Line data    Source code

       1             : //* This file is part of the MOOSE framework
       2             : //* https://mooseframework.inl.gov
       3             : //*
       4             : //* All rights reserved, see COPYRIGHT for full restrictions
       5             : //* https://github.com/idaholab/moose/blob/master/COPYRIGHT
       6             : //*
       7             : //* Licensed under LGPL 2.1, please see LICENSE for details
       8             : //* https://www.gnu.org/licenses/lgpl-2.1.html
       9             : 
      10             : #pragma once
      11             : 
      12             : #include <vector>
      13             : #include <string>
      14             : 
      15             : #include "Moose.h"
      16             : 
      17             : /**
      18             :  * Base class for linear least squares fit method. Derived classes must implement
      19             :  * the fillMatrix() and sample() methods with the functional form of the fit.
      20             :  *
      21             :  * Requires: LAPACK
      22             :  */
      23             : class LeastSquaresFitBase
      24             : {
      25             : public:
      26             :   LeastSquaresFitBase();
      27             :   LeastSquaresFitBase(const std::vector<Real> & x, const std::vector<Real> & y);
      28             : 
      29         198 :   virtual ~LeastSquaresFitBase() = default;
      30             : 
      31             :   /**
      32             :    * Generate the fit. This function must be called prior to using sample.
      33             :    * Note: If you pass a vector that contains duplicate independent measures
      34             :    * the call to LAPACK will fail
      35             :    */
      36             :   virtual void generate();
      37             : 
      38             :   /**
      39             :    * This function will take an independent variable input and will return the
      40             :    * dependent variable based on the generated fit
      41             :    * @param x independent variable
      42             :    * @return dependent variable
      43             :    */
      44             :   virtual Real sample(Real x) = 0;
      45             : 
      46             :   /**
      47             :    * Size of the array holding the points
      48             :    * @return number of sample points
      49             :    */
      50             :   unsigned int getSampleSize();
      51             : 
      52             :   /**
      53             :    * Const reference to the vector of coefficients of the least squares fit
      54             :    * @param return vector of coefficients
      55             :    */
      56             :   const std::vector<Real> & getCoefficients();
      57             : 
      58             :   void setVariables(const std::vector<Real> & x, const std::vector<Real> & y);
      59             : 
      60             : protected:
      61             :   /**
      62             :    * Helper function that creates the matrix necessary for the least squares algorithm
      63             :    */
      64             :   virtual void fillMatrix() = 0;
      65             : 
      66             :   /**
      67             :    * Wrapper for the LAPACK dgels function. Called by generate() to perform the
      68             :    * least squares fit
      69             :    */
      70             :   void doLeastSquares();
      71             : 
      72             :   /// Independent variable
      73             :   std::vector<Real> _x;
      74             :   /// Dependent variable
      75             :   std::vector<Real> _y;
      76             :   /// Basis functions evaluated at each independent variable (note: actually a vector)
      77             :   std::vector<Real> _matrix;
      78             :   /// Vector of coefficients of the least squares fit
      79             :   std::vector<Real> _coeffs;
      80             :   /// The number of coefficients
      81             :   unsigned int _num_coeff;
      82             : };