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eSIGNAL: SWAMICHARTS

For this month’s Traders’ Tip, we’ve provided the formula SwamiCharts_Stochastic.efs based on the code from John Ehlers & Ric Way’s article in this issue, “Introducing SwamiCharts.”

The study contains formula parameters to set the values for the fastest period, lowest period, and line thickness, which may be configured through the Edit Chart window (right-click on the chart and select “edit chart”).

To discuss this study or download complete copies of the formula code, please visit the EFS Library Discussion Board forum under the forums link from the support menu at www.esignal.com or visit our EFS KnowledgeBase at http://www.esignal.com/support/kb/efs/. The eSignal formula script (EFS) is also available below for download or for copying and pasting.

/*********************************
Provided By:  
    Interactive Data Corporation (Copyright © 2012) 
    All rights reserved. This sample eSignal Formula Script (EFS)
    is for educational purposes only. Interactive Data Corporation
    reserves the right to modify and overwrite this EFS file with 
    each new release. 

Description:        
    Introducing SwamiCharts by John Ehlers
	
Version:            1.00  11/01/2012

Formula Parameters:                     Default:
Fastest Period                          6
Lowest Period                           48
Line Thickness                          5

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

**********************************/
var fpArray = new Array();

function preMain () {
    
    setStudyTitle("SwamiCharts_Stochastic");
    
    setShowCursorLabel(false);
           
    setComputeOnClose(true);
    
    var x=0;      
    fpArray[x] = new FunctionParameter("fastPeriod", FunctionParameter.NUMBER);
    with(fpArray[x++])
    {
        setName("Fastest Period");
        setLowerLimit(1);
        setUpperLimit(20);
        setDefault(6);
    }
    
    fpArray[x] = new FunctionParameter("slowPeriod", FunctionParameter.NUMBER);
    with(fpArray[x++])
    {
        setName("Lowest Period");
        setLowerLimit(40);
        setUpperLimit(100);
        setDefault(48);
    }	
    
    fpArray[x] = new FunctionParameter("lineThickness", FunctionParameter.NUMBER);
    with(fpArray[x++])
    {
        setName("Line Thickness");
        setLowerLimit(1);
        setUpperLimit(20);
        setDefault(5);
    }	
}

var bInit = false;
var bVersion = null;

var resArray = null;
var xhhArray = null;
var xllArray = null;
var numArray = null;
var denomArray = null;
var stochArray = null;

function main (fastPeriod, slowPeriod, lineThickness) 
{
    if (bVersion == null) bVersion = verify();
    if (bVersion == false) return;    
	
    if (!bInit) 
    {
        resArray = new Array();         
        xhhArray = new Array();
        xllArray = new Array();
        numArray = new Array();
        denomArray = new Array();
        stochArray = new Array();    
        
        for (var i = fastPeriod; i <= slowPeriod; i++) 
        {
            resArray.push(i);
            
            xhhArray.push(hhv(i, high()));
            xllArray.push(llv(i, low()));                                  
                        
            numArray.push(0);
            denomArray.push(0);
            stochArray.push(0);
            
            setDefaultBarThickness(lineThickness, i - fastPeriod);
	}
				
	bInit = true;
    }

    for (var i = 0; i <= slowPeriod - fastPeriod; i++) 
    {
        var vhh = xhhArray[i].getValue(0);
        var vll = xllArray[i].getValue(0);         
        
        if (vhh == null || vll == null)
            return;
        
	numArray[i] = (close(0) - vll + numArray[i]) / 2;
	denomArray[i] = (vhh - vll + denomArray[i]) / 2;
            
	if (denomArray[i] != 0)
            stochArray[i] = 0.2 * (numArray[i] / denomArray[i]) + 0.8 * stochArray[i];

	var colorR = 255;
	var colorG = 255;
	var colorB = 0;

	if (stochArray[i] > 0.5)
	{
            colorR = 255 * (2 - 2 * stochArray[i]);
	}
	else 
	{
            colorG = 255 * 2 * stochArray[i];
	}
             
	setBarFgColor(Color.RGB(colorR, colorG, colorB), i);
    }

    return resArray;
}


// verify version
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;
}

A sample chart is shown in Figure 2.

FIGURE 2: ESIGNAL, SWAMICHARTS STOCHASTICS

—Jason Keck
eSignal, an Interactive Data company
800 779-6555, www.eSignal.com