https://github.com/hkproj/pytorch-stable-diffusion/blob/6e6900078372af15eb1b13e73068cd563784f377/sd/ddpm.py#L64C9-L64C39
The implementation makes sense from what the equations say but I was confused for a minute with using the term beta_prod_t.
What is beta?
beta = 1 - alpha
and
alpha_prod_t = prod(alpha_0, alpha_1, ...., alpha_t)
What will be the product of beta till timestep t?
(IIUC) beta_prod_t = prod(1-alpha_0, 1-alpha_1, ..., 1-alpha_t)
which is not equivalent to 1 - alpha_prod_t
What do you think?