function preMain() {
     
    setDefaultBarFgColor(Color.yellow , 0); // %K
    setDefaultBarFgColor(Color.cyan , 1); // %D
    
}

function main(inputLength, inputSmoothingK, inputSmoothingD) {
    if(inputLength == null)
        inputLength = 15;
    if(inputSmoothingK == null)
        inputSmoothingK = 3;
    if(inputSmoothingD == null)
        inputSmoothingD = 5;
  
    var nOffset = 0;
    var nLength = inputLength;
    var nSmoothingK = inputSmoothingK;
    var nSmoothingD = inputSmoothingD;
    var d_wma_K = 0.0;
    var d_wma_D = 0.0;
    
    d_wma_K = GetK(nLength , nSmoothingK , 0);
    d_wma_D = GetD(nLength , nSmoothingK , nSmoothingD);
    
    if (d_wma_K  == null || d_wma_D == null)
        return;
   
    return new Array(d_wma_K , d_wma_D);
}

function GetK(nLength , nSmoothingK , nOffset){
    var raw_K = new StochStudy(nLength, 1 , 1);
    var sum_K = 0.0;
    var KVals;
    
    // Returns an array of raw K's 
    KVals = raw_K.getValue(StochStudy.FAST , nOffset , -nSmoothingK);   
    
    if (KVals == null)
        return null;
       
    for(i=0; i < nSmoothingK; i++){
        sum_K += KVals[i] * (nSmoothingK - i);
    }
    sum_K /= (nSmoothingK * (nSmoothingK + 1) /2);
    
    return sum_K;
}
    
function GetD(nLength , nSmoothingK , nSmoothingD){
    var raw_K = new StochStudy(nLength, 1 , 1);
    var sum_K = 0.0;
    var KVals;
    
    // Returns an array of raw K's 
    KVals = raw_K.getValue(StochStudy.FAST ,0 , -(nSmoothingK+nSmoothingD+1));   
    if (KVals == null)
        return null;
    
    var ema_K = 0.0;
    var sum_D = 0.0;
    var sum_K = 0.0;
    var i;
    var k;
    
    for(i=0;i < nSmoothingD; i++){
        // ema_K = GetK(nLength , nSmoothingK , -i);
        var ncount = 0;
        for(k=i; k < (i+nSmoothingK); k++){
            sum_K += KVals[k] * (nSmoothingK - ncount);
            ncount++;
        }
        sum_K /= (nSmoothingK * (nSmoothingK + 1) /2);
        sum_D += sum_K * (nSmoothingD -i);     
    }
 
    sum_D /= (nSmoothingD * (nSmoothingD + 1) / 2);
        
    return sum_D;
}