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import pdb

from diffusion import gaussian_diffusion as gd
from diffusion.respace import SpacedDiffusion, space_timesteps



def create_gaussian_diffusion(DiffusionClass=SpacedDiffusion,use_ddim=False):
    noise_schedule = 'cosine'
    sigma_small = True
    lambda_vel = 0.0
    lambda_rcxyz = 0.0
    lambda_fc = 0.0

    # default params
    predict_xstart = True  # we always predict x_start (a.k.a. x0), that's our deal!
    steps = 1000
    scale_beta = 1.  # no scaling
    timestep_respacing =None
    if use_ddim:
        timestep_respacing = 'ddim50'  # can be used for ddim sampling, we don't use it.
    learn_sigma = False
    rescale_timesteps = False

    betas = gd.get_named_beta_schedule(noise_schedule, steps, scale_beta)
    loss_type = gd.LossType.MSE

    if not timestep_respacing:
        timestep_respacing = [steps]

    return DiffusionClass(
        use_timesteps=space_timesteps(steps, timestep_respacing),
        betas=betas,
        model_mean_type=(
            gd.ModelMeanType.EPSILON if not predict_xstart else gd.ModelMeanType.START_X
        ),
        model_var_type=(
            (
                gd.ModelVarType.FIXED_LARGE
                if not sigma_small
                else gd.ModelVarType.FIXED_SMALL
            )
            if not learn_sigma
            else gd.ModelVarType.LEARNED_RANGE
        ),
        loss_type=loss_type,
        rescale_timesteps=rescale_timesteps,
        lambda_vel=lambda_vel,
        lambda_rcxyz=lambda_rcxyz,
        lambda_fc=lambda_fc,
    )