Llama2 + Haystack on Colab

I recently conducted some experiments with Llama2 and Haystack (https://github.com/deepset-ai/haystack), the NLP/LLM framework.

The notebook can be helpful for those trying to load Llama2 on Colab.

1) Installed Transformers from the main branch (and other libraries)

2) Loaded Llama-2-13b-chat-hf on Colab using 4-bit quantizazion, thanks to the material shared by Younes Belkada

3) Disabled Tensor Parallelism, which caused some issues

4) Installed a minimal version of Haystack

5) Found a hacky way to load the model in Haystack's PromptNode

6) Had a fun chat session with the model, discussing everything from David Guetta to Don Matteo (an Italian TV series)!