//! *this file is freware. Use it at your own risk.
  //! @file hyp.hpp
  //! @author Dejan D. M. Milosavljevic
  //! @version 1.0
  //! @date 2003
  //! Missig hyperbolic functions from standard math library.
  //! *this file is freware. Use it at your own risk.
  
#ifndef Dh_DDMRM_hyp_HPP_
 #define Dh_DDMRM_hyp_HPP_

 #include <cmath>

 //namespace S_DDMRM
  //{
   //namespace S_math
    //{
    
     template< typename N_number >
      inline
      N_number
      asinh
       (
        N_number const& x 
       ) 
       { 
        return  N_number( log( x+sqrt(x*x+ N_number(1)) ) ); 
       }
     
     template< typename N_number >
      inline
      N_number
      acosh
       (
        N_number const& x 
       ) 
       { 
        return  N_number( log( x+sqrt(x*x- N_number(1)) ) ); 
       }
     
     template< typename N_number >
      inline
      N_number
      atanh
       (
        N_number const& x 
       ) 
       { 
        return  N_number( log(( N_number(1)+x)/( N_number(1)-x))/ N_number(2) ); 
       }

     

     template< typename N_number >
      inline
      N_number
      sech
       (
        N_number const& x 
       ) 
       { 
        return   N_number( N_number(1)/sinh(x) ); 
       }
     
     template< typename N_number >
      inline
      N_number
      asech
       (
        N_number const& x 
       ) 
       { 
        return  N_number( asinh( N_number(1)/x) ); 
       }

    
     template< typename N_number >
      inline
      N_number
      csech
       (   
        N_number const& x 
       ) 
       { 
        return   N_number( N_number(1)/cosh(x) ); 
       }
     
     template< typename N_number >
      inline
      N_number
      acsech
       (  
        N_number const& x
       ) 
       { 
        return  N_number( acosh( N_number(1)/x) ); 
       }

     
     template< typename N_number >
      inline
      N_number
      ctanh(   N_number const& x ) 
       {  
       N_number  a = N_number( exp(x) ), b=N_number( exp(-x) );  // optimal ???
        return (a+b)/(a-b); 
       }
     
     template< typename N_number >
      inline
      N_number
      actanh
       ( 
        N_number const& x 
       ) 
       { 
        return  N_number( 0.5 ) * N_number( log( ( x +  N_number(1) ) / ( x -  N_number(1) ) ) ); 
       }


    
  //  }
// }

#endif