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[apps/regression] Set coefficient c initial value to 0

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This commit is contained in:
Hugo Saint-Vignes
2020-12-09 14:36:44 +01:00
committed by LeaNumworks
parent fe4e2e3e9d
commit d0f40f0177
1 changed files with 7 additions and 4 deletions
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11
apps/regression/model/trigonometric_model.cpp
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@@ -73,9 +73,6 @@ double TrigonometricModel::partialDerivate(double * modelCoefficients, int deriv
void TrigonometricModel::specializedInitCoefficientsForFit(double * modelCoefficients, double defaultValue, Store * store, int series) const {
assert(store != nullptr && series >= 0 && series < Store::k_numberOfSeries && !store->seriesIsEmpty(series));
for (int i = 1; i < k_numberOfCoefficients - 1; i++) {
modelCoefficients[i] = defaultValue;
}
/* We try a better initialization than the default value. We hope that this
* will improve the gradient descent to find correct coefficients.
*
@@ -88,6 +85,7 @@ void TrigonometricModel::specializedInitCoefficientsForFit(double * modelCoeffic
modelCoefficients[k_numberOfCoefficients - 1] = store->meanOfColumn(series, 1);
// Init the b coefficient
double rangeX = store->maxValueOfColumn(series, 0) - store->minValueOfColumn(series, 0);
double radian = toRadians(Poincare::Preferences::sharedPreferences()->angleUnit());
if (rangeX > 0) {
/* b/2π represents the frequency of the sine (in radians). Instead of
* initializing it to 0, we use the inverse of X series' range as an order
@@ -95,9 +93,14 @@ void TrigonometricModel::specializedInitCoefficientsForFit(double * modelCoeffic
* data with a very high frequency. This period also depends on the
* angleUnit. We take it into account so that it doesn't impact the result
* (although coefficients b and c depends on the angleUnit). */
double radian = toRadians(Poincare::Preferences::sharedPreferences()->angleUnit());
modelCoefficients[1] = (2.0 * M_PI / radian) / rangeX;
} else {
// Coefficient b must not depend on angleUnit.
modelCoefficients[1] = defaultValue * M_PI / radian;
}
/* No shift is assumed, coefficient c is set to 0.
* If it were to be non-null, angleUnit must be taken into account. */
modelCoefficients[2] = 0.0 * M_PI / radian;
}
Expression TrigonometricModel::expression(double * modelCoefficients) {