Image Generation with Probabilistic Diffusion Models on MNIST dataset

1. Implement DDPM (Denoising Diffusion Probabilistic Models) and test it on MNIST dataset. You need to generate samples and perform an interpolation experiment with your trained model. 2. Implement DDIM (DENOISING DIFFUSION IMPLICIT MODELS) and test it on MNIST dataset. You need to generate samples and perform an interpolation experiment with your trained model. 3. Implement FastDPM (On Fast Sampling of Diffusion Probabilistic Models) and test it on MNIST dataset. You need to generate samples and perform an interpolation experiment with your trained model.