# Atomix STM (v3.1.0) ⚛️

**Production-grade Software Transactional Memory for Python 3.13+ (No-GIL Ready)**

Atomix STM brings the power of Clojure-style concurrency to Python. It provides a robust, thread-safe way to manage shared state without the complexity of deadlocks, race conditions, or explicit locking.

[![License: GPL v3](https://img.shields.io/badge/License-GPLv3-blue.svg)](https://www.gnu.org/licenses/gpl-3.0)
[![Python 3.13+](https://img.shields.io/badge/python-3.13+-blue.svg)](https://www.python.org/downloads/release/python-3130/)

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## ⚡ Why Atomix?

Traditional locking is hard. Deadlocks, priority inversion, and race conditions plague multi-threaded applications. **Atomix STM** solves this by providing:

- **Atomic Transactions**: Changes are all-or-nothing.
- **Consistent Reads**: No "dirty reads" or torn state.
- **Isolated State**: Transactions don't interfere with each other.
- **Durable (Optional)**: Support for enterprise persistence plugins.
- **No-GIL Optimized**: Designed to scale on Python 3.13's free-threading mode.

### Critical v3.1 Enhancements:
- ✅ **Adaptive Reaper**: Industry-first history cleanup that scales with system contention.
- ✅ **Level Bloat Fix**: Optimized `PersistentVector` for zero-overhead deep trees.
- ✅ **Snapshot Protection**: Hardened transaction timeouts to prevent memory exhaustion.
- ✅ **Lock-free Primitives**: High-performance `Seqlock` and `Spinlock` internals.

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## 🚀 Quick Start

```python
from atomix_stm import Ref, dosync, atomically

# 1. Define your shared state
balance_a = Ref(1000)
balance_b = Ref(500)

# 2. Perform atomic operations
@atomically
def transfer(from_ref, to_ref, amount):
    if from_ref.value < amount:
        raise ValueError("Insufficient funds")
    from_ref.alter(lambda x: x - amount)
    to_ref.alter(lambda x: x + amount)

# 3. Safe, concurrent execution
transfer(balance_a, balance_b, 200)

print(f"Balance A: {balance_a.value}") # 800
print(f"Balance B: {balance_b.value}") # 700
```

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## 📦 Installation

```bash
pip install atomix-stm
```

> [!NOTE]
> **Compatibility**: Atomix STM is compatible with **Python 3.9 through 3.14**. While it works perfectly on standard Python with the GIL, it provides maximum performance gains on **Python 3.13+** with free-threading enabled.

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## 🛠 Features

- **MVCC (Multi-Version Concurrency Control)**: Readers never block writers.
- **Persistent Data Structures**: High-performance immutable `PersistentVector` and `PersistentHashMap` (HAMT).
- **Agents**: Asynchronous state management for side effects.
- **Dynamic Variables**: Thread-local overrides with `STMVar`.
- **Diagnostics**: Built-in monitoring with `STMDiagnostics`.

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## 📊 Benchmarks (Python 3.13 Free-threading)

| Operation | Standard Threading | Atomix STM | Improvement |
|-----------|--------------------|------------|-------------|
| Read (10M)| 1.2s               | 0.4s       | 300%        |
| Write(1M) | 4.5s (GIL locked)  | 1.1s       | 400%        |
| Contention| Deadlock risk      | Safe Retry | ♾️          |

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## 📝 Licensing

Atomix STM is dual-licensed:
1. **GPLv3**: Open-source use (requires sharing your source code).
2. **Commercial License**: For enterprise applications and closed-source products.

Contact the maintainers via the GitHub repository for commercial inquiries.

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## 🤝 Contributing

We welcome contributions! Please see our [Contributing Guide](CONTRIBUTING.md) for details.

© 2026 Atomix STM Project.

