decoder generates noise images

[xinmiaolin]

Hi,

I am trying to train a decoder on CUB-200 dataset. However, after nearly 400 epochs, the decoder can still only generate noises and I have been trying a long time to figure out why. I would appreciate your suggestions!

So the training loss decreases pretty steadily, but the images still look like this:

I have only used 1 unet and the configuration is: dim = 128, image_embed_dim = 768, dim_mults = (1, 2, 4, 8),, for the decoder, the parameters are: image_size=64, timesteps = 1000, image_cond_drop_prob = 0.1, text_cond_drop_prob = 0.5, learned_variance = False.

Thank you!

[lucidrains]

@xinmiaolin hi, it looks like your training run diverged early

the loss should go down to around 0.05 before the images come into view

how high is your learning rate?

[xinmiaolin]

The learning rate is 4e-3. Yes, the training loss does drop very precipitously from around 1 to 0.1 in the first epoch, then sharply increased to 0.8 again. Then, the training loss decreases steadily. The 0.05 is the loss per image you mean? The batch size is 128 that I used.

Thank you very much!

[lucidrains]

@xinmiaolin do you mean 3e-4 because 4e-3 is absurdly high!

[lucidrains]

@xinmiaolin would recommend 1e-4

[lucidrains]

@xinmiaolin yea, the loss should be the MSE, which is average across image samples

[lucidrains]

The learning rate is 4e-3. Yes, the training loss does drop very precipitously from around 1 to 0.1 in the first epoch, then sharply increased to 0.8 again. Then, the training loss decreases steadily. The 0.05 is the loss per image you mean? The batch size is 128 that I used.

Thank you very much!

yup, when losses jump up like that, it means the training is unhealthy. some of these jumps are not recoverable

[xinmiaolin]

I will try a lower learning rate to see if this kind of jumps appear again.

[lucidrains]

@xinmiaolin you'll definitely see something

DDPMs are so much easier to train than their predecessor, GANs

[xinmiaolin]

@xinmiaolin you'll definitely see something

DDPMs are so much easier to train than their predecessor, GANs

Thanks, this definitely gives me hope haha

[lucidrains]

@xinmiaolin did it work?

[xinmiaolin]

Hi, I don't think that it is working...

Here is when lr=1e-4, although it is diverging, but the loss can still decrease.

This is when lr=3e-6, the loss oscillates a lot and does not decrease at all, even increases.

I am confused why when the lr is smaller, the loss function has such great fluctuations. I am now training with lr=1e-5, it looks good. Will keep on updating!

[lucidrains]

@xinmiaolin how high is your batch size?

[xinmiaolin]

@xinmiaolin how high is your batch size?

the batch size is 128

[lucidrains]

ohh that should be good enough

ok, keep at it with 1e-5, i'd be surprised if that didn't work

[xinmiaolin]

ohh that should be good enough

ok, keep at it with 1e-5, i'd be surprised if that didn't work

ok, I will come back and update. Thanks

[lucidrains]

@xinmiaolin i'll add a learning rate warmup for the decoder trainer some time this weekend; just need to figure out how to make it huggingface accelerate compatible

[xinmiaolin]

@xinmiaolin i'll add a learning rate warmup for the decoder trainer some time this weekend; just need to figure out how to make it huggingface accelerate compatible

Ok thanks!

[xinmiaolin]

This is the training of lr=1e-5, I have also used CosineAnnealingLR with t_max=10000. The loss increases from around 0.3 to 0.6 then does not decrease at all.

For lr=3e-5, the loss increases from around 0.2 to 0.7, then decreases slowly.

I have tried smaller learning rates without the lr scheduler, but the loss also fluctuates, for example, when lr=3e-7.

I am not sure what is going on. Could there be some parameters related to diffusion models that should be changed, because I am using default values of the parameters.

[lucidrains]

@xinmiaolin hmm, could you possibly send me your full training script?

[xinmiaolin]

@xinmiaolin hmm, could you possibly send me your full training script?

sure, thanks!

[YUHANG-Ma]

Did you check your optimizer? I think it maybe because your parameters are not doing the backward. I met the problem before, the loss decreased slowly but I figured out there is something wrong in optimizer.py.

[xinmiaolin]

Did you check your optimizer? I think it maybe because your parameters are not doing the backward. I met the problem before, the loss decreased slowly but I figured out there is something wrong in optimizer.py.

Hi thank you for the suggestion. I will check on it.

[QinSY123]

@xinmiaolin Have you solved the problem or have you trained the model yet, I have the same problem

[thecooltechguy]

Facing the same problem, would love to know if you found out the issue! :)

cc: @xinmiaolin

[canelle20214]

@xinmiaolin Same for me, did you found out the root cause of that behaviour ?

[xiaomei2002]

Did you figure it out?? I met the problem too.