129 lines
3.5 KiB
Perl
129 lines
3.5 KiB
Perl
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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% clp(q,r) version 1.3.3 %
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% %
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% (c) Copyright 1992,1993,1994,1995 %
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% Austrian Research Institute for Artificial Intelligence (OFAI) %
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% Schottengasse 3 %
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% A-1010 Vienna, Austria %
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% %
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% File: bb.pl %
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% Author: Christian Holzbaur christian@ai.univie.ac.at %
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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bb_inf( Is, Term, Inf) :-
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bb_inf( Is, Term, Inf, _, 0.001).
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bb_inf( Is, Term, Inf, Vertex, Eps) :-
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nf( Eps, ENf),
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nf_constant( ENf, EpsN),
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wait_linear( Term, Nf, bb_inf_internal(Is,Nf,EpsN,Inf,Vertex)).
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% ---------------------------------------------------------------------
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bb_inf_internal( Is, Lin, Eps, _, _) :-
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bb_intern( Is, IsNf),
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( bb_delete( incumbent, _) -> true ; true ),
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repair( Lin, LinR), % bb_narrow ...
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deref( LinR, Lind),
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var_with_def_assign( Dep, Lind),
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determine_active_dec( Lind),
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bb_loop( Dep, IsNf, Eps),
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fail.
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bb_inf_internal( _, _, _, Inf, Vertex) :-
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bb_delete( incumbent, InfVal-Vertex), % GC
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{ Inf =:= InfVal }.
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bb_loop( Opt, Is, Eps) :-
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bb_reoptimize( Opt, Inf),
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bb_better_bound( Inf),
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vertex_value( Is, Ivs),
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( bb_first_nonint( Is, Ivs, Eps, Viol, Floor, Ceiling) ->
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bb_branch( Viol, Floor, Ceiling),
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bb_loop( Opt, Is, Eps)
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;
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round_values( Ivs, RoundVertex),
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% print( incumbent( Inf-RoundVertex)), nl,
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bb_put( incumbent, Inf-RoundVertex)
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).
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%
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% added ineqs may have led to binding
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%
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bb_reoptimize( Obj, Inf) :- var( Obj), iterate_dec( Obj, Inf).
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bb_reoptimize( Obj, Inf) :- nonvar( Obj), Inf = Obj.
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bb_better_bound( Inf) :-
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bb_get( incumbent, Inc-_),
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!,
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arith_eval( Inf < Inc).
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bb_better_bound( _).
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bb_branch( V, U, _) :- { V =< U }.
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bb_branch( V, _, L) :- { V >= L }.
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vertex_value( [], []).
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vertex_value( [X|Xs], [V|Vs]) :-
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rhs_value( X, V),
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vertex_value( Xs, Vs).
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rhs_value( Xn, Value) :- nonvar(Xn), Value=Xn.
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rhs_value( Xn, Value) :- var(Xn),
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deref_var( Xn, Xd),
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decompose( Xd, _, R, I),
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arith_eval( R+I, Value).
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%
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% Need only one as we branch on the first anyway ...
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%
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bb_first_nonint( [I|Is], [Rhs|Rhss], Eps, Viol, F, C) :-
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( arith_eval( floor(Rhs), Floor),
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arith_eval( ceiling(Rhs), Ceiling),
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arith_eval(min(Rhs-Floor,Ceiling-Rhs) > Eps) ->
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Viol = I,
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F = Floor,
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C = Ceiling
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;
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bb_first_nonint( Is, Rhss, Eps, Viol, F, C)
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).
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round_values( [], []).
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round_values( [X|Xs], [Y|Ys]) :-
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arith_eval( round(X), Y),
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round_values( Xs, Ys).
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bb_intern( [], []).
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bb_intern( [X|Xs], [Xi|Xis]) :-
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nf( X, Xnf),
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bb_intern( Xnf, Xi, X),
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bb_intern( Xs, Xis).
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%
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% allow more general expressions and conditions? integral(Exp) ???
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%
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bb_intern( [], X, _) :- !, arith_eval( 0, X).
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bb_intern( [v(I,[])], X, _) :- !, X=I.
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bb_intern( [v(One,[X^1])], X, _) :-
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arith_eval(One=:=1),
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!,
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get_atts( X, [type(T),strictness(S)]),
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bb_narrow( T, S, X).
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bb_intern( _, _, Term) :-
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raise_exception( instantiation_error(bb_inf(Term,_,_),1)).
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bb_narrow( t_l(L), S, V) :-
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S /\ 2'10 =\= 0,
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!,
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arith_eval( floor(1+L), B),
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{ V >= B }.
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bb_narrow( t_u(U), S, V) :-
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S /\ 2'01 =\= 0,
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!,
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arith_eval( ceiling(U-1), B),
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{ V =< B }.
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bb_narrow( t_lu(L,U), S, V) :- !,
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bb_narrow( t_l(L), S, V),
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bb_narrow( t_u(U), S, V).
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bb_narrow( _, _, _).
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