func3 function

({double a, double b, double c}) func3(List<DataPoint> p, double f0(double), double f1(double), double f2(double),)

Fits y = af0(x) + bf1(x) + c*f2(x) to sample data.

Implementation

({double a, double b, double c}) func3(
  List<DataPoint> p,
  double Function(double) f0,
  double Function(double) f1,
  double Function(double) f2,
) {
  var m = 0.0, pp = 0.0, q = 0.0, r = 0.0, s = 0.0;
  var t = 0.0, u = 0.0, v = 0.0, w = 0.0;
  for (final pt in p) {
    final y0 = f0(pt.x);
    final y1 = f1(pt.x);
    final y2 = f2(pt.x);
    m += y0 * y0;
    pp += y0 * y1;
    q += y0 * y2;
    r += y1 * y1;
    s += y1 * y2;
    t += y2 * y2;
    u += pt.y * y0;
    v += pt.y * y1;
    w += pt.y * y2;
  }
  final d = m * r * t + 2 * pp * q * s - m * s * s - r * q * q - t * pp * pp;
  return (
    a: (u * (r * t - s * s) + v * (q * s - pp * t) + w * (pp * s - q * r)) / d,
    b: (u * (s * q - pp * t) + v * (m * t - q * q) + w * (pp * q - m * s)) / d,
    c: (u * (pp * s - r * q) + v * (pp * q - m * s) + w * (m * r - pp * pp)) / d,
  );
}