few mistakes

[houdezaiwu2019]

code in diffusion_basic.py has some problems,:

for t in range(timesteps):
    if t%20==0 or t==timesteps - 1:
        sample = x_t.copy()
        processed_xs.append(sample[0])
    
    x_t = forward_process_ddpm_v2(x_0, alpha_bar, t=t)

_, ax = plt.subplots(1, len(processed_xs), figsize=(15, 6))

we should replace sample[0] to sample