Dynamic Momentum Index

#region Namespaces
using System;
#endregion

namespace ScriptCode {
	/// <summary>
	/// Indicator scripts are used for calculating a series of numerical values.
	/// 
	/// This script can be used in several ways:
	/// (1) It can be used on a chart.
	/// (2) It can be used from another script.
	/// (3) It can be used as a script column in a watchlist.
	/// </summary>
	public partial class MyIndicator : IndicatorScriptBase // NEVER CHANGE THE CLASS NAME
	{
#region Variables
		// The indicator on which to calculate the indicator.
		private Indicator _indicator;
		// The number of periods to include in the calculation.
		private int _periods;
		// The smoothed gains.
		private double _gains;
		// The smoothed losses.
		private double _losses;
		// The smoothing factor.
		private double _smoothFactor;
#endregion

#region OnInitialize
		/// <summary>
		/// This function accepts the user parameters for the script and is called when a new indicator instance is created. 
		/// One of the parameters accepted by it must be that of a symbol or another script that is
		/// based on a symbol (drawing, indicator, pattern or signal). This symbol will be used as the underlying symbol for the indicator.
		/// 
		/// The parameter values can be specified from the user interface (UI) or from another script, depending on usage.
		/// </summary>
		/// --------------------------------------------------------------------------------------------------
		/// PLEASE USE THE SCRIPT WIZARD (CTRL+W) TO ADD, EDIT AND REMOVE THE SCRIPT PARAMETERS
		/// --------------------------------------------------------------------------------------------------
		/// YOU MUST SET A PARAM TAG FOR EACH PARAMETER ACCEPTED BY THIS FUNCTION.
		/// ALL PARAM TAGS SHOULD BE SET IN THE 'OnInitialize' REGION, RIGHT ABOVE THE 'OnInitialize' FUNCTION.
		/// THE ORDER OF THE TAGS MUST MATCH THE ORDER OF THE ACTUAL PARAMETERS.

		/// REQUIRED ATTRIBUTES:
		/// (1) name: The exact parameter name.
		/// (2) type: The type of data to collect from the user: 
		/// Set to "Integer" when the data type is 'int'
		/// Set to "IntegerArray" when the data type is 'int[]'
		/// Set to "DateTime" when the data type is 'long'  
		/// Set to "DateTimeArray" when the data type is 'long[]'  
		/// Set to "Boolean" when the data type is 'bool'
		/// Set to "BooleanArray" when the data type is 'bool[]'
		/// Set to "Double" when the data type is 'double'
		/// Set to "DoubleArray" when the data type is 'double[]'
		/// Set to "String" when the data type is 'string'
		/// Set to "StringArray" when the data type is 'string[]'
		/// Set to "Indicator" when the data type is 'Indicator'
		/// Set to "Pattern" when the data type is 'Pattern'
		/// Set to "Signal" when the data type is 'Signal'
		/// Set to "Drawing" when the data type is 'Drawing'
		/// Set to "Symbol" when the data type is 'int' representing a symbol index.

		/// OPTIONAL ATTRIBUTES:
		/// (3) default: The default parameter value is only valid when the type is Integer, Boolean, Double or String. 
		/// (4) min: The minimum parameter value is only valid when the type is Integer or Double.
		/// (5) max: The maximum parameter value is only valid when the type is Integer or Double.

		/// EXAMPLE: <param name="" type="" default="" min="" max="">Enter the parameter description here.</param> 
		/// --------------------------------------------------------------------------------------------------
		/// <param name="indicator" type="Indicator">The indicator on which to calculate the indicator.</param>
		/// <param name="periods" type="Integer" default="14">The number of periods to include in the calculation.</param>
		public void OnInitialize(
			Indicator indicator,
			int periods) {
			// Set the indicator.
			_indicator = indicator;
			// Set the number of periods.
			_periods = periods;
			// Set the smoothing factor.
			_smoothFactor = 1 / (double) _periods;
		}
#endregion

#region OnBarUpdate
		/// <summary>
		/// This function is used for calculating the indicator value for the latest bar (see the Indicator functions).
		/// </summary>
		/// <returns>The indicator value for the latest bar.</returns>
		public override double OnBarUpdate() {
			// Check whether the number of indicator values is lower than the number of values needed.
			if (IndicatorValueCount() < _periods + 1)
				return 0;

			double diff = 0;
			double currentGain = 0;
			double currentLoss = 0;
			// Calculate the indicator value for the current bar. 
			for (int i = _periods - 1; i >= 0; i--) {
				// Calculate the difference between the two values.
				diff = _indicator[i] - _indicator[i + 1];
				// Check whether there was a gain.
				if (diff >= 0) {
					// Set the gain.
					currentGain = diff;
					// Reset the loss.
					currentLoss = 0;
				}
				else {
					// Set the current loss.
					currentLoss = - 1 * diff;
					// Reset the gain.
					currentGain = 0;
				}

				if (_gains != 0 && _gains != 0)
					_gains = (1 - _smoothFactor) * _gains + _smoothFactor * currentGain;
				else
					_gains = currentGain;


				if (_losses != 0 && _losses != 0)
					_losses = (1 - _smoothFactor) * _losses + _smoothFactor * currentLoss;
				else
					_losses = currentLoss;
			}
			// Calculate the DMI value.
			return 100 - (100 / (1 + (_gains / _losses)));
		}
#endregion

#region OnChartSetup
		/// <summary>
		/// This function is used for setting up the indicator on the chart and registering its pens (see the IndicatorChartRegisterPenRGB function).
		/// </summary>
		public override void OnChartSetup() {
			// Register a pen.
			IndicatorChartRegisterPenRGB(0, "Pen",new int[] { 22 ,81, 238, 255 }, C_DashStyle.SOLID, 2);
			// Set the indicator in a new chart panel.
			IndicatorChartSetNewPanel(true);
			// Set the plot style.
			IndicatorChartSetPlotStyle(C_PlotStyle.LINE);
			// Set the indicator range.
			IndicatorChartSetRange(0, 100);
			// Set the overbought range.
			IndicatorChartSetColorZone(70, 100, new int[] {  255, 75, 75, 50 }, new int[] {  255, 75, 75, 255 }, C_DashStyle.SOLID, 2);
			// Set the oversold range.
			IndicatorChartSetColorZone(0, 30, new int[] { 0, 160, 120, 50 }, new int[] { 0, 160, 120, 255 }, C_DashStyle.SOLID, 2);
		}
#endregion

#region OnSelectPen
		/// <summary>
		/// This function is used for selecting a registered indicator pen with which to color the latest indicator value.
		/// Call the IndicatorChartRegisterPenRGB function from the OnChartSetup function in order to register an indicator pen.
		/// </summary>
		/// <returns>The indicator pen index to use for coloring the latest indicator value.</returns>
		public override byte OnSelectPen() {
			// Color the indicator value with the zero pen.
			return 0;
		}
#endregion
	}
}