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aiomql/src/aiomql/ta_libs/pandas_ta/overlap/ssf.py
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2025-08-10 16:42:21 +01:00

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Python

# -*- coding: utf-8 -*-
from numpy import copy, cos, exp, zeros_like
from numba import njit
from pandas import Series
from pandas_ta._typing import Array, DictLike, Int, IntFloat
from pandas_ta.utils import v_bool, v_offset, v_pos_default, v_series
# Ehlers's Super Smoother Filter
# http://traders.com/documentation/feedbk_docs/2014/01/traderstips.html
@njit(cache=True)
def nb_ssf(x, n, pi, sqrt2):
m, ratio, result = x.size, sqrt2 / n, copy(x)
a = exp(-pi * ratio)
b = 2 * a * cos(180 * ratio)
c = a * a - b + 1
# result[:2] = x[:2]
for i in range(2, m):
result[i] = 0.5 * c * (x[i] + x[i - 1]) + b * result[i - 1] \
- a * a * result[i - 2]
return result
# John F. Ehlers's Super Smoother Filter by Everget (2 poles), Tradingview
# https://www.tradingview.com/script/VdJy0yBJ-Ehlers-Super-Smoother-Filter/
@njit(cache=True)
def nb_ssf_everget(x, n, pi, sqrt2):
m, arg, result = x.size, pi * sqrt2 / n, copy(x)
a = exp(-arg)
b = 2 * a * cos(arg)
# result[:2] = x[:2]
for i in range(2, m):
result[i] = 0.5 * (a * a - b + 1) * (x[i] + x[i - 1]) \
+ b * result[i - 1] - a * a * result[i - 2]
return result
def ssf(
close: Series, length: Int = None,
everget: bool = None, pi: IntFloat = None, sqrt2: IntFloat = None,
offset: Int = None, **kwargs: DictLike
) -> Series:
"""Ehlers's Super Smoother Filter
This indicator, by John F. Ehlers's © 2013, is a (Recursive) Digital
Filter that attempts to reduce lag and remove aliases. This version
has two poles.
Sources:
* [mql5](https://www.mql5.com/en/code/588)
* [traders.com](http://traders.com/documentation/feedbk_docs/2014/01/traderstips.html)
* [tradingview](https://www.tradingview.com/script/VdJy0yBJ-Ehlers-Super-Smoother-Filter/)
Parameters:
close (pd.Series): ```close``` Series
length (int): The period. Default: ```20```
everget (bool): Everget's implementation of ssf that uses pi
instead of 180 for the b factor of ssf. Default: ```False```
pi (float): The default is Ehlers's truncated value: ```3.14159```.
Default: ```3.14159```
sqrt2 (float): The default is Ehlers's truncated value: ```1.414```.
Default: ```1.414```
offset (int): Post shift. Default: ```0```
Other Parameters:
fillna (value): ```pd.DataFrame.fillna(value)```
Returns:
(pd.Series): 1 column
Note:
* Everget's calculation on TradingView:
```pi=np.pi```, ```sqrt2=np.sqrt(2)```
Danger:
Possible Data Leak
"""
# Validate
length = v_pos_default(length, 20)
close = v_series(close, length)
if close is None:
return
pi = v_pos_default(pi, 3.14159)
sqrt2 = v_pos_default(sqrt2, 1.414)
everget = v_bool(everget, False)
offset = v_offset(offset)
# Calculate
np_close = close.to_numpy()
if everget:
ssf = nb_ssf_everget(np_close, length, pi, sqrt2)
else:
ssf = nb_ssf(np_close, length, pi, sqrt2)
ssf = Series(ssf, index=close.index)
# Offset
if offset != 0:
ssf = ssf.shift(offset)
# Fill
if "fillna" in kwargs:
ssf.fillna(kwargs["fillna"], inplace=True)
# Name and Category
ssf.name = f"SSF{'e' if everget else ''}_{length}"
ssf.category = "overlap"
return ssf