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Program Listing for File constants.hpp
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.. code-block:: cpp

   
   /*****************************************************************************
   ** Ifdefs
   *****************************************************************************/
   
   #ifndef ECL_MATH_CONSTANTS_HPP_
   #define ECL_MATH_CONSTANTS_HPP_
   
   /*****************************************************************************
   ** Includes
   *****************************************************************************/
   
   #include <cmath>
   
   /*****************************************************************************
   ** Namespaces
   *****************************************************************************/
   
   namespace ecl {
   
   #ifdef M_PI // defined by all POSIX systems and some non-POSIX ones
       double const pi = M_PI; 
       const double two_pi  = 2.0*pi;  
       const double pi_2    = pi/2.0;  
       const double pi_4    = pi/4.0;  
       const float  two_pi_f= two_pi;  
       const float  pi_f    = pi;  
       const float  pi_2_f  = pi_2;  
       const float  pi_4_f  = pi_4;  
   #else
       double const pi = 4.0*std::atan(1.0); 
       const double two_pi  = 2.0*pi;  
       const double pi_2    = pi/2.0;  
       const double pi_4    = pi/4.0;  
       const float  two_pi_f= two_pi;  
       const float  pi_f    = pi;  
       const float  pi_2_f  = pi_2;  
       const float  pi_4_f  = pi_4;  
   #endif
   
   // Above method of setting is more intelligent.
   //const double two_pi  = 6.283185307179586476925286766559005768394338798750211641949888;  /**< @brief Mathematical constant for 2*pi. */
   //const double pi      = 3.141592653589793238462643383279502884197169399375105820974944;  /**< @brief Mathematical constant for pi. */
   //const double pi_2    = 1.57079632679489661923;  /**< @brief Mathematical constant for pi/2. */
   //const double pi_4    = 0.78539816339744830962;  /**< @brief Mathematical constant for pi/4. */
   //const float  two_pi_f= 6.283185307179586476925286766559005768394338798750211641949888;  /**< @brief Mathematical constant (float format) for 2*pi. */
   //const float  pi_f    = 3.141592653589793238462643383279502884197169399375105820974944;  /**< @brief Mathematical constant (float format) for pi. */
   //const float  pi_2_f  = 1.57079632679489661923;  /**< @brief Mathematical constant (float format) for pi/2. */
   //const float  pi_4_f  = 0.78539816339744830962;  /**< @brief Mathematical constant (float format) for pi/4. */
   
   
   } // namespace ecl
   
   #endif /*ECL_MATH_CONSTANTS_HPP_*/