Files
QuanTAlib/Source/Statistics/KURTOSIS_Series.cs
T
Miha Kralj 73e3420379 COVAR
semver fix


VAR test fix


new: COVAR, ZSCORE, CORR, LINREG


versioning


refactoring
2022-11-17 11:05:20 -08:00

57 lines
2.2 KiB
C#

namespace QuanTAlib;
using System;
using System.Linq;
/* <summary>
KURT: Kurtosis of population
Kurtosis characterizes the relative peakedness or flatness of a distribution
compared with the normal distribution. Positive kurtosis indicates a relatively
peaked distribution. Negative kurtosis indicates a relatively flat distribution.
The normal curve is called Mesokurtic curve. If the curve of a distribution is
more outlier prone (or heavier-tailed) than a normal or mesokurtic curve then
it is referred to as a Leptokurtic curve. If a curve is less outlier prone (or
lighter-tailed) than a normal curve, it is called as a platykurtic curve.
Calculation:
sum4 = Σ(close-SMA)^4
sum2 = (Σ(close-SMA)^2)^2
KURT = length * (sum4/sum2)
Sources:
https://en.wikipedia.org/wiki/Kurtosis
https://stats.oarc.ucla.edu/other/mult-pkg/faq/general/faq-whats-with-the-different-formulas-for-kurtosis/
</summary> */
public class KURTOSIS_Series : Single_TSeries_Indicator
{
public KURTOSIS_Series(TSeries source, int period, double logbase = 2.0, bool useNaN = false) : base(source, period, useNaN)
{
this._logbase = logbase;
if (base._data.Count > 0) { base.Add(base._data); }
}
protected double _logbase;
private readonly System.Collections.Generic.List<double> _buffer = new();
public override void Add((System.DateTime t, double v) TValue, bool update)
{
Add_Replace_Trim(_buffer, TValue.v, _p, update);
double _n = this._buffer.Count;
double _avg = _buffer.Average();
double _s2 = 0;
double _s4 = 0;
for (int i = 0; i < this._buffer.Count; i++)
{
_s2 += (_buffer[i] - _avg) * (_buffer[i] - _avg);
_s4 += (_buffer[i] - _avg) * (_buffer[i] - _avg) * (_buffer[i] - _avg) * (_buffer[i] - _avg);
}
double _Vx = _s2 / (_n - 1);
double _kurt = (_n > 3) ? ((((_n * (_n + 1)) / (((_n - 1) * (_n - 2)) * (_n - 3))) * (_s4 / (_Vx * _Vx))) - (3 * (((_n - 1) * (_n - 1)) / ((_n - 2) * (_n - 3))))) : Double.NaN;
var result = (TValue.t, (this.Count < this._p - 1 && this._NaN) ? Double.NaN : _kurt);
base.Add(result, update);
}
}