GPT (Generative Pretrained Trasnsformer) is a variant of the transformer architecture built upon the original decoder submodule and is designed for generative tasks. It was introduced by the paper “Improving Language Understanding by Generative Pre-Training” and specialises in generating texts and its application includes machine translation, text summarization, fiction writing, writing computer code, and more.
This type of models were primarily designed and trained for text completion tasks but they showed very versatile capabilities, both with zero-shot and few-shot learning tasks.