f/metrics.py
Greg Pomerantz d8703a7a63 Stock & Portfolio Analyzer: full UI rework
- single spec grammar for symbol and benchmark fields: commas join one
  portfolio (MSFT:0.6,V:0.4), spaces separate distinct symbols/portfolios;
  both fields accept one or many entries
- benchmarks simulated with the same scheme/cost/tax rules; per-benchmark
  beta/alpha columns; after-tax benchmark curves
- global Curve mode (pre/after/both) above the tabs; clean names in
  single-curve mode
- live updates: field commits on Enter/blur, page recomputes per rerun;
  portfolio+tax sims cached (st.cache_data); plotly.js from CDN (4.6MB ->
  browser-cached) with F_INLINE_PLOTLY=1 offline fallback
- chart: legend underneath, solid lines, pan sticks to data edges
  (width-preserving), zoom edge-clamped
- inputs persist in settings.json across reloads/restarts/devices
- tests: tests/test_app.py (AppTest) + tests/test_e2e_browser.py
  (Playwright) via ./run_tests.sh
2026-08-24 16:05:27 -04:00

103 lines
3.3 KiB
Python

"""Performance statistics on price/return series (daily, 252 days/yr).
All functions accept a price series (or DataFrame) and return scalars or
Series. Kept deliberately dependency-light (pandas/numpy only) so every
metric is transparent and tweakable. `empyrical-reloaded` is a fine
drop-in for more metrics if you ever want them.
"""
from __future__ import annotations
import numpy as np
import pandas as pd
ANN = 252
def daily_returns(price: pd.Series | pd.DataFrame) -> pd.Series | pd.DataFrame:
return price.pct_change().fillna(0.0)
def total_return(price: pd.Series | pd.DataFrame) -> float:
return float(price.iloc[-1] / price.iloc[0] - 1.0)
def annualized_return(price: pd.Series | pd.DataFrame) -> float:
n = len(price)
return float((price.iloc[-1] / price.iloc[0]) ** (ANN / n) - 1.0)
def annualized_vol(returns: pd.Series | pd.DataFrame) -> float:
return float(returns.std() * np.sqrt(ANN))
def sharpe(returns: pd.Series, rf: float = 0.0) -> float:
r = returns - rf / ANN
sd = r.std()
return float(r.mean() / sd * np.sqrt(ANN)) if sd > 0 else 0.0
def sortino(returns: pd.Series, rf: float = 0.0) -> float:
r = returns - rf / ANN
dd = float(np.sqrt(np.mean(np.minimum(r, 0.0) ** 2)))
return float(r.mean() / dd * np.sqrt(ANN)) if dd > 0 else 0.0
def max_drawdown(price: pd.Series | pd.DataFrame) -> float:
peak = price.cummax()
return float((price / peak - 1.0).min())
def calmar(price: pd.Series | pd.DataFrame) -> float:
mdd = max_drawdown(price)
return float(annualized_return(price) / -mdd) if mdd < 0 else 0.0
def beta_alpha(returns: pd.Series, bench: pd.Series, rf: float = 0.0):
"""CAPM regression. Returns (beta, annualized_alpha)."""
r = (returns - rf / ANN).dropna()
b = (bench - rf / ANN).dropna()
r, b = r.align(b, join="inner")
beta = np.cov(r, b)[0, 1] / np.var(b)
alpha_daily = r.mean() - (rf / ANN + beta * (b.mean() - rf / ANN))
return float(beta), float(alpha_daily * ANN)
def summary(price: pd.Series, bench: pd.Series | None = None,
rf: float = 0.0) -> dict[str, float]:
r = daily_returns(price)
out = {
"total_return": total_return(price),
"ann_return": annualized_return(price),
"ann_vol": annualized_vol(r),
"sharpe": sharpe(r, rf),
"sortino": sortino(r, rf),
"max_dd": max_drawdown(price),
"calmar": calmar(price),
}
if bench is not None:
b, a = beta_alpha(r, daily_returns(bench), rf)
out["beta"] = b
out["alpha_ann"] = a
out["ann_return_bench"] = annualized_return(bench)
return out
def format_summary_table(summaries: dict[str, dict[str, float]]) -> pd.DataFrame:
"""{label: summary_dict} -> transposed table, percentages pre-formatted.
Benchmark columns may carry a ' [<benchmark>] ' suffix when there are
several benchmarks; all of them are formatted by prefix.
"""
df = pd.DataFrame(summaries).T
pct = ("total_return", "ann_return", "ann_vol", "max_dd", "alpha_ann",
"ann_return_bench")
two = ("sharpe", "sortino", "calmar", "beta")
for c in df.columns:
base = c.split(" [")[0]
if base in pct:
df[c] = df[c].map(lambda v: f"{v:,.1%}")
elif base in two:
df[c] = df[c].map(lambda v: f"{v:.2f}")
return df