calculateCurve function

List<CurvePoint> calculateCurve(List<DataPoint> dataPoints)

Implementation

List<CurvePoint> calculateCurve(List<DataPoint> dataPoints) {
  List<CurvePoint> curve = [];
  int numPoints = dataPoints.length;
  double x1, x2, x3, y1, y2, y3, a, b, c;

  double rate =
      (dataPoints[1].B - dataPoints[0].B) / (dataPoints[1].A - dataPoints[0].A);
  curve.add(
      CurvePoint(A: 0, B: rate, C: dataPoints[0].B - dataPoints[0].A * rate));

  for (int i = 1; i < numPoints - 1; i++) {
    x1 = dataPoints[i - 1].A;
    x2 = dataPoints[i].A;
    x3 = dataPoints[i + 1].A;
    y1 = dataPoints[i - 1].B;
    y2 = dataPoints[i].B;
    y3 = dataPoints[i + 1].B;
    a = ((y3 - y1) * (x2 - x1) - (y2 - y1) * (x3 - x1)) /
        ((x3 * x3 - x1 * x1) * (x2 - x1) - (x2 * x2 - x1 * x1) * (x3 - x1));
    b = (y2 - y1 - a * (x2 * x2 - x1 * x1)) / (x2 - x1);
    c = y1 - (a * x1 * x1 + b * x1);
    curve.add(CurvePoint(A: a, B: b, C: c));
  }
  curve.add(CurvePoint(A: 0, B: 0, C: dataPoints[numPoints - 1].B));
  return curve;
}