liblinbox-dev 1.1.6~rc0-4.1 / usr / include / linbox / field / param-fuzzy.h

/* -*- mode: C++; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */

/* linbox/field/param-fuzzy.h
 * Copyright (C) 1999-2001 William J Turner,
 *               2001 Bradford Hovinen
 *
 * Written by William J Turner <wjturner@math.ncsu.edu>,
 *            Bradford Hovinen <hovinen@cis.udel.edu>
 *
 * Updated by bds 8/02
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#ifndef __FIELD_PARAM_FUZZY_H
#define __FIELD_PARAM_FUZZY_H

#include <iostream>

#include "linbox/integer.h"
#include <linbox/field/field-interface.h>
#include <linbox/field/field-traits.h>

// Namespace in which all LinBox code resides
namespace LinBox 
{ 
	// Forward declarations
	class ParamFuzzyRandIter;

	/** Abstract parameterized field of "fuzzy" doubles.
	 * Field has (non-static, non-negative) member to contain "fuzz value" of 
	 * field.  Doubles within this fuzz value are considered to be equal.
	\ingroup field
	 */
	class ParamFuzzy : public FieldInterface
	{
	    public:

		/** element type.
		 * It must meet the common object interface of elements as given in the
		 * the archetype ElementArchetype.
		 */
		typedef double Element;

		/** Random iterator generator type.
		 * It must meet the common object interface of random element generators
		 * as given in the the archetype RandIterArchetype.
		 */
		typedef ParamFuzzyRandIter RandIter;

		/** @name Object Management
		 */
		//@{
 
		/** Default constructor.
		 */
		//ParamFuzzy (void) {}

		/** Constructor from an integer.
		 * Sets the fuzz value of the field throug the static member of the 
		 * element type.
		 * @param value constant reference to double fuzz value
		 */
		ParamFuzzy (const double &value = .000000001) : _fuzz (value) {}

		/** Copy constructor.
		 * Constructs ParamFuzzy object by copying the field.
		 * This is required to allow field objects to be passed by value
		 * into functions.
		 * @param  F ParamFuzzy object.
		 */
		ParamFuzzy (const ParamFuzzy &F) : _fuzz (F._fuzz) {}
 
		/** Assignment operator.
		 * @return reference to ParamFuzzy object for self
		 * @param F constant reference to ParamFuzzy object
		 */
		ParamFuzzy &operator= (const ParamFuzzy &F)
			{ return *this; }

		/** Initialization of field base element from an integer.
		 * Behaves like C++ allocator construct.
		 * This function assumes the output field base element x has already been
		 * constructed, but that it is not already initialized.
		 * This is not a specialization of the template function because
		 * such a specialization is not allowed inside the class declaration.
		 * @return reference to field base element.
		 * @param x field base element to contain output (reference returned).
		 * @param y integer.
		 */
		Element &init (Element &x, const integer &y) const
			{ return x = static_cast<double> (y); }
 
		/** Conversion of field base element to a template class T.
		 * This function assumes the output field base element x has already been
		 * constructed, but that it is not already initialized.
		 * @return reference to template class T.
		 * @param x template class T to contain output (reference returned).
		 * @param y constant field base element.
		 */
		integer &convert (integer &x, const Element &y) const
			{ return x = static_cast<integer> (y); }
 
		/** Assignment of one field base element to another.
		 * This function assumes both field base elements have already been
		 * constructed and initialized.
		 * @return reference to x
		 * @param  x field base element (reference returned).
		 * @param  y field base element.
		 */
		Element &assign (Element &x, const Element &y) const
			{ return x = y; }

		/** Cardinality.
		 * Return integer representing cardinality of the domain.
		 * Returns a non-negative integer for all domains with finite
		 * cardinality, and returns -1 to signify a domain of infinite
		 * cardinality.
		 * @return integer representing cardinality of the domain
		 */
		integer &cardinality (integer &c) const { return c = -1; }
 
		/** Characteristic.
		 * Return integer representing characteristic of the domain.
		 * Returns a positive integer to all domains with finite characteristic,
		 * and returns 0 to signify a domain of infinite characteristic.
		 * @return integer representing characteristic of the domain.
		 */
		integer &characteristic (integer &c) const { return c = 0; }

		//@} Object Management

		/** @name Arithmetic Operations
		 * x <- y op z; x <- op y
		 * These operations require all elements, including x, to be initialized
		 * before the operation is called.  Uninitialized field base elements will
		 * give undefined results.
		 */
		//@{

		/** Equality of two elements.
		 * This function assumes both field base elements have already been
		 * constructed and initialized.
		 * @return boolean true if equal, false if not.
		 * @param  x field base element
		 * @param  y field base element
		 */
		bool areEqual (const Element &x, const Element &y) const
			{ return ( ( x - y <= _fuzz ) && ( y - x <= _fuzz ) ); }

		/** Addition.
		 * x = y + z
		 * This function assumes all the field base elements have already been
		 * constructed and initialized.
		 * @return reference to x.
		 * @param  x field base element (reference returned).
		 * @param  y field base element.
		 * @param  z field base element.
		 */
		Element &add (Element &x, const Element &y, const Element &z) const
			{ return x = y + z; }
 
		/** Subtraction.
		 * x = y - z
		 * This function assumes all the field base elements have already been
		 * constructed and initialized.
		 * @return reference to x.
		 * @param  x field base element (reference returned).
		 * @param  y field base element.
		 * @param  z field base element.
		 */
		Element &sub (Element &x, const Element &y, const Element &z) const
			{ return x = y - z; }
 
		/** Multiplication.
		 * x = y * z
		 * This function assumes all the field base elements have already been
		 * constructed and initialized.
		 * @return reference to x.
		 * @param  x field base element (reference returned).
		 * @param  y field base element.
		 * @param  z field base element.
		 */
		Element &mul (Element &x, const Element &y, const Element &z) const
			{ return x = y * z; }
 
		/** Division.
		 * x = y / z
		 * This function assumes all the field base elements have already been
		 * constructed and initialized.
		 * @return reference to x.
		 * @param  x field base element (reference returned).
		 * @param  y field base element.
		 * @param  z field base element.
		 */
		Element &div (Element &x, const Element &y, const Element &z) const
			{ return x = y / z; }
 
		/** Additive Inverse (Negation).
		 * x = - y
		 * This function assumes both field base elements have already been
		 * constructed and initialized.
		 * @return reference to x.
		 * @param  x field base element (reference returned).
		 * @param  y field base element.
		 */
		Element &neg (Element &x, const Element &y) const
			{ return x = - y; }
 
		/** Multiplicative Inverse.
		 * x = 1 / y
		 * This function assumes both field base elements have already been
		 * constructed and initialized.
		 * @return reference to x.
		 * @param  x field base element (reference returned).
		 * @param  y field base element.
		 */
		Element &inv (Element &x, const Element &y) const
			{ return x = static_cast<double> (1) / y; }

		/** Natural AXPY.
		 * r  = a * x + y
		 * This function assumes all field elements have already been 
		 * constructed and initialized.
		 * @return reference to r.
		 * @param  r field element (reference returned).
		 * @param  a field element.
		 * @param  x field element.
		 * @param  y field element.
		 */
		Element &axpy (Element &r, 
			       const Element &a, 
			       const Element &x, 
			       const Element &y) const
			{ return r = a * x + y; }

		//@} Arithmetic Operations

		/** @name Inplace Arithmetic Operations
		 * x <- x op y; x <- op x
		 */
		//@{

		/** Zero equality.
		 * Test if field base element is equal to zero.
		 * This function assumes the field base element has already been
		 * constructed and initialized.
		 * @return boolean true if equals zero, false if not.
		 * @param  x field base element.
		 */
		bool isZero (const Element &x) const
			{ return ( ( x <= _fuzz ) && ( - x <= _fuzz ) ); }

		/** One equality.
		 * Test if field base element is equal to one.
		 * This function assumes the field base element has already been
		 * constructed and initialized.
		 * @return boolean true if equals one, false if not.
		 * @param  x field base element.
		 */
		bool isOne (const Element &x) const
			{ return ( ( x - 1 <= _fuzz ) && ( 1 - x <= _fuzz ) ); }

		/** Inplace Addition.
		 * x += y
		 * This function assumes both field base elements have already been
		 * constructed and initialized.
		 * @return reference to x.
		 * @param  x field base element (reference returned).
		 * @param  y field base element.
		 */
		Element &addin (Element &x, const Element &y) const { return x += y; } 

		/** Inplace Subtraction.
		 * x -= y
		 * This function assumes both field base elements have already been
		 * constructed and initialized.
		 * @return reference to x.
		 * @param  x field base element (reference returned).
		 * @param  y field base element.
		 */
		Element &subin (Element &x, const Element &y) const { return x -= y; }
 
		/** Inplace Multiplication.
		 * x *= y
		 * This function assumes both field base elements have already been
		 * constructed and initialized.
		 * @return reference to x.
		 * @param  x field base element (reference returned).
		 * @param  y field base element.
		 */
		Element &mulin (Element &x, const Element &y) const { return x *= y; }
 
		/** Inplace Division.
		 * x /= y
		 * This function assumes both field base elements have already been
		 * constructed and initialized.
		 * @return reference to x.
		 * @param  x field base element (reference returned).
		 * @param  y field base element.
		 */
		Element &divin (Element &x, const Element &y) const { return x /= y; }

		/** Inplace Additive Inverse (Inplace Negation).
		 * x = - x
		 * This function assumes the field base element has already been
		 * constructed and initialized.
		 * @return reference to x.
		 * @param  x field base element (reference returned).
		 */
		Element &negin (Element &x) const { return x = -x; }
 
		/** Inplace Multiplicative Inverse.
		 * x = 1 / x
		 * This function assumes the field base elementhas already been
		 * constructed and initialized.
		 * @return reference to x.
		 * @param  x field base element (reference returned).
		 */
		Element &invin (Element &x) const
			{ return x = static_cast<double> (1) / x; }

		/** Inplace AXPY.
		 * r  += a * x
		 * This function assumes all field elements have already been 
		 * constructed and initialized.
		 * Purely virtual
		 * @return reference to r.
		 * @param  r field element (reference returned).
		 * @param  a field element.
		 * @param  x field element.
		 */
		Element &axpyin (Element &r, const Element &a, const Element &x) const
			{ return r += a * x; }
 
		//@} Inplace Arithmetic Operations
		
		/** @name Input/Output Operations */
		//@{

		/** Print field.
		 * @return output stream to which field is written.
		 * @param  os  output stream to which field is written.
		 */
		std::ostream &write (std::ostream &os) const 
			{ return os << " fuzz value " << _fuzz; }
 
		/** Read field.
		 * @return input stream from which field is read.
		 * @param  is  input stream from which field is read.
		 */
		std::istream &read (std::istream &is) { return is >> _fuzz; }

		/** Print field base element.
		 * This function assumes the field base element has already been
		 * constructed and initialized.
		 * @return output stream to which field base element is written.
		 * @param  os  output stream to which field base element is written.
		 * @param  x   field base element.
		 */
		std::ostream &write (std::ostream &os, const Element &x) const
			{ return os << x; }
 
		/** Read field base element.
		 * This function assumes the field base element has already been
		 * constructed and initialized.
		 * @return input stream from which field base element is read.
		 * @param  is  input stream from which field base element is read.
		 * @param  x   field base element.
		 */
		std::istream &read (std::istream &is, Element &x) const
		{
			is >> x;
			return is; 
		}

		//@}

	    private:

		/// Private static double for fuzz value
		double _fuzz;

	}; // class ParamFuzzy

	typedef ParamFuzzy DoubleRealApproximation;

} // namespace LinBox

#include "linbox/randiter/param-fuzzy.h"

#endif // __FIELD_PARAM_FUZZY_H