1/* Part of CLP(Q) (Constraint Logic Programming over Rationals) 2 3 Author: Leslie De Koninck 4 E-mail: Leslie.DeKoninck@cs.kuleuven.be 5 WWW: http://www.swi-prolog.org 6 http://www.ai.univie.ac.at/cgi-bin/tr-online?number+95-09 7 Copyright (C): 2006, K.U. Leuven and 8 1992-1995, Austrian Research Institute for 9 Artificial Intelligence (OFAI), 10 Vienna, Austria 11 12 This software is based on CLP(Q,R) by Christian Holzbaur for SICStus 13 Prolog and distributed under the license details below with permission from 14 all mentioned authors. 15 16 This program is free software; you can redistribute it and/or 17 modify it under the terms of the GNU General Public License 18 as published by the Free Software Foundation; either version 2 19 of the License, or (at your option) any later version. 20 21 This program is distributed in the hope that it will be useful, 22 but WITHOUT ANY WARRANTY; without even the implied warranty of 23 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 24 GNU General Public License for more details. 25 26 You should have received a copy of the GNU Lesser General Public 27 License along with this library; if not, write to the Free Software 28 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 29 30 As a special exception, if you link this library with other files, 31 compiled with a Free Software compiler, to produce an executable, this 32 library does not by itself cause the resulting executable to be covered 33 by the GNU General Public License. This exception does not however 34 invalidate any other reasons why the executable file might be covered by 35 the GNU General Public License. 36*/ 37 38:- module(clpcd_geler, 39 [ 40 geler/3, 41 project_nonlin/3, 42 collect_nonlin/3 43 ]). 44 45:- use_module(library(apply)). 46 47:- meta_predicate 48 geler(,,). 49 50attr_unify_hook(g(CLP,goals(Gx),_),Y) :- 51 !, 52 ( var(Y), 53 ( get_attr(Y,clpcd_geler,g(A,B,C)) 54 -> ignore((CLP \== A, 55 throw(error(permission_error( 56 'apply CLPCD constraints on', 57 'variable of a different subdomain',Y), 58 context(_))))), 59 ( % possibly mutual goals. these need to be run. 60 % other goals are run as well to remove redundant goals. 61 B = goals(Gy) 62 -> Later = [Gx,Gy], 63 ( C = n 64 -> del_attr(Y,clpcd_geler) 65 ; put_attr(Y,clpcd_geler,g(CLP,n,C)) 66 ) 67 ; % no goals in Y, so no mutual goals of X and Y, store 68 % goals of X in Y 69 % no need to run any goal. 70 Later = [], 71 put_attr(Y,clpcd_geler,g(CLP,goals(Gx),C)) 72 ) 73 ; Later = [], 74 put_attr(Y,clpcd_geler,g(CLP,goals(Gx),n)) 75 ) 76 ; nonvar(Y), 77 Later = [Gx] 78 ), 79 maplist(call,Later). 80attr_unify_hook(_,_). % no goals in X 81 82% 83% called from project.pl 84% 85project_nonlin(_,Cvas,Reachable) :- 86 collect_nonlin(Cvas,L,[]), 87 sort(L,Ls), 88 term_variables(Ls,Reachable). 89 %put_attr(_,all_nonlin(Ls)). 90 91 92collect_nonlin([]) --> []. 93collect_nonlin([X|Xs]) --> 94 ( { get_attr(X,clpcd_geler,g(_,goals(Gx),_)) } 95 -> trans(Gx), 96 collect_nonlin(Xs) 97 ; collect_nonlin(Xs) 98 ). 99 100% trans(Goals,OutList,OutListTail) 101% 102% transforms the goals (of the form run(Mutex,Goal) 103% that are in Goals (in the conjunction form) 104% that have not been run (Mutex = variable) into a readable output format 105% and notes that they're done (Mutex = 'done'). Because of the Mutex 106% variable, each goal is only added once (so not for each variable). 107 108trans((A,B)) --> 109 trans(A), 110 trans(B). 111trans(run(Mutex,Gs)) --> 112 ( { var(Mutex) } 113 -> { Mutex = done }, 114 transg(Gs) 115 ; [] 116 ). 117 118transg((A,B)) --> 119 !, 120 transg(A), 121 transg(B). 122transg(M:G) --> 123 !, 124 M:transg(G). 125transg(G) --> [G]. 126 127:- public run/2. 128:- meta_predicate run(, ). 129 130% run(Mutex,G) 131% 132% Calls goal G if it has not yet run (Mutex is still variable) 133% and stores that it has run (Mutex = done). This is done so 134% that when X = Y and X and Y are in the same goal, that goal 135% is called only once. 136 137run(Mutex,_) :- nonvar(Mutex), !. 138run(Mutex,G) :- 139 var(Mutex), 140 Mutex = done, 141 call(G). 142 143% geler(Vars,Goal) 144% 145% called by nf.pl when an unsolvable non-linear expression is found 146% Vars contain the variables of the expression, Goal contains the predicate of 147% nf.pl to be called when the variables are bound. 148 149geler(CLP,Vars,Goal) :- 150 attach(Vars,CLP,run(_Mutex,Goal)). 151 % one goal gets the same mutex on every var, so it is run only once 152 153% attach(Vars,Goal) 154% 155% attaches a new goal to be awoken when the variables get bounded. 156% when the old value of the attribute goals = OldGoal, then the new value = 157% (Goal,OldGoal) 158 159attach([],_,_). 160attach([V|Vs],CLP,Goal) :- 161 var(V), 162 ( get_attr(V,clpcd_geler,g(A,B,C)) 163 -> ( CLP \== A 164 -> throw(error(permission_error('apply CLP(Q) constraints on', 165 'CLP(R) variable',V),context(_))) 166 ; ( B = goals(Goals) 167 -> put_attr(V,clpcd_geler,g(A,goals((Goal,Goals)),C)) 168 ; put_attr(V,clpcd_geler,g(A,goals(Goal),C)) 169 ) 170 ) 171 ; put_attr(V,clpcd_geler,g(CLP,goals(Goal),n)) 172 ), 173 attach(Vs,CLP,Goal)