JTrigonometric.hh

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#ifndef __JMATH__JTRIGONOMETRIC__
#define __JMATH__JTRIGONOMETRIC__
 
#include <istream>
#include <ostream>
#include <cmath>
 
#include "JLang/JException.hh"
 
 
/**
 * \author mdejong
 */
 
namespace JMATH {}
namespace JPP { using namespace JMATH; }
 
namespace JMATH {
 
  using JLANG::JException;
  
  
  /**
   * Trigonometric function object for <tt>sin</tt> and <tt>cos</tt>.
   *
   * Evaluation of function, derivative and integral values.
   */
  class JTrigonometric {
  public:
    /**
     * Type definition of pointer to trigonometric function.
     */
    typedef double (*pF)(double); 
 
    
    /**
     * Constructor.
     *
     * \param  f1         pointer to function
     * \param  factor     multiplication factor
     */
    JTrigonometric(pF f1, const double factor = 1.0)
    {
      if (f1 != (double (*)(double)) sin && f1 != (double (*)(double)) cos) {
        THROW(JException, "Invalid trigonometric function.");
      }
      
      this->f1     = f1;
      this->factor = factor;
    }
 
 
    /**
     * Function value.
     *
     * \param  x          abscissa value
     * \return            function value
     */
    double getValue(const double x) const
    {
      return factor * f1(x);
    }
 
 
    /**
     * Derivative value.
     *
     * \param  x          abscissa value
     * \return            derivative value
     */
    double getDerivative(const double x) const
    {
      return getDerivative().getValue(x);
    }
 
 
    /**
     * Integral value.
     *
     * \param  x          abscissa value
     * \return            integral value
     */
    double getIntegral(const double x) const
    {
      return getIntegral().getValue(x);
    }
 
 
    /**
     * Function value.
     *
     * \param  x          abscissa value
     * \return            function value
     */
    double operator()(const double x) const
    {
      return getValue(x);
    }
 
 
    /**
     * Derivative function.
     *
     * \return            derivative function
     */
    JTrigonometric getDerivative() const
    {
      if      (f1 == (double (*)(double)) sin)
        return JTrigonometric(cos, +factor);
      else if (f1 == (double (*)(double)) cos)
        return JTrigonometric(sin, -factor);
      else
        THROW(JException, "Invalid trigonometric function.");
    }
 
 
    /**
     * Integral function.
     *
     * \return            integral function
     */
    JTrigonometric getIntegral() const
    {
      if      (f1 == (double (*)(double)) sin)
        return JTrigonometric(cos, -factor);
      else if (f1 == (double (*)(double)) cos)
        return JTrigonometric(sin, +factor);
      else
        THROW(JException, "Invalid trigonometric function.");
    }
 
 
    /**
     * Read trigonometric from input.
     *
     * \param  in         input stream
     * \param  object     trigonometric
     * \return            input stream
     */
    friend inline std::istream& operator>>(std::istream& in, JTrigonometric& object)
    {
      std::string buffer;
 
      if (in >> object.factor >> buffer) {
        if      (buffer == "sin")
          object.f1 = sin;
        else if (buffer == "cos")
          object.f1 = cos;
        else
          THROW(JException, "Invalid trigonometric function.");
      }
      
      return in;
    }
 
 
    /**
     * Write trigonometric to output.
     *
     * \param  out        output stream
     * \param  object     trigonometric
     * \return            output stream
     */
    friend inline std::ostream& operator<<(std::ostream& out, const JTrigonometric& object)
    {
      out << object.factor;
 
      if      (object.f1 == (double (*)(double)) sin)
        out << ' ' << "sin";
      else if (object.f1 == (double (*)(double)) cos)
        out << ' ' << "cos";
      else
        THROW(JException, "Invalid trigonometric function.");
 
      return out;
    }
    
  protected:
    pF     f1;
    double factor;
  };
}
 
#endif