AxesMapping.h

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// # AxesMapping.h: Info about mapping array axes to another order
// # Copyright (C) 2000,2001
// # Associated Universities, Inc. Washington DC, USA.
// #
// # This library is free software; you can redistribute it and/or modify it
// # under the terms of the GNU Library 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 Library General Public
// # License for more details.
// #
// # You should have received a copy of the GNU Library General Public License
// # along with this library; if not, write to the Free Software Foundation,
// # Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
// #
// # Correspondence concerning AIPS++ should be addressed as follows:
// #        Internet email: casa-feedback@nrao.edu.
// #        Postal address: AIPS++ Project Office
// #                        National Radio Astronomy Observatory
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#ifndef CASA_AXESMAPPING_2_H
#define CASA_AXESMAPPING_2_H
 
// # Includes
#include "IPosition.h"
 
namespace casacore {  // # NAMESPACE CASACORE - BEGIN
 
// # Forward Declarations
class Slicer;
 
// <summary>
// Info about mapping array axes to another order.
// </summary>
 
// <use visibility=local>
 
// <reviewed reviewer="" date="yyyy/mm/dd" tests="tAxesSpecifier.cc" demos="">
// </reviewed>
 
// <prerequisite>
//   <li> <linkto class="IPosition">IPosition</linkto>
//   <li> <linkto class="AxesSpecifier">AxesSpecifier</linkto>
// </prerequisite>
 
// <synopsis>
// AxesMapping holds the information about mapping axes to another order.
// It can be constructed by <linkto class=AxesSpecifier>AxesSpecifier</linkto>
// by applying a shape to the axes specification.
// <br>AxesMapping is thereafter used to map positions, shapes, and
// slices to the new axes or backwards.
// <note role=caution>
// Shapes and positions are both represented by class IPosition.
// However, they have to be treated differently in this class,
// because removed axes for a position have value 0, while for a
// shape they have value 1. Hence there are different functions for them
// and the user has to take care that the correct function is called.
// </note>
// </synopsis>
 
// <example>
// <srcblock>
//
// </srcblock>
// </example>
 
// <motivation>
// The class encapsulates the mapping functionality.
// It is meant as a helper class for casacore's SubLattice.
// </motivation>
 
// # <todo asof="yyyy/mm/dd">
// # </todo>
 
class AxesMapping {
 public:
  // The default constructor creates empty maps.
  AxesMapping();
 
  // Construct it with the mapping from old to new axes order.
  // A value of -1 means that the old axes is ignored in the new one.
  // Another value gives the new axis number.
  // <br>It determines if axes are removed and/or reordered.
  explicit AxesMapping(const IPosition& oldToNew);
 
  // Are axes removed?
  bool isRemoved() const { return itsRemoved; }
 
  // Is the axes order reordered?
  bool isReordered() const { return itsReordered; }
 
  // Get the mapping of old->new.
  // The length of the resulting IPosition is the dimensionality of
  // the original lattice. A value of -1 indicates that the corresponding
  // axis in the original lattice is removed.
  // Another value is the axis number in the new lattice,
  const IPosition& getToNew() const { return itsToNew; }
 
  // Get the mapping of new->old.
  // The length of the resulting IPosition is the dimensionality of
  // the new lattice. Its values give the axes in the original lattice.
  const IPosition& getToOld() const { return itsToOld; }
 
  // Map an old position to the new one.
  // In debug-mode it checks if the removed axes have position 0
  // in the input position.
  IPosition posToNew(const IPosition& pos) const;
 
  // Map a new position or shape to the old one.
  IPosition posToOld(const IPosition& pos) const;
 
  // Map an old shape to the new one.
  // In debug-mode it checks if the removed axes have length 1
  // in the input shape.
  IPosition shapeToNew(const IPosition& shape) const;
 
  // Map a new position or shape to the old one.
  IPosition shapeToOld(const IPosition& shape) const;
 
  // Map an old shape to the new one.
  // In debug-mode it checks if the removed axes have length 1
  // in the input slicer.
  Slicer slicerToNew(const Slicer& slicer) const;
 
  // Map a new position or shape to the old one.
  Slicer slicerToOld(const Slicer& slicer) const;
 
 private:
  IPosition itsToNew;
  IPosition itsToOld;
  bool itsRemoved;
  bool itsReordered;
};
 
}  // namespace casacore
 
#endif