Files
lowkey_backtest/engine/risk.py

396 lines
14 KiB
Python
Raw Permalink Normal View History

"""
Risk management utilities for backtesting.
Handles funding rate calculations and liquidation detection.
"""
from dataclasses import dataclass
import pandas as pd
from engine.logging_config import get_logger
from engine.market import MarketConfig, calculate_liquidation_price
logger = get_logger(__name__)
@dataclass
class LiquidationEvent:
"""
Record of a liquidation event during backtesting.
Attributes:
entry_time: Timestamp when position was opened
entry_price: Price at position entry
liquidation_time: Timestamp when liquidation occurred
liquidation_price: Calculated liquidation price
actual_price: Actual price that triggered liquidation (high/low)
direction: 'long' or 'short'
margin_lost_pct: Percentage of margin lost (typically 100%)
"""
entry_time: pd.Timestamp
entry_price: float
liquidation_time: pd.Timestamp
liquidation_price: float
actual_price: float
direction: str
margin_lost_pct: float = 1.0
def calculate_funding(
close: pd.Series,
long_entries: pd.DataFrame,
long_exits: pd.DataFrame,
short_entries: pd.DataFrame,
short_exits: pd.DataFrame,
market_config: MarketConfig,
leverage: int
) -> float:
"""
Calculate total funding paid/received for perpetual positions.
Simplified model: applies funding rate every 8 hours to open positions.
Positive rate means longs pay shorts.
Args:
close: Price series
long_entries: Long entry signals
long_exits: Long exit signals
short_entries: Short entry signals
short_exits: Short exit signals
market_config: Market configuration with funding parameters
leverage: Position leverage
Returns:
Total funding paid (positive) or received (negative)
"""
if market_config.funding_interval_hours == 0:
return 0.0
funding_rate = market_config.funding_rate
interval_hours = market_config.funding_interval_hours
# Determine position state at each bar
long_position = long_entries.cumsum() - long_exits.cumsum()
short_position = short_entries.cumsum() - short_exits.cumsum()
# Clamp to 0/1 (either in position or not)
long_position = (long_position > 0).astype(int)
short_position = (short_position > 0).astype(int)
# Find funding timestamps (every 8 hours: 00:00, 08:00, 16:00 UTC)
funding_times = close.index[close.index.hour % interval_hours == 0]
total_funding = 0.0
for ts in funding_times:
if ts not in close.index:
continue
price = close.loc[ts]
# Long pays funding, short receives (when rate > 0)
if isinstance(long_position, pd.DataFrame):
long_open = long_position.loc[ts].any()
short_open = short_position.loc[ts].any()
else:
long_open = long_position.loc[ts] > 0
short_open = short_position.loc[ts] > 0
position_value = price * leverage
if long_open:
total_funding += position_value * funding_rate
if short_open:
total_funding -= position_value * funding_rate
return total_funding
def inject_liquidation_exits(
close: pd.Series,
high: pd.Series,
low: pd.Series,
long_entries: pd.DataFrame | pd.Series,
long_exits: pd.DataFrame | pd.Series,
short_entries: pd.DataFrame | pd.Series,
short_exits: pd.DataFrame | pd.Series,
leverage: int,
maintenance_margin_rate: float
) -> tuple[pd.DataFrame | pd.Series, pd.DataFrame | pd.Series, list[LiquidationEvent]]:
"""
Modify exit signals to force position closure at liquidation points.
This function simulates realistic liquidation behavior by:
1. Finding positions that would be liquidated before their normal exit
2. Injecting forced exit signals at the liquidation bar
3. Recording all liquidation events
Args:
close: Close price series
high: High price series
low: Low price series
long_entries: Long entry signals
long_exits: Long exit signals
short_entries: Short entry signals
short_exits: Short exit signals
leverage: Position leverage
maintenance_margin_rate: Maintenance margin rate for liquidation
Returns:
Tuple of (modified_long_exits, modified_short_exits, liquidation_events)
"""
if leverage <= 1:
return long_exits, short_exits, []
liquidation_events: list[LiquidationEvent] = []
# Convert to DataFrame if Series for consistent handling
is_series = isinstance(long_entries, pd.Series)
if is_series:
long_entries_df = long_entries.to_frame()
long_exits_df = long_exits.to_frame()
short_entries_df = short_entries.to_frame()
short_exits_df = short_exits.to_frame()
else:
long_entries_df = long_entries
long_exits_df = long_exits.copy()
short_entries_df = short_entries
short_exits_df = short_exits.copy()
modified_long_exits = long_exits_df.copy()
modified_short_exits = short_exits_df.copy()
# Process long positions
long_mask = long_entries_df.any(axis=1)
for entry_idx in close.index[long_mask]:
entry_price = close.loc[entry_idx]
liq_price = calculate_liquidation_price(
entry_price, leverage, is_long=True,
maintenance_margin_rate=maintenance_margin_rate
)
# Find the normal exit for this entry
subsequent_exits = long_exits_df.loc[entry_idx:].any(axis=1)
exit_indices = subsequent_exits[subsequent_exits].index
normal_exit_idx = exit_indices[0] if len(exit_indices) > 0 else close.index[-1]
# Check if liquidation occurs before normal exit
price_range = low.loc[entry_idx:normal_exit_idx]
if (price_range < liq_price).any():
liq_bar = price_range[price_range < liq_price].index[0]
# Inject forced exit at liquidation bar
for col in modified_long_exits.columns:
modified_long_exits.loc[liq_bar, col] = True
# Record the liquidation event
liquidation_events.append(LiquidationEvent(
entry_time=entry_idx,
entry_price=entry_price,
liquidation_time=liq_bar,
liquidation_price=liq_price,
actual_price=low.loc[liq_bar],
direction='long',
margin_lost_pct=1.0
))
logger.warning(
"LIQUIDATION (Long): Entry %s ($%.2f) -> Liquidated %s "
"(liq=$%.2f, low=$%.2f)",
entry_idx.strftime('%Y-%m-%d'), entry_price,
liq_bar.strftime('%Y-%m-%d'), liq_price, low.loc[liq_bar]
)
# Process short positions
short_mask = short_entries_df.any(axis=1)
for entry_idx in close.index[short_mask]:
entry_price = close.loc[entry_idx]
liq_price = calculate_liquidation_price(
entry_price, leverage, is_long=False,
maintenance_margin_rate=maintenance_margin_rate
)
# Find the normal exit for this entry
subsequent_exits = short_exits_df.loc[entry_idx:].any(axis=1)
exit_indices = subsequent_exits[subsequent_exits].index
normal_exit_idx = exit_indices[0] if len(exit_indices) > 0 else close.index[-1]
# Check if liquidation occurs before normal exit
price_range = high.loc[entry_idx:normal_exit_idx]
if (price_range > liq_price).any():
liq_bar = price_range[price_range > liq_price].index[0]
# Inject forced exit at liquidation bar
for col in modified_short_exits.columns:
modified_short_exits.loc[liq_bar, col] = True
# Record the liquidation event
liquidation_events.append(LiquidationEvent(
entry_time=entry_idx,
entry_price=entry_price,
liquidation_time=liq_bar,
liquidation_price=liq_price,
actual_price=high.loc[liq_bar],
direction='short',
margin_lost_pct=1.0
))
logger.warning(
"LIQUIDATION (Short): Entry %s ($%.2f) -> Liquidated %s "
"(liq=$%.2f, high=$%.2f)",
entry_idx.strftime('%Y-%m-%d'), entry_price,
liq_bar.strftime('%Y-%m-%d'), liq_price, high.loc[liq_bar]
)
# Convert back to Series if input was Series
if is_series:
modified_long_exits = modified_long_exits.iloc[:, 0]
modified_short_exits = modified_short_exits.iloc[:, 0]
return modified_long_exits, modified_short_exits, liquidation_events
def calculate_liquidation_adjustment(
liquidation_events: list[LiquidationEvent],
init_cash: float,
leverage: int
) -> tuple[float, float]:
"""
Calculate the return adjustment for liquidated positions.
VectorBT calculates trade P&L using close price at exit bar.
For liquidations, the actual loss is 100% of the position margin.
This function calculates the difference between what VectorBT
recorded and what actually would have happened.
In our portfolio setup:
- Long/short each get half the capital (init_cash * leverage / 2)
- Each trade uses 100% of that allocation (size=1.0, percent)
- On liquidation, the margin for that trade is lost entirely
The adjustment is the DIFFERENCE between:
- VectorBT's calculated P&L (exit at close price)
- Actual liquidation P&L (100% margin loss)
Args:
liquidation_events: List of liquidation events
init_cash: Initial portfolio cash (before leverage)
leverage: Position leverage used
Returns:
Tuple of (total_margin_lost, adjustment_pct)
- total_margin_lost: Estimated total margin lost from liquidations
- adjustment_pct: Percentage adjustment to apply to returns
"""
if not liquidation_events:
return 0.0, 0.0
# In our setup, each side (long/short) gets half the capital
# Margin per side = init_cash / 2
margin_per_side = init_cash / 2
# For each liquidation, VectorBT recorded some P&L based on close price
# The actual P&L should be -100% of the margin used for that trade
#
# We estimate the adjustment as:
# - Each liquidation should have resulted in ~-20% loss (at 5x leverage)
# - VectorBT may have recorded a different value
# - The margin loss is (1/leverage) per trade that gets liquidated
# Calculate liquidation loss rate based on leverage
# At 5x leverage, liquidation = ~19.6% adverse move = 100% margin loss
liq_loss_rate = 1.0 / leverage # Approximate loss per trade as % of position
# Count liquidations
n_liquidations = len(liquidation_events)
# Estimate total margin lost:
# Each liquidation on average loses the margin for that trade
# Since VectorBT uses half capital per side, and we trade 100% size,
# each liquidation loses approximately margin_per_side
# But we cap at available capital
total_margin_lost = min(n_liquidations * margin_per_side * liq_loss_rate, init_cash)
# Calculate as percentage of initial capital
adjustment_pct = (total_margin_lost / init_cash) * 100
return total_margin_lost, adjustment_pct
def check_liquidations(
close: pd.Series,
high: pd.Series,
low: pd.Series,
long_entries: pd.DataFrame,
long_exits: pd.DataFrame,
short_entries: pd.DataFrame,
short_exits: pd.DataFrame,
leverage: int,
maintenance_margin_rate: float
) -> int:
"""
Check for liquidation events and log warnings.
Args:
close: Close price series
high: High price series
low: Low price series
long_entries: Long entry signals
long_exits: Long exit signals
short_entries: Short entry signals
short_exits: Short exit signals
leverage: Position leverage
maintenance_margin_rate: Maintenance margin rate for liquidation
Returns:
Count of liquidation warnings
"""
warnings = 0
# For long positions
long_mask = (
long_entries.any(axis=1)
if isinstance(long_entries, pd.DataFrame)
else long_entries
)
for entry_idx in close.index[long_mask]:
entry_price = close.loc[entry_idx]
liq_price = calculate_liquidation_price(
entry_price, leverage, is_long=True,
maintenance_margin_rate=maintenance_margin_rate
)
subsequent = low.loc[entry_idx:]
if (subsequent < liq_price).any():
liq_bar = subsequent[subsequent < liq_price].index[0]
logger.warning(
"LIQUIDATION WARNING (Long): Entry at %s ($%.2f), "
"would liquidate at %s (liq_price=$%.2f, low=$%.2f)",
entry_idx, entry_price, liq_bar, liq_price, low.loc[liq_bar]
)
warnings += 1
# For short positions
short_mask = (
short_entries.any(axis=1)
if isinstance(short_entries, pd.DataFrame)
else short_entries
)
for entry_idx in close.index[short_mask]:
entry_price = close.loc[entry_idx]
liq_price = calculate_liquidation_price(
entry_price, leverage, is_long=False,
maintenance_margin_rate=maintenance_margin_rate
)
subsequent = high.loc[entry_idx:]
if (subsequent > liq_price).any():
liq_bar = subsequent[subsequent > liq_price].index[0]
logger.warning(
"LIQUIDATION WARNING (Short): Entry at %s ($%.2f), "
"would liquidate at %s (liq_price=$%.2f, high=$%.2f)",
entry_idx, entry_price, liq_bar, liq_price, high.loc[liq_bar]
)
warnings += 1
return warnings