Stability Generative Models

• Release SD-XL 0.9-base and SD-XL 0.9-refiner models
• Release new sgm codebase
• Remove extensive subclassing
• Handle all types of conditioning inputs (vectors, sequences and spatial conditionings, and all combinations thereof) in a single class GeneralConditioner
• Separate guiders and samplers independent of the model
• Adopt the "denoiser framework" for both training and inference
• Discrete times models are special case of continuous time models
• Make independent following features: weighting of the diffusion loss function, preconditioning of the network, and sampling of noise levels during training
• Clean up Autoencoding models