STLMath.h

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// # STLMath.h: Math operations on STL-like containers
// # Copyright (C) 2014
// # 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 CASA_STLMATH_H
#define CASA_STLMATH_H
 
// # Includes
#include <casacore/casa/aips.h>
#include <casacore/casa/BasicMath/Functors.h>
#include <vector>
#include <algorithm>
 
namespace casacore {  // # NAMESPACE CASACORE - BEGIN
 
// <summary>
//    Math operations on STL-like containers
// </summary>
 
// <use visibility=export>
 
// <reviewed reviewer="Paul Shannon" date="1995/02/21" tests="" demos="">
// </reviewed>
 
// <prerequisite>
//   <li> STL container concept
// </prerequisite>
 
// <synopsis>
// This file defines a few functions with a math operation on a vector.
// Others can be added later.
// </synopsis>
 
// <group name="Container Math">
 
// Throw an exception that two container sizes mismatch.
void throwContainerSizes(const char* name, size_t l1, size_t l2);
 
// Check if the sizes of both containers are the same.
template <typename CONTAINER>
inline void checkContainerSizes(const CONTAINER& left, const CONTAINER& right, const char* name) {
  if (left.size() != right.size()) {
    throwContainerSizes(name, left.size(), right.size());
  }
}
 
// Reverse a Casacore container like IPosition, Block, or Vector.
template <typename CONTAINER>
inline CONTAINER reversedCasaContainer(const CONTAINER& in) {
  size_t sz = in.size();
  CONTAINER out(sz);
  for (size_t i = 0; i < sz; ++i) {
    out[i] = in[sz - i - 1];
  }
  return out;
}
 
// Add two std::vector objects.
template <class T>
std::vector<T> operator+(const std::vector<T>& left, const std::vector<T>& right) {
  checkContainerSizes(left, right, "+");
  std::vector<T> result(left.size());
  std::transform(left.begin(), left.end(), right.begin(), result.begin(), std::plus<T>());
  return result;
}
 
// Divide a vector by a scalar.
template <class T>
std::vector<T> operator/(const std::vector<T>& left, const T& right) {
  std::vector<T> result(left.size());
  std::transform(left.begin(), left.end(), result.begin(), [right](T x) { return x / right; });
  return result;
}
 
// </group>
 
}  // namespace casacore
 
#endif