LIGEN: Open-Set Grounded Text-to-Image
Generation. Scheduled Sampling factor is only varied for
scheduled sampling during inference for improved quality and controllability.   negative_prompt (str or List[str], optional) —
The prompt or prompts to guide what to not include in image generation. If not defined, you need to
pass negative_prompt_embeds instead. Ignored when not using guidance (guidance_scale < 1).   num_images_per_prompt (int, opti