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:- meta_predicate 45 geler(,,). 46 47attr_unify_hook(g(CLP,goals(Gx),_),Y) :- 48 !, 49 ( var(Y), 50 ( get_attr(Y,clpcd_geler,g(A,B,C)) 51 -> ignore((CLP \== A, 52 throw(error(permission_error( 53 'apply CLPCD constraints on', 54 'variable of a different subdomain',Y), 55 context(_))))), 56 ( % possibly mutual goals. these need to be run. 57 % other goals are run as well to remove redundant goals. 58 B = goals(Gy) 59 -> Later = [Gx,Gy], 60 ( C = n 61 -> del_attr(Y,clpcd_geler) 62 ; put_attr(Y,clpcd_geler,g(CLP,n,C)) 63 ) 64 ; % no goals in Y, so no mutual goals of X and Y, store 65 % goals of X in Y 66 % no need to run any goal. 67 Later = [], 68 put_attr(Y,clpcd_geler,g(CLP,goals(Gx),C)) 69 ) 70 ; Later = [], 71 put_attr(Y,clpcd_geler,g(CLP,goals(Gx),n)) 72 ) 73 ; nonvar(Y), 74 Later = [Gx] 75 ), 76 maplist(call,Later). 77attr_unify_hook(_,_). % no goals in X 78 79% 80% called from project.pl 81% 82project_nonlin(_,Cvas,Reachable) :- 83 collect_nonlin(Cvas,L,[]), 84 sort(L,Ls), 85 term_variables(Ls,Reachable). 86 %put_attr(_,all_nonlin(Ls)). 87 88 89collect_nonlin([]) --> []. 90collect_nonlin([X|Xs]) --> 91 ( { get_attr(X,clpcd_geler,g(_,goals(Gx),_)) } 92 -> trans(Gx), 93 collect_nonlin(Xs) 94 ; collect_nonlin(Xs) 95 ). 96 97% trans(Goals,OutList,OutListTail) 98% 99% transforms the goals (of the form run(Mutex,Goal) 100% that are in Goals (in the conjunction form) 101% that have not been run (Mutex = variable) into a readable output format 102% and notes that they're done (Mutex = 'done'). Because of the Mutex 103% variable, each goal is only added once (so not for each variable). 104 105trans((A,B)) --> 106 trans(A), 107 trans(B). 108trans(run(Mutex,Gs)) --> 109 ( { var(Mutex) } 110 -> { Mutex = done }, 111 transg(Gs) 112 ; [] 113 ). 114 115transg((A,B)) --> 116 !, 117 transg(A), 118 transg(B). 119transg(M:G) --> 120 !, 121 M:transg(G). 122transg(G) --> [G]. 123 124:- public run/2. 125:- meta_predicate run(, ). 126 127% run(Mutex,G) 128% 129% Calls goal G if it has not yet run (Mutex is still variable) 130% and stores that it has run (Mutex = done). This is done so 131% that when X = Y and X and Y are in the same goal, that goal 132% is called only once. 133 134run(Mutex,_) :- nonvar(Mutex), !. 135run(Mutex,G) :- 136 var(Mutex), 137 Mutex = done, 138 call(G). 139 140% geler(Vars,Goal) 141% 142% called by nf.pl when an unsolvable non-linear expression is found 143% Vars contain the variables of the expression, Goal contains the predicate of 144% nf.pl to be called when the variables are bound. 145 146geler(CLP,Vars,Goal) :- 147 attach(Vars,CLP,run(_Mutex,Goal)). 148 % one goal gets the same mutex on every var, so it is run only once 149 150% attach(Vars,Goal) 151% 152% attaches a new goal to be awoken when the variables get bounded. 153% when the old value of the attribute goals = OldGoal, then the new value = 154% (Goal,OldGoal) 155 156attach([],_,_). 157attach([V|Vs],CLP,Goal) :- 158 var(V), 159 ( get_attr(V,clpcd_geler,g(A,B,C)) 160 -> ( CLP \== A 161 -> throw(error(permission_error('apply CLP(Q) constraints on', 162 'CLP(R) variable',V),context(_))) 163 ; ( B = goals(Goals) 164 -> put_attr(V,clpcd_geler,g(A,goals((Goal,Goals)),C)) 165 ; put_attr(V,clpcd_geler,g(A,goals(Goal),C)) 166 ) 167 ) 168 ; put_attr(V,clpcd_geler,g(CLP,goals(Goal),n)) 169 ), 170 attach(Vs,CLP,Goal)