15404b3835
- do not call goal expansion on meta-calls (that is done by undef). - docs updates - fix init code
101 lines
3.2 KiB
Prolog
101 lines
3.2 KiB
Prolog
%%============================================================================
|
|
%% CNF.pl
|
|
%% Convertor of Boolean formulae to CNF
|
|
%% Copyright (c) 2006, Michael Codish, Vitaly Lagoon, and Peter J. Stuckey
|
|
%%
|
|
%% Permission is hereby granted, free of charge, to any person obtaining a
|
|
%% copy of this software and associated documentation files (the
|
|
%% "Software"), to deal in the Software without restriction, including
|
|
%% without limitation the rights to use, copy, modify, merge, publish,
|
|
%% distribute, sublicense, and/or sell copies of the Software, and to
|
|
%% permit persons to whom the Software is furnished to do so, subject to
|
|
%% the following conditions:
|
|
%%
|
|
%% The above copyright notice and this permission notice shall be included
|
|
%% in all copies or substantial portions of the Software.
|
|
%%
|
|
%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
|
|
%% OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
|
|
%% MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
|
|
%% NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
|
|
%% LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
|
|
%% OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
|
|
%% WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
|
|
|
|
:- module(cnf,[cnf/2,cnf_dl/2]).
|
|
|
|
cnf(F,Cnf) :- cnf_dl(F,Cnf-[]).
|
|
|
|
cnf_dl(F,[[B]|Cnf1]-Cnf2) :- iff(F,+,B,Cnf2,Cnf1).
|
|
|
|
|
|
iff(V,_,B,Acc,Cnf) :- var(V), !, V=B, Cnf=Acc.
|
|
iff(1,_,B,Acc,Cnf) :- !, B=1, Cnf=Acc.
|
|
iff(0,_,B,Acc,Cnf) :- !, B=0, Cnf=Acc.
|
|
|
|
iff(-X,+,B,Acc,Cnf) :- !, iff(X,-,BX,Acc,Cnf), neglit(BX,B).
|
|
iff(-X,-,B,Acc,Cnf) :- !, iff(X,+,BX,Acc,Cnf), neglit(BX,B).
|
|
iff(-X,*,B,Acc,Cnf) :- !, iff(X,*,BX,Acc,Cnf), neglit(BX,B).
|
|
|
|
iff((X+Y),Polarity,B,Acc,Cnf) :- !,
|
|
iff(X,Polarity,BX,Acc,AccX),
|
|
iff(Y,Polarity,BY,AccX,AccXY),
|
|
(
|
|
Polarity == + -> Cnf = [[-B,BX,BY]|AccXY]
|
|
;
|
|
Polarity == - -> Cnf = [[B,-BX],[B,-BY]|AccXY]
|
|
;
|
|
Cnf = [[-B,BX,BY], [B,-BX], [B,-BY] | AccXY]
|
|
).
|
|
|
|
iff((X*Y),Polarity,B,Acc,Cnf) :- !,
|
|
iff(X,Polarity,BX,Acc,AccX),
|
|
iff(Y,Polarity,BY,AccX,AccXY),
|
|
(
|
|
Polarity == + -> Cnf = [[-B,BX],[-B,BY]|AccXY]
|
|
;
|
|
Polarity == - -> Cnf = [[B,-BX,-BY]|AccXY]
|
|
;
|
|
Cnf = [[B,-BX,-BY], [-B,BX], [-B,BY] | AccXY]
|
|
).
|
|
|
|
iff((X==Y),Polarity,B,Acc,Cnf) :- !,
|
|
iff(X,*,BX,Acc,AccX),
|
|
iff(Y,*,BY,AccX,AccXY),
|
|
(
|
|
Polarity == + -> Cnf = [[-BX,BY,-B],[BX,-BY,-B] | AccXY]
|
|
;
|
|
Polarity == - -> Cnf = [[-BX,-BY,B],[BX,BY,B] | AccXY]
|
|
;
|
|
Cnf = [[-BX,BY,-B],[BX,-BY,-B],[-BX,-BY,B],[BX,BY,B] | AccXY]
|
|
).
|
|
|
|
iff((xor(X, Y)),Polarity,B,Acc,Cnf) :- !,
|
|
iff(X,*,BX,Acc,AccX),
|
|
iff(Y,*,BY,AccX,AccXY),
|
|
(
|
|
Polarity == + -> Cnf = [[-BX,-BY,-B],[BX,BY,-B] | AccXY]
|
|
;
|
|
Polarity == - -> Cnf = [[-BX,BY,B],[BX,-BY,B] | AccXY]
|
|
;
|
|
Cnf = [[-BX,BY,B],[BX,-BY,B],[-BX,-BY,-B],[BX,BY,-B] | AccXY]
|
|
).
|
|
|
|
iff((X->Y;Z),Polarity,B,Acc,Cnf) :- !,
|
|
iff(X,*,BX,Acc,AccX),
|
|
iff(Y,Polarity,BY,AccX,AccXY),
|
|
iff(Z,Polarity,BZ,AccXY,AccXYZ),
|
|
(
|
|
Polarity == + -> Cnf = [[-BX,BY,-B],[BX,BZ,-B],[BY,BZ,-B]|AccXYZ]
|
|
;
|
|
Polarity == - -> Cnf = [[-BX,-BY,B],[BX,-BZ,B],[-BY,-BZ,B]|AccXYZ]
|
|
;
|
|
Cnf = [[-BX,BY,-B], [BX,BZ,-B], [BY,BZ,-B],
|
|
[-BX,-BY,B], [BX,-BZ,B], [-BY,-BZ,B] | AccXYZ]
|
|
).
|
|
|
|
neglit(V,-V) :- var(V), !.
|
|
neglit(-V,V).
|
|
neglit(0,1).
|
|
neglit(1,0).
|