finance datagen¶

Standard financial data generation

Overview¶

finance-datagen produces synthetic financial time series for testing, demos, and benchmarking the rest of the finance-* stack without relying on real market data. The numerical core is implemented in Rust and emits Apache Arrow RecordBatch values; the Python layer wraps each generator so the public API returns polars.DataFrame objects.

All public generator classes inherit from DataGenerator, a pydantic base model that validates typed parameters on construction. Use .generate() for the table output, or next(generator) for one-shot iterator-style use. Convenience functions such as generate_prices(...), generate_gbm(...), and generate_signal(...) instantiate the matching model and return .generate().

Generators¶

Price models (Rust core)¶

Symbol	Model	Output columns
`GBMGenerator`	Geometric Brownian Motion (log-Euler)	`timestamp, symbol, price`
`HestonGenerator`	Heston (1993) stochastic volatility (full-truncation Euler)	`timestamp, symbol, price, variance`
`GARCHGenerator`	GARCH(1,1) returns	`timestamp, symbol, price, return, sigma`
`ohlc_from_close`	OHLCV synthesis from any close series	`timestamp, symbol, open, high, low, close, volume`

Price-path convenience wrappers are also exported as generate_prices, generate_gbm, generate_heston, and generate_garch. generate_prices is a plain alias for generate_gbm for examples and tests that want a model-neutral name.

Python generators¶

Symbol	Output
`SignalGenerator`	Long-form `[date, symbol, signal, fwd_returns]` with target Pearson IC
`FactorLoadingsGenerator`	Wide `[symbol, market, value, momentum, size, quality]` Barra-style loadings
`BenchmarkGenerator`	`[date, benchmark]` Gaussian benchmark return series
`PositionsGenerator`	Long-form position panel `[date, symbol, price, quantity, market_value, weight]`
`TransactionsGenerator`	Transaction log with enum-backed side/position-effect labels and explicit costs
`OrdersGenerator`	Enum-backed order fixtures with side, order type, status, and time-in-force
`ExecutionsGenerator`	Enum-backed execution fixtures for simulated fills
`MultiAssetGBMGenerator`	Correlated multi-asset GBM panel `[timestamp, symbol, price, return]`
`RegimeSwitchingGenerator`	Markov regime-switching price path `[timestamp, symbol, price, return, regime]`
`MarketImpactCurveGenerator`	Participation-rate impact curves with temporary, permanent, and total impact in bps
`StatisticalRiskModelGenerator`	PCA-style factor loadings, factor returns, and specific variance
`FundamentalRiskModelGenerator`	Barra-style enum-backed sector/style loadings plus specific variance
`FactorCovarianceGenerator`	Symmetric positive semidefinite factor covariance matrix
`SpecificVarianceGenerator`	Positive idiosyncratic variance vector

Every Python generator has a matching generate_* convenience wrapper, including the legacy generate_signal, generate_factor_loadings, and generate_benchmark functions.

All Rust generators accept an optional seed: int for bit-reproducible output across platforms (ChaCha8 RNG); the Python generators accept a seed for numpy.random.default_rng.

Portfolio, transaction, order, execution, and market-model generators also support enum-backed metadata columns where applicable, including currency, exchange, region, instrument_type, market_type, and venue_type. Portfolio and transaction generators can use finance-dates.Calendar exchange calendars so generated dates and timestamps align with actual business days and session hours.

Quick start¶

from finance_datagen import OrdersGenerator, generate_prices, generate_signal, ohlc_from_close

closes = generate_prices(symbol="ACME", seed=0)
bars   = ohlc_from_close(closes["price"], symbol="ACME", seed=0)
signal = generate_signal(n_dates=20, n_assets=50, seed=0)
orders = OrdersGenerator(n_dates=3, n_assets=5, orders_per_day=10, exchange="XNYS", currency="USD", seed=0).generate()

See the Data page for model math, parameter ranges, and output schemas, and the API page for a complete function-level reference.

Architecture¶

The Rust core (rust/src/) is polars-free: every generator builds an arrow_array::RecordBatch and returns it through the Arrow C Data Interface PyCapsule via pyo3-arrow. The Python wrappers call polars.from_arrow(batch) on the receiving end. This keeps the polars-rs and polars-py codebases on opposite sides of a stable ABI boundary, avoiding the binary-incompatibility issues that come with linking polars from both Rust and CPython.