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Hyperparameter

Make configurable AI applications. Build for Python/Rust hackers.

Hyperparameter is a versatile library designed to streamline the management and control of hyperparameters in machine learning algorithms and system development. Tailored for AI researchers and Machine Learning Systems (MLSYS) developers, Hyperparameter offers a unified solution with a focus on ease of use in Python, high-performance access in Rust and C++, and a set of macros for seamless hyperparameter management.

5-Minute Try

pip install hyperparameter

# Run a ready-to-use demo
python -m hyperparameter.examples.quickstart

# Try the @hp.param CLI: override defaults from the command line
python -m hyperparameter.examples.quickstart --define greet.name=Alice --enthusiasm=3

# Inspect params and defaults
python -m hyperparameter.examples.quickstart -lps
python -m hyperparameter.examples.quickstart -ep greet.name

# Running from source? Use module mode or install editable
# python -m hyperparameter.examples.quickstart
# or: pip install -e .

Why Hyperparameter?

🚀 Unmatched Performance (vs Hydra)

Hyperparameter is built on a high-performance Rust backend, making it significantly faster than pure Python alternatives like Hydra, especially in inner-loop parameter access.

Method	Time (1M iters)	Speedup (vs Hydra)
HP: Injected (Native Speed)	0.0184s	856.73x 🚀
HP: Dynamic (Optimized)	2.4255s	6.50x ⚡️
Hydra (Baseline)	15.7638s	1.00x

Benchmark scenario: Accessing a nested parameter model.layers.0.size 1,000,000 times in a loop. See benchmark/ folder for reproduction scripts.

✨ Zero-Dependency Schema Validation

Hyperparameter supports structural validation using standard Python type hints without introducing heavy dependencies (like Pydantic or OmegaConf).

from dataclasses import dataclass
import hyperparameter as hp

@dataclass
class AppConfig:
    host: str
    port: int
    debug: bool = False

# Validates types and converts automatically: "8080" -> 8080 (int)
cfg = hp.config("config.toml", schema=AppConfig)

Key Features

For Python Users

Pythonic Syntax: Define hyperparameters using keyword argument syntax;
Intuitive Scoping: Control parameter scope through with statement;
Configuration File: Easy to load parameters from config files (JSON/TOML/YAML) with composition and interpolation support;
Zero-Overhead Validation: Optional schema validation using standard Python type hints;

For Rust and C++ Users

High-Performance Backend: Hyperparameter is implemented in Rust, providing a robust and high-performance backend for hyperparameter management. Access hyperparameters in Rust and C++ with minimal overhead, making it ideal for ML and system developers who prioritize performance.
Macro-Based Parameter Management: Hyperparameter provides a set of macros for both Rust and C++ users. These macros mimic Python's with statements and adhere to language-specific scoping rules.
Compile-Time Hashing: Both Rust and C++ interfaces utilize compile-time hashing of hyperparameter names, reducing runtime hash computation overhead.

Quick Start

Installation

pip install hyperparameter

Python

import hyperparameter as hp

@hp.param("foo")
def foo(x=1, y="a"):
    return f"x={x}, y={y}"

foo()  # x=1, y='a'

with hp.scope(**{"foo.x": 2}):
    foo()  # x=2, y='a'

Rust

fn foo() -> i32 {
    with_params! {
        @get x = foo.x or 1i32; // Read hyperparameter with default value

        println!("x={}", x);
    }
}

fn main() {
    foo(); // x=1

    with_params! {
        @set foo.x = 2i32; // Set hyperparameter

        foo(); // x=2
    }

    foo(); // x=1
}

C++

ASSERT(1 == GET_PARAM(a.b, 1), "get undefined param");
{
  auto guard = WITH_PARAMS(a, 1,        //
                            a.b, 2.0,    //
                            a.b.c, true, //
                            a.b.c.d, "str");
  ASSERT(1 == GET_PARAM(a, 0), "get int value");
  ASSERT(1 == GET_PARAM(a, 0), "get int value");
}

Detailed Usage Examples

Support for Default Values

Python

x = hp.scope.foo.x | "default value"

Rust

@get x = foo.x or "default value";

Scope Control of Parameter Values

Python

with hp.scope() as ps: # 1st scope start
    ps.foo.x=1
    with hp.scope() as ps2: # 2nd scope start
        ps.foo.y=2
    # 2nd scope end
# 1st scope end

Rust

with_params!{ // 1st scope start
    @set foo.x=1;

    with_params!{ //2nd scope start
        @set foo.y=2

        ...
    } // 2nd scope end
} // 1st scope end

Thread Isolation/Thread Safety

Python

@hp.param("foo")
def foo(x=1): # Print hyperparameter foo.x
    print(f"foo.x={x}")

with hp.scope() as ps:
    ps.foo.x=2 # Modify foo.x in the current thread

    foo() # foo.x=2
    threading.Thread(target=foo).start() # foo.x=1, new thread's hyperparameter value is not affected by the main thread

Rust

fn foo() { // Print hyperparameter foo.x
    with_params!{
        @get x = foo.x or 1;

        println!("foo.x={}", x);
    }
}

fn main() {
    with_params!{
        @set foo.x = 2; // Modify foo.x in the current thread

        foo(); // foo.x=2
        thread::spawn(foo); // foo.x=1, new thread's hyperparameter value is not affected by the main thread
    }
}

Command Line Application

In command line applications, it's common to define hyperparameters using command line arguments (e.g., -D, --define) and control hyperparameters on the command line. Here's an example in Python and Rust:

Python

# example.py
import hyperparameter as hp

@hp.param("example")
def main(a=0, b=1):
    print(f"example.a={a}, example.b={b}")

if __name__ == "__main__":
    import argparse
    parser = argparse.ArgumentParser()

    parser.add_argument("-D", "--define", nargs="*", default=[], action="extend")
    args = parser.parse_args()

    with hp.scope(*args.define):
        main()

Rust

// example.rs
use hyperparameter::*;
use hyperparameter_derive::Parser;

fn main() {
    #[derive(Parser, Debug)]
    struct DeriveArgs {
        #[arg(short = 'D', long)]
        define: Vec<String>,
    }

    let args = DeriveArgs::parse();

    with_params! {
        params ParamScope::from(&args.define);

        foo()
    }
}

fn foo() {
    with_params! {
        @get a = example.a or 0;
        @get b = example.b or 1;

        println!("example.a={}, example.b={}",a ,b);
    }
}

More Examples

parameter tuning for researchers

This example demonstrates how to use hyperparameter in research projects, and make experiments reproducible.

experiment tracing for data scientists

This example showcases experiment management with hyperparameter and result tracing with mlflow.tracing.

Behavior Guarantees (Semantic Contract)

Keys & hashing: keys use . for nesting, case is preserved, and hashing uses the same UTF-8 input and seed across Python/Rust/C++; invalid characters are an error.
Read precedence: current thread’s innermost scope > parent scopes outward > frozen global snapshot > user default. Writes only affect the current scope and rollback on exit.
Defaults vs. missing: only missing keys fall back to defaults; explicit None/False/0 are treated as existing values. Type conversion rules (bool/int/float/str) are consistent across languages; invalid values use a best-effort conversion and otherwise fall back to the provided default (no silent random values).
Threads & frozen(): each thread starts from the frozen global snapshot; mutations stay in-thread unless frozen() is called, which atomically updates the global snapshot. Global mutations are lock-protected in the Python backend, matching Rust semantics.
Error model: reading an undefined key without a default raises a key error; backend load failure falls back to the Python backend without noisy tracebacks; no silent failure on type errors.
Multiprocess notice: cross-process consistency requires a shared backend (e.g., Rust backend or user-provided storage adapter); the built-in Python backend only guards threads, not processes.