One CPU

 I have solved it with a cpu installation by installing this : https://github.com/krychu/llama instead of https://github.com/facebookresearch/llama

Complete process to install :

1. download the original version of Llama from : https://github.com/facebookresearch/llama and extract it to a llama-main folder
2. download th cpu version from : https://github.com/krychu/llama and extract it and replace files in the llama-main folder
3. run the download.sh script in a terminal, passing the URL provided when prompted to start the download
4. go to the llama-main folder
5. cretate an Python3 env : python3 -m venv env and activate it : source env/bin/activate
6. install the cpu version of pytorch : python3 -m pip install torch torchvision torchaudio --index-url https://download.pytorch.org/whl/cpu #pour la version cpu
7. install dependencies off llama : python3 -m pip install -e .
8. run if you have downloaded llama-2-7b :

torchrun --nproc_per_node 1 example_text_completion.py \
    --ckpt_dir llama-2-7b/ \
    --tokenizer_path tokenizer.model \
    --max_seq_len 128 --max_batch_size 1 #(instead of 4)