This repository has been archived on 2023-08-20. You can view files and clone it, but cannot push or open issues or pull requests.
yap-6.3/CLPBN/clpbn/evidence.yap
vsc 7acacd1618 new version
git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@1212 b08c6af1-5177-4d33-ba66-4b1c6b8b522a
2004-12-16 06:07:07 +00:00

123 lines
3.0 KiB
Prolog

%
%
%
%
:- module(evidence, [
store_evidence/1,
incorporate_evidence/2
]).
:- use_module(library(clpbn), [
{}/1,
clpbn_flag/3,
set_clpbn_flag/2
]).
:- use_module(library(rbtrees), [
new/1,
lookup/3,
insert/4
]).
:- meta_predicate store_evidence(:).
:- dynamic node/4, reachable_from_evidence/2, evidence/2.
%
% new evidence storagea algorithm. The idea is that instead of
% redoing all the evidence every time we query the network, we shall
% keep a precompiled version around. The precompiled
%
% the format is as follows:
% evidence_store:parent(Key,ParentList,[EvidenceChildren])
%
%
store_evidence(G) :-
clpbn_flag(solver,Solver, graphs),
compute_evidence(G, Solver).
compute_evidence(G, PreviousSolver) :-
catch(call_residue(G, Vars), Ball, evidence_error(Ball,PreviousSolver)), !,
store_graph(Vars,KEv),
mark_from_evidence(Vars,KEv),
set_clpbn_flag(solver,PreviousSolver).
compute_evidence(_, PreviousSolver) :-
set_clpbn_flag(solver,PreviousSolver).
evidence_error(Ball,PreviousSolver) :-
set_clpbn_flag(solver,PreviousSolver),
throw(Ball).
store_graph([], _).
store_graph([_-node(K,Dom,CPT,TVs,Ev)|Vars], Kev) :-
\+ node(K,_,_,_), !,
assert(node(K,Dom,CPT,TVs)),
( nonvar(Ev) -> assert(evidence(K,Ev)), Kev = K ; true),
store_graph(Vars, Kev).
store_graph([_|Vars], Kev) :-
store_graph(Vars, Kev).
mark_from_evidence([], _).
mark_from_evidence([_-node(K,_,_,_,_)|Vars], Kev) :-
\+ reachable_from_evidence(K,Kev), !,
assert(reachable_from_evidence(K,Kev)),
mark_from_evidence(Vars, Kev).
mark_from_evidence([_|Vars], Kev) :-
mark_from_evidence(Vars, Kev).
incorporate_evidence(Vs,AllVs) :-
new(Cache0),
create_open_list(Vs, OL, FL, Cache0, CacheI),
do_variables(OL, FL, CacheI),
extract_vars(OL, AllVs).
create_open_list([], L, L, C, C).
create_open_list([V|Vs], [K-V|OL], FL, C0, CF) :-
clpbn:get_atts(V,[key(K)]),
add_evidence(K, V),
insert(C0, K, V, CI),
create_open_list(Vs, OL, FL, CI, CF).
do_variables([], [], _) :- !.
do_variables([K-V|Vs], Vf, C0) :-
check_for_evidence(K, V, Vf, Vff, C0, Ci),
do_variables(Vs, Vff, Ci).
create_new_variable(K, V, Vf0, Vff, C0, Cf) :-
node(K,Dom, CPT, TVs),
{ V = K with p(Dom, CPT, NTVs) },
add_evidence(K, V),
add_variables(TVs, NTVs, Vf0, Vff, C0, Cf).
add_variables([], [], Vf, Vf, C, C).
add_variables([K|TVs], [V|NTVs], Vf0, Vff, C0, Cf) :-
lookup(K, V, C0), !,
add_variables(TVs, NTVs, Vf0, Vff, C0, Cf).
add_variables([K|TVs], [V|NTVs], [K-V|Vf0], Vff, C0, Cf) :-
insert(C0, K, V, C1),
create_new_variable(K, V, Vf0, Vf1, C1, C2),
add_variables(TVs, NTVs, Vf1, Vff, C2, Cf).
extract_vars([], []).
extract_vars([_-V|Cache], [V|AllVs]) :-
extract_vars(Cache, AllVs).
add_evidence(K, V) :-
evidence(K, Ev), !,
listing(evidence),
clpbn:put_atts(V, [evidence(Ev)]).
add_evidence(_, _).
check_for_evidence(_, V, Vf, Vf, C, C) :-
clpbn:get_atts(V, [evidence(_)]), !.
check_for_evidence(K, _, Vf0, Vff, C0, Ci) :-
findall(Rt,reachable_from_evidence(K,Rt),Rts),
add_variables(Rts, _, Vf0, Vff, C0, Ci).