c33738d557
git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@1417 b08c6af1-5177-4d33-ba66-4b1c6b8b522a
86 lines
2.8 KiB
Prolog
86 lines
2.8 KiB
Prolog
/* $Id: arith_r.pl,v 1.1 2005-10-28 17:51:01 vsc Exp $
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Part of CPL(R) (Constraint Logic Programming over Reals)
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Author: Leslie De Koninck
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E-mail: Tom.Schrijvers@cs.kuleuven.ac.be
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WWW: http://www.swi-prolog.org
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http://www.ai.univie.ac.at/cgi-bin/tr-online?number+95-09
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Copyright (C): 2004, K.U. Leuven and
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1992-1995, Austrian Research Institute for
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Artificial Intelligence (OFAI),
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Vienna, Austria
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This software is part of Leslie De Koninck's master thesis, supervised
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by Bart Demoen and daily advisor Tom Schrijvers. It is based on CLP(Q,R)
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by Christian Holzbaur for SICStus Prolog and distributed under the
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license details below with permission from all mentioned authors.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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As a special exception, if you link this library with other files,
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compiled with a Free Software compiler, to produce an executable, this
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library does not by itself cause the resulting executable to be covered
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by the GNU General Public License. This exception does not however
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invalidate any other reasons why the executable file might be covered by
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the GNU General Public License.
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*/
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:- module(arith_r,
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[
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arith_eps/1,
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arith_normalize/2,
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integerp/1,
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integerp/2
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]).
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arith_eps(1.0e-10). % for Monash #zero expansion 1.0e-12
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eps(1.0e-10,-1.0e-10).
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arith_normalize(X,Norm) :-
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var(X),
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!,
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raise_exception(instantiation_error(arith_normalize(X,Norm),1)).
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arith_normalize(rat(N,D),Norm) :- rat_float(N,D,Norm).
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arith_normalize(X,Norm) :-
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number(X),
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Norm is float(X).
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integerp(X) :-
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floor(/*float?*/X)=:=X.
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integerp(X,I) :-
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floor(/*float?*/X)=:=X,
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I is integer(X).
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% copied from arith.pl.
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rat_float(Nx,Dx,F) :-
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limit_encoding_length(Nx,Dx,1023,Nxl,Dxl),
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F is Nxl / Dxl.
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limit_encoding_length(0,D,_,0,D) :- !. % msb ...
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limit_encoding_length(N,D,Bits,Nl,Dl) :-
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Shift is min(max(msb(abs(N)),msb(D))-Bits,
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min(msb(abs(N)),msb(D))),
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Shift > 0,
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!,
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Ns is N>>Shift,
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Ds is D>>Shift,
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Gcd is gcd(Ns,Ds),
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Nl is Ns//Gcd,
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Dl is Ds//Gcd.
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limit_encoding_length(N,D,_,N,D).
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