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ansigpt

What it is

ansigpt is a portable, zero-dependency C89 implementation of microgpt. It provides a minimal, readable version of a GPT-like transformer model written in standard ANSI C.

What problem it solves

It solves the complexity problem of modern LLM implementations by stripping them down to their core mathematical and structural components, making them accessible for educational study and highly portable across different operating systems and architectures.

Where it fits in the stack

Category: Tool / Framework

Typical use cases

  • Education: Learning the inner workings of the transformer architecture through a minimal C implementation.
  • Embedded AI: Running extremely small models on hardware that only supports C89.
  • Portability Testing: Verifying model logic on older or non-standard computing environments.

Strengths

  • Zero Dependencies: Requires only a standard C compiler.
  • High Portability: Compatible with virtually any system with a C89-compliant compiler.
  • Readability: The codebase is small enough to be understood in its entirety by a single developer.

Limitations

  • Capacity: Based on microgpt, meaning it is designed for tiny models with very limited reasoning or knowledge.
  • Performance: Lacks the heavy optimizations (SIMD, GPU acceleration) found in projects like llama.cpp.

When to use it

  • Use when you want to study the fundamental implementation of a GPT model without the noise of large-scale framework overhead.
  • Use for minimal AI tasks on restricted or legacy hardware.

When not to use it

  • Not suitable for running production-grade LLMs (e.g., Llama 3, Mixtral).
  • Not for tasks requiring complex reasoning or large context windows.

Sources / references