Update RSI_Series to check for period != 0 before calculating RSI

Calculations/_Updated/FWMA_Series.cs

@@ -0,0 +1,100 @@
+namespace QuanTAlib;
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using System.Numerics;
+using System.Linq;
+
+/* <summary>
+FWMA: Fibonacci's Weighted Moving Average is similar to a Weighted Moving Average
+		(WMA) where the weights are based on the Fibonacci Sequence.
+
+</summary> */
+public class FWMA_Series : TSeries {
+	private readonly List<double> _buffer = new();
+	private List<double> _weights = new();
+	protected readonly int _period;
+	protected readonly bool _NaN;
+	protected readonly TSeries _data;
+	protected int _len;
+
+	public FWMA_Series(int period, bool useNaN) : base() {
+		_period = period;
+		_NaN = useNaN;
+		Name = $"FWMA({period})";
+		_len = 0;
+		_weights = CalculateWeights(_period);
+	}
+
+	public FWMA_Series(TSeries source, int period, bool useNaN) : this(period, useNaN) {
+		_data = source;
+		Name = Name.Substring(0, Name.IndexOf(")")) + $", {(string.IsNullOrEmpty(_data.Name) ? "data" : _data.Name)})";
+		_data.Pub += Sub;
+		Add(_data);
+	}
+
+	public FWMA_Series() : this(period: 0, useNaN: false) { }
+	public FWMA_Series(int period) : this(period: period, useNaN: false) { }
+	public FWMA_Series(TBars source) : this(source.Close, 0, false) { }
+	public FWMA_Series(TBars source, int period) : this(source.Close, period, false) { }
+	public FWMA_Series(TBars source, int period, bool useNaN) : this(source.Close, period, useNaN) { }
+	public FWMA_Series(TSeries source, int period) : this(source: source, period: period, useNaN: false) { }
+
+	//////////////////
+	// core Add() algo
+	public override (DateTime t, double v) Add((DateTime t, double v) TValue, bool update = false) {
+		BufferTrim(buffer: _buffer, value: TValue.v, period: _period, update: update);
+		if (_period == 0) {
+			_len++;
+			_weights = CalculateWeights(_len);
+		}
+		double _fwma = 0;
+		double totalWeights = _weights.Sum();
+		object lockObj = new object();
+		Parallel.For(0, _buffer.Count, i =>
+		{
+			double temp = _buffer[i] * _weights[i];
+			lock (lockObj) { _fwma += temp; }
+		});
+		_fwma /= totalWeights;
+		var res = (TValue.t, Count < _period - 1 && _NaN ? double.NaN : _fwma);
+		return base.Add(res, update);
+	}
+	public override (DateTime t, double v) Add(TSeries data) {
+		if (data == null) { return (DateTime.Today, Double.NaN); }
+		foreach (var item in data) { Add(item, false); }
+		return _data.Last;
+	}
+	public new (DateTime t, double v) Add((DateTime t, double v) TValue) {
+		return Add(TValue, false);
+	}
+	public (DateTime t, double v) Add(bool update) {
+		return this.Add(TValue: _data.Last, update: update);
+	}
+	public (DateTime t, double v) Add() {
+		return Add(TValue: _data.Last, update: false);
+	}
+	private new void Sub(object source, TSeriesEventArgs e) {
+		Add(TValue: _data.Last, update: e.update);
+	}
+
+	private static List<double> CalculateWeights(int period) {
+		//to prevent overflow, max period can be no more than 1476
+		period = (period > 1476) ? 1476 : period;
+		List<double> weights = new List<double>(period);
+		BigInteger a = 0;
+		BigInteger b = 1;
+		for (int i = 0; i < period; i++) {
+			BigInteger temp = a;
+			a = b;
+			b = temp + b;
+			weights.Add((double)Decimal.Parse(a.ToString()));
+		}
+		return weights;
+	}
+
+	public override void Reset() {
+		_weights = CalculateWeights(_period);
+		_buffer.Clear();
+	}
+}