#ifndef ALGO_BLAST_GUMBEL_PARAMS__INCLUDED_NJN_APPROX
#define ALGO_BLAST_GUMBEL_PARAMS__INCLUDED_NJN_APPROX

/* $Id: njn_approx.hpp 183505 2010-02-18 16:10:58Z boratyng $
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*               National Center for Biotechnology Information
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/*****************************************************************************

File name: njn_approx.hpp

Author: John Spouge

Contents: 

******************************************************************************/

#include <corelib/ncbistl.hpp>
#include <float.h>
#include <math.h>

BEGIN_NCBI_SCOPE
BEGIN_SCOPE(blast)

BEGIN_SCOPE(Njn)
BEGIN_SCOPE(Approx)

      // Approximation

      const float FLT_THRESHOLD =       10.0F; // Rounding threshold
      const float FLT_ROUND  =          FLT_THRESHOLD * FLT_EPSILON; // Rounding error threshold

      const double DBL_THRESHOLD =      100.0; // Rounding threshold
      const double DBL_ROUND  =         DBL_THRESHOLD * DBL_EPSILON; // Rounding error threshold

      template <typename T> inline bool approx (T x_, T y_, T eps_);
      template <typename T> inline bool relApprox (T x_, T y_, T eps_);
      template <typename T> inline bool absRelApprox (T x_, T y_, T tol_, T rtol_);

      // Rounding

      template <typename T> inline bool eq (T x_, T y_, T round_);
      template <typename T> inline bool ge (T x_, T y_, T round_);
      template <typename T> inline bool gt (T x_, T y_, T round_);
      template <typename T> inline bool ne (T x_, T y_, T round_);
      template <typename T> inline bool lt (T x_, T y_, T round_);
      template <typename T> inline bool le (T x_, T y_, T round_);


      // Approximation

      template <typename T> bool approx (T x_, T y_, T eps_) {return fabs (x_ - y_) <= fabs (eps_);}
      template <typename T> bool relApprox (T x_, T y_, T eps_) {return approx <T> (x_, y_, eps_ * y_);}
      template <typename T> bool absRelApprox (T x_, T y_, T tol_, T rtol_) {return approx <T> (x_, y_, tol_) || relApprox <T> (x_, y_, rtol_);}

      // Rounding

      template <typename T> bool eq (T x_, T y_, T round_) {return relApprox <T> (x_, y_, round_);}
      template <typename T> bool ge (T x_, T y_, T round_) {return (x_ - y_) >= -(fabs (y_)) * round_;}
      template <typename T> bool gt (T x_, T y_, T round_) {return (x_ - y_) >   (fabs (y_)) * round_;}
      template <typename T> bool ne (T x_, T y_, T round_) {return ! eq (x_, y_, round_);}
      template <typename T> bool lt (T x_, T y_, T round_) {return ! ge (x_, y_, round_);}
      template <typename T> bool le (T x_, T y_, T round_) {return ! gt (x_, y_, round_);}

END_SCOPE(Approx)
END_SCOPE(Njn)

END_SCOPE(blast)
END_NCBI_SCOPE

#endif //! ALGO_BLAST_GUMBEL_PARAMS__INCLUDED_NJN_APPROX
