logarithmic_model.cpp
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#include "logarithmic_model.h"
#include "../store.h"
#include "../../poincare/include/poincare_layouts.h"
#include <math.h>
#include <assert.h>
using namespace Poincare;
namespace Regression {
ExpressionLayout * LogarithmicModel::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('l', KDText::FontSize::Small),
new CharLayout('n', KDText::FontSize::Small),
new CharLayout('(', KDText::FontSize::Small),
new CharLayout('X', KDText::FontSize::Small),
new CharLayout(')', KDText::FontSize::Small),
new CharLayout('+', KDText::FontSize::Small),
new CharLayout('b', KDText::FontSize::Small)
};
layout = new HorizontalLayout(layoutChildren, 9, false);
}
return layout;
}
double LogarithmicModel::evaluate(double * modelCoefficients, double x) const {
double a = modelCoefficients[0];
double b = modelCoefficients[1];
return a*log(x)+b;
}
double LogarithmicModel::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 exp((y-b)/a);
}
double LogarithmicModel::partialDerivate(double * modelCoefficients, int derivateCoefficientIndex, double x) const {
if (derivateCoefficientIndex == 0) {
// Derivate: ln(x)
assert(x >0);
return log(x);
}
if (derivateCoefficientIndex == 1) {
// Derivate: 1
return 1;
}
assert(false);
return 0.0;
}
bool LogarithmicModel::dataSuitableForFit(Store * store, int series) const {
if (!Model::dataSuitableForFit(store, series)) {
return false;
}
int numberOfPairs = store->numberOfPairsOfSeries(series);
for (int j = 0; j < numberOfPairs; j++) {
if (store->get(series, 0, j) <= 0) {
return false;
}
}
return true;
}
}