一个更精度的平滑涵数, 可用于股票交易系统.用于Amibroker 平台

				//------------------------------------------------------------------------------
				//
				//  Formula Name:    Reverse EMA function
				//  Author/Uploader: Dimitris Tsokakis 
				//  E-mail:          tsokakis@oneway.gr
				//  Date/Time Added: 2003-06-13 03:44:35
				//  Origin:          
				//  Keywords:        
				//  Level:           basic
				//  Flags:           indicator
				//  Formula URL:     http://www.amibroker.com/library/formula.php?id=286
				//  Details URL:     http://www.amibroker.com/library/detail.php?id=286
				//
				//------------------------------------------------------------------------------
				//
				//  EMA is a function of todays Close and yesterdays EMA.
				//
				//  The mechanism is analytically described in AFL>AFL Scripting
				//  Host>Examples>a) Indicator example - Exponential moving average
				//
				//  After the math transormation, we may solve for C and get the Reverse EMA
				//  function.
				//
				//  I will call it CLOSEviaEMA to be more expressive.
				//
				//  In Indicator builder paste the
				//
				//  // Reverse EMA function, by D.Tsokakis, June 2003
				//
				//  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);
				//
				//  to see actual Close and CLOSEviaEMA matching.
				//
				//  The Reverse EMA function is useful to anticipate next bar Close, if we
				//  suppose next bar EMA.
				//
				//------------------------------------------------------------------------------
				
				// Reverse EMA function, by D.Tsokakis, June 2003
				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);