Tensorless PyTorch

Tensorless PyTorch is a lightweight toolkit for turning ordinary text and tabular data into portable PyTorch models with minimal setup. It supports text generation, text classification, tabular classification, and regression.

The distribution is installed as tensorless-pytorch; the stable Python import remains tensorless for compatibility.

Install

pip install tensorless-pytorch

Train on your data

import tensorless as tl

model = tl.train("./corpus.txt", task="text-generation")
print(model.generate("The", max_new_tokens=40))

Text files are trained as next-token language models. BPE is the default tokenizer; use tokenizer="char" for a character-level model. Tensorless PyTorch derives model size, batch size, epochs, validation, device, and BPE vocabulary size from the data, while every setting can be overridden.

Text is tokenized once up front (not re-tokenized every epoch) and streamed through PyTorch in fixed-size batches. Model size is auto-scaled with corpus size across four tiers -- small, lower-mid, upper-mid, large -- capped at "upper-mid" (roughly 50M-350M parameters) unless you pass explicit d_model=/layers=/etc. yourself. New training runs use the architecture="v2" backbone (RoPE + RMSNorm + SwiGLU + KV-cached generation); older .tl checkpoints keep loading and running on the original "v1" backbone automatically. CUDA training automatically uses fp16 or bf16 when supported (with gradient scaling and checkpointed scaler state), TPU (XLA) training is supported via device="tpu", and large auto-sized models enable gradient checkpointing automatically to fit in memory. Reduce batch_size if memory is limited. The model that actually gets saved is always the best checkpoint seen during training (lowest validation loss, or lowest train loss when there's no validation split), not just whatever the final epoch happened to land on -- this protects against late-training instability (e.g. a run that looks fine for a while and then diverges) silently producing a broken saved model. This applies to both tl.train() and tl.pretrain().

English starter pretraining

import tensorless as tl

model = tl.pretrain(out="english.tl", epochs=20, max_seq_len=128)
print(model.generate("A complete sentence", max_new_tokens=30))

This offline starter corpus contains English prose and grammar examples. It is for demos and smoke tests, not a replacement for a large language dataset. For real pretraining, pass your own .txt corpus to tl.train() and increase the training settings as your hardware allows.

Pretrain, then fine-tune

import tensorless as tl

# 1. Pretrain a base model on a large general corpus
base = tl.train("./big_corpus.txt", task="text-generation", out="base.tl", epochs=20)

# 2. Fine-tune it on a smaller, task-specific dataset
tuned = tl.train("./my_conversations.json", task="text-generation",
                  out="tuned.tl", pretrained="base.tl", epochs=5)

pretrained= initializes training from an existing .tl checkpoint's weights instead of from scratch. The architecture (d_model, layers, heads, etc.) and tokenizer are locked to match the pretrained model exactly -- passing a conflicting override raises a clear error rather than silently ignoring it, since fine-tuning only works if token ids and embeddings line up with what the pretrained weights actually learned. You can also switch tasks while fine-tuning (e.g. a pretrained text-generation backbone into a text-classification model): matching layers (embeddings, attention, MLP blocks) transfer, and only the mismatched task head is reinitialized.

Other tasks

tl.train("reviews/", task="text-classification")
tl.train("housing.csv", task="regression")

Tabular preprocessing automatically handles numeric values, ISO dates, and high-cardinality categories. Missing and rare values are handled using the fitted training data, and the same preprocessing is stored in the .tl file.

Flexible data formats

tl.train() accepts far more than a single {"text": "..."} shape. JSON/JSONL/YAML records are auto-detected and normalized, in order: a known text field; chat-style turn lists ("messages"/"conversations", OpenAI- or ShareGPT-style); flat conversational pairs under common aliases (user/bot, human/gpt, instruction/input/output, prompt/ completion, ...); and, as a last resort, any other record is flattened into readable text rather than rejected. See docs/training.md for the full list.

tl.train("chats.jsonl", task="text-generation")  # [{"user": "...", "bot": "..."}, ...] just works

Internet browsing at inference time

Off by default; turn it on per-call, per-session, or from the CLI to let a text-generation model search the web for extra context before answering:

model = tl.load("model.tl")
model.generate("What's new in PyTorch this week?", internet="connect")

tensorless run model.tl --internet connect

See docs/inference.md.

Models are saved as .tl files and can be loaded later:

model = tl.load("model.tl")
print(model.info())

See the documentation for data formats, configuration, mixed precision, checkpointing, and the command-line interface.

Documentation map

• Installation - requirements, accelerators, and verification
• Quick start - the shortest path from data to a model
• Training - supported formats, task behavior, and training controls
• Configuration - every tl.train() option
• Inference - generation, prediction, chat, and optional web browsing
• Checkpointing - resume behavior and checkpoint contents
• CLI reference - tensorless train, run, inspect, and info
• API reference - stable Python API and errors

Version and compatibility

Check the installed version with:

python -c "import tensorless; print(tensorless.__version__)"

New training runs use the v2 transformer architecture. Existing .tl files retain their saved architecture and remain loadable when the installed format supports them. A .tl file contains the model weights, tokenizer or tabular preprocessor, resolved configuration, and metadata, so the original dataset is not required for inference.