Training IWSLT on CPU

[comja]

Hello!

Thank you very much for your contribution.

I wonder how to adapt the code in order to train a model on IWSLT data on my PC without GPUs.

It seems like MultiGPULossCompute should be replaced in run_epoch, but SimpleLossCompute doesn't seem like an appropriate candidate.

I would appreciate any hint.

[srush]

I think SimpleLossCompute should work fine on CPU if you have enough memory. Do you get an error?

There is a variant you could use, where you split into chunks like MultiGPULossCompute, but do not use data parallel. Let me know if SimpleLossCompute fails

[comja]

it seems like MultiGPULossCompute does a good job separating data into chunks. SimpleLossCompute fails, I think because there is no enough RAM.

But adapted MultiGPULossCompute fails because of something else. The log is following.

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-38-240a851d50f5> in <module>()
      9                   MultiGPULossCompute(model.generator, criterion, 
     10 #                                       devices=devices,
---> 11                                       opt=model_opt))
     12         model.eval()
     13         loss = run_epoch((rebatch(pad_idx, b) for b in valid_iter), 

<ipython-input-26-3c250c9d9ec4> in run_epoch(data_iter, model, loss_compute)
      8         out = model.forward(batch.src, batch.trg, 
      9                             batch.src_mask, batch.trg_mask)
---> 10         loss = loss_compute(out, batch.trg_y, batch.ntokens)
     11         total_loss += loss
     12         total_tokens += batch.ntokens

<ipython-input-36-46d56c947589> in __call__(self, out, targets, normalize)
     37                              for o in out]
     38 
---> 39             gen = generator(out_column)
     40 #             gen = nn.parallel.parallel_apply(generator, out_column)
     41 

~/miniconda2/envs/py36/lib/python3.6/site-packages/torch/nn/modules/module.py in __call__(self, *input, **kwargs)
    355             result = self._slow_forward(*input, **kwargs)
    356         else:
--> 357             result = self.forward(*input, **kwargs)
    358         for hook in self._forward_hooks.values():
    359             hook_result = hook(self, input, result)

<ipython-input-4-96c707961385> in forward(self, x)
      6 
      7     def forward(self, x):
----> 8         return F.log_softmax(self.proj(x), dim=-1)

~/miniconda2/envs/py36/lib/python3.6/site-packages/torch/nn/modules/module.py in __call__(self, *input, **kwargs)
    355             result = self._slow_forward(*input, **kwargs)
    356         else:
--> 357             result = self.forward(*input, **kwargs)
    358         for hook in self._forward_hooks.values():
    359             hook_result = hook(self, input, result)

~/miniconda2/envs/py36/lib/python3.6/site-packages/torch/nn/modules/linear.py in forward(self, input)
     53 
     54     def forward(self, input):
---> 55         return F.linear(input, self.weight, self.bias)
     56 
     57     def __repr__(self):

~/miniconda2/envs/py36/lib/python3.6/site-packages/torch/nn/functional.py in linear(input, weight, bias)
    831         - Output: :math:`(N, *, out\_features)`
    832     """
--> 833     if input.dim() == 2 and bias is not None:
    834         # fused op is marginally faster
    835         return torch.addmm(bias, input, weight.t())

AttributeError: 'list' object has no attribute 'dim'

[srush]

Did you figure this out? I would like to leave it open.

[comja]

Unfortunately SimpleLossCompute still does not work (and this is not because of RAM).
It fails on the validation step with the following error message

   loss.backward()
  File "/home/melpuser/miniconda2/envs/py36/lib/python3.6/site-packages/torch/autograd/variable.py", line 167, in backward
    torch.autograd.backward(self, gradient, retain_graph, create_graph, retain_variables)
  File "/home/melpuser/miniconda2/envs/py36/lib/python3.6/site-packages/torch/autograd/__init__.py", line 99, in backward
    variables, grad_variables, retain_graph)
RuntimeError: element 0 of variables tuple is volatile

For some reason it doesn't like calculating loss.backward() in SimpleLossCompute while calculating loss on the validation set.

I've tried to adapt MultiGPULossCompute to simple CPU version, but so far with no success, cannot deal with x and y - TypeError: forward() missing 1 required positional argument: 'target'

[yoheikikuta]

@comja @srush

I tackled the same problem and found the following codes worked.

• PyTorch version
  pip install http://download.pytorch.org/whl/cpu/torch-0.3.1-cp36-cp36m-linux_x86_64.whl

After ## Multi-GPU Training of the notebook,

pad_idx = TGT.vocab.stoi["<blank>"]
model = make_model(len(SRC.vocab), len(TGT.vocab), N=6)
criterion = LabelSmoothing(size=len(TGT.vocab), padding_idx=pad_idx, smoothing=0.1)

BATCH_SIZE = 100

train_iter = MyIterator(train, batch_size=BATCH_SIZE,
                        repeat=False, sort_key=lambda x: (len(x.src), len(x.trg)),
                        batch_size_fn=batch_size_fn, train=True)
valid_iter = MyIterator(val, batch_size=BATCH_SIZE,
                        repeat=False, sort_key=lambda x: (len(x.src), len(x.trg)),
                        batch_size_fn=batch_size_fn, train=False)

(I changed BATCH_SIZE for my environment.)

model_opt = NoamOpt(model.src_embed[0].d_model, 1, 2000,
        torch.optim.Adam(model.parameters(), lr=0, betas=(0.9, 0.98), eps=1e-9))

for epoch in range(10):
    model.train()
    run_epoch((rebatch(pad_idx, b) for b in train_iter), model, 
              SimpleLossCompute(model.generator, criterion, model_opt))
    model.eval()
    print(run_epoch((rebatch(pad_idx, b) for b in train_iter), model, 
                    SimpleLossCompute(model.generator, criterion, None)))

NOTE: I just checked the script doesn't return errors, so I'm not sure whether the training goes well or not (I mean I didn't check the performance of a trained model).