LinearFit.h

Go to the documentation of this file.

//     ____   ______ __
//    / __ \ / ____// /
//   / /_/ // /    / /
//  / ____// /___ / /___   PixInsight Class Library
// /_/     \____//_____/   PCL 2.7.0
// ----------------------------------------------------------------------------
// pcl/LinearFit.h - Released 2024-06-18T15:48:54Z
// ----------------------------------------------------------------------------
// This file is part of the PixInsight Class Library (PCL).
// PCL is a multiplatform C++ framework for development of PixInsight modules.
//
// Copyright (c) 2003-2024 Pleiades Astrophoto S.L. All Rights Reserved.
//
// Redistribution and use in both source and binary forms, with or without
// modification, is permitted provided that the following conditions are met:
//
// 1. All redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
//
// 2. All redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
//
// 3. Neither the names "PixInsight" and "Pleiades Astrophoto", nor the names
//    of their contributors, may be used to endorse or promote products derived
//    from this software without specific prior written permission. For written
//    permission, please contact info@pixinsight.com.
//
// 4. All products derived from this software, in any form whatsoever, must
//    reproduce the following acknowledgment in the end-user documentation
//    and/or other materials provided with the product:
//
//    "This product is based on software from the PixInsight project, developed
//    by Pleiades Astrophoto and its contributors (https://pixinsight.com/)."
//
//    Alternatively, if that is where third-party acknowledgments normally
//    appear, this acknowledgment must be reproduced in the product itself.
//
// THIS SOFTWARE IS PROVIDED BY PLEIADES ASTROPHOTO AND ITS CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL PLEIADES ASTROPHOTO OR ITS
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
// EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, BUSINESS
// INTERRUPTION; PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; AND LOSS OF USE,
// DATA OR PROFITS) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
// ----------------------------------------------------------------------------
 
#ifndef __PCL_LinearFit_h
#define __PCL_LinearFit_h
 
 
#include <pcl/Defs.h>
 
#include <pcl/Exception.h>
#include <pcl/Math.h>
 
namespace pcl
{
 
// ----------------------------------------------------------------------------
 
class PCL_CLASS StatusMonitor;
 
class PCL_CLASS LinearFit
{
public:
 
   double a = 0;
 
   double b = 0;
 
   double adev = 0;
 
   bool IsValid() const
   {
      return IsFinite( b );
   }
 
   bool IsXAxis() const
   {
      return 1 + a == 1 && 1 + b == 1;
   }
 
   bool IsIdentity() const
   {
      return 1 + a == 1 && 1 - b == 0;
   }
 
   double operator ()( double x ) const
   {
      return a + b*x;
   }
 
   LinearFit() = default;
 
   LinearFit( const LinearFit& ) = default;
 
   template <typename T>
   LinearFit( T x1, T y1, T x2, T y2 )
   {
      b = double( y2 - y1 )/double( x2 - x1 );
      a = (y2 - b*x2 + y1 - b*x1)/2;
      adev = 0;
   }
 
   template <typename T>
   LinearFit( const T* x, const T* y, size_type n, StatusMonitor* status = nullptr )
   {
      if ( n < 2 )
         throw Error( "LinearFit::LinearFit(): Less than two data points specified." );
 
      if ( n == 2 )
      {
         b = double( y[1] - y[0] )/double( x[1] - x[0] );
         a = (y[1] - b*x[1] + y[0] - b*x[0])/2;
         adev = 0;
      }
      else
         Fit( a, b, adev, x, y, n, status );
   }
 
   template <class C>
   LinearFit( const C& x, const C& y, StatusMonitor* status = nullptr )
   {
      size_type n = Min( x.Length(), y.Length() );
      if ( n < 2 )
         throw Error( "LinearFit::LinearFit(): Less than two data points specified." );
 
      if ( n == 2 )
      {
         b = double( y[1] - y[0] )/double( x[1] - x[0] );
         a = (y[1] - b*x[1] + y[0] - b*x[0])/2;
         adev = 0;
      }
      else
         Fit( a, b, adev, x.Begin(), y.Begin(), n, status );
   }
 
private:
 
   static void Fit( double& a, double& b, double& adev,
                    const float* fx, const float* fy, size_type n, StatusMonitor* status );
   static void Fit( double& a, double& b, double& adev,
                    const double* fx, const double* fy, size_type n, StatusMonitor* status );
};
 
// ----------------------------------------------------------------------------
 
} // pcl
 
#endif   // __LinearFit_h
 
// ----------------------------------------------------------------------------
// EOF pcl/LinearFit.h - Released 2024-06-18T15:48:54Z