Upper-Lower Pro Band.

[eSignal]

File Name: Upper_LowerProBand.efs

Description:
Upper-Lower Pro Band

Formula Parameters:
Length: 14

Notes:
Bands define the upper and lower boundaries of a security's normal trading
range. A sell signal is generated when the security reaches the upper band
whereas a buy signal is generated at the lower band. The optimum percentage
shift depends on the volatility of the security--the more volatile, the larger
the percentage.


Download File:
Upper_LowerProBand.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:        
    Upper-Lower Pro Band

Version:            1.0  10/04/2008

Notes:
    Bands define the upper and lower boundaries of a security's normal trading
    range. A sell signal is generated when the security reaches the upper band
    whereas a buy signal is generated at the lower band. The optimum percentage
    shift depends on the volatility of the security--the more volatile, the larger
    the percentage.

Formula Parameters:                     Default:
    Length                                14

**********************************/

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

function preMain(){
    setPriceStudy(true);
    setStudyTitle("Upper-Lower Pro Band");
    setCursorLabelName("PU", 0);
    setCursorLabelName("PL", 1);
    setDefaultBarFgColor(Color.blue, 0);
    setDefaultBarFgColor(Color.red, 1);
   

    var x=0;    
    fpArray[x] = new FunctionParameter("Length", FunctionParameter.NUMBER);
    with(fpArray[x++]){
        setLowerLimit(1);  
        setDefault(14);
    }
}

var xUpper = null;
var xLower = null;

function main(Length) {
var nState = getBarState();
var nUpper = 0;
var nLower = 0;

    if (nState == BARSTATE_ALLBARS) {
        if (Length == null) Length = 14;
    }


    if ( bInit == false ) { 
    var SumBars = Length * (Length - 1) * .5;
    var SumSqrBars = (Length - 1) * Length * (2 * Length - 1) / 6;
        xUpper = efsInternal("Calc_Upper", Length, SumBars, SumSqrBars);
        xLower = getSeries(xUpper,1);        
        bInit = true; 
    } 

    nUpper = xUpper.getValue(0);
    nLower = xLower.getValue(0);

    if (nUpper == null || nLower == null) return;

    return new Array (nUpper, nLower);
}



var xInit = false;
var xHigh = null;
var xLow = null;


function Calc_Upper(Length, SumBars, SumSqrBars){
var SH = 0.0;
var Sum1_2 = 0.0;
var SumY2 = 0.0;
var SL = 0.0;
var Sum1_1 = 0.0;
var SumY1 = 0.0;
var i = 0;

    if(xInit==false){
        xHigh = high();
        xLow = low();
        xInit = true;
    }

    if(xHigh.getValue(-Length) == null || xLow.getValue(-Length) == null) return;

    for (i = 0; i < Length; i++){
        Sum1_2 += i * xHigh.getValue(-i);
        SumY2 += xHigh.getValue(-i);
        Sum1_1 += i * xLow.getValue(-i);
        SumY1 += xLow.getValue(-i);
    } 

    var Sum2_2 = SumBars * SumY2;
    var Num1_2 = Length * Sum1_2 - Sum2_2;
    var Sum2_1 = SumBars * SumY1;
    var Num1_1 = Length * Sum1_1 - Sum2_1;
    var Num2 = SumBars * SumBars - Length * SumSqrBars;

    SH = Num1_2 / Num2;
    SL = Num1_1 / Num2;

    var Value3 = 0.0;
    var PU = 0.0;
    var Value2 = 0.0;
    var PL = 0.0;

    for (i = 1; i <= Length; i++){
        Value3=xHigh.getValue(-i + 1) + (SH * (i - 1));
        Value2=xLow.getValue(-i + 1) + (SL * (i - 1));
        if (i == 1){
            PU=Value3;
            PL=Value2;
        }
        if (Value3 > PU) PU = Value3;
        if (Value2 < PL) PL = Value2;
    }

 
    return new Array (PU, PL);
}