2002 Jul: Zero-Lag Data Smoothers, by John Ehlers

[eSignal]

File Name: AdjustableLagFltr.efs

Description:
Zero-Lag Data Smoothers, by John Ehlers

Formula Parameters:
Lag Reduction: 1.5
Line Thickness: 2
Line Color: Green
Display Cursor Labels: True


Notes:
The related article is copyrighted material. If you are not
a subscriber of Stocks & Commodities, please visit www.traders.com.


Download File:
AdjustableLagFltr.efs



EFS Code:

/*********************************
Provided By:  
    eSignal (Copyright c eSignal), a division of Interactive Data 
    Corporation. 2008. All rights reserved. This sample eSignal 
    Formula Script (EFS) is for educational purposes only and may be 
    modified and saved under a new file name.  eSignal is not responsible
    for the functionality once modified.  eSignal reserves the right 
    to modify and overwrite this EFS file with each new release.

Description:        
    Zero-Lag Data Smoothers, by John Ehlers 

Version:            1.0  12/05/2008

Formula Parameters:                     Default:
    Lag Reduction                       1.5
    Line Thickness                      2
    Line Color                          Green
    Display Cursor Labels               True
    
Notes:
    The related article is copyrighted material. If you are not
    a subscriber of Stocks & Commodities, please visit [url]www.traders.com.[/url]
**********************************/

var fpArray = new Array();
var bInit = false;
var bVersion = null;

function preMain() {
    setPriceStudy(true);
    setShowCursorLabel(false);
    setShowTitleParameters( false );
    setStudyTitle("Adjustable Lag Fltr");
    setCursorLabelName("ALF", 0);
    setDefaultBarFgColor(Color.red, 0);
    setPlotType(PLOTTYPE_LINE, 0); 
    setDefaultBarThickness(2, 0);

    askForInput();
    var x=0;
    fpArray[x] = new FunctionParameter("LineColor", FunctionParameter.COLOR);
    with(fpArray[x++]){
        setName("Line Color");
        setDefault(Color.green);
    }    
    fpArray[x] = new FunctionParameter("ViewValue", FunctionParameter.BOOLEAN);
    with(fpArray[x++]){
        setName("Display Cursor Labels");
        setDefault(true);
    }    
    fpArray[x] = new FunctionParameter("LagReduction", FunctionParameter.NUMBER);
    with(fpArray[x++]){
        setName("Lag Reduction");
        setLowerLimit(0.01);        
        setDefault(1.5);
    }
    fpArray[x] = new FunctionParameter("Thickness", FunctionParameter.NUMBER);
    with(fpArray[x++]){
        setName("Line Thickness");
        setLowerLimit(1);        
        setDefault(2);
    }
}

var nDenominator = 0;
var aCoeff = new Array(7);

function main(LagReduction, Thickness, LineColor, ViewValue) {
var nNumerator = 0;
var nFilter = 0;
    if (bVersion == null) bVersion = verify();
    if (bVersion == false) return;   

    if ( bInit == false ) { 
        setDefaultBarFgColor(LineColor, 0);
        setDefaultBarThickness(Thickness, 0);
        setShowCursorLabel(ViewValue);        
        bInit = true; 
    } 

    if (getCurrentBarCount() == 1) {
        aCoeff[1] = 1;
        aCoeff[2] = 2 + LagReduction;
        aCoeff[3] = 3 + LagReduction;
        aCoeff[4] = 3;
        aCoeff[5] = 2 - LagReduction;
        aCoeff[6] = 1 - LagReduction;
        aCoeff[7] = 0 - LagReduction;
        nDenominator = SummationArray(aCoeff, 7);
    }

    nNumerator = 0 ;
    for (var nValue1 = 1; nValue1 <= 7; nValue1++) {
        nNumerator += aCoeff[nValue1] * close(-nValue1 + 1);
    }
 
    nFilter = nNumerator / nDenominator ;
    return nFilter; 
}

function SummationArray(aArray, nLength){
var nRes = 0;
    for (var i = 1; i <= nLength; i++) {
           nRes += aArray[i]; 
    } 
    if (nRes == null) nRes = 1;
    return nRes;
}

function verify() {
    var b = false;
    if (getBuildNumber() < 779) {
        drawTextAbsolute(5, 35, "This study requires version 8.0 or later.", 
            Color.white, Color.blue, Text.RELATIVETOBOTTOM|Text.RELATIVETOLEFT|Text.BOLD|Text.LEFT,
            null, 13, "error");
        drawTextAbsolute(5, 20, "Click HERE to upgrade.@URL=http://www.esignal.com/download/default.asp", 
            Color.white, Color.blue, Text.RELATIVETOBOTTOM|Text.RELATIVETOLEFT|Text.BOLD|Text.LEFT,
            null, 13, "upgrade");
        return b;
    } else {
        b = true;
    }
    return b;
}