bunker-stats-rs 0.2.8

Ultra-fast Rust-powered statistics and time-series utilities for Python.

💥 bunker-stats

A Rust powered statistical toolkit with a Python API and pandas Styler integration.

---

🔧 Overview

bunker-stats is a hybrid Rust and Python library providing:

• Fast statistical primitives\
• Rolling window analytics\
• Distribution tools\
• pandas Styler visualizations

Everything runs on Rust for speed and correctness.

---

🧭 Project Philosophy and Status

v0.1 is an intentional early release.

This library focuses on correctness, clean APIs, and solid statistical foundations.

🔮 Future Focus

• Performance tuning (SIMD, fused loops, BLAS ops)\
• Smarter rolling window engines\
• More visualization helpers\
• NaN safe variants\
• Multi column Rust kernels\
• Faster correlation matrix engine

---

🚀 Features

Core statistics (Rust)

• Mean, variance, standard deviation\
• Sample vs population versions\
• Z scores\
• MAD\
• Percentiles and quantiles\
• IQR and Tukey fences\
• Covariance, correlation\
• Welford one pass algorithms\
• EWMA

Rolling analytics

• Rolling mean, std, z score\
• Rolling covariance, correlation\
• Planned fused pipelines

Distribution tools

• ECDF\
• Gaussian KDE\
• Quantile binning\
• Winsorization

Transforms

• Robust scaling using Median and MAD\
• diff, pct_change, cumsum, cummean

pandas Styler

• demean_style(df, column)\
• zscore_style(df, column, threshold=...)\
• iqr_outlier_style(df, column)\
• corr_heatmap(df)\
• robust_scale_column(df, column)

🧩 API Map (v0.2.7): Functions + Module Locations

bunker-stats exposes SciPy-style numerical routines from Rust via Python bindings. Internally, the crate is organized into two main Rust modules:

• src/lib.rs — public Python-facing wrappers + core vector ops
• src/infer/* — inference / hypothesis tests (SciPy parity focus)
• src/kernels/* — internal kernels used by wrappers (rolling, quantiles, robust, matrices, etc.)

Python calling style: functions are imported from bunker_stats (or whichever top-level module you expose in __init__.py). Below, “Location” refers to the Rust source module.

bunker-stats v0.2.8 — Release Notes

🔁 Sandbox Integration (Major Internal Milestone)

v0.2.8 integrates nearly all functionality from the sandbox into the main library, consolidating experimental work into a single, coherent Rust core with a stable Python API.

This release significantly expands the scope of bunker-stats beyond core statistics into resampling, time-series diagnostics, and distribution utilities, while keeping the original performance and numerical-stability goals intact.

---

✨ New & Expanded Capabilities

Resampling utilities

Bootstrap utilities

• bootstrap_mean
• bootstrap_mean_ci
• bootstrap_ci
• bootstrap_corr

Jackknife utilities

• jackknife_mean
• jackknife_mean_ci

All resampling routines are implemented in Rust and exposed via Python, avoiding Python-level resampling loops.

---

Time-series diagnostics & analysis

Stationarity tests

• Augmented Dickey–Fuller (ADF)
• KPSS
• Phillips–Perron (PP)

Diagnostic tests

• Ljung–Box
• Durbin–Watson

Autocorrelation tools

• ACF
• PACF
• Rolling autocorrelation

Spectral analysis

• Periodogram
  (currently skipped in benchmarks; see Known Issues)

---

Distribution helpers

Normal distribution

• norm_pdf
• norm_cdf
• norm_ppf

Exponential distribution

• exp_pdf
• exp_cdf

Uniform distribution

• unif_pdf
• unif_cdf

These helpers are lightweight numerical kernels designed for fast evaluation on large arrays.

---

Benchmarking focus (continued)

Benchmarks remain a first-class concern in this release:

• 500k-row workloads
• Subprocess isolation per function
• Warmups + repeated runs
• Percentile latency reporting (p50 / p95 / p99)
• Coefficient of variation (CV) for stability
• Optional peak memory tracking

This ensures results reflect realistic orchestration costs, not just microbenchmarks.

---

📈 Performance Summary

Strongest wins remain concentrated in:

• Rolling / windowed statistics
• Pairwise operations (covariance, correlation, rolling cov/corr)
• Several inference tests (e.g., chi-square, t-tests)

Performance improvements come primarily from:

• Fewer passes over data
• Reduced allocations
• Cache-friendly Rust loops
• Avoidance of Python-level rolling and masking logic

---

⚠️ Known Issues (Short & Explicit)

• bg_test is currently skipped (known correctness issue)
• periodogram is currently skipped in benchmarks
• norm_ppf currently expects inputs in [0, 1]
  (input validation and error handling to be improved)

---

🔮 Planned for v0.2.9

Performance & architecture

• Matrix / axis-wise performance fixes
• Reduce Python ↔ Rust marshaling overhead
  • Avoid Vec<Vec<f64>> rebuilds
  • Minimize copies
  • Return contiguous buffers more efficiently

Safety & correctness

• Replace internal panics with clean Python exceptions
• Improve input validation (e.g., norm_ppf and similar edge cases)

Benchmark & API hardening

• Tighten parity tolerances where appropriate
• Ensure benchmarks reflect the cleaned surface API
  • No _np-name coupling
  • Benchmark against public, documented functions only

General improvements

• Optimization pass on hotspots revealed by 500k-row benchmarks
• Documentation & docstrings for Python-facing APIs
  • Clear parameter semantics
  • Short usage examples

---

📦 What Else Came from the Sandbox (sand_lib.rs → lib.rs)

In addition to the headline features above, the sandbox also contributed:

• Internal Rust kernel refactors that:
  • Standardized slice-based APIs (&[f64]) for statistical routines
  • Reduced duplicated logic across inference and resampling paths
• Shared numerical helpers reused by:
  • Bootstrap
  • Jackknife
  • Hypothesis tests
• Consistent return-value conventions across:
  • Scalars
  • Tuples (e.g.

---

✅ Inference (SciPy parity) — src/infer/*

These are registered from src/lib.rs but implemented in the infer module:

Function (Python syntax)	Location (Rust)
t_test_1samp_np(x, popmean, alternative="two-sided") -> {"statistic": float, "pvalue": float}	src/infer/ttest.rs (infer::ttest::t_test_1samp_np)
t_test_2samp_np(x, y, equal_var=False, alternative="two-sided") -> {"statistic": float, "pvalue": float}	src/infer/ttest.rs (infer::ttest::t_test_2samp_np)
chi2_gof_np(observed, expected=None) -> {"statistic": float, "pvalue": float}	src/infer/chi2.rs (infer::chi2::chi2_gof_np)
chi2_independence_np(table) -> {"statistic": float, "pvalue": float, ...}	src/infer/chi2.rs (infer::chi2::chi2_independence_np)
mean_diff_ci_np(x, y, confidence=0.95) -> {"mean_diff": float, "ci_low": float, "ci_high": float}	src/infer/effect.rs (infer::effect::mean_diff_ci_np)
cohens_d_2samp_np(x, y, pooled=True) -> float	src/infer/effect.rs (infer::effect::cohens_d_2samp_np)
mann_whitney_u_np(x, y, alternative="two-sided") -> {"statistic": float, "pvalue": float}	src/infer/mann_whitney.rs (infer::mann_whitney::mann_whitney_u_np)
ks_1samp_np(x, dist="norm", args=None, alternative="two-sided") -> {"statistic": float, "pvalue": float}	src/infer/ks.rs (infer::ks::ks_1samp_np)

---

⚙️ Core numeric + transforms — src/lib.rs

Below are the Python-callable functions defined/registered in src/lib.rs. (Internally, many call kernels in src/kernels/*.)

Basic statistics (1D)

• mean_np(a) -> float — src/lib.rs
• mean_skipna_np(a) -> float — src/lib.rs
• mean_nan_np(a) -> float — src/lib.rs
• var_np(a) -> float — src/lib.rs
• var_skipna_np(a) -> float — src/lib.rs
• var_nan_np(a) -> float — src/lib.rs
• std_np(a) -> float — src/lib.rs
• std_skipna_np(a) -> float — src/lib.rs
• std_nan_np(a) -> float — src/lib.rs
• zscore_np(a) -> np.ndarray — src/lib.rs
• zscore_skipna_np(a) -> np.ndarray — src/lib.rs
• skew_np(a) -> float — src/lib.rs
• kurtosis_np(a) -> float — src/lib.rs

Quantiles / robust summaries

• percentile_np(a, q) -> float — src/lib.rs (kernel: src/kernels/quantile/percentile.rs)
• iqr_np(a) -> (q1, q2, q3) — src/lib.rs (kernel: src/kernels/quantile/iqr.rs)
• iqr_width_np(a) -> float — src/lib.rs
• mad_np(a) -> float — src/lib.rs (kernel: src/kernels/robust/mad.rs)
• trimmed_mean_np(a, proportion_to_cut) -> float — src/lib.rs (kernel: src/kernels/robust/trimmed_mean.rs)
• winsorize_np(a, limits=(low, high)) -> np.ndarray — src/lib.rs (kernel: src/kernels/quantile/winsor.rs)
• winsorize_clip_np(a, lower, upper) -> np.ndarray — src/lib.rs

Rolling windows (1D + axis-0)

• rolling_mean_np(a, window, center=False) -> np.ndarray — src/lib.rs (kernel: src/kernels/rolling/*)

• rolling_var_np(a, window, center=False) -> np.ndarray — src/lib.rs

• rolling_std_np(a, window, center=False) -> np.ndarray — src/lib.rs

• rolling_mean_std_np(a, window, center=False) -> (means, stds) — src/lib.rs

• rolling_zscore_np(a, window, center=False) -> np.ndarray — src/lib.rs

• rolling_mean_axis0_np(a2d, window) -> np.ndarray — src/lib.rs (kernel: src/kernels/rolling/axis0.rs)

• rolling_std_axis0_np(a2d, window) -> np.ndarray — src/lib.rs

• rolling_mean_std_axis0_np(a2d, window) -> (means, stds) — src/lib.rs

Pairwise covariance/correlation (1D) + rolling variants

• cov_np(x, y) -> float — src/lib.rs

• corr_np(x, y) -> float — src/lib.rs

• cov_nan_np(x, y) -> float — src/lib.rs

• corr_nan_np(x, y) -> float — src/lib.rs

• rolling_cov_np(x, y, window) -> np.ndarray — src/lib.rs (kernel: src/kernels/rolling/covcorr.rs)

• rolling_corr_np(x, y, window) -> np.ndarray — src/lib.rs

• rolling_cov_nan_np(x, y, window) -> np.ndarray — src/lib.rs

• rolling_corr_nan_np(x, y, window) -> np.ndarray — src/lib.rs

Matrix outputs (2D)

• cov_matrix_np(a2d) -> np.ndarray — src/lib.rs (kernel: src/kernels/matrix/cov.rs)
• corr_matrix_np(a2d) -> np.ndarray — src/lib.rs (kernel: src/kernels/matrix/corr.rs)

Scaling / preprocessing

• standard_scale_np(a) -> np.ndarray — src/lib.rs
• minmax_scale_np(a, feature_range=(0,1)) -> np.ndarray — src/lib.rs
• robust_scale_np(a) -> np.ndarray — src/lib.rs

Time-series style transforms

• diff_np(a, periods=1) -> np.ndarray — src/lib.rs
• pct_change_np(a, periods=1) -> np.ndarray — src/lib.rs
• cumsum_np(a) -> np.ndarray — src/lib.rs
• cummean_np(a) -> np.ndarray — src/lib.rs

Distribution / empirical helpers

• ecdf_np(a) -> (x_sorted, y) — src/lib.rs
• quantile_bins_np(a, q) -> np.ndarray[int] — src/lib.rs

Debug / masks / misc utilities

• sign_mask_np(a) -> np.ndarray[bool] — src/lib.rs
• demean_with_signs_np(a, signs) -> np.ndarray — src/lib.rs
• pad_nan_np(a, left, right) -> np.ndarray — src/lib.rs

Extra / niche

• welford_np(a) -> (mean, variance, n) — src/lib.rs
• kde_gaussian_np(a, bw=None) -> (grid, density) — src/lib.rs

Effect sizes (also available from core wiring)

• hedges_g_2samp_np(x, y, pooled=None) -> float — src/lib.rs
• hedges_g_2samp_raw_np(x, y, pooled=True) -> float — src/lib.rs

---

🔧 Internal kernels (not called directly from Python) — src/kernels/*

Many wrappers in src/lib.rs delegate to optimized kernels, including:

• src/kernels/rolling/* — rolling engines, axis-0 rolling, rolling cov/corr, fused zscore
• src/kernels/quantile/* — percentile (quickselect), IQR, winsorization
• src/kernels/robust/* — MAD, trimmed mean
• src/kernels/matrix/* — covariance/correlation matrices

These are implementation details, but the module split is what makes the library fast and maintainable.

Importing bunker-stats

Although bunker-stats is internally organized into Rust modules (e.g. inference and numeric kernels), the Python API is intentionally flat.

All functions are imported from the top-level package:

import bunker_stats as bs

bs.rolling_mean_np(x, window=30)
bs.mann_whitney_u_np(x, y)
bs.ks_1samp_np(x, dist="norm")



---

## Senior-dev recommendation (very clear)

For **v0.2.7**, your current approach is **correct**:
- flat Python API
- internal Rust modularization
- zero breaking changes for users

Don’t expose Python submodules until:
- the API is larger
- you need namespacing for clarity
- you’re closer to v1.0

If you want, next I can:
- audit your `__init__.py` for API cleanliness
- help you design a future `bunker_stats.infer` layout
- or write a “Quick Start” section for the README

But as of now: **users import it exactly like they always did.**

------------------------------------------------------------------------

| Function                 | Bunker-stats syntax                                   | NumPy equivalent                               | pandas equivalent                              | Unique feature in `bunker-stats`                                                                 |
|-------------|-------------|-------------|-------------|--------------------|
| `mean`                   | `bs.mean(x)`                                          | `np.mean(x)`                                   | `s.mean()`                                     | 1D mean helper; always treats input as 1D numeric, thin Rust-backed wrapper.                     |
| `mean_skipna`            | `bs.mean_skipna(x)`                                   | `np.nanmean(x)` / manual mask                  | `s.mean(skipna=True)`                          | NaN-aware mean with explicit “skipna” semantics, matching pandas mental model.                   |
| `var`                    | `bs.var(x)`                                           | `np.var(x, ddof=1)`                            | `s.var(ddof=1)`                                | 1D **sample** variance (`ddof=1`) by default; matches stats textbooks.                           |
| `var_skipna`             | `bs.var_skipna(x)`                                    | `np.nanvar(x, ddof=1)` / mask                  | `s.var(skipna=True, ddof=1)`                   | NaN-aware sample variance in one call.                                                           |
| `std`                    | `bs.std(x)`                                           | `np.std(x, ddof=1)`                            | `s.std(ddof=1)`                                | 1D sample std with fixed `ddof=1`, consistent with `var`.                                        |
| `std_skipna`             | `bs.std_skipna(x)`                                    | `np.nanstd(x, ddof=1)` / mask                  | `s.std(skipna=True, ddof=1)`                   | NaN-aware sample std; avoids writing masks every time.                                           |
| `percentile`             | `bs.percentile(x, q=0.95)`                            | `np.quantile(x, 0.95)` / `np.percentile`       | `np.quantile(s, 0.95)`                         | Clean 1D percentile with your interpolation; integrated with other robust stats.                 |
| `mad`                    | `bs.mad(x)`                                           | manual median/MAD                              | custom or `s.mad()` (mean abs dev, not median) | True median absolute deviation used by `robust_scale`.                                           |
| `iqr`                    | `q1, q3, iqr = bs.iqr(x)`                             | `scipy.stats.iqr(x, rng=(25,75))`              | `s.quantile([0.25, 0.75])`                     | Returns `(q1, q3, iqr)` in one go; no juggling multiple calls / indices.                         |
| `mean_axis`              | `bs.mean_axis(X, axis=0, skipna=False)`               | `np.mean(X, axis=0)`                           | `df.mean(axis=0, skipna=...)`                  | Axis-wise mean for 1D/2D arrays with optional `skipna`.                                          |
| `var_axis`               | `bs.var_axis(X, axis=1, skipna=True)`                 | `np.var(X, axis=1, ddof=1)` (no native skipna) | `df.var(axis=1, skipna=...)`                   | Axis-wise sample variance with built-in NaN handling.                                            |
| `std_axis`               | `bs.std_axis(X, axis=1, skipna=True)`                 | `np.std(X, axis=1, ddof=1)` (no native skipna) | `df.std(axis=1, skipna=...)`                   | Axis-wise sample std + `skipna`; aligns pandas mental model with NumPy arrays.                   |
| `mean_last_axis`\*       | `bs.mean_last_axis(X)` *(if exposed)*                 | `np.mean(X, axis=-1)`                          | `df.to_numpy().mean(axis=-1)`                  | N-D mean over last axis, consistent with your N-D rolling API.                                   |
| `rolling_mean_last_axis` | `bs.rolling_mean_last_axis(X, window=3)`              | manual reshape + loop / `np.apply_along_axis`  | no built-in; need groupby+apply / custom logic | Shape-preserving N-D rolling mean over **last axis** (e.g. `(batch, feat, time)`).               |
| `rolling_std_last_axis`  | `bs.rolling_std_last_axis(X, window=3)`               | same as above                                  | same                                           | N-D rolling std over last axis; perfect for batched time-series / ML tensors.                    |
| `rolling_mean`           | `bs.rolling_mean(x, window=5)`                        | manual loop or `np.convolve` trick             | `s.rolling(5).mean()`                          | Fast 1D rolling mean (truncated length) with no index overhead.                                  |
| `rolling_std`            | `bs.rolling_std(x, window=5)`                         | manual loop                                    | `s.rolling(5).std()`                           | 1D rolling std at Rust speed, sample variance convention.                                        |
| `rolling_zscore`         | `bs.rolling_zscore(x, window=20)`                     | manual window loop                             | `s.rolling(20).apply(custom)`                  | Rolling z-score in a single function; avoids `apply`/UDF overhead.                               |
| `ewma`                   | `bs.ewma(x, alpha=0.1)`                               | manual recurrence                              | `s.ewm(alpha=0.1).mean()`                      | Minimal EWMA for pure numeric arrays, no pandas object overhead.                                 |
| `df_rolling_mean`        | `bs.df_rolling_mean(df, window=5)`                    | `np.convolve` per column                       | `df.rolling(5).mean()`                         | DataFrame in / out, but columns powered by Rust rolling mean.                                    |
| `df_rolling_std`         | `bs.df_rolling_std(df, window=5)`                     | manual per-column                              | `df.rolling(5).std()`                          | Same for std; uses your rolling core but preserves pandas index.                                 |
| `df_ewma`                | `bs.df_ewma(df, alpha=0.1)`                           | manual per-column EWMA                         | `df.ewm(alpha=0.1).mean()`                     | Per-column EWMA with Rust engine, lighter than full pandas EWM machinery.                        |
| `col_mean`               | `bs.col_mean(df, skipna=True)`                        | `np.mean(df.to_numpy(), axis=0)`               | `df.mean(axis=0, skipna=True)`                 | Column-wise mean; internally uses `mean_axis` + `skipna`, returns labeled Series.                |
| `row_mean`               | `bs.row_mean(df, skipna=True)`                        | `np.mean(df.to_numpy(), axis=1)`               | `df.mean(axis=1, skipna=True)`                 | Row-wise mean with Rust numeric core + pandas index.                                             |
| `cov_df`                 | `bs.cov_df(df)`                                       | `np.cov(df.to_numpy().T, ddof=1)`              | `df.cov()`                                     | Full covariance matrix via Rust `cov_matrix`, but returned as a DataFrame.                       |
| `corr_df`                | `bs.corr_df(df)`                                      | `np.corrcoef(df.to_numpy().T)`                 | `df.corr()`                                    | Correlation matrix backed by your Rust correlation engine.                                       |
| `rolling_mean_series`    | `bs.rolling_mean_series(s, window=10)`                | manual 1D loop                                 | `s.rolling(10).mean()`                         | Series-in / Series-out convenience wrapper around Rust rolling mean.                             |
| `rolling_std_series`     | `bs.rolling_std_series(s, window=10)`                 | manual 1D loop                                 | `s.rolling(10).std()`                          | Same for std; keeps index alignment, uses Rust core.                                             |
| `iqr_outliers`           | `bs.iqr_outliers(x, k=1.5)`                           | `iqr = scipy.stats.iqr(x); mask = ...`         | quantiles + boolean mask                       | Returns a boolean outlier mask in one call using IQR rule.                                       |
| `zscore_outliers`        | `bs.zscore_outliers(x, threshold=3.0)`                | `(np.abs((x-x.mean())/x.std()) > 3)`           | same logic on `Series`                         | One-liner z-score outlier mask; integrates with your `mean`/`std` semantics.                     |
| `minmax_scale`           | `scaled, mn, mx = bs.minmax_scale(x)`                 | manual `(x-mn)/(mx-mn)`                        | use `MinMaxScaler` from sklearn                | Returns both **scaled data** and the `(min, max)` used (for inverse-transform/reuse).            |
| `robust_scale`           | `scaled, med, mad = bs.robust_scale(x, scale_factor)` | manual MAD calculation                         | `RobustScaler` or custom                       | All-in-one robust scaling with returned `(median, MAD)`; pairs with your `mad`.                  |
| `winsorize`              | `bs.winsorize(x, lower_q=0.05, upper_q=0.95)`         | `scipy.stats.mstats.winsorize(x, limits=...)`  | custom quantile clipping                       | 1D winsorization in Rust, single call returning a full adjusted array.                           |
| `diff`                   | `bs.diff(x, periods=1)`                               | `np.diff(x, n=1)` (shorter) / manual padding   | `s.diff(periods=1)`                            | Full-length diff with NaNs where necessary; supports negative `periods`.                         |
| `pct_change`             | `bs.pct_change(x, periods=1)`                         | manual `(x[i]-x[i-p]) / x[i-p]`                | `s.pct_change(periods=1)`                      | Includes divide-by-zero → NaN handling; symmetric for positive/negative lags.                    |
| `cumsum`                 | `bs.cumsum(x)`                                        | `np.cumsum(x)`                                 | `s.cumsum()`                                   | Rust implementation; value is performance on large 1D arrays.                                    |
| `cummean`                | `bs.cummean(x)`                                       | `np.cumsum(x)/np.arange(1,len(x)+1)`           | `s.expanding().mean()`                         | Streaming cumulative mean without constructing expanding windows.                                |
| `ecdf`                   | `vals, probs = bs.ecdf(x)`                            | manual sort + rank                             | custom `rank`/`value_counts`                   | Returns **sorted values + CDF** in one go; perfect for ECDF plots.                               |
| `quantile_bins`          | `bins = bs.quantile_bins(x, n_bins=10)`               | manual rank + binning                          | `pd.qcut(x, q=10)` (Categorical)               | Returns plain integer bin labels `0..n_bins-1` as a NumPy array (ML-friendly).                   |
| `sign_mask`              | `mask = bs.sign_mask(x)`                              | `np.sign(x).astype(np.int8)`                   | `(s > 0) - (s < 0)`                            | Encodes sign into `{-1, 0, 1}`; useful for discrete signal features.                             |
| `demean_with_signs`      | `demeaned, signs = bs.demean_with_signs(x)`           | `(x - x.mean(), np.sign(x - x.mean()))`        | custom                                         | Returns **both** demeaned data and sign mask in one pass.                                        |
| `cov`                    | `bs.cov(x, y)`                                        | `np.cov(x, y, ddof=1)[0,1]`                    | `s1.cov(s2)`                                   | 1D sample covariance as a simple scalar function.                                                |
| `corr`                   | `bs.corr(x, y)`                                       | `np.corrcoef(x, y)[0,1]`                       | `s1.corr(s2)`                                  | 1D Pearson correlation using your var/std core.                                                  |
| `cov_skipna`             | `bs.cov_skipna(x, y)`                                 | manual pairwise dropna + `np.cov`              | `s1.cov(s2)` with aligned/dropna               | Pairwise NaN dropping built in for 1D covariance.                                                |
| `corr_skipna`            | `bs.corr_skipna(x, y)`                                | manual pairwise dropna + `np.corrcoef`         | `s1.corr(s2)` with dropna                      | Same but for correlation; hides the messy mask-bookkeeping.                                      |
| `cov_matrix`             | `bs.cov_matrix(X)`                                    | `np.cov(X, rowvar=False, ddof=1)`              | `df.cov()`                                     | Symmetric covariance matrix with Rust loops; tuned for tabular X.                                |
| `corr_matrix`            | `bs.corr_matrix(X)`                                   | `np.corrcoef(X, rowvar=False)`                 | `df.corr()`                                    | Correlation matrix built on your cov/std stack; consistent behaviour across code paths.          |
| `rolling_cov`            | `bs.rolling_cov(x, y, window=50)`                     | manual sliding window + `np.cov`               | `df['x'].rolling(50).cov(df['y'])`             | Rolling 1D covariance without pandas overhead; good for streaming stats.                         |
| `rolling_corr`           | `bs.rolling_corr(x, y, window=50)`                    | manual sliding window + `np.corrcoef`          | `df['x'].rolling(50).corr(df['y'])`            | Rolling 1D correlation in one Rust call; no custom loop needed in Python.                        |
| `kde_gaussian`           | `grid, dens = bs.kde_gaussian(x, n_points=256)`       | `scipy.stats.gaussian_kde(x)` + evaluation     | no direct builtin (need SciPy)                 | Lightweight 1D Gaussian KDE; returns `(grid, density)` using a simple bandwidth rule by default. |

## 📦 Installation

\`\`\`bash git clone https://github.com/bunker-stats.git cd bunker-stats

python -m venv .venv source .venv/bin/activate \# Windows: .venv\Scripts\activate

pip install maturin maturin develop