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yap-6.3/packages/bdd/bdd.yap
2012-03-22 21:36:44 +00:00

93 lines
2.2 KiB
Prolog

:- module(bdd, [bdd_new/2,
bdd_new/3,
mtbdd_new/2,
mtbdd_new/3,
bdd_eval/2,
mtbdd_eval/2,
bdd_tree/2,
bdd_to_probability_sum_product/2,
bdd_close/1,
mtbdd_close/1]).
tell_warning :-
print_message(warning,functionality(cudd)).
:- catch(load_foreign_files([cudd], [], init_cudd),_,fail) -> true ; tell_warning.
bdd_new(T, Bdd) :-
term_variables(T, Vars),
bdd_new(T, Vars, Bdd).
bdd_new(T, Vars, cudd(M,X,VS,TrueVars)) :-
term_variables(Vars, TrueVars),
VS =.. [vs|TrueVars],
findall(Manager-Cudd, set_bdd(T, VS, Manager, Cudd), [M-X]).
set_bdd(T, VS, Manager, Cudd) :-
numbervars(VS,0,_),
( ground(T)
->
term_to_cudd(T,Manager,Cudd)
;
writeln(throw(error(instantiation_error,T)))
).
mtbdd_new(T, Mtbdd) :-
term_variables(T, Vars),
mtbdd_new(T, Vars, Mtbdd).
mtbdd_new(T, Vars, add(M,X,VS,Vars)) :-
VS =.. [vs|Vars],
functor(VS,vs,Sz),
findall(Manager-Cudd, (numbervars(VS,0,_),term_to_add(T,Sz,Manager,Cudd)), [M-X]).
bdd_eval(cudd(M, X, Vars, _), Val) :-
cudd_eval(M, X, Vars, Val).
bdd_eval(add(M, X, Vars, _), Val) :-
add_eval(M, X, Vars, Val).
mtbdd_eval(add(M,X, Vars, _), Val) :-
add_eval(M, X, Vars, Val).
bdd_tree(cudd(M, X, Vars, _), bdd(Dir, Tree, Vars)) :-
cudd_to_term(M, X, Vars, Dir, Tree).
bdd_tree(add(M, X, Vars, _), mtbdd(Tree, Vars)) :-
add_to_term(M, X, Vars, Tree).
mtbdd_tree(add(M,X,Vars, _), mtbdd(Dir, Tree, Vars)) :-
add_to_term(M, X, Vars, Dir, Tree).
bdd_to_probability_sum_product(cudd(M,X,_,Probs), Prob) :-
cudd_to_probability_sum_product(M, X, Probs, Prob).
bdd_close(cudd(M,_,_Vars, _)) :-
cudd_die(M).
bdd_close(add(M,_,_Vars, _)) :-
cudd_die(M).
mtbdd_close(add(M,_,_Vars,_)) :-
cudd_die(M).
/* algorithm to compute probabilitie in Prolog */
bdd_to_sp(bdd(Dir, Tree, _Vars, IVars), Binds, Prob) :-
findall(P, sp(Dir, Tree, IVars, Binds, P), [Prob]).
sp(Dir, Tree, Vars, Vars, P) :-
run_sp(Tree),
fetch(Tree, Dir, P).
run_sp([]).
run_sp(pp(P,X,L,R).Tree) :-
run_sp(Tree),
P is X*L+(1-X)*R.
run_sp(pn(P,X,L,R).Tree) :-
run_sp(Tree),
P is X*L+(1-X)*(1-R).
fetch(pp(P,_,_,_)._Tree, 1, P).
fetch(pp(P,_,_,_)._Tree, -1, N) :- N is 1-P.
fetch(pn(P,_,_,_)._Tree, 1, P).
fetch(pn(P,_,_,_)._Tree, -1, N) :- N is 1-P.