Termux-BitNet

Production 1.58-bit (i2_s) BitNet On-Device Inference SDK & Dual Engine for Android Termux & ARM64.

[!WARNING]

Public Engineering Disclosure & Upstream Contributions: Permanent Elimination of Interim Heuristics

In earlier development iterations prior to v1.3.0, when confronted with upstream ARM dequantization mismatches and missing NEON kernel paths in the upstream repository, an interim heuristic fallback was temporarily utilized to produce candidate outputs under mobile device constraints.

This technical limitation has been completely resolved, validated on real hardware, and permanently eliminated. Through architectural reverse engineering and direct upstream contributions to Microsoft's official microsoft/BitNet ecosystem:

1. Upstream PR #551 (microsoft/BitNet#551): Identified and isolated the original ARM i2_s tensor corruption ("word salad") and layout divergence on mobile architectures.
2. Upstream PR #624 (microsoft/BitNet#624): Fully implemented the missing __ARM_NEON 4-row parallel kernel (1x4_32W) utilizing ARMv8.2-A sdot hardware dot-product acceleration, automated Android Termux environment detection, and validated genuine on-device inference on Samsung Galaxy devices (Snapdragon 8 Elite and Exynos 1380).
3. Mathematical Resolution of Dequantization Centering: Solved the 32-way interleaved dequantization center mismatch (correcting unsigned raw ${0, 1, 2}$ mapping vs. centered ${-1, 0, 1}$ dot product with activation summation), eradicating repetitive token degeneration defects.
4. Strict Zero-Mock & Fail-Fast Engineering Standard: Operating strictly with 100% genuine on-device C++ inference. If a native binary or kernel cannot execute, the engine strictly fails fast with explicit error codes and remediation steps rather than emitting deceptive mock responses.

Verified Real-Device On-Device Benchmarks (BitNet b1.58 2B-4T i2_s natively inside Android Termux):

• Samsung Galaxy S25 (Snapdragon 8 Elite / Oryon CPU): 5.12 tokens/sec (~195.3 ms/tok prompt eval)
• Samsung Galaxy A35 5G (Samsung Exynos 1380): 1.57 tokens/sec (~636.9 ms/tok prompt eval)

1. Overview & Architecture

termux-bitnet is an optimized on-device inference engine and dual SDK (Python & Node.js) engineered for running 1.58-bit quantized Large Language Models (BitNet b1.58) natively on Android Termux, ARM64 mobile processors, and edge devices.

The underlying computation engine executes 1.58-bit ternary quantized weights {-1, 0, +1} directly via hand-vectorized ARM64 NEON SIMD and DotProd vector instructions (vdotq_s32), replacing floating-point matrix multiplications with integer additions and subtractions under a sub-250MB RAM footprint.

[Python Application / CLI]        [Node.js / TypeScript App]
       │                                     │
       ▼ (BitNetEngine / ctypes)             ▼ (BitNetEngine / FFI)
[termux-bitnet Python SDK]        [termux-bitnet npm Thin Gateway]
       │                                     │
       └──────────────────┬──────────────────┘
                          │
                          ▼ (Strict C ABI: libtermux_bitnet.so)
         [Native C++17 BitNet Core Engine]
                          │
                          ▼
    [ARM64 NEON + DotProd (vdotq_s32) Vector Kernels]

2. Verified BitNet GGUF Model Registry

termux-bitnet provides deterministic model downloading and caching from verified Hugging Face repositories with HTTP Range resume capability:

3. Installation & Verification

3.1 Automated Installer (Precompiled Binary or Fast Native Build)

The recommended installation method uses install.sh, which automatically downloads verified ARM64 prebuilt binaries from GitHub Releases or compiles the native C++ core on the device:

curl -sL https://raw.githubusercontent.com/uno-km/termux-bitnet/main/install.sh | bash

3.2 Python Package (PyPI)

# Inside Android Termux (prerequisites: clang cmake python openblas)
pkg update && pkg install -y clang cmake python openblas
pip install termux-bitnet

3.3 Node.js / TypeScript Thin Gateway (npm)

# Global CLI installation (Provides 'termux-bitnet-js' command)
npm install -g termux-bitnet

3.4 Hardened Manual Compilation Workflow

To compile the native C++ engine manually with verified hardware acceleration on Samsung Exynos (Cortex-A78/A55) or Qualcomm Snapdragon (Oryon/Kryo):

# 1. Install prerequisites in Termux
pkg install -y clang cmake openblas libandroid-execinfo

# 2. Configure CMake with explicit NEON + DotProd and Clang toolchain
cmake -B build   -DGGML_NEON=ON   -DGGML_ARM_DOTPROD=ON   -DCMAKE_C_COMPILER=clang   -DCMAKE_CXX_COMPILER=clang++   -DCMAKE_BUILD_TYPE=Release

# 3. Build native standalone CLI and shared library
cmake --build build --target termux-bitnet-cli -j$(nproc 2>/dev/null || echo 4)

4. CLI Usage

4.1 Python CLI (termux-bitnet)

# 1. Hardware Diagnostic (ARM NEON & DotProd SIMD Verification)
termux-bitnet info

# 2. List Available Verified Models
termux-bitnet models

# 3. Download Model with Range Resume Support
termux-bitnet download bitnet-2b

# 4. Run On-Device Inference
termux-bitnet run -m ~/.cache/termux-bitnet/models/bitnet-2b-ggml-model-i2_s.gguf   -p "Explain quantum computing in one sentence."   -t 4 -c 2048 -n 64 --temp 0.7 --top-p 0.95

4.2 Node.js CLI (termux-bitnet-js)

# 1. Hardware Diagnostic
termux-bitnet-js info

# 2. Model Registry List
termux-bitnet-js models

# 3. Run Inference via Node.js Gateway
termux-bitnet-js run -m ~/.cache/termux-bitnet/models/bitnet-2b-ggml-model-i2_s.gguf   -p "Explain quantum computing in one sentence." -t 4 -n 64

5. Programmatic API

5.1 Python SDK

from termux_bitnet import BitNetEngine, BitNetConfig

# 1. Configure Engine Parameters
config = BitNetConfig(
    model_path="models/bitnet-2b.gguf",
    n_threads=4,
    device="auto",
    temperature=0.7,
    top_p=0.95,
    top_k=40,
    min_p=0.05,
    repeat_penalty=1.15,
)

# 2. Stream Generation with Dynamic Parameters
with BitNetEngine(config) as engine:
    print("[Prompt]: Write a Python palindrome check function")
    print("[Response]: ", end="", flush=True)
    for token in engine.generate_stream("Write a Python palindrome check function:"):
        print(token, end="", flush=True)
    print()
    metrics = engine.get_last_metrics()
    print(f"Speed: {metrics.tokens_per_second:.2f} tok/s, Prompt tokens: {metrics.prompt_tokens}")

5.2 Node.js & TypeScript SDK

const { createEngine } = require('termux-bitnet');

async function main() {
  const engine = createEngine({
    modelPath: 'models/bitnet-2b.gguf',
    threads: 4,
    device: 'auto',
    temperature: 0.7,
    topP: 0.95,
  });

  console.log('[Prompt]: Explain quantum computing in one sentence');
  console.log('[Response]: ');

  await engine.generateStream(
    'Explain quantum computing in one sentence',
    64,
    (token) => {
      process.stdout.write(token);
    }
  );
  console.log('\n');
}

main();

6. Configuration Parameter Matrix (BitNetConfig)

7. Official Documentation & Specifications

• Official Documentation Site: https://uno-km.vercel.app/lib/bitnet/
• AI Agent Context Feed: llms.txt
• Full Technical Specification: llms-full.txt

8. License & Foundation

Released under the Apache License 2.0.
Engineered under the AMEVA Open-Source Foundation (AOSF) & uno-km ecosystem.