Trend Factor

TrendFactor.efs  
EFSLibrary - Discussion Board  

File Name: TrendFactor.efs

Description:
Trend Factor

Formula Parameters:

• Length : 10
• Source of Price : Close

Notes:

Download File:
TrendFactor.efs


EFS Code:

/*********************************
Provided By:  
    eSignal (Copyright c eSignal), a division of Interactive Data 
    Corporation. 2009. 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:        
    Trend Factor 
    
Version:            1.0  06/15/2009
 
Formula Parameters:                     Default:
    Length                              10
    Source of Price                     Close
    
Notes:

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

function preMain(){
    setPriceStudy(false);
    setShowCursorLabel(true);
    setShowTitleParameters(false);
    setStudyTitle("Trend Factor");
    setCursorLabelName("Trend Factor", 0);
    setDefaultBarFgColor(Color.black, 0);
    setPlotType(PLOTTYPE_HISTOGRAM, 0);
    setDefaultBarThickness(2, 0);
    var x = 0;
    fpArray[x] = new FunctionParameter("Length", FunctionParameter.NUMBER);
    with(fpArray[x++]) {
        setLowerLimit(1);
        setDefault(10);
    }    
    fpArray[x] = new FunctionParameter("sPrice", FunctionParameter.STRING);
	with(fpArray[x++]){
        setName("Source of Price");
        addOption("open"); 
        addOption("high");
        addOption("low");
        addOption("close");
        addOption("hl2");
        addOption("hlc3");
        addOption("ohlc4"); 
        setDefault("close"); 
    }    
}

var xTF = null;

function main(Length, sPrice) {
var nBarState = getBarState();
var nTF = 0;
    if (nBarState == BARSTATE_ALLBARS) {
        if(Length == null) Length = 10;
        if(sPrice == null) sPrice = "close";
	}
	if (bInit == false) {
        addBand(0, PS_SOLID, 1, Color.black, "Zero");	
        xTF = efsInternal("Calc_TF", Length, sPrice);
        bInit = true;
	}
    nTF = xTF.getValue(0);
    if (nTF == null) return;
    if (nTF > 0) setBarFgColor(Color.green, 0);
    if (nTF < 0) setBarFgColor(Color.red, 0);    
	return nTF;
}

var bSecondInit = false;
var xPriceV = null;

function Calc_TF(Length, sPrice) {
var nRes = 0;
var nRef = ref(-1);
var nTF = 0;
    if (bSecondInit == false) {
        xPriceV = efsInternal("Calc_PriceV", Length, sPrice);
        bSecondInit = true;
    }
    if (xPriceV.getValue(-1) == null) return;
    nTF =0.5 * Math.log((1 + xPriceV.getValue(0))/(1 - xPriceV.getValue(0))) + 0.5 * nRef;
    return nTF;
}

var bThirdInit = false;
var xHH = null;
var xLL = null;
var xPrice = null;

function Calc_PriceV(Length, sPrice) {
var nRes = 0;
var nRef = ref(-1);
var nValue = 0;
    if (bThirdInit == false) {
        xHH = upperDonchian(Length);
        xLL = lowerDonchian(Length);
        xPrice = eval(sPrice)();
        bThirdInit = true;
    }
    if (xPrice.getValue(-2) == null) return;
    nValue=0.33 * 2 * ((xPrice.getValue(0) - xLL.getValue(0)) / (xHH.getValue(0) - xLL.getValue(0)) - 0.5) + 0.67 * nRef;
    nRes= Math.min(Math.max(nValue, -0.999), 0.999);
    return nRes;
}