GRINSTesting::RegressionHelper Class Reference

#include <regression_helper.h>

Inheritance diagram for GRINSTesting::RegressionHelper:

Protected Member Functions
libMesh::Real	linear_slope (std::vector< libMesh::Real > x, std::vector< libMesh::Real > y, unsigned int start_index, unsigned int end_index)
	Slope for linear regression. More...
libMesh::Real	linear_intercept (std::vector< libMesh::Real > x, std::vector< libMesh::Real > y, unsigned int start_index, unsigned int end_index)
	y-intercept for linear regression More...
void	check_convergence_rate (std::vector< libMesh::Real > x, std::vector< libMesh::Real > y, unsigned int start_index, unsigned int end_index, libMesh::Real convergence_rate, libMesh::Real tol)
	Check the convergence rate of the supplied data to within the given absolute tolerance. More...

Detailed Description

Provides helper functions for fitting data to a curve.

Currently supports linear regression

Definition at line 46 of file regression_helper.h.

Member Function Documentation

void GRINSTesting::RegressionHelper::check_convergence_rate ( std::vector< libMesh::Real >  x, std::vector< libMesh::Real >  y, unsigned int  start_index, unsigned int  end_index, libMesh::Real  convergence_rate, libMesh::Real  tol  )

inlineprotected

Check the convergence rate of the supplied data to within the given absolute tolerance.

Definition at line 110 of file regression_helper.h.

References linear_slope().

Referenced by GRINSTesting::IntegratedFunctionTest::test_convergence().

    {
      libmesh_assert(tol > 0.0);
      libmesh_assert(x.size() == y.size());
      libmesh_assert(start_index < end_index);
      libmesh_assert(end_index < x.size());

      libMesh::Real calculated_rate = linear_slope(x,y,start_index,end_index);

#ifdef GRINS_HAVE_CPPUNIT

      CPPUNIT_ASSERT_DOUBLES_EQUAL(convergence_rate,calculated_rate,tol);
#else
      if (std::abs(convergence_rate - calculated_rate) > tol)
        {
          std::stringstream ss;
          ss <<"ERROR" <<std::endl
             <<"calculated convergence rate: " <<calculated_rate <<std::endl
             <<"desired convergence rate: " <<convergence_rate <<std::endl
             <<"tolerance: " <<tol <<std::endl;

          libmesh_error_msg(ss.str());
        }
#endif // GRINS_HAVE_CPPUNIT
    }

libMesh::Real GRINSTesting::RegressionHelper::linear_intercept ( std::vector< libMesh::Real >  x, std::vector< libMesh::Real >  y, unsigned int  start_index, unsigned int  end_index  )

inlineprotected

y-intercept for linear regression

Definition at line 81 of file regression_helper.h.

    {
      libmesh_assert(x.size() == y.size());
      libmesh_assert(start_index < end_index);

      unsigned int n = x.size();
      libmesh_assert(end_index < n);

      libMesh::Real sum_y = 0.0,
        sum_x2 = 0.0,
        sum_x = 0.0,
        sum_xy = 0.0;

      for (unsigned int i=start_index; i<=end_index; i++)
        {
          libMesh::Real xi = x[i];
          libMesh::Real yi = y[i];

          sum_y  += yi;
          sum_x2 += xi*xi;
          sum_x  += xi;
          sum_xy += xi*yi;
        }

      libMesh::Real intercept = ( sum_y*sum_x2 - sum_x*sum_xy )/( n*sum_x2 - (sum_x*sum_x) );
      return intercept;
    }

libMesh::Real GRINSTesting::RegressionHelper::linear_slope ( std::vector< libMesh::Real >  x, std::vector< libMesh::Real >  y, unsigned int  start_index, unsigned int  end_index  )

inlineprotected

Slope for linear regression.

Definition at line 51 of file regression_helper.h.

Referenced by check_convergence_rate().

    {
      libmesh_assert(x.size() == y.size());
      libmesh_assert(start_index < end_index);

      unsigned int n = x.size();
      libmesh_assert(end_index < n);

      libMesh::Real sum_y = 0.0,
        sum_x2 = 0.0,
        sum_x = 0.0,
        sum_xy = 0.0;

      for (unsigned int i=start_index; i<=end_index; i++)
        {
          libMesh::Real xi = x[i];
          libMesh::Real yi = y[i];

          sum_y  += yi;
          sum_x2 += xi*xi;
          sum_x  += xi;
          sum_xy += xi*yi;
        }


      libMesh::Real slope = ( n*sum_xy - sum_x*sum_y )/( n*sum_x2 - (sum_x*sum_x) );
      return slope;
    }

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The documentation for this class was generated from the following file:

• test/common/regression_helper.h