@MicPie Thank you so much! IT was a dimension missmatch. Now though I receive this:
/usr/local/lib/python3.6/dist-packages/fastai/basic_train.py in fit(self, epochs, lr, wd, callbacks)
197 callbacks = [cb(self) for cb in self.callback_fns + listify(defaults.extra_callback_fns)] + listify(callbacks)
198 if defaults.extra_callbacks is not None: callbacks += defaults.extra_callbacks
--> 199 fit(epochs, self, metrics=self.metrics, callbacks=self.callbacks+callbacks)
200
201 def create_opt(self, lr:Floats, wd:Floats=0.)->None:
/usr/local/lib/python3.6/dist-packages/fastai/basic_train.py in fit(epochs, learn, callbacks, metrics)
99 for xb,yb in progress_bar(learn.data.train_dl, parent=pbar):
100 xb, yb = cb_handler.on_batch_begin(xb, yb)
--> 101 loss = loss_batch(learn.model, xb, yb, learn.loss_func, learn.opt, cb_handler)
102 if cb_handler.on_batch_end(loss): break
103
/usr/local/lib/python3.6/dist-packages/fastai/basic_train.py in loss_batch(model, xb, yb, loss_func, opt, cb_handler)
31
32 if opt is not None:
---> 33 loss,skip_bwd = cb_handler.on_backward_begin(loss)
34 if not skip_bwd: loss.backward()
35 if not cb_handler.on_backward_end(): opt.step()
/usr/local/lib/python3.6/dist-packages/fastai/callback.py in on_backward_begin(self, loss)
290 self.smoothener.add_value(loss.detach().cpu())
291 self.state_dict['last_loss'], self.state_dict['smooth_loss'] = loss, self.smoothener.smooth
--> 292 self('backward_begin', call_mets=False)
293 return self.state_dict['last_loss'], self.state_dict['skip_bwd']
294
/usr/local/lib/python3.6/dist-packages/fastai/callback.py in __call__(self, cb_name, call_mets, **kwargs)
249 if call_mets:
250 for met in self.metrics: self._call_and_update(met, cb_name, **kwargs)
--> 251 for cb in self.callbacks: self._call_and_update(cb, cb_name, **kwargs)
252
253 def set_dl(self, dl:DataLoader):
/usr/local/lib/python3.6/dist-packages/fastai/callback.py in _call_and_update(self, cb, cb_name, **kwargs)
239 def _call_and_update(self, cb, cb_name, **kwargs)->None:
240 "Call `cb_name` on `cb` and update the inner state."
--> 241 new = ifnone(getattr(cb, f'on_{cb_name}')(**self.state_dict, **kwargs), dict())
242 for k,v in new.items():
243 if k not in self.state_dict:
/usr/local/lib/python3.6/dist-packages/fastai/basic_train.py in on_backward_begin(self, smooth_loss, **kwargs)
468 self.losses.append(smooth_loss)
469 if self.pbar is not None and hasattr(self.pbar,'child'):
--> 470 self.pbar.child.comment = f'{smooth_loss:.4f}'
471
472 def on_epoch_end(self, epoch:int, num_batch:int, smooth_loss:Tensor,
/usr/local/lib/python3.6/dist-packages/torch/tensor.py in __format__(self, format_spec)
385 if self.dim() == 0:
386 return self.item().__format__(format_spec)
--> 387 return object.__format__(self, format_spec)
388
389 def __ipow__(self, other):
TypeError: unsupported format string passed to Tensor.__format__
To me it looks like something may be wrong with the loss function or callbacks?