38247e38fc
simplification of module handling; new timestamp implementation git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@52 b08c6af1-5177-4d33-ba66-4b1c6b8b522a
1265 lines
32 KiB
Prolog
1265 lines
32 KiB
Prolog
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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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: bv.pl %
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% Author: Christian Holzbaur christian@ai.univie.ac.at %
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%
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% simplex with bounded variables, ch, 93/12
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%
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%
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% TODO: +) var/bound/state classification and maintainance
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% +) inc/dec_step: take the best?, at least find unconstrained var first
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% +) trivially implied values
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% +) avoid eval_rhs through an extra column (Coeff=Rhs)
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% +) if an optimum is encountered, record the value as bound !!!
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% +) generalized (transparent) attribute handling
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% +) coordinate reconsideration cascades
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% +) =\=
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% +) strict inequalities via =\=
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% -) decompose via nonvar test -> no symbolic constants any more ?
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% constants complicate the nonlin solver anyway ...
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% +) join t_l,l(L), .... into t_l(L), ...
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% +) shortcuts for strict ineqs
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% -) extra types for vars with l/u bound zero
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% -) occurrence lists for indep vars (with coeffs) ???
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% each solve produces one dep var -> push
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% only complication: pivots
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% -) *incremental* REVISED simplex ?!!
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%
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% sicstus2.1.9.clp conversion:
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%
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% -) stable ordering through extra attribute ...
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% interpreted vs compiled yields different var order
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% -> nasty in R (need different eps)
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%
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% -) check determinism again
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%
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%
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:- public {}/1, maximize/1, minimize/1, sup/2, inf/2, imin/2. % xref.pl
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:- use_module( library(ordsets), [ord_add_element/3]).
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% :- use_module( library(deterministic)).
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%
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% For the rhs maint. the following events are important:
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%
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% -) introduction of an indep var at active bound B
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% -) narrowing of active bound
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% -) swap active bound
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% -) pivot
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%
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%
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% a variables bound (L/U) can have the states:
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%
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% -) t_none
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% -) t_l has a lower bound (not active yet)
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% -) t_u
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% -) t_L has an active lower bound
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% -) t_U
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% -) t_lu
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% -) t_Lu
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% -) t_lU
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%
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% ----------------------------------- deref ------------------------------------ %
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:- mode deref( +, -).
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%
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deref( Lin, Lind) :-
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split( Lin, H, I),
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normalize_scalar( I, Nonvar),
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length( H, Len),
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log_deref( Len, H, [], Restd),
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add_linear_11( Nonvar, Restd, Lind).
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:- mode log_deref( +, +, -, -).
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%
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log_deref( 0, Vs, Vs, Lin) :- !,
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arith_eval( 0, Z),
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Lin = [Z,Z].
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log_deref( 1, [v(K,[X^1])|Vs], Vs, Lin) :- !,
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deref_var( X, Lx),
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mult_linear_factor( Lx, K, Lin).
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log_deref( 2, [v(Kx,[X^1]),v(Ky,[Y^1])|Vs], Vs, Lin) :- !,
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deref_var( X, Lx),
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deref_var( Y, Ly),
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add_linear_ff( Lx, Kx, Ly, Ky, Lin).
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log_deref( N, V0, V2, Lin) :-
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P is N >> 1,
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Q is N - P,
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log_deref( P, V0,V1, Lp),
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log_deref( Q, V1,V2, Lq),
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add_linear_11( Lp, Lq, Lin).
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/*
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%
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% tail recursive version
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%
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deref( Lin, Lind) :-
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split( Lin, H, I),
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normalize_scalar( I, Nonvar),
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lin_deref( H, Nonvar, Lind).
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log_deref( _, Lin, [], Res) :- % called from nf.pl
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arith_eval( 0, Z),
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lin_deref( Lin, [Z,Z], Res).
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lin_deref( [], Ld, Ld).
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lin_deref( [v(K,[X^1])|Vs], Li, Lo) :-
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deref_var( X, Lx),
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add_linear_f1( Lx, K, Li, Lii),
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lin_deref( Vs, Lii, Lo).
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*/
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%
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% If we see a nonvar here, this is a fault
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%
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deref_var( X, Lin) :-
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get_atts( X, lin(Lin)), !.
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deref_var( X, Lin) :- % create a linear var
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arith_eval( 0, Z),
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arith_eval( 1, One),
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Lin = [Z,Z,X*One],
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put_atts( X, [order(_),lin(Lin),type(t_none),strictness(2'00)]).
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var_with_def_assign( Var, Lin) :-
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decompose( Lin, Hom, _, I),
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( Hom = [], % X=k
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Var = I
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; Hom = [V*K|Cs],
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( Cs = [],
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arith_eval(K=:=1),
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arith_eval(I=:=0) -> % X=Y
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Var = V
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; % general case
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var_with_def_intern( t_none, Var, Lin, 2'00)
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)
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).
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var_with_def_intern( Type, Var, Lin, Strict) :-
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put_atts( Var, [order(_),lin(Lin),type(Type),strictness(Strict)]),
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decompose( Lin, Hom, _, _),
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get_or_add_class( Var, Class),
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same_class( Hom, Class).
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var_intern( Type, Var, Strict) :-
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arith_eval( 0, Z),
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arith_eval( 1, One),
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Lin = [Z,Z,Var*One],
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put_atts( Var, [order(_),lin(Lin),type(Type),strictness(Strict)]),
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get_or_add_class( Var, _Class).
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% ------------------------------------------------------------------------------
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%
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% [V-Binding]*
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% Only place where the linear solver binds variables
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%
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export_binding( []).
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export_binding( [X-Y|Gs]) :-
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export_binding( Y, X),
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export_binding( Gs).
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%
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% numerical stabilizer, clp(r) only
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%
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export_binding( Y, X) :- var(Y), !, Y=X. %vsc: added cut here (01/06/06)
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export_binding( Y, X) :- nonvar(Y),
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( arith_eval( Y=:=0) ->
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arith_eval( 0, X)
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;
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Y = X
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).
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'solve_='( Nf) :-
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deref( Nf, Nfd),
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solve( Nfd).
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'solve_=\\='( Nf) :- % vsc
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deref( Nf, Lind),
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decompose( Lind, Hom, _, Inhom),
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( Hom = [], arith_eval( Inhom =\= 0)
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; Hom = [_|_], var_with_def_intern( t_none, Nz, Lind, 2'00),
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put_atts( Nz, nonzero)
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).
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'solve_<'( Nf) :-
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split( Nf, H, I),
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ineq( H, I, Nf, strict).
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'solve_=<'( Nf) :-
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split( Nf, H, I),
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ineq( H, I, Nf, nonstrict).
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maximize( Term) :-
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minimize( -Term).
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%
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% This is NOT coded as minimize(Expr) :- inf(Expr,Expr).
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%
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% because the new version of inf/2 only visits
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% the vertex where the infimum is assumed and returns
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% to the 'current' vertex via backtracking.
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% The rationale behind this construction is to eliminate
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% all garbage in the solver data structures produced by
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% the pivots on the way to the extremal point caused by
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% {inf,sup}/{2,4}.
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%
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% If we are after the infimum/supremum for minimizing/maximizing,
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% this strategy may have adverse effects on performance because
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% the simplex algorithm is forced to re-discover the
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% extremal vertex through the equation {Inf =:= Expr}.
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%
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% Thus the extra code for {minimize,maximize}/1.
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%
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% In case someone comes up with an example where
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%
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% inf(Expr,Expr)
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%
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% outperforms the provided formulation for minimize - so be it.
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% Both forms are available to the user.
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%
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minimize( Term) :-
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wait_linear( Term, Nf, minimize_lin(Nf)).
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minimize_lin( Lin) :-
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deref( Lin, Lind),
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var_with_def_intern( t_none, Dep, Lind, 2'00),
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determine_active_dec( Lind),
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iterate_dec( Dep, Inf),
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{ Dep =:= Inf }.
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sup( Expression, Sup) :-
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sup( Expression, Sup, [], []).
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sup( Expression, Sup, Vector, Vertex) :-
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inf( -Expression, -Sup, Vector, Vertex).
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inf( Expression, Inf) :-
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inf( Expression, Inf, [], []).
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inf( Expression, Inf, Vector, Vertex) :-
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wait_linear( Expression, Nf, inf_lin(Nf,Inf,Vector,Vertex)).
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inf_lin( Lin, _, Vector, _) :-
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deref( Lin, Lind),
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var_with_def_intern( t_none, Dep, Lind, 2'00),
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determine_active_dec( Lind),
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iterate_dec( Dep, Inf),
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vertex_value( Vector, Values),
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bb_put( inf, [Inf|Values]),
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fail.
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inf_lin( _, Infimum, _, Vertex) :-
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bb_delete( inf, L),
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assign( [Infimum|Vertex], L).
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assign( [], []).
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assign( [X|Xs], [Y|Ys]) :-
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{X =:= Y}, % more defensive/expressive than X=Y
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assign( Xs, Ys).
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% --------------------------------- optimization ------------------------------- %
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%
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% The _sn(S) =< 0 row might be temporarily infeasible.
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% We use reconsider/1 to fix this.
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%
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% s(S) e [_,0] = d +xi ... -xj, Rhs > 0 so we want to decrease s(S)
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%
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% positive xi would have to be moved towards their lower bound,
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% negative xj would have to be moved towards their upper bound,
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%
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% the row s(S) does not limit the lower bound of xi
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% the row s(S) does not limit the upper bound of xj
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%
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% a) if some other row R is limiting xk, we pivot(R,xk),
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% s(S) will decrease and get more feasible until (b)
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% b) if there is no limiting row for some xi: we pivot(s(S),xi)
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% xj: we pivot(s(S),xj)
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% which cures the infeasibility in one step
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%
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%
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% fails if Status = unlimited/2
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%
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iterate_dec( OptVar, Opt) :-
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get_atts( OptVar, lin(Lin)),
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decompose( Lin, H, R, I),
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% arith_eval( R+I, Now), print(min(Now)), nl,
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% dec_step_best( H, Status),
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%vsc: added -> (01/06/06)
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dec_step( H, Status),
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( Status = applied -> iterate_dec( OptVar, Opt)
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; Status = optimum -> arith_eval( R+I, Opt)
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).
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iterate_inc( OptVar, Opt) :-
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get_atts( OptVar, lin(Lin)),
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decompose( Lin, H, R, I),
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inc_step( H, Status),
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%vsc: added -> (01/06/06)
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( Status = applied -> iterate_inc( OptVar, Opt)
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; Status = optimum -> arith_eval( R+I, Opt)
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).
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%
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% Status = {optimum,unlimited(Indep,DepT),applied}
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% If Status = optimum, the tables have not been changed at all.
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% Searches left to right, does not try to find the 'best' pivot
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% Therefore we might discover unboundedness only after a few pivots
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%
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dec_step( [], optimum).
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dec_step( [V*K|Vs], Status) :-
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get_atts( V, type(W)),
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%vsc: added -> (01/06/06)
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( W = t_U(U) ->
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( arith_eval( K > 0) ->
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( lb( V, Vub-Vb-_) ->
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Status = applied,
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pivot_a(Vub,V,Vb,t_u(U))
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;
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Status = unlimited(V,t_u(U))
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)
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;
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dec_step( Vs, Status)
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)
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; W = t_lU(L,U) ->
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( arith_eval( K > 0) ->
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Status = applied,
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arith_eval( L-U, Init),
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basis( V, Deps),
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lb( Deps, V, V-t_Lu(L,U)-Init, Vub-Vb-_),
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pivot_b(Vub,V,Vb,t_lu(L,U))
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;
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dec_step( Vs, Status)
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)
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; W = t_L(L) ->
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( arith_eval( K < 0) ->
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( ub( V, Vub-Vb-_) ->
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Status = applied,
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pivot_a(Vub,V,Vb,t_l(L))
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;
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Status = unlimited(V,t_l(L))
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)
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;
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dec_step( Vs, Status)
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)
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; W = t_Lu(L,U) ->
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( arith_eval( K < 0) ->
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Status = applied,
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arith_eval( U-L, Init),
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basis( V, Deps),
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ub( Deps, V, V-t_lU(L,U)-Init, Vub-Vb-_),
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pivot_b(Vub,V,Vb,t_lu(L,U))
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;
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dec_step( Vs, Status)
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)
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; W = t_none ->
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Status = unlimited(V,t_none)
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).
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inc_step( [], optimum).
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inc_step( [V*K|Vs], Status) :-
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get_atts( V, type(W)),
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%vsc: added -> (01/06/06)
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( W = t_U(U) ->
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( arith_eval( K < 0) ->
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( lb( V, Vub-Vb-_) ->
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Status = applied,
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pivot_a(Vub,V,Vb,t_u(U))
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;
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Status = unlimited(V,t_u(U))
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)
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;
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inc_step( Vs, Status)
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)
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; W = t_lU(L,U) ->
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( arith_eval( K < 0) ->
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Status = applied,
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arith_eval( L-U, Init),
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basis( V, Deps),
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lb( Deps, V, V-t_Lu(L,U)-Init, Vub-Vb-_),
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pivot_b(Vub,V,Vb,t_lu(L,U))
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;
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inc_step( Vs, Status)
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)
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; W = t_L(L) ->
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( arith_eval( K > 0) ->
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( ub( V, Vub-Vb-_) ->
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Status = applied,
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pivot_a(Vub,V,Vb,t_l(L))
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;
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Status = unlimited(V,t_l(L))
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)
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;
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inc_step( Vs, Status)
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)
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; W = t_Lu(L,U) ->
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( arith_eval( K > 0) ->
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Status = applied,
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arith_eval( U-L, Init),
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basis( V, Deps),
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ub( Deps, V, V-t_lU(L,U)-Init, Vub-Vb-_),
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pivot_b(Vub,V,Vb,t_lu(L,U))
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;
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inc_step( Vs, Status)
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)
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; W = t_none ->
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Status = unlimited(V,t_none)
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).
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% ------------------------------ best first heuristic -------------------------- %
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%
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% A replacement for dec_step/2 that uses a local best first heuristic.
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%
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%
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dec_step_best( H, Status) :-
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dec_eval( H, E),
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( E = unlimited(_,_),
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Status = E
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; E = [],
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Status = optimum
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; E = [_|_],
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Status = applied,
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keysort( E, [_-Best|_]),
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( Best = pivot_a(Vub,V,Vb,Wd), pivot_a(Vub,V,Vb,Wd)
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; Best = pivot_b(Vub,V,Vb,Wd), pivot_b(Vub,V,Vb,Wd)
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)
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).
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dec_eval( [], []).
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dec_eval( [V*K|Vs], Res) :-
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get_atts( V, type(W)),
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( W = t_U(U),
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( arith_eval( K > 0) ->
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( lb( V, Vub-Vb-Limit) ->
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arith_eval( float(Limit*K), Delta),
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Res = [Delta-pivot_a(Vub,V,Vb,t_u(U)) | Tail],
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dec_eval( Vs, Tail)
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;
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Res = unlimited(V,t_u(U))
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)
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;
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dec_eval( Vs, Res)
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)
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; W = t_lU(L,U),
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( arith_eval( K > 0) ->
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arith_eval( L-U, Init),
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basis( V, Deps),
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lb( Deps, V, V-t_Lu(L,U)-Init, Vub-Vb-Limit),
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arith_eval( float(Limit*K), Delta),
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Res = [Delta-pivot_b(Vub,V,Vb,t_lu(L,U)) | Tail],
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dec_eval( Vs, Tail)
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;
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dec_eval( Vs, Res)
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)
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; W = t_L(L),
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( arith_eval( K < 0) ->
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( ub( V, Vub-Vb-Limit) ->
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arith_eval( float(Limit*K), Delta),
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Res = [Delta-pivot_a(Vub,V,Vb,t_l(L)) | Tail],
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dec_eval( Vs, Tail)
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;
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Res = unlimited(V,t_l(L))
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)
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;
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dec_eval( Vs, Res)
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)
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; W = t_Lu(L,U),
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( arith_eval( K < 0) ->
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arith_eval( U-L, Init),
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basis( V, Deps),
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ub( Deps, V, V-t_lU(L,U)-Init, Vub-Vb-Limit),
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arith_eval( float(Limit*K), Delta),
|
|
Res = [Delta-pivot_b(Vub,V,Vb,t_lu(L,U)) | Tail],
|
|
dec_eval( Vs, Tail)
|
|
;
|
|
dec_eval( Vs, Res)
|
|
)
|
|
; W = t_none,
|
|
Res = unlimited(V,t_none)
|
|
).
|
|
|
|
% ------------------------- find the most constraining row --------------------- %
|
|
%
|
|
% The code for the lower and the upper bound are dual versions of each other.
|
|
% The only difference is in the orientation of the comparisons.
|
|
% Indeps are ruled out by their types.
|
|
% If there is no bound, this fails.
|
|
%
|
|
% *** The actual lb and ub on an indep variable X are [lu]b + b(X), where b(X)
|
|
% is the value of the active bound.
|
|
%
|
|
% Nota bene: We must NOT consider infeasible rows as candidates to
|
|
% leave the basis!
|
|
%
|
|
|
|
ub( X, Ub) :-
|
|
basis( X, Deps),
|
|
ub_first( Deps, X, Ub).
|
|
|
|
:- mode ub_first( +, ?, -).
|
|
%
|
|
ub_first( [Dep|Deps], X, Tightest) :-
|
|
( get_atts( Dep, [lin(Lin),type(Type)]),
|
|
ub_inner( Type, X, Lin, W, Ub),
|
|
arith_eval( Ub >= 0) ->
|
|
ub( Deps, X, Dep-W-Ub, Tightest)
|
|
;
|
|
ub_first( Deps, X, Tightest)
|
|
).
|
|
|
|
%
|
|
% Invariant: Ub >= 0 and decreasing
|
|
%
|
|
:- mode ub( +, ?, +, -).
|
|
%
|
|
ub( [], _, T0,T0).
|
|
ub( [Dep|Deps], X, T0,T1) :-
|
|
( get_atts( Dep, [lin(Lin),type(Type)]),
|
|
ub_inner( Type, X, Lin, W, Ub),
|
|
T0 = _-Ubb,
|
|
arith_eval( Ub < Ubb),
|
|
arith_eval( Ub >= 0) -> % rare failure
|
|
ub( Deps, X, Dep-W-Ub,T1)
|
|
;
|
|
ub( Deps, X, T0,T1)
|
|
).
|
|
|
|
lb( X, Lb) :-
|
|
basis( X, Deps),
|
|
lb_first( Deps, X, Lb).
|
|
|
|
:- mode lb_first( +, ?, -).
|
|
%
|
|
lb_first( [Dep|Deps], X, Tightest) :-
|
|
( get_atts( Dep, [lin(Lin),type(Type)]),
|
|
lb_inner( Type, X, Lin, W, Lb),
|
|
arith_eval( Lb =< 0) ->
|
|
lb( Deps, X, Dep-W-Lb, Tightest)
|
|
;
|
|
lb_first( Deps, X, Tightest)
|
|
).
|
|
|
|
%
|
|
% Invariant: Lb =< 0 and increasing
|
|
%
|
|
:- mode lb( +, ?, +, -).
|
|
%
|
|
lb( [], _, T0,T0).
|
|
lb( [Dep|Deps], X, T0,T1) :-
|
|
( get_atts( Dep, [lin(Lin),type(Type)]),
|
|
lb_inner( Type, X, Lin, W, Lb),
|
|
T0 = _-Lbb,
|
|
arith_eval( Lb > Lbb),
|
|
arith_eval( Lb =< 0) -> % rare failure
|
|
lb( Deps, X, Dep-W-Lb,T1)
|
|
;
|
|
lb( Deps, X, T0,T1)
|
|
).
|
|
|
|
%
|
|
% Lb =< 0 for feasible rows
|
|
%
|
|
:- mode lb_inner( +, ?, +, -, -).
|
|
%
|
|
lb_inner( t_l(L), X, Lin, t_L(L), Lb) :-
|
|
nf_rhs_x( Lin, X, Rhs, K),
|
|
arith_eval( K > 0),
|
|
arith_eval( (L-Rhs)/K, Lb).
|
|
lb_inner( t_u(U), X, Lin, t_U(U), Lb) :-
|
|
nf_rhs_x( Lin, X, Rhs, K),
|
|
arith_eval( K < 0),
|
|
arith_eval( (U-Rhs)/K, Lb).
|
|
lb_inner( t_lu(L,U), X, Lin, W, Lb) :-
|
|
nf_rhs_x( Lin, X, Rhs, K),
|
|
case_signum( K,
|
|
(
|
|
W = t_lU(L,U),
|
|
arith_eval( (U-Rhs)/K, Lb)
|
|
),
|
|
fail,
|
|
(
|
|
W = t_Lu(L,U),
|
|
arith_eval( (L-Rhs)/K, Lb)
|
|
)).
|
|
|
|
%
|
|
% Ub >= 0 for feasible rows
|
|
%
|
|
:- mode ub_inner( +, ?, +, -, -).
|
|
%
|
|
ub_inner( t_l(L), X, Lin, t_L(L), Ub) :-
|
|
nf_rhs_x( Lin, X, Rhs, K),
|
|
arith_eval( K < 0),
|
|
arith_eval( (L-Rhs)/K, Ub).
|
|
ub_inner( t_u(U), X, Lin, t_U(U), Ub) :-
|
|
nf_rhs_x( Lin, X, Rhs, K),
|
|
arith_eval( K > 0),
|
|
arith_eval( (U-Rhs)/K, Ub).
|
|
ub_inner( t_lu(L,U), X, Lin, W, Ub) :-
|
|
nf_rhs_x( Lin, X, Rhs, K),
|
|
case_signum( K,
|
|
(
|
|
W = t_Lu(L,U),
|
|
arith_eval( (L-Rhs)/K, Ub)
|
|
),
|
|
fail,
|
|
(
|
|
W = t_lU(L,U),
|
|
arith_eval( (U-Rhs)/K, Ub)
|
|
)).
|
|
|
|
% ---------------------------------- equations --------------------------------- %
|
|
%
|
|
% backsubstitution will not make the system infeasible, if the bounds on the indep
|
|
% vars are obeyed, but some implied values might pop up in rows where X occurs
|
|
% -) special case X=Y during bs -> get rid of dependend var(s), alias
|
|
%
|
|
|
|
solve( Lin) :-
|
|
decompose( Lin, H, _, I),
|
|
solve( H, Lin, I, Bindings, []),
|
|
export_binding( Bindings).
|
|
|
|
solve( [], _, I, Bind0,Bind0) :-
|
|
arith_eval( I=:=0). % redundant or trivially unsat
|
|
%vsc: changed to list in head (01/06/06)
|
|
solve( [HHd|HTl], Lin, _, Bind0,BindT) :-
|
|
%
|
|
% [] is an empty ord_set, anything will be preferred
|
|
% over 9-9
|
|
%
|
|
sd( [HHd|HTl], [],ClassesUniq, 9-9-0,Category-Selected-_, NV,NVT),
|
|
|
|
isolate( Selected, Lin, Lin1),
|
|
|
|
%vsc: added -> (01/06/06)
|
|
( Category = 1 ->
|
|
put_atts( Selected, lin(Lin1)),
|
|
decompose( Lin1, Hom, _, Inhom),
|
|
bs_collect_binding( Hom, Selected, Inhom, Bind0,BindT),
|
|
eq_classes( NV, NVT, ClassesUniq)
|
|
; Category = 2 ->
|
|
get_atts( Selected, class(NewC)),
|
|
class_allvars( NewC, Deps),
|
|
( ClassesUniq = [_] -> % rank increasing
|
|
bs_collect_bindings( Deps, Selected, Lin1, Bind0,BindT)
|
|
;
|
|
Bind0 = BindT,
|
|
bs( Deps, Selected, Lin1)
|
|
),
|
|
eq_classes( NV, NVT, ClassesUniq)
|
|
; Category = 3 ->
|
|
put_atts( Selected, lin(Lin1)),
|
|
get_atts( Selected, type(Type)),
|
|
deactivate_bound( Type, Selected),
|
|
eq_classes( NV, NVT, ClassesUniq),
|
|
basis_add( Selected, Basis),
|
|
undet_active( Lin1),
|
|
decompose( Lin1, Hom, _, Inhom),
|
|
bs_collect_binding( Hom, Selected, Inhom, Bind0,Bind1),
|
|
rcbl( Basis, Bind1,BindT)
|
|
; Category = 4 ->
|
|
get_atts( Selected, [type(Type),class(NewC)]),
|
|
class_allvars( NewC, Deps),
|
|
( ClassesUniq = [_] -> % rank increasing
|
|
bs_collect_bindings( Deps, Selected, Lin1, Bind0,Bind1)
|
|
;
|
|
Bind0 = Bind1,
|
|
bs( Deps, Selected, Lin1)
|
|
),
|
|
deactivate_bound( Type, Selected),
|
|
basis_add( Selected, Basis),
|
|
% eq_classes( NV, NVT, ClassesUniq), % 4 -> var(NV)
|
|
equate( ClassesUniq, _),
|
|
undet_active( Lin1),
|
|
rcbl( Basis, Bind1,BindT)
|
|
).
|
|
|
|
%
|
|
% Much like solve, but we solve for a particular variable of type
|
|
% t_none
|
|
%
|
|
solve_x( Lin, X) :-
|
|
decompose( Lin, H, _, I),
|
|
solve_x( H, Lin, I, X, Bindings, []),
|
|
export_binding( Bindings).
|
|
|
|
solve_x( [], _, I, _, Bind0,Bind0) :-
|
|
arith_eval( I=:=0). % redundant or trivially unsat
|
|
solve_x( H, Lin, _, Selected, Bind0,BindT) :-
|
|
H = [_|_], % indexing
|
|
sd( H, [],ClassesUniq, 9-9-0,_, NV,NVT),
|
|
|
|
isolate( Selected, Lin, Lin1),
|
|
|
|
( get_atts( Selected, class(NewC)) ->
|
|
class_allvars( NewC, Deps),
|
|
( ClassesUniq = [_] -> % rank increasing
|
|
bs_collect_bindings( Deps, Selected, Lin1, Bind0,BindT)
|
|
;
|
|
Bind0 = BindT,
|
|
bs( Deps, Selected, Lin1)
|
|
),
|
|
eq_classes( NV, NVT, ClassesUniq)
|
|
;
|
|
put_atts( Selected, lin(Lin1)),
|
|
decompose( Lin1, Hom, _, Inhom),
|
|
bs_collect_binding( Hom, Selected, Inhom, Bind0,BindT),
|
|
eq_classes( NV, NVT, ClassesUniq)
|
|
).
|
|
|
|
|
|
|
|
sd( [], Class0,Class0, Preference0,Preference0, NV0,NV0).
|
|
sd( [X*K|Xs], Class0,ClassN, Preference0,PreferenceN, NV0,NVt) :-
|
|
( get_atts( X, class(Xc)) -> % old
|
|
NV0 = NV1,
|
|
ord_add_element( Class0, Xc, Class1),
|
|
( get_atts( X, type(t_none)) ->
|
|
preference( Preference0, 2-X-K, Preference1)
|
|
;
|
|
preference( Preference0, 4-X-K, Preference1)
|
|
)
|
|
; % new
|
|
Class1 = Class0,
|
|
'C'( NV0, X, NV1),
|
|
( get_atts( X, type(t_none)) ->
|
|
preference( Preference0, 1-X-K, Preference1)
|
|
;
|
|
preference( Preference0, 3-X-K, Preference1)
|
|
)
|
|
),
|
|
sd( Xs, Class1,ClassN, Preference1,PreferenceN, NV1,NVt).
|
|
|
|
%
|
|
% A is best sofar, B is current
|
|
%
|
|
preference( A, B, Pref) :-
|
|
A = Px-_-_,
|
|
B = Py-_-_,
|
|
compare( Rel, Px, Py),
|
|
%vsc: added -> (01/06/06)
|
|
( Rel = = -> Pref = B
|
|
% ( arith_eval(abs(Ka)=<abs(Kb)) -> Pref=A ; Pref=B )
|
|
; Rel = < -> Pref = A
|
|
; Rel = > -> Pref = B
|
|
).
|
|
|
|
%
|
|
% equate after attach_class because other classes may contribute
|
|
% nonvars and will bind the tail of NV
|
|
%
|
|
eq_classes( NV, _, Cs) :- var( NV), !,
|
|
equate( Cs, _).
|
|
eq_classes( NV, NVT, Cs) :-
|
|
class_new( Su, NV,NVT, []),
|
|
attach_class( NV, Su),
|
|
equate( Cs, Su).
|
|
|
|
equate( [], _).
|
|
equate( [X|Xs], X) :- equate( Xs, X).
|
|
|
|
%
|
|
% assert: none of the Vars has a class attribute yet
|
|
%
|
|
attach_class( Xs, _) :- var( Xs), !.
|
|
attach_class( [X|Xs], Class) :-
|
|
put_atts( X, class(Class)),
|
|
attach_class( Xs, Class).
|
|
|
|
/**
|
|
unconstrained( [X*K|Xs], Uc,Kuc, Rest) :-
|
|
( get_atts( X, type(t_none)) ->
|
|
Uc = X,
|
|
Kuc = K,
|
|
Rest = Xs
|
|
;
|
|
Rest = [X*K|Tail],
|
|
unconstrained( Xs, Uc,Kuc, Tail)
|
|
).
|
|
**/
|
|
/**/
|
|
unconstrained( Lin, Uc,Kuc, Rest) :-
|
|
decompose( Lin, H, _, _),
|
|
sd( H, [],_, 9-9-0,Category-Uc-_, _,_),
|
|
Category =< 2,
|
|
delete_factor( Uc, Lin, Rest, Kuc).
|
|
/**/
|
|
|
|
%
|
|
% point the vars in Lin into the same equivalence class
|
|
% maybe join some global data
|
|
%
|
|
same_class( [], _).
|
|
same_class( [X*_|Xs], Class) :-
|
|
get_or_add_class( X, Class),
|
|
same_class( Xs, Class).
|
|
|
|
get_or_add_class( X, Class) :-
|
|
get_atts( X, class(ClassX)),
|
|
!,
|
|
ClassX = Class. % explicit =/2 because of cut
|
|
get_or_add_class( X, Class) :-
|
|
put_atts( X, class(Class)),
|
|
class_new( Class, [X|Tail],Tail, []). % initial class atts
|
|
|
|
allvars( X, Allvars) :-
|
|
get_atts( X, class(C)),
|
|
class_allvars( C, Allvars).
|
|
|
|
deactivate_bound( t_l(_), _).
|
|
deactivate_bound( t_u(_), _).
|
|
deactivate_bound( t_lu(_,_), _).
|
|
deactivate_bound( t_L(L), X) :- put_atts( X, type(t_l(L))).
|
|
deactivate_bound( t_Lu(L,U), X) :- put_atts( X, type(t_lu(L,U))).
|
|
deactivate_bound( t_U(U), X) :- put_atts( X, type(t_u(U))).
|
|
deactivate_bound( t_lU(L,U), X) :- put_atts( X, type(t_lu(L,U))).
|
|
|
|
intro_at( X, Value, Type) :-
|
|
put_atts( X, type(Type)),
|
|
( arith_eval( Value =:= 0) ->
|
|
true
|
|
;
|
|
backsubst_delta( X, Value)
|
|
).
|
|
|
|
|
|
%
|
|
% The choice t_lu -> t_Lu is arbitrary
|
|
%
|
|
undet_active( Lin) :-
|
|
decompose( Lin, Lin1, _, _),
|
|
undet_active_h( Lin1).
|
|
|
|
undet_active_h( []).
|
|
undet_active_h( [X*_|Xs]) :-
|
|
get_atts( X, type(Type)),
|
|
undet_active( Type, X),
|
|
undet_active_h( Xs).
|
|
|
|
undet_active( t_none, _). % type_activity
|
|
undet_active( t_L(_), _).
|
|
undet_active( t_Lu(_,_), _).
|
|
undet_active( t_U(_), _).
|
|
undet_active( t_lU(_,_), _).
|
|
undet_active( t_l(L), X) :- intro_at( X, L, t_L(L)).
|
|
undet_active( t_u(U), X) :- intro_at( X, U, t_U(U)).
|
|
undet_active( t_lu(L,U), X) :- intro_at( X, L, t_Lu(L,U)).
|
|
|
|
determine_active_dec( Lin) :-
|
|
decompose( Lin, Lin1, _, _),
|
|
arith_eval( -1, Mone),
|
|
determine_active( Lin1, Mone).
|
|
|
|
determine_active_inc( Lin) :-
|
|
decompose( Lin, Lin1, _, _),
|
|
arith_eval( 1, One),
|
|
determine_active( Lin1, One).
|
|
|
|
determine_active( [], _).
|
|
determine_active( [X*K|Xs], S) :-
|
|
get_atts( X, type(Type)),
|
|
determine_active( Type, X, K, S),
|
|
determine_active( Xs, S).
|
|
|
|
determine_active( t_L(_), _, _, _).
|
|
determine_active( t_Lu(_,_), _, _, _).
|
|
determine_active( t_U(_), _, _, _).
|
|
determine_active( t_lU(_,_), _, _, _).
|
|
determine_active( t_l(L), X, _, _) :- intro_at( X, L, t_L(L)).
|
|
determine_active( t_u(U), X, _, _) :- intro_at( X, U, t_U(U)).
|
|
determine_active( t_lu(L,U), X, K, S) :-
|
|
case_signum( K*S,
|
|
intro_at( X, L, t_Lu(L,U)),
|
|
fail,
|
|
intro_at( X, U, t_lU(L,U))).
|
|
|
|
%
|
|
% Careful when an indep turns into t_none !!!
|
|
%
|
|
detach_bounds( V) :-
|
|
get_atts( V, lin(Lin)),
|
|
put_atts( V, [type(t_none),strictness(2'00)]),
|
|
( indep( Lin, V) ->
|
|
( ub( V, Vub-Vb-_) -> % exchange against thightest
|
|
basis_drop( Vub),
|
|
pivot( Vub, V, Vb)
|
|
; lb( V, Vlb-Vb-_) ->
|
|
basis_drop( Vlb),
|
|
pivot( Vlb, V, Vb)
|
|
;
|
|
true
|
|
)
|
|
;
|
|
basis_drop( V)
|
|
).
|
|
|
|
% ----------------------------- manipulate the basis --------------------------- %
|
|
|
|
basis_drop( X) :-
|
|
get_atts( X, class(Cv)),
|
|
class_basis_drop( Cv, X).
|
|
|
|
basis( X, Basis) :-
|
|
get_atts( X, class(Cv)),
|
|
class_basis( Cv, Basis).
|
|
|
|
basis_add( X, NewBasis) :-
|
|
get_atts( X, class(Cv)),
|
|
class_basis_add( Cv, X, NewBasis).
|
|
|
|
basis_pivot( Leave, Enter) :-
|
|
get_atts( Leave, class(Cv)),
|
|
class_basis_pivot( Cv, Enter, Leave).
|
|
|
|
% ----------------------------------- pivot ------------------------------------ %
|
|
|
|
%
|
|
% Pivot ignoring rhs and active states
|
|
%
|
|
pivot( Dep, Indep) :-
|
|
get_atts( Dep, lin(H)),
|
|
delete_factor( Indep, H, H0, Coeff),
|
|
arith_eval( -1/Coeff, K),
|
|
arith_eval( -1, Mone),
|
|
arith_eval( 0, Z),
|
|
add_linear_ff( H0, K, [Z,Z,Dep*Mone], K, Lin),
|
|
backsubst( Indep, Lin).
|
|
|
|
|
|
pivot_a( Dep, Indep, Vb,Wd) :-
|
|
basis_pivot( Dep, Indep),
|
|
pivot( Dep, Indep, Vb),
|
|
put_atts( Indep, type(Wd)).
|
|
|
|
pivot_b( Vub, V, Vb, Wd) :-
|
|
( Vub == V ->
|
|
put_atts( V, type(Vb)),
|
|
pivot_b_delta( Vb, Delta), % nonzero(Delta)
|
|
backsubst_delta( V, Delta)
|
|
;
|
|
pivot_a( Vub, V, Vb,Wd)
|
|
).
|
|
|
|
pivot_b_delta( t_Lu(L,U), Delta) :- arith_eval( L-U, Delta).
|
|
pivot_b_delta( t_lU(L,U), Delta) :- arith_eval( U-L, Delta).
|
|
|
|
select_active_bound( t_L(L), L).
|
|
select_active_bound( t_Lu(L,_), L).
|
|
select_active_bound( t_U(U), U).
|
|
select_active_bound( t_lU(_,U), U).
|
|
select_active_bound( t_none, Z) :- arith_eval( 0, Z).
|
|
%
|
|
% for project.pl
|
|
%
|
|
select_active_bound( t_l(_), Z) :- arith_eval( 0, Z).
|
|
select_active_bound( t_u(_), Z) :- arith_eval( 0, Z).
|
|
select_active_bound( t_lu(_,_), Z) :- arith_eval( 0, Z).
|
|
|
|
|
|
%
|
|
% Pivot taking care of rhs and active states
|
|
%
|
|
pivot( Dep, Indep, IndAct) :-
|
|
get_atts( Dep, lin(H)),
|
|
put_atts( Dep, type(IndAct)),
|
|
select_active_bound( IndAct, Abv), % Dep or Indep
|
|
delete_factor( Indep, H, H0, Coeff),
|
|
arith_eval( -1/Coeff, K),
|
|
arith_eval( 0, Z),
|
|
arith_eval( -1, Mone),
|
|
arith_eval( -Abv, Abvm),
|
|
add_linear_ff( H0, K, [Z,Abvm,Dep*Mone], K, Lin),
|
|
backsubst( Indep, Lin).
|
|
|
|
backsubst_delta( X, Delta) :-
|
|
arith_eval( 1, One),
|
|
arith_eval( 0, Z),
|
|
backsubst( X, [Z,Delta,X*One]).
|
|
|
|
backsubst( X, Lin) :-
|
|
allvars( X, Allvars),
|
|
bs( Allvars, X, Lin).
|
|
%
|
|
% valid if nothing will go ground
|
|
%
|
|
bs( Xs, _, _) :- var( Xs), !.
|
|
bs( [X|Xs], V, Lin) :-
|
|
( get_atts( X, lin(LinX)),
|
|
nf_substitute( V, Lin, LinX, LinX1) ->
|
|
put_atts( X, lin(LinX1)),
|
|
bs( Xs, V, Lin)
|
|
;
|
|
bs( Xs, V, Lin)
|
|
).
|
|
|
|
|
|
%
|
|
% rank increasing backsubstitution
|
|
%
|
|
bs_collect_bindings( Xs, _, _, Bind0,BindT) :- var( Xs), !, Bind0=BindT.
|
|
bs_collect_bindings( [X|Xs], V, Lin, Bind0,BindT) :-
|
|
( get_atts( X, lin(LinX)),
|
|
nf_substitute( V, Lin, LinX, LinX1) ->
|
|
put_atts( X, lin(LinX1)),
|
|
decompose( LinX1, Hom, _, Inhom),
|
|
bs_collect_binding( Hom, X, Inhom, Bind0,Bind1),
|
|
bs_collect_bindings( Xs, V, Lin, Bind1,BindT)
|
|
;
|
|
bs_collect_bindings( Xs, V, Lin, Bind0,BindT)
|
|
).
|
|
|
|
%
|
|
% The first clause exports bindings,
|
|
% the second (no longer) aliasings
|
|
%
|
|
bs_collect_binding( [], X, Inhom) --> [ X-Inhom ].
|
|
bs_collect_binding( [_|_], _, _) --> [].
|
|
/*
|
|
bs_collect_binding( [Y*K|Ys], X, Inhom) -->
|
|
( { Ys = [],
|
|
Y \== X,
|
|
arith_eval( K=:=1),
|
|
arith_eval( Inhom=:=0)
|
|
} ->
|
|
[ X-Y ]
|
|
;
|
|
[]
|
|
).
|
|
*/
|
|
|
|
%
|
|
% reconsider the basis
|
|
%
|
|
rcbl( [], Bind0,Bind0).
|
|
rcbl( [X|Continuation], Bind0,BindT) :-
|
|
( rcb( X, Status, Violated) -> % have a culprit
|
|
rcbl_status( Status, X, Continuation, Bind0,BindT, Violated)
|
|
;
|
|
rcbl( Continuation, Bind0,BindT)
|
|
).
|
|
|
|
%
|
|
% reconsider one element of the basis
|
|
% later: lift the binds
|
|
%
|
|
reconsider( X) :-
|
|
rcb( X, Status, Violated),
|
|
!,
|
|
rcbl_status( Status, X, [], Binds,[], Violated),
|
|
export_binding( Binds).
|
|
reconsider( _).
|
|
|
|
%
|
|
% Find a basis variable out of its bound or at its bound
|
|
% Try to move it into whithin its bound
|
|
% a) impossible -> fail
|
|
% b) optimum at the bound -> implied value
|
|
% c) else look at the remaining basis variables
|
|
%
|
|
rcb( X, Status, Violated) :-
|
|
get_atts( X, [lin(Lin),type(Type)]),
|
|
decompose( Lin, H, R, I),
|
|
( Type = t_l(L),
|
|
arith_eval( R+I =< L),
|
|
Violated = l(L),
|
|
inc_step( H, Status)
|
|
|
|
; Type = t_u(U),
|
|
arith_eval( R+I >= U),
|
|
Violated = u(U),
|
|
dec_step( H, Status)
|
|
|
|
; Type = t_lu(L,U),
|
|
arith_eval( R+I, At),
|
|
(
|
|
arith_eval( At =< L),
|
|
Violated = l(L),
|
|
inc_step( H, Status)
|
|
;
|
|
arith_eval( At >= U),
|
|
Violated = u(U),
|
|
dec_step( H, Status)
|
|
)
|
|
%
|
|
% don't care for other types
|
|
%
|
|
).
|
|
|
|
rcbl_status( optimum, X, Cont, B0,Bt, Violated) :- rcbl_opt( Violated, X, Cont, B0,Bt).
|
|
rcbl_status( applied, X, Cont, B0,Bt, Violated) :- rcbl_app( Violated, X, Cont, B0,Bt).
|
|
rcbl_status( unlimited(Indep,DepT), X, Cont, B0,Bt, Violated) :- rcbl_unl( Violated, X, Cont, B0,Bt, Indep, DepT).
|
|
|
|
%
|
|
% Might reach optimum immediately without changing the basis,
|
|
% but in general we must assume that there were pivots.
|
|
% If the optimum meets the bound, we backsubstitute the implied
|
|
% value, solve will call us again to check for further implied
|
|
% values or unsatisfiability in the rank increased system.
|
|
%
|
|
rcbl_opt( l(L), X, Continuation, B0,B1) :-
|
|
get_atts( X, [lin(Lin),strictness(Strict),type(Type)]),
|
|
decompose( Lin, _, R, I),
|
|
arith_eval( R+I, Opt),
|
|
case_signum( L-Opt,
|
|
(
|
|
narrow_u( Type, X, Opt), % { X =< Opt }
|
|
rcbl( Continuation, B0,B1)
|
|
),
|
|
(
|
|
Strict /\ 2'10 =:= 0, % meets lower
|
|
arith_eval( -Opt, Mop),
|
|
normalize_scalar( Mop, MopN),
|
|
add_linear_11( MopN, Lin, Lin1),
|
|
decompose( Lin1, Hom, _, Inhom),
|
|
%vsc: added -> (01/06/06)
|
|
( Hom = [] -> rcbl( Continuation, B0,B1) % would not callback
|
|
; Hom = [_|_] -> solve( Hom, Lin1, Inhom, B0,B1)
|
|
)
|
|
),
|
|
fail
|
|
).
|
|
rcbl_opt( u(U), X, Continuation, B0,B1) :-
|
|
get_atts( X, [lin(Lin),strictness(Strict),type(Type)]),
|
|
decompose( Lin, _, R, I),
|
|
arith_eval( R+I, Opt),
|
|
case_signum( U-Opt,
|
|
fail,
|
|
(
|
|
Strict /\ 2'01 =:= 0, % meets upper
|
|
arith_eval( -Opt, Mop),
|
|
normalize_scalar( Mop, MopN),
|
|
add_linear_11( MopN, Lin, Lin1),
|
|
decompose( Lin1, Hom, _, Inhom),
|
|
%vsc: added -> (01/06/06)
|
|
( Hom = [] -> rcbl( Continuation, B0,B1) % would not callback
|
|
; Hom = [_|_] -> solve( Hom, Lin1, Inhom, B0,B1)
|
|
)
|
|
),
|
|
(
|
|
narrow_l( Type, X, Opt), % { X >= Opt }
|
|
rcbl( Continuation, B0,B1)
|
|
)).
|
|
|
|
%
|
|
% Basis has already changed when this is called
|
|
%
|
|
rcbl_app( l(L), X, Continuation, B0,B1) :-
|
|
get_atts( X, lin(Lin)),
|
|
decompose( Lin, H, R, I),
|
|
( arith_eval( R+I > L) -> % within bound now
|
|
rcbl( Continuation, B0,B1)
|
|
;
|
|
% arith_eval( R+I, Val), print( rcbl_app(X:L:Val)), nl,
|
|
inc_step( H, Status),
|
|
rcbl_status( Status, X, Continuation, B0,B1, l(L))
|
|
).
|
|
rcbl_app( u(U), X, Continuation, B0,B1) :-
|
|
get_atts( X, lin(Lin)),
|
|
decompose( Lin, H, R, I),
|
|
( arith_eval( R+I < U) -> % within bound now
|
|
rcbl( Continuation, B0,B1)
|
|
;
|
|
dec_step( H, Status),
|
|
rcbl_status( Status, X, Continuation, B0,B1, u(U))
|
|
).
|
|
|
|
%
|
|
% This is never called for a t_lu culprit
|
|
%
|
|
rcbl_unl( l(L), X, Continuation, B0,B1, Indep, DepT) :-
|
|
pivot_a( X, Indep, t_L(L), DepT), % changes the basis
|
|
rcbl( Continuation, B0,B1).
|
|
rcbl_unl( u(U), X, Continuation, B0,B1, Indep, DepT) :-
|
|
pivot_a( X, Indep, t_U(U), DepT), % changes the basis
|
|
rcbl( Continuation, B0,B1).
|
|
|
|
narrow_u( t_u(_), X, U) :- put_atts( X, type(t_u(U))).
|
|
narrow_u( t_lu(L,_), X, U) :- put_atts( X, type(t_lu(L,U))).
|
|
|
|
narrow_l( t_l(_), X, L) :- put_atts( X, type(t_l(L))).
|
|
narrow_l( t_lu(_,U), X, L) :- put_atts( X, type(t_lu(L,U))).
|
|
|
|
% ----------------------------------- dump -------------------------------------
|
|
|
|
dump_var( t_none, V, I,H) --> !,
|
|
( { H=[W*K],V==W,arith_eval(I=:=0),arith_eval(K=:=1) } -> % indep var
|
|
[]
|
|
;
|
|
{ nf2sum( H, I, Sum) },
|
|
[ V = Sum ]
|
|
).
|
|
dump_var( t_L(L), V, I,H) --> !, dump_var( t_l(L), V, I,H).
|
|
dump_var( t_l(L), V, I,H) --> !,
|
|
{
|
|
H= [_*K|_], % avoid 1 >= 0
|
|
get_atts( V, strictness(Strict)),
|
|
Sm is Strict /\ 2'10,
|
|
arith_eval( 1/K, Kr),
|
|
arith_eval( Kr*(L-I), Li),
|
|
mult_hom( H, Kr, H1),
|
|
arith_eval( 0, Z), nf2sum( H1, Z, Sum),
|
|
( arith_eval( K > 0) ->
|
|
dump_strict( Sm, Sum >= Li, Sum > Li, Result)
|
|
;
|
|
dump_strict( Sm, Sum =< Li, Sum < Li, Result)
|
|
)
|
|
},
|
|
[ Result ].
|
|
dump_var( t_U(U), V, I,H) --> !, dump_var( t_u(U), V, I,H).
|
|
dump_var( t_u(U), V, I,H) --> !,
|
|
{
|
|
H= [_*K|_], % avoid 0 =< 1
|
|
get_atts( V, strictness(Strict)),
|
|
Sm is Strict /\ 2'01,
|
|
arith_eval( 1/K, Kr),
|
|
arith_eval( Kr*(U-I), Ui),
|
|
mult_hom( H, Kr, H1),
|
|
arith_eval( 0, Z), nf2sum( H1, Z, Sum),
|
|
( arith_eval( K > 0) ->
|
|
dump_strict( Sm, Sum =< Ui, Sum < Ui, Result)
|
|
;
|
|
dump_strict( Sm, Sum >= Ui, Sum > Ui, Result)
|
|
)
|
|
},
|
|
[ Result ].
|
|
dump_var( t_Lu(L,U), V, I,H) --> !, dump_var( t_l(L), V,I,H),
|
|
dump_var( t_U(U), V,I,H).
|
|
dump_var( t_lU(L,U), V, I,H) --> !, dump_var( t_l(L), V,I,H),
|
|
dump_var( t_U(U), V,I,H).
|
|
dump_var( t_lu(L,U), V, I,H) --> !, dump_var( t_l(L), V,I,H),
|
|
dump_var( t_U(U), V,I,H).
|
|
dump_var( T, V, I,H) -->
|
|
[ V:T:I+H ].
|
|
|
|
dump_strict( 0, Result, _, Result).
|
|
dump_strict( 1, _, Result, Result).
|
|
dump_strict( 2, _, Result, Result).
|
|
|
|
dump_nz( _, H, I) -->
|
|
{
|
|
H = [_*K|_],
|
|
arith_eval( 1/K, Kr),
|
|
arith_eval( -Kr*I, I1),
|
|
mult_hom( H, Kr, H1),
|
|
arith_eval( 0, Z), nf2sum( H1, Z, Sum)
|
|
},
|
|
[ Sum =\= I1 ].
|