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FIXED: CLP(B): weighted_maximum/3 with repeated variables

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Many thanks to @jburse for reporting this issue:

    https://github.com/triska/clpz/issues/15

Example:

    ?- sat(~(Y*X)), sat(Z=:=Y), weighted_maximum([7,2,5],[X,Y,Z],W).
       W = 7, Y = 0, X = 1, Z = 0
    ;  W = 7, Y = 1, X = 0, Z = 1
    ;  false.
This commit is contained in:
Markus Triska
2021-03-05 18:35:19 +01:00
parent 87abcd6a52
commit 0fb74b56b3
1 changed files with 6 additions and 1 deletions
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7
src/lib/clpb.pl
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@@ -1276,13 +1276,18 @@ weighted_maximum(Ws, Vars, Max) :-
maplist(var_with_index, Vars, IVs), maplist(var_with_index, Vars, IVs),
pairs_keys_values(Pairs0, IVs, Ws), pairs_keys_values(Pairs0, IVs, Ws),
keysort(Pairs0, Pairs1), keysort(Pairs0, Pairs1),
pairs_keys_values(Pairs1, IVs1, WeightsIndexOrder), % sum linear combinations of repeated variables
group_pairs_by_key(Pairs1, Groups),
maplist(group_sumweights_pair, Groups, Pairs2),
pairs_keys_values(Pairs2, IVs1, WeightsIndexOrder),
pairs_values(IVs1, VarsIndexOrder), pairs_values(IVs1, VarsIndexOrder),
% Pairs is a list of Var-Weight terms, in index order of Vars % Pairs is a list of Var-Weight terms, in index order of Vars
pairs_keys_values(Pairs, VarsIndexOrder, WeightsIndexOrder), pairs_keys_values(Pairs, VarsIndexOrder, WeightsIndexOrder),
bdd_maximum(BDD, Pairs, Max), bdd_maximum(BDD, Pairs, Max),
max_labeling(BDD, Pairs). max_labeling(BDD, Pairs).
group_sumweights_pair((I-V)-Ws, (I-V)-W) :- sum_list(Ws, W).
max_labeling(1, Pairs) :- max_upto(Pairs, _, _). max_labeling(1, Pairs) :- max_upto(Pairs, _, _).
max_labeling(node(_,Var,Low,High,Aux), Pairs0) :- max_labeling(node(_,Var,Low,High,Aux), Pairs0) :-
max_upto(Pairs0, Var, Pairs), max_upto(Pairs0, Var, Pairs),