Testing GPT-4's ability to predict sales

Experimenting with GPT-4's ability to code in R and forecast future sales in the Kaggle store sales competition. Prepares and merges the data, implements parallel processing, then trains Meta's Prophet model and scores .50559 (top 200 at the time of posting). I mostly let GPT-4 lead the way and debug it's own code, but ultimately had to do some heavy nudging to get a decent solution. Clone the repo, download and unzip the data into the cloned directory, then run the script.