OpenAI, Unknown Size, Not Open Source, API Access Only
Announced on March 14, 2023, GPT (Generative Pre-trained Transformer) 4 is Open AI’s latest model. While not strictly a language-only model as it can take as inputs images as well as text, it shows impressive performance on a variety of tasks including several professional medical and law exams.
GPT-4 also expands on the maximum input length compared to previous iterations, increasing it to a maximum of 32,768 tokens (about 50 pages of text!). Unfortunately little has been revealed about the model architecture or datasets used for training this model.