#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Weffc++"
#include "simplelinearregression.h"
#include <cassert>
#include <iostream>
#include <numeric>
#include <stdexcept>
#include <sstream>
#include "testtimer.h"
#include "trace.h"
#pragma GCC diagnostic pop
double ribi::SimpleLinearRegression::CalculateCovariance(
const std::vector<double>& xs,
const std::vector<double>& ys)
{
assert(xs.size() == ys.size());
const std::size_t sz { xs.size() };
std::vector<double> ps(sz);
for (std::size_t i=0; i!=sz; ++i)
{
ps[i] = xs[i] * ys[i];
}
const double mean_x { CalculateMean(xs) };
const double mean_y { CalculateMean(ys) };
const double mean_p { CalculateMean(ps) };
return mean_p - (mean_x * mean_y);
}
double ribi::SimpleLinearRegression::CalculateVariance(
const std::vector<double>& v)
{
assert(!v.empty());
const double mean { CalculateMean(v) };
const double mean_of_squares {
std::accumulate(v.begin(),v.end(),0.0,
[](const double init, const double x)
{
return init + (x * x);
}
) / static_cast<double>(v.size())
};
return mean_of_squares - (mean * mean);
}
std::vector<double> ribi::SimpleLinearRegression::GetAnscombesQuartetX(const int index)
{
switch (index)
{
case 1:
case 2:
case 3:
return { 10.0,8.0,13.0,9.0,11.0,14.0,6.0,4.0,12.0,7.0,5.0 };
case 4:
return { 8.0,8.0,8.0,8.0,8.0,8.0,8.0,19.0,8.0,8.0,8.0 };
default:
{
std::stringstream s;
s << "ERROR ("
<< __func__
<< "): Anscombe's Quartet has index 1 to and including 4, given index is: "
<< index;
std::cerr << s << std::endl;
assert(!"Should not get here: ");
throw std::logic_error(s.str());
}
}
}
std::vector<double>
ribi::SimpleLinearRegression::GetAnscombesQuartetY(const int index)
{
switch (index)
{
case 1:
return { 8.04,6.95,7.58,8.81,8.33,9.96,7.24,4.26,10.84,4.82,5.68 };
case 2:
return { 9.14,8.14,8.74,8.77,9.26,8.1,6.13,3.1,9.13,7.26,4.74 };
case 3:
return { 7.46,6.77,12.74,7.11,7.81,8.84,6.08,5.39,8.15,6.42,5.73 };
case 4:
return { 6.58,5.76,7.71,8.84,8.47,7.04,5.25,12.5,5.56,7.91,6.89 };
default:
{
std::stringstream s;
s << "ERROR ("
<< __func__
<< "): Anscombe's Quartet has index 1 to and including 4, given index is: "
<< index;
std::cerr << s << std::endl;
assert(!"Should not get here: ");
throw std::logic_error(s.str());
}
}
}
std::string ribi::SimpleLinearRegression::GetVersion() noexcept
{
return "1.1";
}
std::vector<std::string> ribi::SimpleLinearRegression::GetVersionHistory() noexcept
{
std::vector<std::string> v {
"2013-08-27: version 1.0: initial version, as ToolTestSimpleLinearRegressionMainDialog",
"2013-08-28: version 1.1: renamed to SimpleLinearRegression, templated CalculateBestFit",
};
return v;
}
#ifndef NDEBUG
void ribi::SimpleLinearRegression::Test() noexcept
{
{
static bool is_tested { false };
if (is_tested) return;
is_tested = true;
}
const TestTimer test_timer(__func__,__FILE__,1.0);
{
const std::vector<double> v { 75.0, 83.0, 96.0, 100.0, 121.0, 125.0 };
const double variance { CalculateVariance(v) };
const double expected { 332.666667 };
assert(std::abs(variance - expected) < 0.0001);
}
{
const std::vector<double> v { 0.23, 0.37, 0.45, 0.49, 0.56, 0.63, 0.63, 0.70, 0.72, 0.82 };
const double variance { CalculateVariance(v) };
const double expected { 0.02846 };
assert(std::abs(variance - expected) < 0.0001);
}
for (int i=1; i!=5; ++i) //Human-based counting, following the Ansombe's Quartet indices
{
const std::vector<double> xs { GetAnscombesQuartetX(i) };
const std::vector<double> ys { GetAnscombesQuartetY(i) };
const std::pair<double,double> p { CalculateBestFit(xs,ys) };
const double mean_x { CalculateMean(xs) };
const double mean_y { CalculateMean(ys) };
const double slope { p.first };
const double intercept { p.second };
//const double variance_x = CalculateVariance(xs);
//const double variance_y = CalculateVariance(ys);
const double expected_mean_x { 9.0 };
const double expected_mean_y { 7.5 }; //to 2 decimal places
const double expected_slope { 0.500 }; //to 3 decimal places
const double expected_intercept { 3.00 }; //to 2 decimal places
const double e { 0.01 };
assert(std::abs(expected_mean_x - mean_x) < e);
assert(std::abs(expected_mean_y - mean_y) < e);
//const double expected_variance_x = 11.0;
//const double expected_variance_y = 4.125; //4.122 or 4.127 (to 3 decimal places)
//const double expected_correlation = 0.816; //to 3 decimal places)
//assert(std::abs(expected_variance_x - variance_x) < e);
//assert(std::abs(expected_variance_y - variance_y) < e);
assert(std::abs(expected_slope - slope) < e);
assert(std::abs(expected_intercept - intercept) < e);
}
}
#endif
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