svn-gvsig-desktop / tags / v1_0_2_Build_906 / libraries / libIverUtiles / src / com / iver / utiles / MathExtension.java @ 10972
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package com.iver.utiles; |
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/* gvSIG. Sistema de Informaci?n Geogr?fica de la Generalitat Valenciana
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*
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* Copyright (C) 2004 IVER T.I. and Generalitat Valenciana.
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*
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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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*
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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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*
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* You should have received a copy of the GNU General Public License
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* along with this program; 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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*
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* For more information, contact:
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*
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* Generalitat Valenciana
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* Conselleria d'Infraestructures i Transport
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* Av. Blasco Ib??ez, 50
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* 46010 VALENCIA
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* SPAIN
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*
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* +34 963862235
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* gvsig@gva.es
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* www.gvsig.gva.es
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*
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* or
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*
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* IVER T.I. S.A
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* Salamanca 50
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* 46005 Valencia
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* Spain
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*
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* +34 963163400
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* dac@iver.es
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*/
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/**
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* Some more mathematical functions that 'java.lang.Math' doesn't have:
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* - Logarithm operations: log2, log2Integer, logX, logXInteger
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*
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* @author Pablo Piqueras Bartolom? (p_queras@hotmail.com)
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*/
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public final class MathExtension { |
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/**
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* 2-base logarithm of a
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* @param a The value to do the calculations
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* @return Logarithm in 2 base of 'a'
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*/
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public static double log2(double a) { |
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return (Math.log(a) / Math.log(2)); |
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} |
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/**
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* 2-base logarithm of a, but the result doesn't have decimals (approximated to the integer number most near by below)
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* @param a The value to do the calculations
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* @return Logarithm in 2 base of 'a', as an integer
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*/
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public static int log2Integer(double a) { |
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return (int) Math.floor(log2(a)); |
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} |
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/**
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* X-base logarithm of a
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* @param a The value to do the calculations
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* @return Logarithm in X base of 'a'
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*/
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public static double logX(double x_base, double a) { |
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return (Math.log(a) / Math.log(x_base)); |
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} |
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/**
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* X-base logarithm of a, but the result doesn't have decimals (approximated to the integer number most near by below)
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* @param a The value to do the calculations
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* @return Logarithm in X base of 'a', as an integer
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*/
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public static int logXInteger(double x_base, double a) { |
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return (int) Math.floor(logX(x_base, a)); |
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} |
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} |