1 package Constants;
   2 #
   3 # $RCSfile: Constants.pm,v $
   4 # $Date: 2008/04/19 16:10:59 $
   5 # $Revision: 1.9 $
   6 #
   7 # Author: Manish Sud <msud@san.rr.com>
   8 #
   9 # Copyright (C) 2004-2008 Manish Sud. All rights reserved.
  10 #
  11 # This file is part of MayaChemTools.
  12 #
  13 # MayaChemTools is free software; you can redistribute it and/or modify it under
  14 # the terms of the GNU Lesser General Public License as published by the Free
  15 # Software Foundation; either version 3 of the License, or (at your option) any
  16 # later version.
  17 #
  18 # MayaChemTools is distributed in the hope that it will be useful, but without
  19 # any warranty; without even the implied warranty of merchantability of fitness
  20 # for a particular purpose.  See the GNU Lesser General Public License for more
  21 # details.
  22 #
  23 # You should have received a copy of the GNU Lesser General Public License
  24 # along with MayaChemTools; if not, see <http://www.gnu.org/licenses/> or
  25 # write to the Free Software Foundation Inc., 59 Temple Place, Suite 330,
  26 # Boston, MA, 02111-1307, USA.
  27 #
  28 use 5.006;
  29 use strict;
  30 use Exporter;
  31 
  32 use vars qw($VERSION @ISA @EXPORT @EXPORT_OK %EXPORT_TAGS);
  33 
  34 $VERSION = '1.00';
  35 @ISA = qw(Exporter);
  36 
  37 # Groups of constants...
  38 my(@MathConstants) = qw(Pi TwoPi PiByTwo PiByFour InversePi OneByPi SqrtTwoPi OneBySqrtTwoPi InverseSqrtTwoPi Phi E);
  39 
  40 # Export all constants...
  41 @EXPORT = (@MathConstants);
  42 @EXPORT_OK = qw();
  43 
  44 # Tags to export individual groups of constants...
  45 %EXPORT_TAGS = (
  46 		math => [@MathConstants],
  47 		all  => [@EXPORT, @EXPORT_OK]
  48 	       );
  49 
  50 # Math constants..
  51 use constant {
  52   Pi => CORE::atan2(0, -1),
  53   TwoPi => 2 * CORE::atan2(0, -1),
  54   PiByTwo => CORE::atan2(1, 0),
  55   PiByFour => CORE::atan2(1, 1),
  56   OneByPi => 1.0 / CORE::atan2(0, -1),
  57   InversePi => 1.0 / CORE::atan2(0, -1),
  58   SqrtTwoPi => CORE::sqrt(2 * CORE::atan2(0, -1)),
  59   OneBySqrtTwoPi => 1 / CORE::sqrt(2 * CORE::atan2(0, -1)),
  60   InverseSqrtTwoPi => 1 / CORE::sqrt(2 * CORE::atan2(0, -1)),
  61 
  62   Phi => (1 + CORE::sqrt(5))/2, # Golden ratio...
  63 
  64   E => CORE::exp(1),
  65 };
  66