linear_model.cpp
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#include "linear_model.h"
#include "../store.h"
#include "../../poincare/include/poincare_layouts.h"
#include <math.h>
#include <assert.h>
using namespace Poincare;
namespace Regression {
ExpressionLayout * LinearModel::layout() {
static ExpressionLayout * layout = nullptr;
if (layout == nullptr) {
const ExpressionLayout * layoutChildren[] = {
new CharLayout('a', KDText::FontSize::Small),
new CharLayout(Ion::Charset::MiddleDot, KDText::FontSize::Small),
new CharLayout('X', KDText::FontSize::Small),
new CharLayout('+', KDText::FontSize::Small),
new CharLayout('b', KDText::FontSize::Small),
};
layout = new HorizontalLayout(layoutChildren, 5, false);
}
return layout;
}
double LinearModel::evaluate(double * modelCoefficients, double x) const {
double a = modelCoefficients[0];
double b = modelCoefficients[1];
return a*x+b;
}
double LinearModel::levelSet(double * modelCoefficients, double xMin, double step, double xMax, double y, Poincare::Context * context) {
double a = modelCoefficients[0];
double b = modelCoefficients[1];
if (a == 0) {
return NAN;
}
return (y-b)/a;
}
void LinearModel::fit(Store * store, int series, double * modelCoefficients, Poincare::Context * context) {
modelCoefficients[0] = store->slope(series);
modelCoefficients[1] = store->yIntercept(series);
}
double LinearModel::partialDerivate(double * modelCoefficients, int derivateCoefficientIndex, double x) const {
if (derivateCoefficientIndex == 0) {
// Derivate: x
return x;
}
if (derivateCoefficientIndex == 1) {
// Derivate: 1;
return 1;
}
assert(false);
return 0.0;
}
}