LELSpectralIndex.h

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// # LELSpectralIndex.h: LEL function to calculate spectral index/
// # Copyright (C) 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
// #                        520 Edgemont Road
// #                        Charlottesville, VA 22903-2475 USA
 
#ifndef LATTICES_LELSPECTRALINDEX_H
#define LATTICES_LELSPECTRALINDEX_H
 
// # Includes
#include <casacore/casa/aips.h>
#include <casacore/lattices/LEL/LELFunction.h>
#include <casacore/casa/Containers/Block.h>
 
namespace casacore {  // # NAMESPACE CASACORE - BEGIN
 
// # Forward Declarations
 
// <summary>
// This LEL class handles calculation of the spectral index.
// </summary>
 
// <use visibility=local>
 
// <reviewed reviewer="" date="yyyy/mm/dd" tests="" demos="">
// </reviewed>
 
// <prerequisite>
//   <li> <linkto class="Lattice"> Lattice</linkto>
//   <li> <linkto class="LatticeExpr"> LatticeExpr</linkto>
//   <li> <linkto class="LatticeExprNode"> LatticeExprNode</linkto>
//   <li> <linkto class="LELInterface"> LELInterface</linkto>
//   <li> <linkto class="LELFunctionEnums"> LELFunctionEnums</linkto>
// </prerequisite>
 
// <synopsis>
// This LEL letter class is derived from LELInterface. It is used to
// construct LEL objects that calculate the sepectral index from 2 other
// LEL expression (usually images).
// It operates on real types (Float,Double)
// </synopsis>
 
// <motivation>
// This is a separate class (instead of being part of a LELFunction class),
// because the calculation of the spectral index requires extra variables
// (the frequencies) and some more complicated code.
// </motivation>
 
template <class T>
class LELSpectralIndex : public LELInterface<T> {
  // # Make members of parent class known.
 protected:
  using LELInterface<T>::setAttr;
 
 public:
  // Constructor takes operation and expressions to be operated upon
  LELSpectralIndex(const Block<LatticeExprNode>& expr);
 
  // Destructor
  ~LELSpectralIndex();
 
  // Recursively evaluate the expression
  virtual void eval(LELArray<T>& result, const Slicer& section) const;
 
  // Get the result of a scalar subexpression.
  // Throws an exception as it is not possible.
  virtual LELScalar<T> getScalar() const;
 
  // Do further preparations (e.g. optimization) on the expression.
  // Returns False.
  virtual Bool prepareScalarExpr();
 
  // Get class name
  virtual String className() const;
 
  // Handle locking/syncing of a lattice in a lattice expression.
  // <group>
  virtual Bool lock(FileLocker::LockType, uInt nattempts);
  virtual void unlock();
  virtual Bool hasLock(FileLocker::LockType) const;
  virtual void resync();
  // </group>
 
 private:
  Int itsFreqAxis;
  Block<Double> itsLogFreq;  // # log(f0/f1)
  LatticeExprNode arg0_p;
  LatticeExprNode arg1_p;
};
 
}  // namespace casacore
 
#ifndef CASACORE_NO_AUTO_TEMPLATES
#include <casacore/lattices/LEL/LELSpectralIndex.tcc>
#endif  // # CASACORE_NO_AUTO_TEMPLATES
#endif