Overloaded function CubicSplines

include/ITABase/Spline.h

@@ -82,12 +82,10 @@ namespace ITABase
 		std::vector<float> vdCoefficients;
 	};
 
-	//! Uses splines of given polynomial order to create a piecewise polynomial for the given data pairs
-	ITA_BASE_API CPiecewisePolynomial Spline(const std::vector<float>& vdSupportingPoints, const std::vector<float>& vdDataPoints, const int iPolynomialOrder);
-
-	//! Uses cubic splines to create a piecewise polynomial (order 3) for the given data pairs. vdSupportingPoints need to be sorted in ascending order
-	ITA_BASE_API CPiecewisePolynomial CubicSpline(const std::vector<float>& vdSupportingPoints, const std::vector<float>& vdDataPoints) { return Spline(vdSupportingPoints, vdDataPoints, 3); };
-
+	//! Uses cubic splines to create a piecewise polynomial (order 3) for the given data pairs vdSupportingPoints and vdDataPoints. vdSupportingPoints need to be sorted in ascending order
+	ITA_BASE_API CPiecewisePolynomial CubicSpline(const std::vector<float>& vdSupportingPoints, const std::vector<float>& vdDataPoints);
+	//! Uses cubic splines to create a piecewise polynomial (order 3) for the given data pairs vdSupportingPoints and vdDataPoints. Evaluates that Polynom at vdCostumPoints. vdSupportingPoints need to be sorted in ascending order. 
+	ITA_BASE_API std::vector<float> CubicSpline(const std::vector<float>& vdSupportingPoints, const std::vector<float>& vdDataPoints, const std::vector<float>& vdCostumPoints);
 }
 
 #endif // IW_ITA_BASE_SPLINE

src/ITABase/Spline.cpp

@@ -88,26 +88,27 @@ std::vector<float>::const_iterator ITABase::CPiecewisePolynomial::CoefficientsOf
 	return vdCoefficients.begin() + idxInterval * NumCoefficients();
 }
 
-
-
-CPiecewisePolynomial ITABase::Spline(const std::vector<float>& vdSupportingPoints, const std::vector<float>& vdDataPoints, const int iPolynomialOrder)
+ITA_BASE_API CPiecewisePolynomial ITABase::CubicSpline(const std::vector<float>& vdSupportingPoints, const std::vector<float>& vdDataPoints)
 {
 	/*setUp the bandmatrix M with the the h values. The vector with the coefficent b is called b.
-	The vector with the linear approximations on the right hand side is called r.
-	M * b = r
-	Solve the bandmatrix M with the thomas algorithm and reconstruct the other coefficients according to:
-	https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwjcofWO_IrqAhUux4sKHT52AigQFjABegQIBRAB&url=http%3A%2F
-	out of the b vector.
-	*/
-	if (vdSupportingPoints.size()!= vdDataPoints.size())
+		The vector with the linear approximations on the right hand side is called r.
+		M * b = r
+		Solve the bandmatrix M with the thomas algorithm and reconstruct the other coefficients according to:
+		https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwjcofWO_IrqAhUux4sKHT52AigQFjABegQIBRAB&url=http%3A%2F
+		out of the b vector.
+		*/
+
+	if (vdSupportingPoints.size() != vdDataPoints.size())
 		ITA_EXCEPT_INVALID_PARAMETER("vdSupportingPoints and vdDataPoints need to have the same size");
-	//TODO andere als Ordnung 3
+	if (vdSupportingPoints.size() < 2)
+		ITA_EXCEPT_INVALID_PARAMETER("vdSupportingPoints and vdDataPoints need to contain at least 3 elements");
 
 	//Calculate h_i, formular 1.27b
+	int iPolynomialOrder = 3;
 	int iPoints = vdSupportingPoints.size();
-	std::vector<float> vdH(iPoints-1);
-	
-	for (int i = 0; i < iPoints-1; i++) {
+	std::vector<float> vdH(iPoints - 1);
+
+	for (int i = 0; i < iPoints - 1; i++) {
 		vdH[i] = vdSupportingPoints[i + 1] - vdSupportingPoints[i];
 		if (vdH[i] < 0) {
 			ITA_EXCEPT_INVALID_PARAMETER("vdSupportingPoints needs to be sorted in ascending order");
@@ -116,32 +117,32 @@ CPiecewisePolynomial ITABase::Spline(const std::vector<float>& vdSupportingPoint
 
 	//SetUp the band matrix with lower, middle and upper diagonals. momentary only natural splines
 	std::vector<float> vdLower(iPoints - 3), vdMiddle(iPoints - 2), vdUpper(iPoints - 3);
-	for (int i = 0; i < iPoints - 3;i++) {
+	for (int i = 0; i < iPoints - 3; i++) {
 		vdLower[i] = vdH[i + 1];
 	}
 	vdUpper = vdLower;//TODO: non natural splines behave different -> put it in the loop
-	
-	for (int i = 0; i < iPoints - 2;i++) {
+
+	for (int i = 0; i < iPoints - 2; i++) {
 		vdMiddle[i] = 2 * (vdH[i] + vdH[i + 1]);
 	}
 
 	//excitation vector
 	//TODO only for natural splines with S0=S_iPoints = 0
 	std::vector<float> vdR(iPoints - 2);
-	for (int i = 0; i < iPoints - 2; i++) 
-		vdR[i] = 3 *( (vdDataPoints[i + 2] - vdDataPoints[i + 1]) / vdH[i + 1] - (vdDataPoints[i + 1] - vdDataPoints[i]) / vdH[i]);
+	for (int i = 0; i < iPoints - 2; i++)
+		vdR[i] = 3 * ((vdDataPoints[i + 2] - vdDataPoints[i + 1]) / vdH[i + 1] - (vdDataPoints[i + 1] - vdDataPoints[i]) / vdH[i]);
 
 	//solve bandmatrix and get the other coefficients
-	std::vector<float> vdB = Math::BandmatrixSolver(vdLower,vdMiddle,vdUpper,vdR);
+	std::vector<float> vdB = Math::BandmatrixSolver(vdLower, vdMiddle, vdUpper, vdR);
 	vdB.insert(vdB.begin(), 0.0);
 
 	std::vector<float> vdA(iPoints - 1);
 	std::vector<float> vdC(iPoints - 1);
 	std::vector<float> vdD(iPoints - 1);
-	
+
 	vdB.push_back(0.0);//for ease of loop
 	for (int i = 0; i < iPoints - 1; i++) {
-		vdC[i] = (vdDataPoints[i + 1] - vdDataPoints[i]) / vdH[i] - (vdH[i]/3) * (2 * vdB[i] + vdB[i + 1]);
+		vdC[i] = (vdDataPoints[i + 1] - vdDataPoints[i]) / vdH[i] - (vdH[i] / 3) * (2 * vdB[i] + vdB[i + 1]);
 		vdA[i] = (vdB[i + 1] - vdB[i]) / (3 * vdH[i]);
 	}
 	vdB.pop_back();
@@ -152,14 +153,19 @@ CPiecewisePolynomial ITABase::Spline(const std::vector<float>& vdSupportingPoint
 	int iCoefficients = (iPoints - 1) * (iPolynomialOrder + 1);
 	std::vector<float> vdCoefficients(iCoefficients);
 	int k = 0;
-	for (int k = 0; k < iPoints - 1;k++) {
-		vdCoefficients[4*k] = vdA[k];
-		vdCoefficients[4*k + 1] = vdB[k];
-		vdCoefficients[4*k + 2] = vdC[k];
-		vdCoefficients[4*k + 3] = vdD[k];
+	for (int k = 0; k < iPoints - 1; k++) {
+		vdCoefficients[4 * k] = vdA[k];
+		vdCoefficients[4 * k + 1] = vdB[k];
+		vdCoefficients[4 * k + 2] = vdC[k];
+		vdCoefficients[4 * k + 3] = vdD[k];
 	}
 
 	return CPiecewisePolynomial(vdSupportingPoints, vdCoefficients, iPolynomialOrder);
 }
 
+ITA_BASE_API std::vector<float> ITABase::CubicSpline(const std::vector<float>& vdSupportingPoints, const std::vector<float>& vdDataPoints, const std::vector<float>& vdCostumPoints)
+{
+	CPiecewisePolynomial myPoly = CubicSpline(vdSupportingPoints, vdDataPoints);
+	return myPoly.Value(vdCostumPoints);
+}
  
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