I am trying to code the following algorithm for SuperTrend indicator in python using pandas.
BASIC UPPERBAND = (HIGH + LOW) / 2 + Multiplier * ATR
BASIC LOWERBAND = (HIGH + LOW) / 2 - Multiplier * ATR
FINAL UPPERBAND = IF( (Current BASICUPPERBAND < Previous FINAL UPPERBAND) or (Previous Close > Previous FINAL UPPERBAND))
THEN (Current BASIC UPPERBAND) ELSE Previous FINALUPPERBAND)
FINAL LOWERBAND = IF( (Current BASIC LOWERBAND > Previous FINAL LOWERBAND) or (Previous Close < Previous FINAL LOWERBAND))
THEN (Current BASIC LOWERBAND) ELSE Previous FINAL LOWERBAND)
SUPERTREND = IF((Previous SUPERTREND = Previous FINAL UPPERBAND) and (Current Close <= Current FINAL UPPERBAND)) THEN
Current FINAL UPPERBAND
ELSE
IF((Previous SUPERTREND = Previous FINAL UPPERBAND) and (Current Close > Current FINAL UPPERBAND)) THEN
Current FINAL LOWERBAND
ELSE
IF((Previous SUPERTREND = Previous FINAL LOWERBAND) and (Current Close >= Current FINAL LOWERBAND)) THEN
Current FINAL LOWERBAND
ELSE
IF((Previous SUPERTREND = Previous FINAL LOWERBAND) and (Current Close < Current FINAL LOWERBAND)) THEN
Current FINAL UPPERBAND
Here is the code that I wrote and tested:
# Compute basic upper and lower bands
df['basic_ub'] = (df['high'] + df['low']) / 2 + multiplier * df[atr]
df['basic_lb'] = (df['high'] + df['low']) / 2 - multiplier * df[atr]
# Compute final upper and lower bands
for i in range(0, len(df)):
if i < period:
df.set_value(i, 'basic_ub', 0.00)
df.set_value(i, 'basic_lb', 0.00)
df.set_value(i, 'final_ub', 0.00)
df.set_value(i, 'final_lb', 0.00)
else:
df.set_value(i, 'final_ub', (df.get_value(i, 'basic_ub')
if df.get_value(i, 'basic_ub') < df.get_value(i-1, 'final_ub') or df.get_value(i-1, 'close') > df.get_value(i-1, 'final_ub')
else df.get_value(i-1, 'final_ub')))
df.set_value(i, 'final_lb', (df.get_value(i, 'basic_lb')
if df.get_value(i, 'basic_lb') > df.get_value(i-1, 'final_lb') or df.get_value(i-1, 'close') < df.get_value(i-1, 'final_lb')
else df.get_value(i-1, 'final_lb')))
# Set the Supertrend value
for i in range(0, len(df)):
if i < period:
df.set_value(i, st, 0.00)
else:
df.set_value(i, 'st', (df.get_value(i, 'final_ub')
if ((df.get_value(i-1, 'st') == df.get_value(i-1, 'final_ub')) and (df.get_value(i, 'close') <= df.get_value(i, 'final_ub')))
else (df.get_value(i, 'final_lb')
if ((df.get_value(i-1, 'st') == df.get_value(i-1, 'final_ub')) and (df.get_value(i, 'close') > df.get_value(i, 'final_ub')))
else (df.get_value(i, 'final_lb')
if ((df.get_value(i-1, 'st') == df.get_value(i-1, 'final_lb')) and (df.get_value(i, 'close') >= df.get_value(i, 'final_lb')))
else (df.get_value(i, 'final_ub')
if((df.get_value(i-1, 'st') == df.get_value(i-1, 'final_lb')) and (df.get_value(i, 'close') < df.get_value(i, 'final_lb')))
else 0.00
)
)
)
)
)
# Mark the trend direction up/down
df['stx'] = np.where((df['st'] > 0.00), np.where((df['close'] < df['st']), 'down', 'up'), np.NaN)
I works, but I am not happy with the for loop. Can anyone help optimise it?
You can find the released code on Github!