def average_true_range(high_arr, low_arr, close_arr, n):
"""Calculate the Average True Range
See https://www.investopedia.com/terms/a/atr.asp for details
:param high_arr: high price of the bar, expect series from cudf
:param low_arr: low price of the bar, expect series from cudf
:param close_arr: close price of the bar, expect series from cudf
:param n: time steps
:return: average true range indicator
"""
tr = true_range(high_arr.data.to_gpu_array(), low_arr.data.to_gpu_array(),
close_arr.data.to_gpu_array())
ATR = Ewm(n, tr).mean()
return cudf.Series(ATR)
def vortex_indicator(high_arr, low_arr, close_arr, n):
"""Calculate the Vortex Indicator for given data.
Vortex Indicator described here:
http://www.vortexindicator.com/VFX_VORTEX.PDF
:param high_arr: high price of the bar, expect series from cudf
:param low_arr: low price of the bar, expect series from cudf
:param close_arr: close price of the bar, expect series from cudf
:param n: time steps to do EWM average
:return: Vortex Indicator in cudf.Series
"""
TR = true_range(high_arr.to_gpu_array(), low_arr.to_gpu_array(),
close_arr.to_gpu_array())
VM = lowhigh_diff(high_arr.to_gpu_array(), low_arr.to_gpu_array())
VI = division(Rolling(n, VM).sum(), Rolling(n, TR).sum())
return cudf.Series(VI, nan_as_null=False)
def average_directional_movement_index(high_arr, low_arr, close_arr, n, n_ADX):
"""Calculate the Average Directional Movement Index for given data.
:param high_arr: high price of the bar, expect series from cudf
:param low_arr: low price of the bar, expect series from cudf
:param close_arr: close price of the bar, expect series from cudf
:param n: time steps to do EWM average
:param n_ADX: time steps to do EWM average of ADX
:return: Average Directional Movement Index in cudf.Series
"""
UpI, DoI = upDownMove(high_arr.to_gpu_array(), low_arr.to_gpu_array())
last_ele = len(high_arr) - 1
tr = true_range(high_arr.to_gpu_array(), low_arr.to_gpu_array(),
close_arr.to_gpu_array())
ATR = Ewm(n, tr).mean()
PosDI = division(Ewm(n, UpI).mean(), ATR)
NegDI = division(Ewm(n, DoI).mean(), ATR)
NORM = division(abs_arr(substract(PosDI, NegDI)), summation(PosDI, NegDI))
NORM[last_ele] = math.nan
ADX = cudf.Series(Ewm(n_ADX, NORM).mean(), nan_as_null=False)
return ADX