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emulateur/epsilon-nofrendo/apps/regression/model/exponential_model.cpp 1.79 KB
6663b6c9   adorian   projet complet av...
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  #include "exponential_model.h"
  #include <math.h>
  #include <assert.h>
  #include "../../poincare/include/poincare_layouts.h"
  
  using namespace Poincare;
  
  namespace Regression {
  
  ExpressionLayout * ExponentialModel::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('e', KDText::FontSize::Small),
        new VerticalOffsetLayout(
            new HorizontalLayout(
              new CharLayout('b', KDText::FontSize::Small),
              new CharLayout(Ion::Charset::MiddleDot, KDText::FontSize::Small),
              new CharLayout('X', KDText::FontSize::Small),
              false),
            VerticalOffsetLayout::Type::Superscript,
            false)
      };
      layout = new HorizontalLayout(layoutChildren, 4, false);
    }
    return layout;
  }
  
  double ExponentialModel::evaluate(double * modelCoefficients, double x) const {
    double a = modelCoefficients[0];
    double b = modelCoefficients[1];
    return a*exp(b*x);
  }
  
  double ExponentialModel::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 || b == 0 || y/a <= 0) {
      return NAN;
    }
    return log(y/a)/b;
  }
  
  double ExponentialModel::partialDerivate(double * modelCoefficients, int derivateCoefficientIndex, double x) const {
    double a = modelCoefficients[0];
    double b = modelCoefficients[1];
    if (derivateCoefficientIndex == 0) {
      // Derivate: exp(b*x)
      return exp(b*x);
    }
    if (derivateCoefficientIndex == 1) {
      // Derivate: a*x*exp(b*x)
      return a*x*exp(b*x);
    }
    assert(false);
    return 0.0;
  }
  
  }