Summary:
This indicator script is used to find trends, and may be used as a trailing stop loss based on prices tending to stay within a parabolic curve during a strong trend.
It is based on the concept that unless a trade can continue to generate more profits over time, it should be liquidated.

Calculation:
Complex, see script.

Developer:
J. Welles Wilder, Jr

Interpretation:
1. Increase: When the indicator script is below the underlying symbol price, the price is likely to increase.
2. Decrease: When the indicator script is above the underlying symbol price, the price is likely to decrease.

                    
#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 // Use for the current acceleration amount. private double _acceleration; // Use for the acceleration factor added each time. private double _accelerationFactor; // Use for the current extreme point. private double _extremePoint; // Use for the maximum acceleration factor. private double _maxAcceleration; // Use for the underlying symbol index on which to calculate the indicator. private int _symbolIndex; // Use for indicating whether the symbol is in an up trend or down trend. private bool _upTrend; // Use for the current SAR value. private double _SAR; #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="symbolIndex" type="Symbol" default="">Use for the underlying symbol index on which to calculate the indicator script.</param> /// <param name="accelerationFactor" type="Double" default="0.02">Use for the acceleration factor added each time.</param> /// <param name="maxAcceleration" type="Double" default="0.2">Use for the maximum acceleration factor.</param> public void OnInitialize( int symbolIndex, double accelerationFactor, double maxAcceleration) { // Set the symbol index. _symbolIndex = symbolIndex; // Set the acceleration factor. _accelerationFactor = accelerationFactor; // Set the max acceleration factor. _maxAcceleration = maxAcceleration; // Set the accelration factor. _acceleration = accelerationFactor; // Set the trend to start of as an up trend. _upTrend = true; } #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() < 2) return 0; _SAR = _SAR + _acceleration * (_extremePoint - _SAR); // Calculate the indicator script value for the current bar. if (_upTrend && BarLow(_symbolIndex, 0) < _SAR) { _SAR = _extremePoint; _upTrend = false; _extremePoint = BarHigh(_symbolIndex, 0); _acceleration = _accelerationFactor; } else if (_upTrend == false && BarHigh(_symbolIndex, 0) > _SAR) { _SAR = _extremePoint; _upTrend = true; _extremePoint = BarLow(_symbolIndex, 0); _acceleration = _accelerationFactor; } if (_upTrend) { if (BarHigh(_symbolIndex, 0) > _extremePoint) { _extremePoint = BarHigh(_symbolIndex, 0); if (_acceleration < _maxAcceleration) { _acceleration += _accelerationFactor; } } } else { if (BarLow(_symbolIndex, 0) < _extremePoint) { _extremePoint = BarLow(_symbolIndex, 0); if (_acceleration < _maxAcceleration) { _acceleration += _accelerationFactor; } } } if (_upTrend) { if (_SAR > BarLow(_symbolIndex, 0)) _SAR = BarLow(_symbolIndex, 0); if (_SAR > BarLow(_symbolIndex, 1)) _SAR = BarLow(_symbolIndex, 1); } else { if (_SAR < BarHigh(_symbolIndex, 0)) _SAR = BarHigh(_symbolIndex, 0); if (_SAR < BarHigh(_symbolIndex, 1)) _SAR = BarHigh(_symbolIndex, 1); } return _SAR; } #endregion #region OnChartSetup /// <summary> /// This function is used for setting up the indicator on the chart and registering its pens (see the IndicatorRegisterPen function). /// </summary> public override void OnChartSetup() { // Register a pen. IndicatorRegisterPen(0, "Pen", IQ_Color.ROYAL_BLUE, IQ_DashStyle.SOLID, 2); // Set the indicator plot style. IndicatorChartSetPlotStyle(IQ_PlotStyle.DOT); } #endregion #region OnSelectPen /// <summary> /// This function is used for selecting a registered indicator pen with which to color the latest indicator value. /// Call the IndicatorRegisterPen 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 } }

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