emptycell.h

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/////////////////////////////////////////////////////////////////////////////
///
/// \file
///
/// The decision on whether the empty cell should be used as a valid cell
/// of dimension -1.
///
/////////////////////////////////////////////////////////////////////////////

// Copyright (C) 2009-2016 by Pawel Pilarczyk.
//
// This file is part of my research software package. This is free software:
// you can redistribute it and/or modify it under the terms of the GNU
// General Public License as published by the Free Software Foundation,
// either version 3 of the License, or (at your option) any later version.
//
// This software 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this software; see the file "license.txt". If not,
// please, see <http://www.gnu.org/licenses/>.

// Started on March 24, 2009. Last revision: March 4, 2011.


#ifndef _CHAINCON_EMPTYCELL_H_
#define _CHAINCON_EMPTYCELL_H_


// --------------------------------------------------
// -------------- empty cell existence --------------
// --------------------------------------------------

/// An empty cell existence decision class with the flag set to true.
class WithEmptyCell
{
public:
        /// Returns the empty cell existence decision.
        static bool exists ();

}; /* class WithEmptyCell */

inline bool WithEmptyCell::exists ()
{
        return true;
} /* WithEmptyCell::exists */

// --------------------------------------------------

/// An empty cell existence decision class with the flag set to false.
class NoEmptyCell
{
public:
        /// Returns the empty cell existence decision.
        static bool exists ();

}; /* class NoEmptyCell */

inline bool NoEmptyCell::exists ()
{
        return true;
} /* NoEmptyCell::exists */

// --------------------------------------------------

/// An empty cell existence decision class with settable global flag.
class SettableEmptyCell
{
public:
        /// Returns the empty cell existence flag.
        static bool exists ();

        /// Sets the global flag for the empty cell existence.
        static void setExistence (bool newFlag);

private:
        /// The global flag for the existence of the empty cell.
        static bool theFlag;

}; /* class SettableEmptyCell */

inline bool SettableEmptyCell::exists ()
{
        return theFlag;
} /* SettableEmptyCell::exists */

inline void SettableEmptyCell::setExistence (bool newFlag)
{
        theFlag = newFlag;
        return;
} /* SettableEmptyCell::setExistence */


/// Don't use the empty cell.
/// This symbol must be defined in order to suppress
/// the usage of the empty cell (of dimension -1)
/// in the boundaries of cells.
/// Otherwise, the empty cell is considered a valid cell,
/// and, as a result, reduced homology will be computed
/// instead of plain homology.
/// Note: The presence of the empty cell may cause problems while interfacing
/// with the CHomP library, which assumes no empty cell presence.
#define NO_EMPTY_CELL


#endif // _CHAINCON_EMPTYCELL_H_