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https://github.com/webclinic017/drift.git
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chore(Linter): reformatted code with black (#211)
* chore(Linter): reformatted code with black * Create black.yaml
This commit is contained in:
+129
-61
@@ -3,6 +3,7 @@ import pandas as pd
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import scipy.stats as ss
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import numpy as np
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def timing_of_flattening_and_flips(target_positions: pd.Series) -> pd.DatetimeIndex:
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"""
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Advances in Financial Machine Learning, Snippet 14.1, page 197
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@@ -15,8 +16,12 @@ def timing_of_flattening_and_flips(target_positions: pd.Series) -> pd.DatetimeIn
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:return: (pd.DatetimeIndex) Timestamps of trades flattening, flipping and last bet
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"""
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empty_positions = target_positions[(target_positions == 0)].index # Empty positions index
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previous_positions = target_positions.shift(1) # Timestamps pointing at previous positions
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empty_positions = target_positions[
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(target_positions == 0)
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].index # Empty positions index
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previous_positions = target_positions.shift(
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1
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) # Timestamps pointing at previous positions
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# Index of positions where previous one wasn't empty
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previous_positions = previous_positions[(previous_positions != 0)].index
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@@ -30,8 +35,12 @@ def timing_of_flattening_and_flips(target_positions: pd.Series) -> pd.DatetimeIn
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# FLIPS - if current position has another direction compared to the next
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flips = multiplied_posions[(multiplied_posions < 0)].index
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flips_and_flattenings = flattening.union(flips).sort_values()
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if target_positions.index[-1] not in flips_and_flattenings: # Appending with last bet
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flips_and_flattenings = flips_and_flattenings.append(target_positions.index[-1:])
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if (
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target_positions.index[-1] not in flips_and_flattenings
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): # Appending with last bet
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flips_and_flattenings = flips_and_flattenings.append(
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target_positions.index[-1:]
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)
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return flips_and_flattenings
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@@ -50,19 +59,23 @@ def average_holding_period(target_positions: pd.Series) -> float:
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:return: (float) Estimated average holding period, NaN if zero or unpredicted
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"""
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holding_period = pd.DataFrame(columns=['holding_time', 'weight'])
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holding_period = pd.DataFrame(columns=["holding_time", "weight"])
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entry_time = 0
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position_difference = target_positions.diff()
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# Time elapsed from the starting time for each position
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time_difference = (target_positions.index - target_positions.index[0]) / np.timedelta64(1, 'D')
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time_difference = (
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target_positions.index - target_positions.index[0]
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) / np.timedelta64(1, "D")
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for i in range(1, target_positions.size):
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# Increased or unchanged position
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if float(position_difference.iloc[i] * target_positions.iloc[i - 1]) >= 0:
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if float(target_positions.iloc[i]) != 0: # And not an empty position
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entry_time = (entry_time * target_positions.iloc[i - 1] +
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time_difference[i] * position_difference.iloc[i]) / target_positions.iloc[i]
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entry_time = (
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entry_time * target_positions.iloc[i - 1]
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+ time_difference[i] * position_difference.iloc[i]
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) / target_positions.iloc[i]
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# Decreased
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if float(position_difference.iloc[i] * target_positions.iloc[i - 1]) < 0:
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@@ -71,19 +84,25 @@ def average_holding_period(target_positions: pd.Series) -> float:
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# Flip of a position
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if float(target_positions.iloc[i] * target_positions.iloc[i - 1]) < 0:
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weight = abs(target_positions.iloc[i - 1])
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holding_period.loc[target_positions.index[i], ['holding_time', 'weight']] = (hold_time, weight)
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holding_period.loc[
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target_positions.index[i], ["holding_time", "weight"]
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] = (hold_time, weight)
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entry_time = time_difference[i] # Reset entry time
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# Only a part of position is closed
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else:
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weight = abs(position_difference.iloc[i])
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holding_period.loc[target_positions.index[i], ['holding_time', 'weight']] = (hold_time, weight)
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holding_period.loc[
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target_positions.index[i], ["holding_time", "weight"]
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] = (hold_time, weight)
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if float(holding_period['weight'].sum()) > 0: # If there were closed trades at all
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avg_holding_period = float((holding_period['holding_time'] * \
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holding_period['weight']).sum() / holding_period['weight'].sum())
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if float(holding_period["weight"].sum()) > 0: # If there were closed trades at all
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avg_holding_period = float(
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(holding_period["holding_time"] * holding_period["weight"]).sum()
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/ holding_period["weight"].sum()
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)
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else:
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avg_holding_period = float('nan')
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avg_holding_period = float("nan")
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return avg_holding_period
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@@ -99,15 +118,15 @@ def bets_concentration(returns: pd.Series) -> float:
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"""
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if returns.size <= 2:
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return float('nan') # If less than 3 bets
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return float("nan") # If less than 3 bets
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weights = returns / returns.sum() # Weights of each bet
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hhi = (weights ** 2).sum() # Herfindahl-Hirschman Index for weights
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hhi = (weights**2).sum() # Herfindahl-Hirschman Index for weights
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hhi = float((hhi - returns.size ** (-1)) / (1 - returns.size ** (-1)))
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return hhi
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def all_bets_concentration(returns: pd.Series, frequency: str = 'M') -> tuple:
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def all_bets_concentration(returns: pd.Series, frequency: str = "M") -> tuple:
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"""
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Advances in Financial Machine Learning, Snippet 14.3, page 201
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Given a pd.Series of returns, derives concentration of positive returns, negative returns
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@@ -131,7 +150,9 @@ def all_bets_concentration(returns: pd.Series, frequency: str = 'M') -> tuple:
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negative_concentration = bets_concentration(returns[returns < 0])
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# Concentration of bets/time period (month by default)
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time_concentration = bets_concentration(returns.groupby(pd.Grouper(freq=frequency)).count())
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time_concentration = bets_concentration(
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returns.groupby(pd.Grouper(freq=frequency)).count()
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)
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return (positive_concentration, negative_concentration, time_concentration)
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@@ -157,35 +178,42 @@ def drawdown_and_time_under_water(returns: pd.Series, dollars: bool = False) ->
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:return: (tuple of pd.Series) Series of drawdowns and time under water
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"""
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frame = returns.to_frame('pnl')
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frame['hwm'] = returns.expanding().max() # Adding high watermarks as column
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frame = returns.to_frame("pnl")
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frame["hwm"] = returns.expanding().max() # Adding high watermarks as column
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# Grouped as min returns by high watermarks
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high_watermarks = frame.groupby('hwm').min().reset_index()
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high_watermarks.columns = ['hwm', 'min']
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high_watermarks = frame.groupby("hwm").min().reset_index()
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high_watermarks.columns = ["hwm", "min"]
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# Time high watermark occurred
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high_watermarks.index = frame['hwm'].drop_duplicates(keep='first').index
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high_watermarks.index = frame["hwm"].drop_duplicates(keep="first").index
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# Picking ones that had a drawdown after high watermark
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high_watermarks = high_watermarks[high_watermarks['hwm'] > high_watermarks['min']]
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high_watermarks = high_watermarks[high_watermarks["hwm"] > high_watermarks["min"]]
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if dollars:
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drawdown = high_watermarks['hwm'] - high_watermarks['min']
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drawdown = high_watermarks["hwm"] - high_watermarks["min"]
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else:
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drawdown = 1 - high_watermarks['min'] / high_watermarks['hwm']
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drawdown = 1 - high_watermarks["min"] / high_watermarks["hwm"]
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time_under_water = ((high_watermarks.index[1:] - high_watermarks.index[:-1]) / np.timedelta64(1, 'Y')).values
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time_under_water = (
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(high_watermarks.index[1:] - high_watermarks.index[:-1])
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/ np.timedelta64(1, "Y")
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).values
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# Adding also period from last High watermark to last return observed.
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time_under_water = np.append(time_under_water,
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(returns.index[-1] - high_watermarks.index[-1]) / np.timedelta64(1, 'Y'))
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time_under_water = np.append(
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time_under_water,
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(returns.index[-1] - high_watermarks.index[-1]) / np.timedelta64(1, "Y"),
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)
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time_under_water = pd.Series(time_under_water, index=high_watermarks.index)
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return drawdown, time_under_water
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def sharpe_ratio(returns: pd.Series, entries_per_year: int = 252, risk_free_rate: float = 0) -> float:
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def sharpe_ratio(
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returns: pd.Series, entries_per_year: int = 252, risk_free_rate: float = 0
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) -> float:
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"""
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Calculates annualized Sharpe ratio for pd.Series of normal or log returns.
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Risk_free_rate should be given for the same period the returns are given.
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@@ -197,12 +225,18 @@ def sharpe_ratio(returns: pd.Series, entries_per_year: int = 252, risk_free_rate
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:return: (float) Annualized Sharpe ratio
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"""
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sharpe_r = (returns.mean() - risk_free_rate) / returns.std() * (entries_per_year) ** (1 / 2)
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sharpe_r = (
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(returns.mean() - risk_free_rate)
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/ returns.std()
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* (entries_per_year) ** (1 / 2)
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)
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return sharpe_r
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def information_ratio(returns: pd.Series, benchmark: float = 0, entries_per_year: int = 252) -> float:
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def information_ratio(
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returns: pd.Series, benchmark: float = 0, entries_per_year: int = 252
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) -> float:
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"""
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Calculates annualized information ratio for pd.Series of normal or log returns.
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Benchmark should be provided as a return for the same time period as that between
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@@ -223,8 +257,13 @@ def information_ratio(returns: pd.Series, benchmark: float = 0, entries_per_year
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return information_r
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def probabilistic_sharpe_ratio(observed_sr: float, benchmark_sr: float, number_of_returns: int,
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skewness_of_returns: float = 0, kurtosis_of_returns: float = 3) -> float:
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def probabilistic_sharpe_ratio(
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observed_sr: float,
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benchmark_sr: float,
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number_of_returns: int,
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skewness_of_returns: float = 0,
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kurtosis_of_returns: float = 3,
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) -> float:
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"""
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Calculates the probabilistic Sharpe ratio (PSR) that provides an adjusted estimate of SR,
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by removing the inflationary effect caused by short series with skewed and/or
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@@ -241,30 +280,47 @@ def probabilistic_sharpe_ratio(observed_sr: float, benchmark_sr: float, number_o
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:return: (float) Probabilistic Sharpe ratio
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"""
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test_value = ((observed_sr - benchmark_sr) * np.sqrt(number_of_returns - 1)) / \
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((1 - skewness_of_returns * observed_sr + (kurtosis_of_returns - 1) / \
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4 * observed_sr ** 2)**(1 / 2))
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test_value = ((observed_sr - benchmark_sr) * np.sqrt(number_of_returns - 1)) / (
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(
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1
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- skewness_of_returns * observed_sr
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+ (kurtosis_of_returns - 1) / 4 * observed_sr**2
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)
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** (1 / 2)
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)
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if np.isnan(test_value):
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warnings.warn('Test value is nan. Please check the input values.', UserWarning)
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warnings.warn("Test value is nan. Please check the input values.", UserWarning)
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return test_value
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if isinstance(test_value, complex):
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warnings.warn('Output is a complex number. You may want to check the input skewness (too high), '
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'kurtosis (too low), or observed_sr values.', UserWarning)
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warnings.warn(
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"Output is a complex number. You may want to check the input skewness (too high), "
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"kurtosis (too low), or observed_sr values.",
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UserWarning,
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)
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if np.isinf(test_value):
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warnings.warn('Test value is infinite. You may want to check the input skewness, '
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'kurtosis, or observed_sr values.', UserWarning)
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warnings.warn(
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"Test value is infinite. You may want to check the input skewness, "
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"kurtosis, or observed_sr values.",
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UserWarning,
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)
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probab_sr = ss.norm.cdf(test_value)
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return probab_sr
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def deflated_sharpe_ratio(observed_sr: float, sr_estimates: list, number_of_returns: int,
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skewness_of_returns: float = 0, kurtosis_of_returns: float = 3,
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estimates_param: bool = False, benchmark_out: bool = False) -> float:
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def deflated_sharpe_ratio(
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observed_sr: float,
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sr_estimates: list,
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number_of_returns: int,
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skewness_of_returns: float = 0,
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kurtosis_of_returns: float = 3,
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estimates_param: bool = False,
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benchmark_out: bool = False,
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) -> float:
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"""
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Calculates the deflated Sharpe ratio (DSR) - a PSR where the rejection threshold is
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adjusted to reflect the multiplicity of trials. DSR is estimated as PSR[SR∗], where
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@@ -290,18 +346,25 @@ def deflated_sharpe_ratio(observed_sr: float, sr_estimates: list, number_of_retu
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# Calculating benchmark_SR from the parameters of estimates
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if estimates_param:
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benchmark_sr = sr_estimates[0] * \
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((1 - np.euler_gamma) * ss.norm.ppf(1 - 1 / sr_estimates[1]) +
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np.euler_gamma * ss.norm.ppf(1 - 1 / sr_estimates[1] * np.e ** (-1)))
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benchmark_sr = sr_estimates[0] * (
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(1 - np.euler_gamma) * ss.norm.ppf(1 - 1 / sr_estimates[1])
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+ np.euler_gamma * ss.norm.ppf(1 - 1 / sr_estimates[1] * np.e ** (-1))
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)
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# Calculating benchmark_SR from a list of estimates
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else:
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benchmark_sr = np.array(sr_estimates).std() * \
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((1 - np.euler_gamma) * ss.norm.ppf(1 - 1 / len(sr_estimates)) +
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np.euler_gamma * ss.norm.ppf(1 - 1 / len(sr_estimates) * np.e ** (-1)))
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benchmark_sr = np.array(sr_estimates).std() * (
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(1 - np.euler_gamma) * ss.norm.ppf(1 - 1 / len(sr_estimates))
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+ np.euler_gamma * ss.norm.ppf(1 - 1 / len(sr_estimates) * np.e ** (-1))
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)
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deflated_sr = probabilistic_sharpe_ratio(observed_sr, benchmark_sr, number_of_returns,
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skewness_of_returns, kurtosis_of_returns)
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deflated_sr = probabilistic_sharpe_ratio(
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observed_sr,
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benchmark_sr,
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number_of_returns,
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skewness_of_returns,
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kurtosis_of_returns,
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)
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if benchmark_out:
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return benchmark_sr
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@@ -309,10 +372,13 @@ def deflated_sharpe_ratio(observed_sr: float, sr_estimates: list, number_of_retu
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return deflated_sr
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def minimum_track_record_length(observed_sr: float, benchmark_sr: float,
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skewness_of_returns: float = 0,
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kurtosis_of_returns: float = 3,
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alpha: float = 0.05) -> float:
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def minimum_track_record_length(
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observed_sr: float,
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benchmark_sr: float,
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skewness_of_returns: float = 0,
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kurtosis_of_returns: float = 3,
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alpha: float = 0.05,
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) -> float:
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"""
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Calculates the minimum track record length (MinTRL) - "How long should a track
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record be in order to have statistical confidence that its Sharpe ratio is above
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@@ -329,8 +395,10 @@ def minimum_track_record_length(observed_sr: float, benchmark_sr: float,
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:return: (float) Minimum number of track records
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"""
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track_rec_length = 1 + (1 - skewness_of_returns * observed_sr +
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(kurtosis_of_returns - 1) / 4 * observed_sr ** 2) * \
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(ss.norm.ppf(1 - alpha) / (observed_sr - benchmark_sr)) ** (2)
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track_rec_length = 1 + (
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1
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- skewness_of_returns * observed_sr
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+ (kurtosis_of_returns - 1) / 4 * observed_sr**2
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) * (ss.norm.ppf(1 - alpha) / (observed_sr - benchmark_sr)) ** (2)
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return track_rec_length
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return track_rec_length
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