Hi all,

I set up an Ubuntu 18.04 system on my laptop (GTX 960M, yeah it’s not super powerful) and got everything running after having to build pyTorch from source to make it work with my older GPU. However, when I run the first training code in the Lesson 1 Notebook, I get this stack trace:

```
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-12-676345a6c308> in <module>()
2 data = ImageClassifierData.from_paths(PATH, bs=8, tfms=tfms_from_model(arch, sz))
3 learn = ConvLearner.pretrained(arch, data, precompute=True)
----> 4 learn.fit(0.01, 2)
~/fastai/fastai/learner.py in fit(self, lrs, n_cycle, wds, **kwargs)
300 self.sched = None
301 layer_opt = self.get_layer_opt(lrs, wds)
--> 302 return self.fit_gen(self.model, self.data, layer_opt, n_cycle, **kwargs)
303
304 def warm_up(self, lr, wds=None):
~/fastai/fastai/learner.py in fit_gen(self, model, data, layer_opt, n_cycle, cycle_len, cycle_mult, cycle_save_name, best_save_name, use_clr, use_clr_beta, metrics, callbacks, use_wd_sched, norm_wds, wds_sched_mult, use_swa, swa_start, swa_eval_freq, **kwargs)
247 metrics=metrics, callbacks=callbacks, reg_fn=self.reg_fn, clip=self.clip, fp16=self.fp16,
248 swa_model=self.swa_model if use_swa else None, swa_start=swa_start,
--> 249 swa_eval_freq=swa_eval_freq, **kwargs)
250
251 def get_layer_groups(self): return self.models.get_layer_groups()
~/fastai/fastai/model.py in fit(model, data, n_epochs, opt, crit, metrics, callbacks, stepper, swa_model, swa_start, swa_eval_freq, visualize, **kwargs)
160
161 if not all_val:
--> 162 vals = validate(model_stepper, cur_data.val_dl, metrics, epoch, seq_first=seq_first, validate_skip = validate_skip)
163 stop=False
164 for cb in callbacks: stop = stop or cb.on_epoch_end(vals)
~/fastai/fastai/model.py in validate(stepper, dl, metrics, epoch, seq_first, validate_skip)
240 loss.append(to_np(l))
241 res.append([f(datafy(preds), datafy(y)) for f in metrics])
--> 242 return [np.average(loss, 0, weights=batch_cnts)] + list(np.average(np.stack(res), 0, weights=batch_cnts))
243
244 def get_prediction(x):
~/anaconda3/envs/fastai/lib/python3.6/site-packages/numpy/lib/function_base.py in average(a, axis, weights, returned)
381 wgt = wgt.swapaxes(-1, axis)
382
--> 383 scl = wgt.sum(axis=axis, dtype=result_dtype)
384 if np.any(scl == 0.0):
385 raise ZeroDivisionError(
~/anaconda3/envs/fastai/lib/python3.6/site-packages/numpy/core/_methods.py in _sum(a, axis, dtype, out, keepdims, initial)
34 def _sum(a, axis=None, dtype=None, out=None, keepdims=False,
35 initial=_NoValue):
---> 36 return umr_sum(a, axis, dtype, out, keepdims, initial)
37
38 def _prod(a, axis=None, dtype=None, out=None, keepdims=False,
TypeError: No loop matching the specified signature and casting
was found for ufunc add
```

This seems to be an error in the fastai library, though I have no idea. I have looked extensively online for a solution to this problem to no avail.

Any help would be greatly appreciated!