited_expression(ID),
828		retractall_invariant_violated(ID),
829		retract_open_node_and_update_processed_nodes(ID),
830		retractall(not_invariant_checked(ID)),
831		(retract(not_interesting(ID)) -> inc_counter_by(not_interesting_nodes,-1) ; true),
832		retractall(max_reached_for_node(ID)),
833		retractall(time_out_for_node(ID,_,_)),
834		retractall(time_out_for_invariant(ID)),
835		retractall(time_out_for_assertions(ID)),
836		retractall(use_no_timeout(ID)),
837		retractall(state_error(ID,_,_)),
838		retractall(transition(ID,_,_,_)),
839		% to do: check if operation_not_yet_covered(_) changes
840		retract_hash(ID),
841		retractall(id_to_marker(ID,_)).
842
843		retract_hash(ID) :- retract(hash_to_id(Hash,ID)), retractall(hash_to_nauty_id(_TermHash,Hash)),fail.
844		retract_hash(_).
845
846		% assert max_operations reachoed
847		assert_max_reached_for_node(Id) :- %print_message(max_reached_for_node(Id)),
848		(max_reached_for_node(Id) -> true ; assertz(max_reached_for_node(Id))).
849
850		:- use_module(probsrc(debug),[debug_mode/1]).
851		assert_time_out_for_node(Id,OpName,TypeOfTimeOut) :-
852		(debug_mode(off),functor(TypeOfTimeOut,virtual_time_out,_) -> true % can easily happen when parameters are unbounded
853		; print_message(time_out_for_node(Id,OpName,TypeOfTimeOut))),
854		(time_out_for_node(Id,OpName,_) -> true ; assertz(time_out_for_node(Id,OpName,TypeOfTimeOut))).
855		assert_time_out_for_invariant(Id) :- print_message(time_out_for_invariant(Id)),
856		(time_out_for_invariant(Id) -> true ; assertz(time_out_for_invariant(Id))).
857		assert_time_out_for_assertions(Id) :- print_message(time_out_for_assertions(Id)),
858		(time_out_for_assertions(Id) -> true ; assertz(time_out_for_assertions(Id))).
859
860		max_reached_or_timeout_for_node(Id) :-
861	?	(max_reached_for_node(Id) ; time_out_for_node(Id,_,_)).
862		/* ---------------------- */
863		/* state space saving */
864		/* ---------------------- */
865
866		:- dynamic state_space_version_in_file/1. %
867		state_space_version(1).
868
869		check_state_space_version :- state_space_version(V),
870		(state_space_version_in_file(F) -> true ; F=0),
871		(V>F -> add_message(state_space,'Warning: saved state_space may be incompatible with current version: ',F:V) ; true).
872
873		% save all infos of state space (transitions, evaluated invariants, ...)
874		tcltk_save_state_space(File) :-
875		print('% saving full state space to: '), print(File),nl,
876		open(File,write,Stream,[encoding(utf8)]),
877		print_state_space(Stream),
878		close(Stream),
879		print_message(done).
880
881
882		:- use_module(tools_printing, [print_dynamic_fact/2,print_dynamic_pred/4]).
883		print_state_space(Stream) :-
884		state_space_version(V),
885		print_dynamic_fact(Stream,state_space_version_in_file(V)),
886		% TO DO: maybe also save some important preferences, and warn user and/or propose to adapt preferences ?
887		print_dynamic_pred(Stream,state_space,history,1),
888		print_dynamic_pred(Stream,state_space,forward_history,1),
889		print_dynamic_pred(Stream,state_space,op_trace_ids,1),
890		print_dynamic_pred(Stream,state_space,current_state_id,1),
891		print_dynamic_pred(Stream,state_space,current_options,1),
892		print_dynamic_pred(Stream,state_space,packed_visited_expression,2),
893		print_dynamic_pred(Stream,state_space,not_invariant_checked,1),
894		print_dynamic_pred(Stream,state_space,not_interesting,1),
895		print_dynamic_pred(Stream,state_space,max_reached_for_node,1),
896		print_dynamic_pred(Stream,state_space,time_out_for_node,3),
897		print_dynamic_pred(Stream,state_space,use_no_timeout,1),
898		print_dynamic_pred(Stream,state_space,transition,4),
899		print_dynamic_pred(Stream,state_space,transition_info,2),
900		print_dynamic_pred(Stream,state_space,operation_not_yet_covered,1),
901		print_dynamic_pred(Stream,state_space,state_error,3),
902		print_state_space_open_nodes(Stream),
903		print_stored_values(Stream),
904		get_counter(states,X),
905		write_term(Stream,saved_gennum_count(X),[quoted(true)]),write(Stream,'.'),nl(Stream).
906
907		saved_gennum_count(99999).
908
909		/* ---------------------- */
910		/* state space loading */
911		/* ---------------------- */
912
913		tcltk_load_state(File) :- state_space_clean_all,
914		print('Loading: '), print(File),nl,
915		user_consult_without_redefine_warning(File), % this will read in bind_skeleton/2, ..., next_value_id/1
916		check_state_space_version,
917		print('Generating open node info'),nl,
918		transfer_open_node_info,
919		print('Transfer state packing info'),nl,
920		transfer_state_packing_info,
921		print('Recomputing hash index'),nl,
922		recompute_all_hash,
923		(saved_gennum_count(X) -> reset_state_counter(X) ; true),
924		reset_processed_nodes_counter, % TO DO: restore or save it
925		reset_next_state_error_id_counter, % DITTO
926		print('Done'),nl,!.
927		tcltk_load_state(File) :-
928		add_error(tcltk_load_state,'Could not load state from file: ',File),
929		state_space_initialise.
930
931		:- dynamic not_all_z_saved/1, not_all_transitions_added_saved/1.
932		:- dynamic bind_skeleton/2, stored_value/2, stored_value_hash_to_id/2, next_value_id/1.
933
934		% transfer facts read into state_space into other modules:
935		transfer_open_node_info :- retract(not_all_z_saved(X)), %print(not_all_z(X)),nl,
936		assert_not_all_z(X),fail.
937		transfer_open_node_info :- retract(not_all_transitions_added_saved(X)),
938		assert_not_all_transitions_added(X),fail.
939		transfer_open_node_info.
940		% now for transferring to state_packing module info generated by print_stored_values
941		transfer_state_packing_info :- retract(bind_skeleton(X,Y)), %print(skel(X)),nl,
942		assertz(state_packing:bind_skeleton(X,Y)),fail.
943		transfer_state_packing_info :- retract(stored_value(X,Y)),
944		assertz(state_packing:stored_value(X,Y)),fail.
945		transfer_state_packing_info :- retract(stored_value_hash_to_id(X,Y)),
946		assertz(state_packing:stored_value_hash_to_id(X,Y)),fail.
947		transfer_state_packing_info :- retract(next_value_id(X)),
948		state_packing:set_next_value_id(X),fail.
949		transfer_state_packing_info.
950
951		recompute_all_hash :-
952		retractall(hash_to_id(_,_)),retractall(id_to_marker(_,_)),
953		retractall(hash_to_nauty_id(_,_)),
954	?	visited_expression(ID,StateTemplate),
955		state_space_exploration_modes:compute_hash(StateTemplate,Hash,Marker),
956		assertz(hash_to_id(Hash,ID)),
957		assertz(id_to_marker(ID,Marker)),
958		fail.
959		recompute_all_hash.
960
961		:- use_module(hashing,[my_term_hash/2]).
962		% generates a hash for the entire state space not depending on the order in which states where added
963		compute_full_state_space_hash(Hash) :-
964		%listing(hash_to_id/2), listing(packed_visited_expression/2),
965		findall(Hash,hash_to_id(Hash,_),ListOfHashCodes),
966		sort(ListOfHashCodes,SortedList),
967		my_term_hash(SortedList,Hash).
968		% TO DO: also provide transition hashes
969
970		:- use_module(tools_meta,[safe_on_exception/3]).
971		user_consult_without_redefine_warning(File) :-
972		get_set_optional_prolog_flag(redefine_warnings, Old, off),
973		get_set_optional_prolog_flag(single_var_warnings, Old2, off),
974		(safe_on_exception(Exc,
975		%consult(File), %
976		load_files([File], [load_type(source),compilation_mode(consult),encoding(utf8)]),
977		(nl,print('Exception occurred:'),print(Exc),nl,fail))
978		-> OK=true ; OK=false),
979		get_set_optional_prolog_flag(redefine_warnings, _, Old),
980		get_set_optional_prolog_flag(single_var_warnings, _, Old2),
981		OK=true.
982
983		% execute a transition id list from current ID and update animator history,...
984		execute_id_trace_from_current(OperationIDList) :-
985		current_state_id(CurID),
986		get_state_list_from_opids(OperationIDList,CurID,StateIDList,NewCurID),
987		execute_id_trace_from_current(NewCurID,OperationIDList,StateIDList).
988
989		get_state_list_from_opids([],CurID,[],CurID).
990		get_state_list_from_opids([TransId|TO],CurID,[NextCurID|TS],FinalCurID) :-
991		transition(CurID,_,TransId,NextCurID),
992		get_state_list_from_opids(TO,NextCurID,TS,FinalCurID).
993
994
995		% execute_id_trace_from_current(NewCurID,OperationIDList,StateIDList)
996		execute_id_trace_from_current(ID,OpIDL,StateIDList) :-
997		current_state_id(CurID),
998		reverse([CurID|StateIDList],Rev),
999		Rev = [Dest|TRev],
1000		(Dest==ID -> true ; print(not_eq(Dest,ID)),nl),
1001		retract(history(H)),
1002		update_forward_history(OpIDL), % check if OpIDL conforms to forward history and keep it
1003		append(TRev,H,NewH),
1004		assertz(history(NewH)),
1005		retract(op_trace_ids(OldTrace)),
1006		reverse(OpIDL,NewTrace),
1007		append(NewTrace,OldTrace,Trace),
1008		assertz(op_trace_ids(Trace)),
1009		retractall(current_state_id(_)),
1010		assertz(current_state_id(ID)).
1011		%execute_trace_to_node(OpL,StateIDList). /* <----- BOTTLENECK FOR LONG SEQUENCES */
1012		%generate_trace([],Acc,Acc).
1013		%generate_trace([OpTerm|T],Acc,Res) :-
1014		% translate:translate_event(OpTerm,OpString),
1015		% generate_trace(T,[action(OpString,OpTerm)|Acc],Res).
1016
1017		update_forward_history(TransitionIds) :-
1018		(retract(forward_history(Forward)),
1019		prune_forward_history(TransitionIds,Forward,NewForward)
1020		-> assert(forward_history(NewForward))
1021		; true).
1022		% try and prune forward history if it matches operation trace
1023		prune_forward_history([],ForwardHistory,ForwardHistory).
1024		prune_forward_history([TransID|T],[forward(_,TransID)|TF],Res) :-
1025		prune_forward_history(T,TF,Res).
1026
1027		try_set_trace_by_transition_ids(TransIds) :-
1028		(set_trace_by_transition_ids(TransIds) -> true
1029		; add_internal_error('Call failed:',set_trace_by_transition_ids(TransIds))).
1030
1031		set_trace_by_transition_ids(TransitionIds) :-
1032		extract_history_from_transition_ids(TransitionIds,root,[],[],Last,History,OpTrace),
1033		%visited_expression(Last,LastState,LastCond),
1034		retractall(history(_)),
1035		retractall(forward_history(_)), % TODO: we could try and recover a new forward history if transition ids match current history^forward history
1036		update_forward_history(TransitionIds),
1037		retractall(current_state_id(_)),
1038		retractall(op_trace_ids(_)),
1039		assertz(history(History)),
1040		assertz(op_trace_ids(OpTrace)),
1041		assertz(current_state_id(Last)).
1042
1043
1044		extract_history_from_transition_ids([],CurrentState,History,Trace,CurrentState,History,Trace).
1045		extract_history_from_transition_ids([TransId|Rest],CurrentState,AccHist,AccTrace,Last,History,Trace) :-
1046		transition(CurrentState,_,TransId,DestState),!,
1047		extract_history_from_transition_ids(Rest,DestState,[CurrentState|AccHist],
1048		[TransId|AccTrace],Last,History,Trace).
1049		extract_history_from_transition_ids([skip|Rest],CurrentState,AccHist,AccTrace,Last,History,Trace) :- !,
1050		extract_history_from_transition_ids(Rest,CurrentState,AccHist,AccTrace,Last,History,Trace).
1051		extract_history_from_transition_ids([TransId|_],CurrentState,_,_,_,_,_Trace) :-
1052		add_error(state_space,'Could not execute transition id: ', TransId:from(CurrentState)),fail.
1053
1054		% extend trace from current state
1055		extend_trace_by_transition_ids(TransitionIds) :-
1056		current_state_id(CurID),
1057		history(OldH), op_trace_ids(OldOT),
1058		extract_history_from_transition_ids(TransitionIds,CurID,OldH,OldOT,Last,History,OpTrace),
1059		retractall(history(_)), retractall(forward_history(_)),
1060		retractall(current_state_id(_)),
1061		retractall(op_trace_ids(_)),
1062		assertz(history(History)),
1063		assertz(op_trace_ids(OpTrace)),
1064		assertz(current_state_id(Last)).
1065
1066		/* --------------------------------- */
1067		:- dynamic max_nr_of_new_nodes/1.
1068
1069		% negative number or non-number signifies no limit
1070		set_max_nr_of_new_impl_trans_nodes(MaxNrOfNewNodes) :-
1071		retractall(max_nr_of_new_nodes(_)),
1072		(number(MaxNrOfNewNodes), MaxNrOfNewNodes>=0
1073		-> assertz(max_nr_of_new_nodes(MaxNrOfNewNodes))
1074		; true). % no need to store limit; we will explore as much as needed
1075
1076		get_max_nr_of_new_impl_trans_nodes(MaxNrOfNewNodes) :-
1077		(max_nr_of_new_nodes(Max) -> MaxNrOfNewNodes=Max; MaxNrOfNewNodes = 0).
1078
1079		% used e.g., in refinement or ltl checker
1080		impl_trans_term(From,ActionAsTerm,TransID,To) :-
1081		compute_transitions_if_necessary_saved(From),
1082	?	transition(From,ActionAsTerm,TransID,To).
1083		impl_trans_term(From,ActionAsTerm,To) :-
1084		compute_transitions_if_necessary_saved(From),
1085	?	transition(From,ActionAsTerm,_TID,To).
1086
1087		% a variation also giving the transition id:
1088		impl_trans_id(From,ActionAsTerm,TransitionID,To) :-
1089		compute_transitions_if_necessary_saved(From),
1090	?	transition(From,ActionAsTerm,TransitionID,To).
1091
1092		impl_trans_term_all(From,Ops) :-
1093		compute_transitions_if_necessary_saved(From),
1094		findall(op(Id,ActionAsTerm,To),
1095		transition(From,ActionAsTerm,Id,To),
1096		Ops).
1097
1098		% true if e.g., a time-out occurred during computation of all transitions
1099		impl_trans_not_complete(From) :- max_reached_or_timeout_for_node(From).
1100
1101		compute_transitions_if_necessary_saved(From) :-
1102		catch(
1103		compute_transitions_if_necessary(From),
1104		error(forced_interrupt_error('User has interrupted the current execution'),_),
1105		user_interrupts:process_interrupted_error_message).
1106
1107		:- use_module(tcltk_interface,[compute_all_transitions_if_necessary/2]).
1108		compute_transitions_if_necessary(From) :-
1109		not_all_transitions_added(From),!,
1110		decrease_max_nr_of_new_nodes(From),
1111		compute_all_transitions_if_necessary(From,false).
1112		compute_transitions_if_necessary(_From).
1113
1114		decrease_max_nr_of_new_nodes(ID) :-
1115		retract(max_nr_of_new_nodes(Max)),!,
1116		( Max>0 ->
1117		NewMax is Max-1,
1118		assertz(max_nr_of_new_nodes(NewMax))
1119		; Max=0 -> NM is -1,
1120		assertz(max_nr_of_new_nodes(NM)),
1121		add_warning(state_space,'Maximum number of new nodes reached for CTL/LTL/refinement check, node id = ',ID),
1122		fail
1123		; % negative number: re-assert and fail
1124		assertz(max_nr_of_new_nodes(Max)),
1125		fail).
1126		decrease_max_nr_of_new_nodes(_). % no limit stored; just proceed
1127
1128		% will be called from TCL/TK side
1129		max_nr_of_new_nodes_limit_not_reached :-
1130		max_nr_of_new_nodes(N),N>0.
1131
1132		:- use_module(specfile,[b_or_z_mode/0, csp_mode/0, csp_with_bz_mode/0]).
1133		retract_open_node(NodeID) :- retract_open_node_and_update_processed_nodes(NodeID),
1134		(b_or_z_mode -> assertz(not_invariant_checked(NodeID)) ; true).
1135
1136		reset_processed_nodes_counter :- reset_counter(processed_nodes).
1137		%reset_processed_nodes_counter(Nr) :- set_counter(processed_nodes,Nr).
1138
1139		retract_open_node_and_update_processed_nodes(NodeID) :-
1140		retract_open_node_direct(NodeID),
1141		inc_processed.
1142
1143		inc_processed :-
1144		inc_counter(processed_nodes).
1145
1146		pop_id_from_front(ID) :- pop_id_from_front_direct(ID), inc_processed.
1147		pop_id_from_end(ID) :- pop_id_from_end_direct(ID), inc_processed.
1148	?	pop_id_oldest(ID) :- pop_id_oldest_direct(ID), inc_processed.
1149
1150
1151
1152		/* --------------------------------- */
1153
1154		% find initialised states; very similar to is_initial_state_id/1
1155		% but is used by ltl/ctl/sap
1156		% TO DO: merge these two variations of the same concept
1157
1158		:- use_module(specfile,[animation_mode/1]).
1159
1160		find_initialised_states(Init) :-
1161		animation_mode(Mode),
1162		( init_states_mode_cst_init(Mode) ->
1163		findall(I,find_init1(root,I,_),Init)
1164		; init_states_mode_one_step(Mode) ->
1165		next_states_from_root(Init)
1166		;
1167		fail).
1168
1169		% find trace to some initialised state
1170		find_trace_to_initial_state(Target,Trace) :- animation_mode(Mode),
1171	?	find_aux(Mode,Target,Trace).
1172		find_aux(Mode,Target,[root,Target]) :-
1173		init_states_mode_one_step(Mode).
1174		find_aux(Mode,Target,[root|Trace]) :-
1175		init_states_mode_cst_init(Mode),
1176	?	find_init1(root,Target,Trace).
1177
1178
1179		init_states_mode_cst_init(b).
1180		init_states_mode_cst_init(z).
1181		init_states_mode_cst_init(csp_and_b).
1182
1183		init_states_mode_one_step(csp).
1184		init_states_mode_one_step(cspm).
1185		init_states_mode_one_step(xtl).
1186		%init_states_mode_one_step(promela).
1187
1188		next_states_from_root(States) :-
1189		impl_trans_term_all(root,Ops),
1190		findall(S, member(op(_Id,_,S),Ops), States).
1191
1192		find_init1(Start,Init,Trace) :- Start==Init,!,Trace=[]. % usually called with Start=Init=root
1193		find_init1(Start,Init,[State|Rest]) :-
1194	?	impl_trans_term(Start,O,State),
1195	?	find_init2(O,State,Init,Rest).
1196		find_init2(O,Init,Init,[]) :-
1197		has_functor_and_maybe_tau(O,'$initialise_machine').
1198		find_init2(O,State,Init,Path) :-
1199		has_functor_and_maybe_tau(O,F),
1200		(F='$setup_constants' ; F='$partial_setup_constants'),
1201	?	find_init1(State,Init,Path).
1202		find_init2(start_cspm_MAIN,State,Init,Path) :-
1203	?	find_init1(State,Init,Path).
1204		find_init2(start_cspm(_Proc),State,Init,Path) :-
1205		find_init1(State,Init,Path).
1206
1207		% has_functor_and_maybe_tau(Term,Functor)
1208		% checks if Term has the form "Functor(...)" or "tau(Functor(...))"
1209		% this is used for CSP||B specification where the initialisation is wrapped with
1210		% in a tau operator
1211		has_functor_and_maybe_tau(tau(Term),Functor) :-
1212		has_functor_and_maybe_tau(Term,Functor),!.
1213		has_functor_and_maybe_tau(Term,Functor) :-
1214		functor(Term,Functor,_).
1215
1216		% compute how far the state is from the root node using back_edge markers (if available)
1217		try_compute_depth_of_state_id(root,R) :- !, R=0.
1218		try_compute_depth_of_state_id(Node,Depth) :- id_back_edge(Node,Depth,_Back).
1219
1220		% optional registering of back_edges: to quickly find trace from root and to computed depth/diameter
1221		register_back_edge(ID,FromID) :-
1222		try_compute_depth_of_state_id(FromID,D),!,
1223		D1 is D+1,
1224		assertz(id_back_edge(ID,D1,FromID)).
1225		register_back_edge(ID,FromID) :- write(cannot_store_back_edge(ID,FromID)),nl.
1226
1227		/* --------------------------------- */
1228
1229		%
1230		% Code to compute equivalence classes
1231		% using the standard DFA minimization algorithm
1232
1233		:- dynamic equivalent/2.
1234		% state_space:compute_equivalence_classes
1235		:- public compute_equivalence_classes/0.
1236
1237		compute_equivalence_classes :- init_equi,
1238		split_equivalence_classes,nl,
1239		print_equi.
1240
1241		print_equi :- state_space:equivalent(A,B), visited_expression(A,State),
1242		visited_expression(B,StateB),
1243		nl,
1244		print(A), print(' : '), print(State),nl,
1245		print(B), print(' : '), print(StateB),nl,fail.
1246		print_equi.
1247
1248		init_equi :- retractall(equivalent(_,_)),
1249		packed_visited_expression(ID,_State),
1250		\+ not_all_transitions_added(ID),
1251		findall(Action,transition(ID,Action,_,_),List),
1252		packed_visited_expression(ID2,_S2), ID2 @> ID,
1253		\+ not_all_transitions_added(ID2),
1254		findall(Action,transition(ID2,Action,_,_),List),
1255		assertz(equivalent(ID,ID2)), % they have the same signature
1256		%print(equivalent(ID,ID2)),nl,
1257		fail.
1258		init_equi :- print(finished_initialising),nl.
1259
1260		split_equivalence_classes :- retractall(echange),
1261		equivalent(ID1,ID2),
1262		transition(ID1,A,_,Dest1),
1263		transition(ID2,A,_,Dest2),
1264		\+ check_equi(Dest1,Dest2),
1265		retract(equivalent(ID1,ID2)), % splitting class
1266		% print(diff(ID1,ID2, A, Dest1, Dest2)),nl,
1267		assert_echange,
1268		fail.
1269		split_equivalence_classes :- echange -> split_equivalence_classes ; true.
1270
1271		:- dynamic echange/0.
1272		assert_echange :- echange -> true ; assertz(echange),print('.'),flush_output.
1273
1274		check_equi(A,B) :- A=B -> true ; A @<B -> equivalent(A,B) ; equivalent(B,A).
1275
1276		/*
1277		% benchmark how much time it takes to copy the state space state_space:bench_state_space.
1278		bench_state_space :-
1279		statistics(walltime,_),
1280		(state_space:packed_visited_expression(ID,S), assertz(pve(ID,S)),fail ; true),
1281		statistics(walltime,[_,Delta]), format('Time to copy packed_visited_expression: ~w ms~n',[Delta]),
1282		(state_space:transition(A,B,C,D), assertz(tr(A,B,C,D)),fail ; true),
1283		statistics(walltime,[_,Delta2]), format('Time to copy transition: ~w ms~n',[Delta2]),
1284		(state_packing:stored_value(A,B), assertz(sv(A,B)),fail ; true),
1285		(state_packing:stored_value_hash_to_id(A,B), assertz(svhi(A,B)),fail ; true),
1286		statistics(walltime,[_,Delta3]), format('Time to copy stored_value: ~w ms~n',[Delta3]).
1287		*/
1288
1289		:- public portray_state_space/0.
1290		portray_state_space :- packed_visited_expression(ID,S), functor(S,F,N),
1291		format('State ~w : ~w/~w~n',[ID,F,N]), fail.
1292		portray_state_space :- transition(ID,Action,TransID,DestID),
1293		format(' ~w: ~w -- ~w --> ~w~n',[TransID,ID,Action,DestID]),fail.
1294		portray_state_space.
1295
1296		bench_state_space :- statistics(walltime,[W1,_]),
1297		(packed_visited_expression(_,_), fail ; true),
1298		statistics(walltime,[W2,_]), T1 is W2-W1,
1299		format('Time to inspect all states: ~w ms walltime~n',[T1]),
1300		(visited_expression(_,_), fail ; true),
1301		statistics(walltime,[W3,_]), T2 is W3-W2,
1302		format('Time to inspect and unpack all states: ~w ms walltime~n',[T2]),
1303		(transition(_,_,_,_), fail ; true),
1304		statistics(walltime,[W4,_]), T3 is W4-W3,
1305		format('Time to inspect all transitions: ~w ms walltime~n',[T3]),
1306		(visited_expression(_,E), my_term_hash(E,_), fail ; true),
1307		statistics(walltime,[W5,_]), T4 is W5-W4,
1308		format('Time to inspect, unpack and hash all states: ~w ms walltime~n',[T4]).
1309
1310		% ----------------------------
1311		% COUNTER EXAMPLE MANAGEMENT
1312
1313		% store counter example nodes and transition ids; used by LTL model checking for example
1314
1315
1316		:- dynamic counterexample_node/1.
1317		:- dynamic counterexample_op/1.
1318
1319		add_counterexample_node(NodeID) :- assertz(counterexample_node(NodeID)).
1320		add_counterexample_op(TransID) :-
1321		(counterexample_op(TransID) -> true ; assertz(counterexample_op(TransID))).
1322
1323
1324		reset_counterexample :-
1325		retractall(counterexample_node(_)),
1326		retractall(counterexample_op(_)).
1327
1328		:- register_event_listener(play_counterexample,reset_counterexample,
1329		'Reset marked nodes from previous counterexamples.').
1330
1331		set_counterexample_by_transition_ids(TransIds) :-
1332		set_trace_by_transition_ids(TransIds),
1333		maplist(add_counterexample_op,TransIds),
1334		extract_history_from_transition_ids(TransIds,root,[],[],_Last,History,_OpTrace),
1335		maplist(add_counterexample_node,History).