public static Line2 FitLine(IList <Vector2> points)
{
var n = points.Count;
if (n < 2)
{
throw new ArgumentException("At least two points are required to fit a line.");
}
var x = new double[n, 2];
var centroid = Vector2.Centroid(points);
for (int i = 0; i < n; i++)
{
x[i, 0] = points[i].X - centroid.X;
x[i, 1] = points[i].Y - centroid.Y;
}
double[] w;
double[,] u, vt;
const int uNeeded = 0; // don't need left singular vectors
const int vtNeeded = 1; // need first set of right singular vectors
const int extraMemoryAllowedSetting = 2; // it's ok to use more memory for performance
alglib.rmatrixsvd(x, n, 2, uNeeded, vtNeeded, extraMemoryAllowedSetting, out w, out u, out vt);
// because alglib.rmatrixsvd promises to return singular values, w, in descending order, we can be sure that w[0] is the greatest
const int IndexOfGreatestSingularValue = 0;
var a = vt[IndexOfGreatestSingularValue, 0];
var b = vt[IndexOfGreatestSingularValue, 1];
var direction = new Vector2(a, b);
return(Line2.FromPointAndDirection(centroid, direction));
}