SparseDiffRep.h

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// # SparseDiffRep.h: Representation of an automatic differential class data
// # Copyright (C) 2007
// # 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
// #                        520 Edgemont Road
// #                        Charlottesville, VA 22903-2475 USA
 
#ifndef SCIMATH_SPARSEDIFFREP_H
#define SCIMATH_SPARSEDIFFREP_H
 
// # Includes
#include <casacore/casa/aips.h>
#include <casacore/casa/vector.h>
#include <utility>
 
// Using
using std::pair;
 
namespace casacore {  // # NAMESPACE CASACORE - BEGIN
 
// # Forward declarations
 
// <summary>
// Representation of data for the spare automatic differentiation calss.
// </summary>
//
// <use visibility=local>
//
// <reviewed reviewer="UNKNOWN" date="" tests="tSparseDiff.cc" demos="">
// </reviewed>
//
// <prerequisite>
// <li> <linkto class=SparseDiff>SparseDiff</linkto>
// </prerequisite>
//
// <etymology>
// Class that represents partial derivatives obtained by automatic
// differentiation.
// </etymology>
//
// <synopsis>
// Class representing
// the data necessary for automatic differentiation. The structure contains a
// value, and the derivatives of the value with respect to a number of
// dependent variables.
//
// The actual differentiation and access is done through the
// <linkto class=SparseDiff>SparseDiff</linkto> class.
//
// <example>
// See the example in <linkto class=SparseDiff>SparseDiff</linkto>
// </example>
//
// <motivation>
// To separate the data container from the actual calculations.
// To be able to create special conatiners; constructors and destructors
// (including memory allocation) to speed up processes.
//
// <templating arg=T>
//  <li> any class that has the standard mathematical and comparison
//  operators defined
// </templating>
//
// <todo asof="2007/11/27">
// <li> Nothing I know of
// </todo>
 
template <class T>
class SparseDiffRep {
 public:
  // # Typedefs
  typedef T value_type;
  typedef value_type &reference;
  typedef const value_type &const_reference;
  typedef value_type *iterator;
  typedef const value_type *const_iterator;
 
  // # Constructors
  //  Construct a constant with a value of zero.  Zero derivatives.
  SparseDiffRep();
 
  // # Operators
  //  Assignment operators
  //  <group>
  SparseDiffRep<T> &operator=(const T &v);
  SparseDiffRep<T> &operator=(const vector<pair<uInt, T>> &grad);
  SparseDiffRep<T> &operator=(const SparseDiffRep<T> &other);
  void operator*=(const T other);
  void operator/=(const T other);
  void operator+=(const T other);
  void operator-=(const T other);
  // </group>
 
  // # Member functions
 
  // Clear for reuse
  void clear() { grad_p.clear(); }
 
  // # Data
  //  The function value
  T val_p;
  // The derivatives
  vector<pair<uInt, T>> grad_p;
  // Link to indicate its status (1=linked in stack; 2=used in modules)
  uInt link_p;
};
 
}  // namespace casacore
 
#ifndef CASACORE_NO_AUTO_TEMPLATES
#include <casacore/scimath/Mathematics/SparseDiffRep.tcc>
#endif  // # CASACORE_NO_AUTO_TEMPLATES
#endif