static public double[] interpolate(double[] arr, int len)
{
int cnt = arr.Length;
mapper map = new mapper(0, cnt - 1, 1, len);
double[] X = new double[cnt], Y = new double[cnt], ans = new double[len];
for (int i = 0; i < cnt; i++)
{
X[i] = map.map(i);
Y[i] = arr[i];
}
var t = FindRegression.Find(X, Y);
Console.Error.WriteLine("LENGTH:" + t.Length);
var f = t[0];
Console.Error.WriteLine("FUNCTION:" + f.Function);
for (int i = 0; i < len; i++)
{
ans[i] = f.GetY(i + 1);
}
return(ans);
}
static Regression[] StrToFun(string str)
=> FindRegression.Find(str.Select((a, i) => (double)i).ToArray(),
str.Select(x => (double)x).ToArray());