/*******************************************************************
Provided By	: TS Support, LLC for eSignal. (c) Copyright 2002  
********************************************************************/
// Tweaked to fix drift - Garth Doverspike 8/3/03

function preMain()
{
    setStudyTitle("Demand Index - tweaked(b)");
    setCursorLabelName("Demand Index", 0);
    setDefaultBarFgColor(Color.red, 0);
    addBand(0, PS_SOLID, 1, Color.black);
    setDefaultBarThickness(1, 0);
    setDefaultBarThickness(1, 1);
    setPlotType(PLOTTYPE_LINE,0);
    setPlotType(PLOTTYPE_HISTOGRAM,1);
}

vAvgTR = new Array();
var VolAvg_1 = 0;
var WghtClose_1 = 0;
var BuyPres_1 = 0;
var SellPres_1 = 0;

//Start Tweak [Garth] - make global so that we can get the values
var WghtClose = 0;
var BuyPres = 1;  
var SellPres = 1;
var VolAvg = 0;
//End Tweak

var DMI = 1;//added by ACM
var DMI_1 = null;//added by ACM
//var DMI_2 = null;
var vFlag=0;

function main(Length) {
	if(Length == null)
		Length = 5;
    	var i;
    	var vSum = 0.0;
    	var hh2, ll2;
    	
    // Start Tweak - moved up from end of study so that end of bar
    // values are used.
    if (getBarState() == BARSTATE_NEWBAR){
		WghtClose_1 = WghtClose;
		DMI_2 = DMI_1;
		DMI_1 = DMI;//added by ACM
		vFlag=0;
		if(getCurrentBarIndex() - getOldestBarIndex() > 5){
			BuyPres_1 = BuyPres;
			SellPres_1 = SellPres;
		}
		VolAvg_1 = VolAvg;
	}
	VolAvg = volume(0);
	WghtClose = 0;
	BuyPres = 1;
	SellPres = 1;
	// End Tweak
	
	var  WtCRatio = 1, VolRatio = 1, BuyP = 1, SellP = 1, Sign = 1, Constant = 1, TempDI = 1,  AvgTR = high(0) - low(0); 
	if(getCurrentBarIndex() - getOldestBarIndex() == 1){
		for(i = -Length + 1; i >= 0; i++)
        		vSum += volume(i);
		VolAvg = vSum / Length;
		
	}
	WghtClose = (high(0) + low() + 2 * close()) * .25;
	if(high() > high(-1))
		hh2 = high(0);
	else
		hh2 = high(-1);
	if(low(0) < low(-1))
		ll2 = low(0);
	else
		ll2 = low(-1);
	if (getBarState() == BARSTATE_NEWBAR){
		for(i = Length - 2; i >= 0; i--)
			vAvgTR[i + 1] = vAvgTR[i]
		vAvgTR[0] = hh2 - ll2;
	}
	vSum = 0;
	for(i = 0; i < Length; i++)
		vSum += vAvgTR[i]
	AvgTR = vSum / Length;
	VolAvg = ((VolAvg_1 * (Length - 1)) + volume(0)) / Length;
	if(WghtClose != 0 && WghtClose_1 != 0 && AvgTR != 0 && VolAvg != 0){
		WtCRatio = (WghtClose - WghtClose_1) / Math.min(WghtClose, WghtClose_1) ; 
        	VolRatio = volume(0) / VolAvg; 
        	Constant   = ((WghtClose * 3) / AvgTR) * Math.abs(WtCRatio); 
		if(Constant > 88)
			Constant = 88;
		Constant   = VolRatio / Math.exp(Constant);
        	if(WtCRatio > 0){
	            BuyP = VolRatio; 
         	    SellP = Constant; 
        	}
        	else{
                    BuyP = Constant; 
        	    SellP = VolRatio; 
        	}
        	
		BuyPres = ((BuyPres_1 * (Length - 1)) + BuyP) / Length; 
        	SellPres = ((SellPres_1 * (Length - 1)) + SellP) / Length; 
		TempDI   =  +1; 

        	if(SellPres  > BuyPres){
                    Sign  =  -1; 
            	    if(SellPres != 0)
            	    	TempDI = BuyPres / SellPres; 
        	}
        	else{
        	     Sign  =  +1; 
            	     if(BuyPres != 0)
            	     	TempDI = SellPres / BuyPres; 
        	}
	
		TempDI = TempDI * Sign; 
        	if(TempDI < 0)
	                DMI = -1 - TempDI; 
        	else 
                	DMI = +1 - TempDI; 
		}
		
		if(vFlag==0){
            if(DMI_1<0.5 && DMI>=0.5||DMI_1>0.5 && DMI<=0.5){
                Alert.playSound("ding.wav");
                vFlag=1;
            }
        }
		
	
        return new Array(DMI,DMI); 

}