1		% (c) 2009-2024 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(counter, [
6		counter_init/0,
7		new_counter/1,
8		get_counter/2,
9		set_counter/2,
10		inc_counter/1, inc_counter/2,
11		inc_counter_by/2,
12		reset_counter/1
13		]).
14
15		:- load_files(library(system), [when(compile_time), imports([environ/2])]).
16		:- (environ(prob_c_counter,X) -> format('environ(prob_c_counter,~w)~n',[X]) ; true).
17
18		:- if((predicate_property(load_foreign_resource(_), _), \+ environ(prob_c_counter,false))).
19
20		% C implementation of counter for better performance on SICStus.
21		% A good test is 1748, where this gains maybe 1 second for 22 second model checking time
22
23		foreign_resource('counter', [new_counter,get_counter,inc_counter,set_counter,reset_counter]).
24		foreign(new_counter, c, new_counter(+atom)).
25		foreign(get_counter, c, get_counter(+atom, [-integer])).
26		foreign(inc_counter, c, inc_counter(+atom, [-integer])).
27		foreign(set_counter, c, set_counter(+atom, +integer)).
28		foreign(reset_counter, c, reset_counter(+atom)).
29
30		% with this line below we need to adapt the Makefile to include the counter resource in the binary:
31		% (maybe this is a good idea)
32		% :- load_foreign_resource(counter).
33
34
35		:- use_module(probsrc(pathes_lib),[safe_load_foreign_resource/2]).
36
37		:- dynamic loaded/1.
38
39		counter_init :-
40		(loaded(_) -> true
41		; assertz(loaded(failure)),
42		%assert_dir,
43		assertz(user:library_directory('.')),
44		(safe_load_foreign_resource(counter,counter)
45		-> retractall(loaded(_)),
46		assertz(loaded(success))
47		; format(user_output,"You can set the environment variable prob_c_counter to false to avoid using the counter C++ library~n",[])
48		)
49		).
50
51		inc_counter_by(Counter,1) :- !,
52		inc_counter(Counter,_).
53		inc_counter_by(Counter,Incr) :-
54		get_counter(Counter,Old),
55		New is Old+Incr,
56		set_counter(Counter,New).
57
58		%-----------------------
59		:- else.
60		%-----------------------
61
62		:- write('Using Prolog counter instead of C++ extension'),nl.
63
64		% Pure Prolog implementation for compatibility.
65
66		% we now use the SICStus blackboard primitives; they are also available in SWI when using expects_dialect(sicstus4).
67		% we have to ensure there are no clashes with other uses of bb_put, bb_get, ...
68		% currently only memoization.pl uses it in profiling mode
69
70		% Previously we used assertz/retract
71		% Note: we first set new value before we retract old value to ensure we have no problem if time-out/CTRL-C happens in th emiddle; maybe we can use clause references to make this efficient
72		% blackboard primitives ensure atomic updates out-of-the-box
73
74
75		counter_init.
76
77		get_counter(Counter,Value) :- bb_get(Counter,Value).
78
79		set_counter(Counter, Value) :- bb_update(Counter,_,Value).
80
81		new_counter(Counter) :- bb_put(Counter,0).
82
83		reset_counter(Counter) :- bb_put(Counter,0).
84
85		inc_counter(Counter, New) :- bb_get(Counter,Old), New is Old+1, bb_update(Counter,_,New).
86
87		inc_counter_by(Counter, Incr) :- bb_get(Counter,Old), New is Old+Incr, bb_update(Counter,_,New).
88
89
90		:- endif.
91		%-----------------------
92
93		% code for both versions:
94
95		inc_counter(Counter) :-
96		inc_counter(Counter, _NewVal).
97
98
99		% :- statistics(walltime,_),counter:new_counter(bench), repeat, counter:inc_counter(bench,N), N>1000000, statistics(walltime,[_,W]), print(W),nl.
100		% C: 465 - 467 ms, Prolog: 721 - 728 ms, SWI Prolog 1955-1960 ms
101		% C dropped to 259 - 266 ms when dropping checking for inc_counter
102
103		% :- statistics(walltime,_),bb_put(b,0), repeat, bb_get(b,C),C1 is C+1, bb_update(b,_,C1), C1>1000000, statistics(walltime,[_,W]), print(W),nl.
104		% around 590 ms -> faster than assertz; we should use this for the Prolog counter !
105		% around 396 in SWI!
106
107		% statistics(walltime,_),counter:new_counter(b), counter:new_counter(c), repeat,counter:set_counter(c,0), counter:inc_counter(b,N), N>1000000, statistics(walltime,[_,W]), print(W),nl.
108		% C : 451 - 459 ms, Prolog: 1306 - 1342 ms
109
110
111		% a good probcli performance test is this one:
112		% probcli ../prob_examples/public_examples/B/PerformanceTests/ModelChecking/Lift_1Million.mch -mc 100000 -disable-time-out