Files
chinese-equity-quant/portfolio/builder.py
T

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2.4 KiB
Python

"""Map signal values to discrete position actions."""
from dataclasses import dataclass
from typing import Optional
@dataclass
class PositionAction:
"""A target action for a single stock on a single bar."""
action: str # "buy", "sell", or "hold"
size_pct: float = 0.0 # target portfolio fraction for buys
class ThresholdBuilder:
"""Open on strong positive signal, close on strong negative signal."""
def __init__(
self,
buy_threshold: float = 0.02,
sell_threshold: float = -0.02,
size_pct: float = 0.95,
):
self.buy_threshold = buy_threshold
self.sell_threshold = sell_threshold
self.size_pct = size_pct
def build(self, signal_value: float, in_position: bool) -> PositionAction:
if not in_position and signal_value >= self.buy_threshold:
return PositionAction("buy", self.size_pct)
if in_position and signal_value <= self.sell_threshold:
return PositionAction("sell", 0.0)
return PositionAction("hold", 0.0)
class RankEqualWeightBuilder:
"""Rank all stocks by signal. Buy top N at equal weight. Sell if drops out.
Called once per bar with ALL stock signals. Returns per-stock actions.
"""
def __init__(self, top_n: int = 5, min_signal: Optional[float] = None):
self.top_n = top_n
self.min_signal = min_signal # optional floor — skip stocks with signal below this
def build(self, signals: dict[str, float]) -> dict[str, PositionAction]:
"""Rank stocks by signal (descending). Top N get 'buy', rest get 'sell' if held.
Args:
signals: {symbol: signal_value} for all stocks on this bar.
Returns:
{symbol: PositionAction}
"""
# Filter by min_signal if set
if self.min_signal is not None:
signals = {s: v for s, v in signals.items() if v >= self.min_signal}
# Sort by signal descending
ranked = sorted(signals.items(), key=lambda x: x[1], reverse=True)
top_symbols = set(sym for sym, _ in ranked[:self.top_n])
size_pct = 1.0 / self.top_n if self.top_n > 0 else 0.0
actions = {}
for sym in signals:
if sym in top_symbols:
actions[sym] = PositionAction("buy", size_pct)
else:
actions[sym] = PositionAction("sell", 0.0)
return actions