class LinearWeightedMovingAverage(CustomFactor, SingleInputMixin):
"""
Weighted Average Value of an arbitrary column
**默认输入**: None
**默认窗口长度**: None
"""
# numpy's nan functions throw warnings when passed an array containing only
# nans, but they still returns the desired value (nan), so we ignore the
# warning.
# # 在因子计算中忽略警告
ctx = ignore_nanwarnings()
def compute(self, today, assets, out, data):
ndays = data.shape[0]
# Initialize weights array
weights = arange(1, ndays + 1, dtype=float64_dtype).reshape(ndays, 1)
# Compute normalizer
normalizer = (ndays * (ndays + 1)) / 2
# Weight the data
weighted_data = data * weights
# Compute weighted averages
out[:] = nansum(weighted_data, axis=0) / normalizer
class SimpleMovingAverage(CustomFactor, SingleInputMixin):
"""
任意列的简单移动平均值
**默认输入**: None
**默认窗口长度**: None
"""
# numpy's nan functions throw warnings when passed an array containing only
# nans, but they still returns the desired value (nan), so we ignore the
# warning.
ctx = ignore_nanwarnings()
def compute(self, today, assets, out, data):
out[:] = nanmean(data, axis=0)
class SimpleMovingAverage(CustomFactor, SingleInputMixin):
"""
Average Value of an arbitrary column
**Default Inputs**: None
**Default Window Length**: None
"""
# numpy's nan functions throw warnings when passed an array containing only
# nans, but they still returns the desired value (nan), so we ignore the
# warning.
ctx = ignore_nanwarnings()
def compute(self, today, assets, out, data):
out[:] = nanmean(data, axis=0)
class MaxDrawdown(CustomFactor, SingleInputMixin):
"""
Max Drawdown
**默认输入** None
**默认窗口长度** None
"""
ctx = ignore_nanwarnings()
def compute(self, today, assets, out, data):
drawdowns = fmax.accumulate(data, axis=0) - data
drawdowns[isnan(drawdowns)] = NINF
drawdown_ends = nanargmax(drawdowns, axis=0)
# TODO: Accelerate this loop in Cython or Numba.
for i, end in enumerate(drawdown_ends):
peak = nanmax(data[:end + 1, i])
out[i] = (peak - data[end, i]) / data[end, i]
