P=20;

CLOSEviaEMA=0.5*((P+1)*EMA(C,P)-(P-1)*Ref(EMA(C,P),-1));

Plot

(C,"CLOSE",1,1);

Plot

(CLOSEviaEMA,"CLOSEviaEMA",7,8); 




                        

                            
public class ReverseEMA : Indicator

    {

        

    //public Series<double> rEMA; 

    int k, calcbar ;     

    double lambda,lambdator, numerator,denominator,quotient;



        

        protected override void OnStateChange()

        {

            if (State == State.SetDefaults)

            {

                Description                            = @"ReverseEMA";

                Name                                = "ReverseEMA";

                Calculate                            = Calculate.OnBarClose;

                IsOverlay                            = true;

                DisplayInDataBox                    = true;

                DrawOnPricePanel                    = true;

                DrawHorizontalGridLines                = true;

                DrawVerticalGridLines                = true;

                PaintPriceMarkers                    = true;

                ScaleJustification                    = NinjaTrader.Gui.Chart.ScaleJustification.Right;

                //Disable this property if your indicator requires custom values that cumulate with each new market data event. 

                //See Help Guide for additional information.

                IsSuspendedWhileInactive            = true;

                Period                    = 10;

                BarsRequiredToPlot = Period; // Do not plot until their are atleast enough bars to calcu REMA

                AddPlot(Brushes.DarkBlue, "REMA");



            }

            else if (State == State.Configure)

            {    

                //rEMA    = new Series<double>(this);

                k = Period;

                lambda=  2.0 / (1 + k);

                lambdator   = 1.0;  

                numerator   = 0.0;

                denominator = 0.0;  // REMA formula-expansion contains +1 at the end, never less, never negative

            }    

        }//protected override void OnStateChange()



        protected override void OnBarUpdate() 

        {    

        if (CurrentBars[0] < BarsRequiredToPlot) return; // Ensures we have enough bars loaded for our iterations and indicator    

        if (CurrentBar == 0) Value[0] = Input[0]; // Sets temp value for indicator first bar

        

/*-----------------------------------------------------------------------------/

        Only used for error checking if Lambda will be independant 

        of Period

-----------------------------------------------------------------------------*/    

/*    

                 

            if (  lambda <= 0.0        // lambda shall not fall on/under  0.0

               || lambda >  1.0        //        shall not grow beyond    1.0

               || k      <= 0          // depth  shall not be negative or 0

               )

               return -1.0;            // context-protecting RET value

        

*/

        

/*-----------------------------------------------------------------------------/

        First way for code formula

-----------------------------------------------------------------------------*/

                 

        double quotient;

        

        for (int ReversePTR  = k; ReversePTR >0; ReversePTR--)

                { 

             calcbar = CurrentBar - ReversePTR;     

             numerator   += Math.Pow(lambda,k-ReversePTR) * Input[calcbar];

             denominator += Math.Pow(lambda,k-ReversePTR);

             quotient =     numerator / denominator;

                            

            Print(" I am on bar " + CurrentBar +  

                "\r\n The CalcBar is " + calcbar +

                "\r\n The Price is " + Input[calcbar] + 

                "\r\n The ReversePTR is " + ReversePTR + 

                "\r\n The current count is " + (k-ReversePTR) +

                "\r\n The Lambda is " + Math.Pow(lambda,k-ReversePTR) + 

                "\r\n The Numerator is " + numerator + 

                "\r\n The Denominator is " + denominator +

                "\r\n The quotient is " + quotient + 

                "\r\n-------------------------");        

            }

        Values[0][0] =  (numerator / denominator);

        Print(" The REMA is " + Values[0][0] +

        "\r\n");





        

/*-----------------------------------------------------------------------------/

        Second way for code formula

------------------------------------------------------------------------------/

        

        for (int ReversePTR  = k; ReversePTR >0; ReversePTR--)

                { 

            calcbar = CurrentBars[0] - ReversePTR;

                

            numerator   += lambdator * Input[calcbar];                                        

            denominator += lambdator;

            lambdator   *= lambda;

            quotient =     numerator / denominator;

                

            Print(" I am on bar " + CurrentBar +  

                "\r\n The CalcBar is " + calcbar +

                "\r\n The Price is " + Input[calcbar] + 

                "\r\n The ReversePTR is " + ReversePTR + 

                "\r\n The current count is " + (k-ReversePTR) +

                "\r\n The Lambdator is " + lambdator + 

                "\r\n The Numerator is " + numerator + 

                "\r\n The Denominator is " + denominator +

                "\r\n The quotient is " + quotient + 

                "\r\n -------------------------");        

            

            }

        Values[0][0] =  (numerator / denominator);

        Print(" The REMA is " + Values[0][0] + 

        "\r\n");

*/

//-----------------------------------------------------------------------                    

        } //protected override void OnBarUpdate()