approximator.cpp

ROSETTA C++库是一个C++类库和例程集合

//-------------------------------------------------------------------
// Author........: Aleksander 豩rn
// Date..........:
// Description...:
// Revisions.....:
//===================================================================

#include <stdafx.h> // Precompiled headers.
#include <copyright.h>

#include <kernel/algorithms/approximator.h>
#include <kernel/algorithms/partitioner.h>
#include <kernel/algorithms/keyword.h>

#include <kernel/structures/decisiontable.h>
#include <kernel/structures/reduct.h>
#include <kernel/structures/equivalenceclass.h>
#include <kernel/structures/equivalenceclasses.h>
#include <kernel/structures/approximation.h>

#include <kernel/utilities/creator.h>

#include <kernel/basic/message.h>

#include <common/objectmanager.h>

//-------------------------------------------------------------------
// Methods for class Approximator.
//===================================================================

//-------------------------------------------------------------------
// Constructors/destructor.
//===================================================================

Approximator::Approximator() {
	decision_   = Undefined::Integer();
	attributes_ = Undefined::String();
	precision_  = 0.0f;
}

Approximator::~Approximator() {
}

//-------------------------------------------------------------------
// Methods inherited from Identifier.
//===================================================================

IMPLEMENTIDMETHODS(Approximator, APPROXIMATOR, Algorithm)

//-------------------------------------------------------------------
// Methods inherited from Algorithm.
//===================================================================

//-------------------------------------------------------------------
// Method........: GetParameters
// Author........: Aleksander 豩rn
// Date..........:
// Description...:
// Comments......:
// Revisions.....:
//===================================================================

String
Approximator::GetParameters() const {

	String parameters, formatted;

	// Decision.
	parameters += Keyword::Decision();
	parameters += Keyword::Assignment();
	parameters += String::Format(GetDecisionValue());

	parameters += Keyword::Separator();

	// Precision.
	parameters += Keyword::Precision();
	parameters += Keyword::Assignment();
	parameters += String::Format(GetPrecision());

	parameters += Keyword::Separator();

	// Attributes.
	parameters += Keyword::Attributes();
	parameters += Keyword::Assignment();
	parameters += GetAttributes();

	return parameters;

}

//-------------------------------------------------------------------
// Method........: SetParameter
// Author........: Aleksander 豩rn
// Date..........:
// Description...:
// Comments......:
// Revisions.....:
//===================================================================

bool
Approximator::SetParameter(const String &keyword, const String &value) {

	// Decision.
  if (keyword == Keyword::Decision() && value.IsInteger())
		return SetDecisionValue(value.GetInteger());

	// Precision.
  if (keyword == Keyword::Precision() && value.IsFloat())
		return SetPrecision(value.GetFloat());

	// Attributes.
	if (keyword == Keyword::Attributes())
		return SetAttributes(value);

	return false;

}

//-------------------------------------------------------------------
// Method........: IsApplicable
// Author........: Aleksander 豩rn
// Date..........:
// Description...: Returns true if the algorithm is applicable to the
//                 structure, false otherwise.
// Comments......:
// Revisions.....:
//===================================================================

bool
Approximator::IsApplicable(const Structure &structure, bool /*warn*/) const {
	return structure.IsA(DECISIONTABLE);
}

//-------------------------------------------------------------------
// Method........: Apply
// Author........: Aleksander 豩rn
// Date..........:
// Description...: Calculates the rough approximation of the set of
//                 objects with a certain decision, using a certain
//                 set of attributes.  A precision level p can be set.
//
//                 Let m be the rough membership value.  Assign the
//                 eq. classes as follows:
//
//                    if m >= 1 - p then in lower appr.
//                    if m >  p     then in upper appr.
//
//                 Note that p = 0 implies the "traditional" meaning
//                 of the lower/upper approximations.
//
//                 The value of p should lie in the range [0, 0.5].
//
// Comments......: Assumes that library clients use handles.
// Revisions.....: A