RumalGPT - Transformer Language Model From Scratch

A hands-on language-model engineering project focused on understanding the full training pipeline by building tokenization, transformer architecture, training loops, evaluation, checkpointing, and scaling experiments from scratch.

PythonPyTorchTransformersBPE TokenizerCUDAMixed PrecisionLLM Training2026

What I did

  • >Built custom byte-pair encoding/tokenization experiments and trained progressively larger decoder-only transformer models.
  • >Implemented configurable training runs with learning-rate scheduling, gradient accumulation, clipping, weight decay, validation, checkpointing, and perplexity tracking.
  • >Scaled experiments from sub-million-parameter prototypes toward a roughly 1B-parameter training configuration to study memory, throughput, convergence, and architecture trade-offs.
  • >Curated and mixed general-text, mathematical reasoning, and programming-oriented datasets for continued pretraining experiments.
  • >Used the project to study quantization, context length, attention, local inference, RAG concepts, evaluation, and the practical limits of consumer GPU hardware.

Case Study

Why I Built It

  • >The goal is to understand LLMs as systems, not only consume hosted APIs.
  • >Building the tokenizer, model, trainer, data pipeline, and evaluation loop exposes the engineering trade-offs hidden by high-level frameworks.

Engineering Focus

  • >Decoder-only transformer design with configurable model depth, width, attention heads, and context length.
  • >Training stability through warmup, learning-rate decay, gradient accumulation, clipping, optimizer tuning, validation, and checkpoints.
  • >Throughput and memory experiments on consumer NVIDIA hardware using mixed precision and GPU-aware training choices.

What It Demonstrates

  • >Comfort moving from infrastructure and backend engineering into ML systems and numerical workloads.
  • >Ability to debug long-running training pipelines using metrics such as loss, perplexity, tokens per second, memory usage, and checkpoint state.
  • >A learning-by-building approach that connects model architecture, data quality, hardware limits, and deployment choices.