protected internal override double doFirstDerivative(double xValue)
{
int lowerIndex = lowerBoundIndex(xValue, xValues);
int higherIndex = lowerIndex + 1;
RealPolynomialFunction1D[] quadFirstDerivative = quadraticsFirstDerivative_Renamed.get();
// at start of curve, or only one interval
if (lowerIndex == 0 || intervalCount == 1)
{
RealPolynomialFunction1D quadraticFirstDerivative = quadFirstDerivative[0];
double x = xValue - xValues[1];
return(quadraticFirstDerivative.applyAsDouble(x));
}
// at end of curve
if (higherIndex >= intervalCount)
{
RealPolynomialFunction1D quadraticFirstDerivative = quadFirstDerivative[intervalCount - 2];
double x = xValue - xValues[intervalCount - 1];
return(quadraticFirstDerivative.applyAsDouble(x));
}
RealPolynomialFunction1D quadratic1 = quadratics_Renamed[lowerIndex - 1];
RealPolynomialFunction1D quadratic2 = quadratics_Renamed[higherIndex - 1];
RealPolynomialFunction1D quadratic1FirstDerivative = quadFirstDerivative[lowerIndex - 1];
RealPolynomialFunction1D quadratic2FirstDerivative = quadFirstDerivative[higherIndex - 1];
double w = WEIGHT_FUNCTION.getWeight((xValues[higherIndex] - xValue) / (xValues[higherIndex] - xValues[lowerIndex]));
return(w * quadratic1FirstDerivative.applyAsDouble(xValue - xValues[lowerIndex]) + (1 - w) * quadratic2FirstDerivative.applyAsDouble(xValue - xValues[higherIndex]) + (quadratic2.applyAsDouble(xValue - xValues[higherIndex]) - quadratic1.applyAsDouble(xValue - xValues[lowerIndex])) / (xValues[higherIndex] - xValues[lowerIndex]));
}
//-------------------------------------------------------------------------
protected internal override double doInterpolate(double xValue)
{
// x-value is less than the x-value of the last node (lowerIndex < intervalCount)
int lowerIndex = lowerBoundIndex(xValue, xValues);
int higherIndex = lowerIndex + 1;
// at start of curve
if (lowerIndex == 0)
{
RealPolynomialFunction1D quadratic = quadratics_Renamed[0];
double x = xValue - xValues[1];
return(quadratic.applyAsDouble(x));
}
// at end of curve
if (higherIndex == intervalCount)
{
RealPolynomialFunction1D quadratic = quadratics_Renamed[intervalCount - 2];
double x = xValue - xValues[intervalCount - 1];
return(quadratic.applyAsDouble(x));
}
// normal case
RealPolynomialFunction1D quadratic1 = quadratics_Renamed[lowerIndex - 1];
RealPolynomialFunction1D quadratic2 = quadratics_Renamed[higherIndex - 1];
double w = WEIGHT_FUNCTION.getWeight((xValues[higherIndex] - xValue) / (xValues[higherIndex] - xValues[lowerIndex]));
return(w * quadratic1.applyAsDouble(xValue - xValues[lowerIndex]) + (1 - w) * quadratic2.applyAsDouble(xValue - xValues[higherIndex]));
}
protected internal override DoubleArray doParameterSensitivity(double xValue)
{
int lowerIndex = lowerBoundIndex(xValue, xValues);
int higherIndex = lowerIndex + 1;
int n = xValues.Length;
double[] result = new double[n];
// at start of curve
if (lowerIndex == 0)
{
double[] temp = quadraticSensitivities(xValues, xValue, 1);
result[0] = temp[0];
result[1] = temp[1];
result[2] = temp[2];
return(DoubleArray.ofUnsafe(result));
}
// at end of curve
if (higherIndex == intervalCount)
{
double[] temp = quadraticSensitivities(xValues, xValue, n - 2);
result[n - 3] = temp[0];
result[n - 2] = temp[1];
result[n - 1] = temp[2];
return(DoubleArray.ofUnsafe(result));
}
// at last node
if (lowerIndex == intervalCount)
{
result[n - 1] = 1;
return(DoubleArray.ofUnsafe(result));
}
double[] temp1 = quadraticSensitivities(xValues, xValue, lowerIndex);
double[] temp2 = quadraticSensitivities(xValues, xValue, higherIndex);
double w = WEIGHT_FUNCTION.getWeight((xValues[higherIndex] - xValue) / (xValues[higherIndex] - xValues[lowerIndex]));
result[lowerIndex - 1] = w * temp1[0];
result[lowerIndex] = w * temp1[1] + (1 - w) * temp2[0];
result[higherIndex] = w * temp1[2] + (1 - w) * temp2[1];
result[higherIndex + 1] = (1 - w) * temp2[2];
return(DoubleArray.ofUnsafe(result));
}
