/*********************************************************
Alexis C. Montenegro © September 2005                     
Use and/or modify this code freely. If you redistribute it
please include this and/or any other comment blocks and a 
description of any changes you make.                      
**********************************************************/

var fpArray = new Array();

function preMain(){
    setPriceStudy(false);
    setStudyTitle("Correlation");
    setCursorLabelName("Corr");
    setPlotType(PLOTTYPE_LINE);
    setDefaultBarFgColor(Color.blue);
    var x=0;
    fpArray[x] = new FunctionParameter("Symbol1", FunctionParameter.STRING);
    with(fpArray[x++]){
        setDefault();
	}
	fpArray[x] = new FunctionParameter("Symbol2", FunctionParameter.STRING);
    with(fpArray[x++]){
        setDefault("$INDU");
	}
	fpArray[x] = new FunctionParameter("Source", FunctionParameter.STRING);
	with(fpArray[x++]){
        addOption("open"); 
        addOption("high");
        addOption("low");
        addOption("close");
        addOption("hl2");
        addOption("hlc3");
        addOption("ohlc4"); 
        setDefault("close"); 
    }
    fpArray[x] = new FunctionParameter("Length", FunctionParameter.NUMBER);
	with(fpArray[x++]){
        setLowerLimit(1);		
        setDefault(25);
    }
    fpArray[x] = new FunctionParameter("Params", FunctionParameter.BOOLEAN);
	with(fpArray[x++]){
        setName("Show Parameters");
        setDefault(true);
    }
}

var bInit = false;
var Ind = null;
var Dep = null;

function main(Symbol1,Symbol2,Source,Length,Params){
    if(bInit==false){
        if(Symbol1==null) Symbol1 = getSymbol();
        Ind = eval(Source)(sym(Symbol1));
        Dep = eval(Source)(sym(Symbol2));
        addBand(0,PS_SOLID,1,Color.black,"0");
        setShowTitleParameters(eval(Params));
        bInit=true;
    }
    var Counter1 = 0;
    var Counter2 = 0;
    var Correlation = 0;
    for (var i=0; i<Length; i++){
        if (Ind.getValue(-i)>=Ind.getValue(-(i+1)) && Dep.getValue(-i)>=Dep.getValue(-(i+1)) ||
            Ind.getValue(-i)<Ind.getValue(-(i+1)) && Dep.getValue(-i)<Dep.getValue(-(i+1))){
                Counter1 += 1;
        } else {
                Counter2 += 1;
        }
    }
    if (Counter1+Counter2>0){
        Correlation = (Counter1 - Counter2) / (Counter1 + Counter2)
    } else {
        Correlation = 0;
    }
    return Correlation;
}