functional.h

Go to the documentation of this file.

#include <cmath>
#include <functional>
#include <dlrNumeric/numericTraits.h>

#ifndef _DLR_NUMERIC_FUNCTIONAL_H_
#define _DLR_NUMERIC_FUNCTIONAL_H_

namespace dlr {

  namespace numeric {
    
    template <class Type>
    struct Gaussian1DFunctor
      : public std::unary_function<Type, Type>
    {
      Gaussian1DFunctor(Type sigma = 1.0)
        : m_k0(1.0 / (std::sqrt(2.0 * M_PI) * sigma)),
          m_k1(-1.0 / (2.0 * sigma * sigma)) {}

    
      inline Type
      operator()(const Type& input) {
        return m_k0 * std::exp(input * input * m_k1);
      }

    private:
      Type m_k0;
      Type m_k1;
    };

  
    template <class Type>
    struct LogFunctor
      : public std::unary_function<Type, Type>
    {
      inline Type
      operator()(const Type& input) {
        return std::log(input);
      }
    };

  
    template <class TypeIn, class TypeOut>
    struct NumericTypeConversionFunctor
      : public std::unary_function<TypeIn, TypeOut>
    {
      inline TypeOut
      operator()(const TypeIn& input) {
        // This "if" should optimize away, since traits are known at compile
        // time.
        if(!NumericTraits<TypeIn>().isIntegral()
           && NumericTraits<TypeOut>().isIntegral()) {
          return static_cast<TypeOut>(input + 0.5);
        }
        return static_cast<TypeOut>(input);
      }
    };

  
    template <class Type>
    struct SquareRootFunctor
      : public std::unary_function<Type, Type>
    {
      inline Type
      operator()(const Type& input) {
        return std::sqrt(input);
      }
    };

  } // namespace numeric

}  // namespace dlr


/* ======= Declarations to maintain compatibility with legacy code. ======= */

namespace dlr {

  using numeric::Gaussian1DFunctor;
  using numeric::LogFunctor;
  using numeric::NumericTypeConversionFunctor;
  using numeric::SquareRootFunctor;

}  // namespace dlr


/* ================= Specializations =================== */

namespace dlr {

  namespace numeric {
    
  // None

  } // namespace numeric
  
}  // namespace dlr

#endif // #ifndef _DLR_NUMERIC_FUNCTIONAL_H_