diff --git a/pandas_ta/overlap/jma.py b/pandas_ta/overlap/jma.py index 60a3ad4..67a8d26 100644 --- a/pandas_ta/overlap/jma.py +++ b/pandas_ta/overlap/jma.py @@ -17,38 +17,48 @@ def jma(close, length=None, phase=0, offset=None, **kwargs): offset = get_offset(offset) if close is None: return - # Calculate base variables - jma = Volty = vsum = np.zeros_like(close) - det0 = det1 = ma2 = bsmax = bsmin = 0.0 - jma[0] = ma1 = close[0] - len1 = max(((math.log(math.sqrt(0.5*(length-1)))/math.log(2.0))+2),0) - len2 = math.sqrt(0.5*(length-1))*len1 - pow1 = max(len1-2.0,0.5) - PR = 0.5 if phase<-100 else (2.5 if phase>100 else phase/100+1.5) - beta = 0.45*(length-1)/(0.45*(length-1)+2) - - # Iterate through the dataset, calculate Volty and jma + # Define base variables + jma = np.zeros_like(close) + Volty = np.zeros_like(close) + vSum = np.zeros_like(close) + Kv = det0 = det1 = ma2 = 0.0 + jma[0] = ma1 = uBand = lBand = close[0] + # Static variables + SumLen = 10 + len = 0.5*(length-1) + PR = 0.5 if phase<-100 else 2.5 if phase>100 else phase*0.01+1.5 + len1 = max((math.log(math.sqrt(len))/math.log(2.0))+2.0, 0) + pow1 = max(len1-2.0, 0.5) + len2 = math.sqrt(len)*len1 + bet = len2/(len2+1) + beta = 0.45*(length-1)/(0.45*(length-1)+2.0) for i in range(1, close.shape[0]): - hprice = np.amax(close[max(i-length,0):i]) - lprice = np.amin(close[max(i-length,0):i]) - del1 = hprice - bsmax - del2 = lprice - bsmin - Volty[i] = abs(del1) if del1>del2 else abs(del2) if del10 else hprice - Kv*del1 - bsmin = lprice if del2<0 else lprice - Kv*del2 - rVolty = max(min(math.pow(len1,1/pow1), Volty[i]/avgVolty),1) - power = math.pow(rVolty,pow1) - alpha = math.pow(beta, power) - ma1 = (1 - alpha) * close[i] + alpha * ma1 - det0 = (close[i] - ma1) * (1 - beta) + beta * det0 - ma2 = ma1 + PR * det0 - det1 = (ma2 - jma[i-1]) * math.pow(1-alpha,2) + math.pow(alpha,2) * det1 - jma[i] = jma[i-1] + det1 + price = close[i] + # Price volatility + del1 = price-uBand + del2 = price-lBand + Volty[i] = max(abs(del1),abs(del2)) if abs(del1)!=abs(del2) else 0 + # Relative price volatility factor + vSum[i] = vSum[i-1] + (Volty[i]-Volty[max(i-SumLen,0)])/SumLen + avgVolty = np.average(vSum[max(i-65,0):i+1]) + dVolty = 0 if avgVolty==0 else Volty[i]/avgVolty + rVolty = max(1.0, min(math.pow(len1, 1/pow1), dVolty)) + # Jurik volatility bands + pow2 = math.pow(rVolty, pow1) + Kv = math.pow(bet, math.sqrt(pow2)) + uBand = price if (del1 > 0) else price - (Kv*del1) + lBand = price if (del2 < 0) else price - (Kv*del2) + # Jurik Dynamic Factor + power = math.pow(rVolty, pow1) + alpha = math.pow(beta, power) + # 1st stage - prelimimary smoothing by adaptive EMA + ma1 = ((1-alpha)*price)+(alpha*ma1) # + # 2nd stage - one more prelimimary smoothing by Kalman filter + det0 = ((price-ma1)*(1-beta))+(beta*det0) + ma2 = ma1+PR*det0 + # 3rd stage - final smoothing by unique Jurik adaptive filter + det1 = ((ma2-jma[i-1])*(1-alpha)*(1-alpha))+(alpha*alpha*det1) + jma[i] = jma[i-1] + det1 # Remove initial lookback data and convert to pandas frame jma[0:length-1] = npNaN @@ -78,7 +88,6 @@ Jurik Moving Average Sources: Implementation of: https://c.mql5.com/forextsd/forum/164/jurik_1.pdf - Jurik volatility: https://www.prorealcode.com/prorealtime-indicators/jurik-volatility-bands/ Calculation: Default Inputs: