Practical overview
When it fits
Use it to study or adapt a PaLM-oriented RLHF training implementation when you can supply the data, model weights and compute needed for training.
Who it is for
- Developers and researchers exploring human-feedback-based fine-tuning workflows for PaLM-style models.
- Learners examining how language-model training, reward modeling and policy optimization fit together.
Documented uses
- Train a PaLM model and generate sequences.
- Train a reward model using curated human feedback and prompt/response masks.
- Provide a PaLM model, reward model and prompt token IDs to an RLHF trainer.
Requirements & limits
The public repository reports an MIT license. The README provides a pip installation command; it does not include a trained model for inference.
- The project is explicitly work in progress, and its README lists additional testing and development as todo items.
- Its examples require PyTorch and use CUDA; Flash Attention is shown as an option.
- The complete workflow depends on curated human-feedback data, prompt data, pretrained weights for the trainer stage, and substantial training resources.
Check current requirements in the official documentation. Source-based guidance does not mean OpenViST has run or independently tested this project.
Train a PaLM model and generate sequences
Run the README's example of autoregressive PaLM training and sequence generation.
Before you start
- Install the package with
pip install palm-rlhf-pytorch. - Use PyTorch and a CUDA device, as shown in the example.
Steps
Import
torchandPaLMfrompalm_rlhf_pytorch.Create a
PaLMinstance withnum_tokens=20000,dim=512,depth=12, andflash_attn=True, then move it to CUDA.Create a CUDA token sequence with
torch.randint(0, 20000, (1, 2048)), calculatepalm(seq, return_loss=True), and callloss.backward().After training, call
palm.generate(2048)to generate a sequence.
Expected outcome
The example computes a training loss and shows sequence generation after training.
Guide limitations
- The project is marked work in progress.
- The repository does not include a trained model for inference; the README describes generation after substantial training.
Train a reward model from curated human feedback
Use the README's example to train a binned-output reward model and obtain a reward score.
Before you start
- Install the package with
pip install palm-rlhf-pytorch. - Have curated human-feedback data; the README's code uses mock tensors as an illustration.
- Use PyTorch and a CUDA device, as shown in the example.
Steps
Import
torch,PaLM, andRewardModelfrompalm_rlhf_pytorch.Create a
PaLMwithnum_tokens=20000,dim=512,depth=12, andcausal=False; wrap it inRewardModelwithnum_binned_output=5and move the reward model to CUDA.Prepare token sequences, a boolean
prompt_maskdistinguishing prompt from response, and rating labels.Compute
reward_model(seq, prompt_mask=prompt_mask, labels=labels)and callloss.backward()to train.After training, call
reward_model(seq, prompt_mask=prompt_mask)to obtain a reward.
Expected outcome
The example computes a reward-model training loss and shows how to obtain a reward after training.
Guide limitations
- The README notes that fine-tuning a reward model from a pretrained transformer had overfitting issues in the original paper; LoRA is presented as an open-research option.
- The repository does not provide a trained model.
Sources & review
Source record details
- Source availability
- Active
- Sources checked
- 13 October 2026
- Original website title
- lucidrains/PaLM-rlhf-pytorch · Official homepage title · retained in its source language

