Files
pandas-ta/pandas_ta/overlap/linreg.py
T
2020-10-01 16:18:01 +01:00

126 lines
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Python

# -*- coding: utf-8 -*-
import math
from pandas_ta.utils import get_offset, verify_series
def linreg(close, length=None, offset=None, **kwargs):
"""Indicator: Linear Regression"""
# Validate arguments
close = verify_series(close)
length = int(length) if length and length > 0 else 14
min_periods = (int(kwargs["min_periods"]) if "min_periods" in kwargs and
kwargs["min_periods"] is not None else length)
offset = get_offset(offset)
angle = kwargs.pop("angle", False)
intercept = kwargs.pop("intercept", False)
degrees = kwargs.pop("degrees", False)
r = kwargs.pop("r", False)
slope = kwargs.pop("slope", False)
tsf = kwargs.pop("tsf", False)
# Calculate Result
x = range(1, length + 1) # [1, 2, ..., n] from 1 to n keeps Sum(xy) low
x_sum = 0.5 * length * (length + 1)
x2_sum = x_sum * (2 * length + 1) / 3
divisor = length * x2_sum - x_sum * x_sum
def linear_regression(series):
y_sum = series.sum()
xy_sum = (x * series).sum()
m = (length * xy_sum - x_sum * y_sum) / divisor
if slope:
return m
b = (y_sum * x2_sum - x_sum * xy_sum) / divisor
if intercept:
return b
if angle:
theta = math.atan(m)
if degrees:
theta *= 180 / math.pi
return theta
if r:
y2_sum = (series * series).sum()
rn = length * xy_sum - x_sum * y_sum
rd = math.sqrt(divisor * (length * y2_sum - y_sum * y_sum))
return rn / rd
return m * length + b if tsf else m * (length - 1) + b
linreg = close.rolling(length, min_periods=length).apply(linear_regression,
raw=False)
# Offset
if offset != 0:
linreg = linreg.shift(offset)
# Handle fills
if "fillna" in kwargs:
linreg.fillna(kwargs["fillna"], inplace=True)
if "fill_method" in kwargs:
linreg.fillna(method=kwargs["fill_method"], inplace=True)
# Name and Categorize it
linreg.name = f"LR"
if slope:
linreg.name += "m"
if intercept:
linreg.name += "b"
if angle:
linreg.name += "a"
if r:
linreg.name += "r"
linreg.name += f"_{length}"
linreg.category = "overlap"
return linreg
linreg.__doc__ = """Linear Regression Moving Average (linreg)
Linear Regression Moving Average (LINREG). This is a simplified version of a
Standard Linear Regression. LINREG is a rolling regression of one variable. A
Standard Linear Regression is between two or more variables.
Source: TA Lib
Calculation:
Default Inputs:
length=14
x = [1, 2, ..., n]
x_sum = 0.5 * length * (length + 1)
x2_sum = length * (length + 1) * (2 * length + 1) / 6
divisor = length * x2_sum - x_sum * x_sum
lr(series):
y_sum = series.sum()
y2_sum = (series* series).sum()
xy_sum = (x * series).sum()
m = (length * xy_sum - x_sum * y_sum) / divisor
b = (y_sum * x2_sum - x_sum * xy_sum) / divisor
return m * (length - 1) + b
linreg = close.rolling(length).apply(lr)
Args:
close (pd.Series): Series of 'close's
length (int): It's period. Default: 10
offset (int): How many periods to offset the result. Default: 0
Kwargs:
angle (bool, optional): Default: False. If True, returns the angle of the slope in radians
degrees (bool, optional): Default: False. If True, returns the angle of the slope in degrees
intercept (bool, optional): Default: False. If True, returns the angle of the slope in radians
r (bool, optional): Default: False. If True, returns it's correlation 'r'
slope (bool, optional): Default: False. If True, returns the slope
tsf (bool, optional): Default: False. If True, returns the Time Series Forecast value.
fillna (value, optional): pd.DataFrame.fillna(value)
fill_method (value, optional): Type of fill method
Returns:
pd.Series: New feature generated.
"""