102 lines
3.1 KiB
Java
102 lines
3.1 KiB
Java
//******************************************************************************
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//
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// File: Bracket.java
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// Package: edu.rit.numeric
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// Unit: Class edu.rit.numeric.Bracket
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//
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// This Java source file is copyright (C) 2013 by Alan Kaminsky. All rights
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// reserved. For further information, contact the author, Alan Kaminsky, at
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// ark@cs.rit.edu.
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//
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// This Java source file is part of the Parallel Java 2 Library ("PJ2"). PJ2 is
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// free software; you can redistribute it and/or modify it under the terms of
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// the GNU General Public License as published by the Free Software Foundation;
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// either version 3 of the License, or (at your option) any later version.
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//
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// PJ2 is distributed in the hope that it will be useful, but WITHOUT ANY
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// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
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// A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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//
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// A copy of the GNU General Public License is provided in the file gpl.txt. You
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// may also obtain a copy of the GNU General Public License on the World Wide
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// Web at http://www.gnu.org/licenses/gpl.html.
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//
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//******************************************************************************
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package edu.rit.numeric;
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/**
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* Class Bracket is the abstract base class for an object that finds a
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* bracketing interval for a root of a {@linkplain Function}. Given a
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* real-valued function of a real-valued variable <I>f</I>(<I>x</I>), an
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* instance of a subclass of class Bracket finds values <I>x</I><SUB>1</SUB> and
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* <I>x</I><SUB>2</SUB> such that <I>f</I>(<I>x</I><SUB>1</SUB>) and
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* <I>f</I>(<I>x</I><SUB>2</SUB>) have opposite signs. Class {@linkplain Root}
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* uses class Bracket.
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*
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* @author Alan Kaminsky
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* @version 06-Oct-2012
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*/
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public abstract class Bracket
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{
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// Exported data members.
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/**
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* First endpoint of bracketing interval.
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*/
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public double x1;
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/**
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* Second endpoint of bracketing interval.
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*/
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public double x2;
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/**
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* Function evaluated at first endpoint of bracketing interval.
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*/
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public double f_x1;
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/**
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* Function evaluated at second endpoint of bracketing interval.
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*/
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public double f_x2;
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// Exported constructors.
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/**
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* Construct a bracketing interval object with the initial bracketing
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* interval <TT>x1</TT> to <TT>x2</TT>.
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*
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* @param x1 Initial bracketing interval first endpoint.
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* @param x2 Initial bracketing interval second endpoint.
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*/
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public Bracket
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(double x1,
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double x2)
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{
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this.x1 = x1;
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this.x2 = x2;
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}
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// Exported operations.
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/**
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* Find a bracketing interval for the given function. When called, fields
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* <TT>x1</TT> and <TT>x2</TT> are the initial bracketing interval
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* endpoints. Upon return, fields <TT>x1</TT> and <TT>x2</TT> have been
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* adjusted to bracket a root; fields <TT>f_x1</TT> and <TT>f_x2</TT>
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* contain the function values at <TT>x1</TT> and <TT>x2</TT>; and
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* <TT>f_x1</TT> and <TT>f_x2</TT> have opposite signs.
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*
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* @param func Function.
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*
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* @exception TooManyIterationsException
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* (unchecked exception) Thrown if too many iterations have occurred
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* without finding a bracketing interval.
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*/
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public abstract void bracket
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(Function func);
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}
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