perf(backtest): 因子批量回测预计算共享下期收益并向量化统计

P1 — run_batch 进入因子循环前对 close 有效序列计算一次 _next_return
(仅依赖 symbol/date/close/rebalance, 与因子无关), 通过 left join 附着到
共享面板; _evaluate_panel 检测到预计算列时直接复用, 跳过逐因子 shift/
调仓日 JOIN。因子空值集中在预热期前缀, 过滤后无内部空洞, 故与逐因子
在过滤后面板上重算的结果完全等价 (daily/weekly/monthly 均数值一致)。

P2 — 将 _calc_group_nav / _calc_group_stats / _calc_long_short 三段
逐行 Python 循环改为向量化:
- 分组净值: Polars cum_prod 替代 dict 累乘
- 分组统计: numpy maximum.accumulate 计算回撤, 向量化周期收益序列
- 多空组合: cumprod 合成净值, 向量化峰值/回撤
峰值初值沿用原逻辑 max(1.0, 历史最高), 400 组随机序列 (含 null/负收益)
下与旧实现逐值等价。

测试: tests/backtest 全量 184 passed。
This commit is contained in:
shy3130
2026-08-14 13:24:24 +08:00
parent 2b792dee44
commit a0cb899163
+107 -68
View File
@@ -205,6 +205,9 @@ class FactorBacktestService:
elapsed_ms=round((time.perf_counter() - t0) * 1000, 1),
)
# P1: 预计算共享下期收益 (仅依赖 close/date/symbol), 避免每个因子重复 shift/调仓日 JOIN。
panel = self._attach_shared_next_return(panel, config)
metadata = {item["id"]: item for item in FACTOR_COLUMNS}
items: list[FactorBatchItem] = []
for factor_name in factor_names:
@@ -294,6 +297,39 @@ class FactorBacktestService:
panel = self._compute_missing_factors(panel, missing)
return panel
@staticmethod
def _attach_shared_next_return(
panel: pl.DataFrame, config: FactorBatchConfig,
) -> pl.DataFrame:
"""对 [start, end] 内 close 有效序列计算一次 _next_return, 复用给批次内每个因子。
_next_return 仅依赖 (symbol, date, close, rebalance), 与具体因子无关; 因子空值
集中在预热期前缀, 过滤后剩余序列无内部空洞, 故与 _evaluate_panel 内逐因子在
过滤后面板上重算的结果完全等价。
"""
if "_next_return" in panel.columns:
return panel
base = (
panel.filter((pl.col("date") >= config.start) & (pl.col("date") <= config.end))
.filter(pl.col("close").is_not_null() & (pl.col("close") > 0))
.select(["symbol", "date", "close"])
.sort(["symbol", "date"])
)
if base.is_empty():
return panel.with_columns(pl.lit(None).cast(pl.Float64).alias("_next_return"))
if config.rebalance == "daily":
base = base.with_columns(
(pl.col("close").shift(-1).over("symbol") / pl.col("close") - 1)
.alias("_next_return")
)
else:
base = FactorBacktestService._calc_period_return(base, config.rebalance)
return panel.join(
base.select(["symbol", "date", "_next_return"]),
on=["symbol", "date"],
how="left",
)
def _evaluate_panel(
self,
source_panel: pl.DataFrame,
@@ -309,7 +345,14 @@ class FactorBacktestService:
return _err(f"因子列 '{factor_col}' 不存在于 enriched 数据中, 且无法从基础行情计算")
if "close" not in source_panel.columns:
return _err("enriched 数据缺少收盘价 close")
panel = source_panel.select(["symbol", "date", "close", factor_col])
# 批量模式由 run_batch 预计算 _next_return 并随 source_panel 传入, 直接复用;
# 单因子 run() 路径未预计算, 仍按原逻辑在此计算。
select_cols = ["symbol", "date", "close", factor_col]
precomputed_return = "_next_return" in source_panel.columns
if precomputed_return:
select_cols.append("_next_return")
panel = source_panel.select(select_cols)
panel = panel.filter((pl.col("date") >= config.start) & (pl.col("date") <= config.end))
# 过滤有效行
@@ -326,16 +369,17 @@ class FactorBacktestService:
n_symbols = panel["symbol"].n_unique()
n_dates = panel["date"].n_unique()
# 计算下期收益
# 根据调仓频率计算不同周期的 forward return
if config.rebalance == "daily":
panel = panel.with_columns(
(pl.col("close").shift(-1).over("symbol") / pl.col("close") - 1)
.alias("_next_return")
)
else:
# weekly/monthly: 计算到下个调仓日的收益
panel = self._calc_period_return(panel, config.rebalance)
# 计算下期收益 — _next_return 仅依赖 (symbol, date, close, rebalance), 与因子无关;
# 因子空值集中在预热期前缀, 过滤后剩余序列无内部空洞, 故预计算与逐因子重算结果等价。
if not precomputed_return:
if config.rebalance == "daily":
panel = panel.with_columns(
(pl.col("close").shift(-1).over("symbol") / pl.col("close") - 1)
.alias("_next_return")
)
else:
# weekly/monthly: 计算到下个调仓日的收益
panel = self._calc_period_return(panel, config.rebalance)
# ── 1. IC 分析 ──
ic_df = self._calc_ic(panel, factor_col)
@@ -578,16 +622,16 @@ class FactorBacktestService:
group_cols = sorted([c for c in pivot.columns if c != "date"], key=FactorBacktestService._group_sort_key)
# 累乘净值曲线
# 向量化累乘净值: null 视为 0 收益 (净值不变); 累乘保持全精度, 输出时 round(4),
# 等价于原 dict 累乘 `nav_values[c] *= (1+ret); entry[c] = round(nav_values[c], 4)`。
nav_df = pivot.with_columns(
[(1.0 + pl.col(c).fill_null(0.0)).cum_prod().alias(c) for c in group_cols]
)
result: list[dict] = []
nav_values: dict[str, float] = {c: 1.0 for c in group_cols}
for row in pivot.iter_rows(named=True):
for row in nav_df.iter_rows(named=True):
entry: dict = {"date": str(row["date"])[:10]}
for c in group_cols:
ret = float(row[c]) if row[c] is not None else 0.0
nav_values[c] *= (1 + ret)
entry[c] = round(nav_values[c], 4)
entry[c] = round(float(row[c]), 4)
result.append(entry)
return result
@@ -608,36 +652,33 @@ class FactorBacktestService:
)
n_days = max((end - start).days, 1)
years = n_days / 365.25
# 夏普 — 年化系数必须匹配 group_nav 的调仓频率 (每个净值点 = 一个调仓周期收益);
# 周/月频收益若乘 √252 会把 Sharpe 高估 √(252/期数) 倍 (月频 ≈4.6x, 周频 ≈2.2x)。
_ann = {"daily": 252, "weekly": 52, "monthly": 12}.get(rebalance, 252)
stats = []
for i, c in enumerate(group_cols):
values = [r[c] for r in group_nav if r.get(c) is not None]
if not values:
continue
total_return = values[-1] - 1.0
annual_return = (values[-1]) ** (1 / max(years, 0.01)) - 1 if values[-1] > 0 else 0.0
arr = np.asarray(values, dtype=np.float64)
last = float(arr[-1])
total_return = last - 1.0
annual_return = last ** (1 / max(years, 0.01)) - 1 if last > 0 else 0.0
# 最大回撤
peak = 1.0
max_dd = 0.0
for v in values:
peak = max(peak, v)
dd = (v - peak) / peak
max_dd = min(max_dd, dd)
# 最大回撤 (向量化): 峰值 = max(1.0, 历史最高), 与原 peak 初值 1.0 的逐行 max 一致
peak = np.maximum(np.maximum.accumulate(arr), 1.0)
max_dd = float(np.min((arr - peak) / peak))
# 收益序列
daily_rets = []
for j in range(1, len(values)):
if values[j - 1] > 0:
daily_rets.append(values[j] / values[j - 1] - 1)
# 夏普 — 年化系数必须匹配 group_nav 的调仓频率 (每个净值点 = 一个调仓周期收益);
# 周/月频收益若乘 √252 会把 Sharpe 高估 √(252/期数) 倍 (月频 ≈4.6x, 周频 ≈2.2x)。
if daily_rets:
arr = np.array(daily_rets)
_ann = {"daily": 252, "weekly": 52, "monthly": 12}.get(rebalance, 252)
sharpe = float(np.mean(arr) / np.std(arr)) * np.sqrt(_ann) if np.std(arr) > 0 else 0.0
win_rate = float(np.mean(arr > 0))
# 周期收益序列 (向量化): nav[t]/nav[t-1] - 1, 仅保留 nav[t-1] > 0 的样本
prev = arr[:-1]
with np.errstate(divide="ignore", invalid="ignore"):
rets = arr[1:] / prev - 1.0
rets = rets[prev > 0]
if rets.size:
std = float(np.std(rets))
sharpe = float(np.mean(rets) / std) * np.sqrt(_ann) if std > 0 else 0.0
win_rate = float(np.mean(rets > 0))
else:
sharpe = 0.0
win_rate = 0.0
@@ -674,38 +715,36 @@ class FactorBacktestService:
top_col = group_cols[-1] # Q5 (最高)
bottom_col = group_cols[0] # Q1 (最低)
# 独立计算 top 和 bottom 的日收益,然后合成
ls_value = 1.0
prev_top = 1.0
prev_bot = 1.0
peak = 1.0
max_dd = 0.0
ls_nav: list[dict] = []
# 向量化: 各组净值 (null 视为 1.0), 前置 1.0 作为初值 prev_top/prev_bot,
# 等价于原逐行 prev_top/prev_bot 初始 1.0 的累乘逻辑。
top = np.array(
[r[top_col] if r.get(top_col) is not None else 1.0 for r in group_nav],
dtype=np.float64,
)
bot = np.array(
[r[bottom_col] if r.get(bottom_col) is not None else 1.0 for r in group_nav],
dtype=np.float64,
)
prev_top = np.concatenate(([1.0], top[:-1]))
prev_bot = np.concatenate(([1.0], bot[:-1]))
for row in group_nav:
top_nav = float(row.get(top_col, 1.0)) if row.get(top_col) is not None else 1.0
bot_nav = float(row.get(bottom_col, 1.0)) if row.get(bottom_col) is not None else 1.0
# 分组收益; prev <= 0 时按原逻辑置 0 (做多 top, 做空 bottom = 取反)
with np.errstate(divide="ignore", invalid="ignore"):
top_ret = np.where(prev_top > 0, top / prev_top - 1.0, 0.0)
bot_ret = np.where(prev_bot > 0, bot / prev_bot - 1.0, 0.0)
ls_ret = (top_ret - bot_ret) / 2.0 # 各分配 50% 资金
ls_value = np.cumprod(1.0 + ls_ret)
# top 组收益 (做多)
top_ret = (top_nav / prev_top - 1) if prev_top > 0 else 0.0
# bottom 组收益 (做空 = 取反)
bot_ret = -(bot_nav / prev_bot - 1) if prev_bot > 0 else 0.0
# 多空组合收益
ls_ret = (top_ret + bot_ret) / 2 # 各分配 50% 资金
ls_value *= (1 + ls_ret)
# 最大回撤: 峰值 = max(1.0, 历史最高), 与原 peak 初值 1.0 一致
peak = np.maximum(np.maximum.accumulate(ls_value), 1.0)
max_dd = float(np.min((ls_value - peak) / peak))
prev_top = top_nav
prev_bot = bot_nav
peak = max(peak, ls_value)
dd = (ls_value - peak) / peak if peak > 0 else 0.0
max_dd = min(max_dd, dd)
ls_nav.append({"date": row["date"], "value": round(ls_value, 4)})
total_ret = ls_value - 1.0
ls_nav = [
{"date": group_nav[k]["date"], "value": round(float(ls_value[k]), 4)}
for k in range(len(group_nav))
]
ls_stats = {
"total_return": round(total_ret, 4),
"total_return": round(float(ls_value[-1]) - 1.0, 4),
"max_drawdown": round(max_dd, 4),
"top_group": top_col,
"bottom_group": bottom_col,