I don’t see EmbeddingModel in the current code for fast.ai on github, was it renamed to MixedInputModel?

# Structured Learner

**kcturgutlu**(Kerem Turgutlu) #43

Yes that is correct. Embedding model’s is what I named it for this purpose. Original model name was always MixedInputModel (conts + cats)

**rohitgeo**(Rohit Singh) #44

@kcturgutlu can you share your notebook of which you’ve taken the screenshot? I tried following along but get an error in lr_find():

```
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-50-d81c6bd29d71> in <module>()
----> 1 learn.lr_find()
~/anaconda3/envs/fastai/lib/python3.6/site-packages/fastai/learner.py in lr_find(self, start_lr, end_lr, wds)
135 layer_opt = self.get_layer_opt(start_lr, wds)
136 self.sched = LR_Finder(layer_opt, len(self.data.trn_dl), end_lr)
--> 137 self.fit_gen(self.model, self.data, layer_opt, 1)
138 self.load('tmp')
139
~/anaconda3/envs/fastai/lib/python3.6/site-packages/fastai/learner.py in fit_gen(self, model, data, layer_opt, n_cycle, cycle_len, cycle_mult, cycle_save_name, metrics, callbacks, **kwargs)
87 n_epoch = sum_geom(cycle_len if cycle_len else 1, cycle_mult, n_cycle)
88 fit(model, data, n_epoch, layer_opt.opt, self.crit,
---> 89 metrics=metrics, callbacks=callbacks, reg_fn=self.reg_fn, clip=self.clip, **kwargs)
90
91 def get_layer_groups(self): return self.models.get_layer_groups()
~/anaconda3/envs/fastai/lib/python3.6/site-packages/fastai/model.py in fit(model, data, epochs, opt, crit, metrics, callbacks, **kwargs)
82 for (*x,y) in t:
83 batch_num += 1
---> 84 loss = stepper.step(V(x),V(y))
85 avg_loss = avg_loss * avg_mom + loss * (1-avg_mom)
86 debias_loss = avg_loss / (1 - avg_mom**batch_num)
~/anaconda3/envs/fastai/lib/python3.6/site-packages/fastai/model.py in step(self, xs, y)
38 def step(self, xs, y):
39 xtra = []
---> 40 output = self.m(*xs)
41 if isinstance(output,(tuple,list)): output,*xtra = output
42 self.opt.zero_grad()
~/anaconda3/envs/fastai/lib/python3.6/site-packages/torch/nn/modules/module.py in __call__(self, *input, **kwargs)
323 for hook in self._forward_pre_hooks.values():
324 hook(self, input)
--> 325 result = self.forward(*input, **kwargs)
326 for hook in self._forward_hooks.values():
327 hook_result = hook(self, input, result)
<ipython-input-40-d4690f427dbe> in forward(self, x_cat, x_cont)
134
135 def forward(self, x_cat, x_cont):
--> 136 x = [emb(x_cat[:, i]) for i, emb in enumerate(self.embs)] # takes necessary emb vectors
137 x = torch.cat(x, 1) ## concatenate along axis = 1 (columns - side by side) # this is our input from cats
138 x = self.emb_drop(x) ## apply dropout to elements of embedding tensor
<ipython-input-40-d4690f427dbe> in <listcomp>(.0)
134
135 def forward(self, x_cat, x_cont):
--> 136 x = [emb(x_cat[:, i]) for i, emb in enumerate(self.embs)] # takes necessary emb vectors
137 x = torch.cat(x, 1) ## concatenate along axis = 1 (columns - side by side) # this is our input from cats
138 x = self.emb_drop(x) ## apply dropout to elements of embedding tensor
~/anaconda3/envs/fastai/lib/python3.6/site-packages/torch/nn/modules/module.py in __call__(self, *input, **kwargs)
323 for hook in self._forward_pre_hooks.values():
324 hook(self, input)
--> 325 result = self.forward(*input, **kwargs)
326 for hook in self._forward_hooks.values():
327 hook_result = hook(self, input, result)
~/anaconda3/envs/fastai/lib/python3.6/site-packages/torch/nn/modules/sparse.py in forward(self, input)
101 input, self.weight,
102 padding_idx, self.max_norm, self.norm_type,
--> 103 self.scale_grad_by_freq, self.sparse
104 )
105
~/anaconda3/envs/fastai/lib/python3.6/site-packages/torch/nn/_functions/thnn/sparse.py in forward(cls, ctx, indices, weight, padding_idx, max_norm, norm_type, scale_grad_by_freq, sparse)
55
56 if indices.dim() == 1:
---> 57 output = torch.index_select(weight, 0, indices)
58 else:
59 output = torch.index_select(weight, 0, indices.view(-1))
TypeError: torch.index_select received an invalid combination of arguments - got (torch.FloatTensor, int, torch.cuda.LongTensor), but expected (torch.FloatTensor source, int dim, torch.LongTensor index)
```

**octaviomm**(Octavio ) #45

Hello, I tried to follow the steps described by @kcturgutlu and I modified the MixedInputModel and StructuredLearner classes in column_data.py, but I get the same error as @rohitgeo . Has anyone succesfully implemented binary classification in structured data? Here is my implementation. I tried using “y” both as a 1D vector and as a one-hot vector.

**rohitgeo**(Rohit Singh) #46

I’ve scoured through the forums and the net and no one has been able to do this. @kcturgutlu apparently was able to do this but he was using PyTorch directly. His github repo has an example, but it’s been modified to do regression, not classification.

**kcturgutlu**(Kerem Turgutlu) #47

Hello,

Since there are many requests about a clarification on how to run classification models using MixedInputModel model in FAST.AI I got excited and prepared a fresh notebook on how to do it using https://www.kaggle.com/c/avazu-ctr-prediction/data as our case.

I was very curious to see how embeddings would perform on such a problem where the winners used FFM which is basically another way of representing categorical data (but including interactions). I don’t know mathematical relations between NN embedddings and FFMs but definitely dig that deeper tomorrow. In meanwhile here is a good read on FFMs https://www.analyticsvidhya.com/blog/2018/01/factorization-machines/.

I’ve created this notebook where you can access from https://github.com/KeremTurgutlu/deeplearning/blob/master/avazu/FAST.AI%20Binary%20Classification%20-%20Kaggle%20Avazu%20CTR.ipynb )

I commented every important part you need to know, e.g hacks we are using, why we are doing so, what else can be done with FAST.AI, and so on. As you dig into source code you will see how flexible it is. I understand why @jeremy didn’t implement a classifier necessarily since it’s very easy to make the changes.

What we do in the notebook in summary:

- we don’t touch MixedInputModel at all
- We change single line in ColumnarDataset to play good along with torch cross entropy
- We change crit of learn object to F.cross_entropy and that’s it (of course if you are interested in ranking probabilities you can either use AUC or Gini).

Hope this helps

**rohitgeo**(Rohit Singh) #50

I’m trying out @kcturgutlu’s notebook with the Avazu data, and getting this errorin lr_find():

`TypeError: torch.index_select received an invalid combination of arguments - got (torch.FloatTensor, int, torch.cuda.LongTensor), but expected (torch.FloatTensor source, int dim, torch.LongTensor index)`

Here’s the full stack trace:

```
<ipython-input-34-d81c6bd29d71> in <module>()
----> 1 learn.lr_find()
~/anaconda3/envs/fastai/lib/python3.6/site-packages/fastai/learner.py in lr_find(self, start_lr, end_lr, wds)
135 layer_opt = self.get_layer_opt(start_lr, wds)
136 self.sched = LR_Finder(layer_opt, len(self.data.trn_dl), end_lr)
--> 137 self.fit_gen(self.model, self.data, layer_opt, 1)
138 self.load('tmp')
139
~/anaconda3/envs/fastai/lib/python3.6/site-packages/fastai/learner.py in fit_gen(self, model, data, layer_opt, n_cycle, cycle_len, cycle_mult, cycle_save_name, metrics, callbacks, **kwargs)
87 n_epoch = sum_geom(cycle_len if cycle_len else 1, cycle_mult, n_cycle)
88 fit(model, data, n_epoch, layer_opt.opt, self.crit,
---> 89 metrics=metrics, callbacks=callbacks, reg_fn=self.reg_fn, clip=self.clip, **kwargs)
90
91 def get_layer_groups(self): return self.models.get_layer_groups()
~/anaconda3/envs/fastai/lib/python3.6/site-packages/fastai/model.py in fit(model, data, epochs, opt, crit, metrics, callbacks, **kwargs)
82 for (*x,y) in t:
83 batch_num += 1
---> 84 loss = stepper.step(V(x),V(y))
85 avg_loss = avg_loss * avg_mom + loss * (1-avg_mom)
86 debias_loss = avg_loss / (1 - avg_mom**batch_num)
~/anaconda3/envs/fastai/lib/python3.6/site-packages/fastai/model.py in step(self, xs, y)
38 def step(self, xs, y):
39 xtra = []
---> 40 output = self.m(*xs)
41 if isinstance(output,(tuple,list)): output,*xtra = output
42 self.opt.zero_grad()
~/anaconda3/envs/fastai/lib/python3.6/site-packages/torch/nn/modules/module.py in __call__(self, *input, **kwargs)
323 for hook in self._forward_pre_hooks.values():
324 hook(self, input)
--> 325 result = self.forward(*input, **kwargs)
326 for hook in self._forward_hooks.values():
327 hook_result = hook(self, input, result)
<ipython-input-2-dd760a043ee0> in forward(self, x_cat, x_cont)
24 def forward(self, x_cat, x_cont):
25 if self.n_emb != 0:
---> 26 x = [e(x_cat[:,i]) for i,e in enumerate(self.embs)]
27 x = torch.cat(x, 1)
28 x = self.emb_drop(x)
<ipython-input-2-dd760a043ee0> in <listcomp>(.0)
24 def forward(self, x_cat, x_cont):
25 if self.n_emb != 0:
---> 26 x = [e(x_cat[:,i]) for i,e in enumerate(self.embs)]
27 x = torch.cat(x, 1)
28 x = self.emb_drop(x)
~/anaconda3/envs/fastai/lib/python3.6/site-packages/torch/nn/modules/module.py in __call__(self, *input, **kwargs)
323 for hook in self._forward_pre_hooks.values():
324 hook(self, input)
--> 325 result = self.forward(*input, **kwargs)
326 for hook in self._forward_hooks.values():
327 hook_result = hook(self, input, result)
~/anaconda3/envs/fastai/lib/python3.6/site-packages/torch/nn/modules/sparse.py in forward(self, input)
101 input, self.weight,
102 padding_idx, self.max_norm, self.norm_type,
--> 103 self.scale_grad_by_freq, self.sparse
104 )
105
~/anaconda3/envs/fastai/lib/python3.6/site-packages/torch/nn/_functions/thnn/sparse.py in forward(cls, ctx, indices, weight, padding_idx, max_norm, norm_type, scale_grad_by_freq, sparse)
55
56 if indices.dim() == 1:
---> 57 output = torch.index_select(weight, 0, indices)
58 else:
59 output = torch.index_select(weight, 0, indices.view(-1))
TypeError: torch.index_select received an invalid combination of arguments - got (torch.FloatTensor, int, torch.cuda.LongTensor), but expected (torch.FloatTensor source, int dim, torch.LongTensor index)
```

Anyone got it to work? Does it have something to do with the version of pytorch? I’m using ‘0.3.0.post4’

**kcturgutlu**(Kerem Turgutlu) #51

I ran everything on cpu, you need to either run on cpu or put variables and model into gpu.

FYI. It’s probably a good idea to search for similar errors on the forum or google before asking, most of these are issues are already discussed.

**jeremy**(Jeremy Howard) #52

This is looking great @kcturgutlu ! Let me know when you’ve got something more polished since I’d love to be able to share this work widely FYI your nb link above is a 404. Correct link seems to be https://github.com/KeremTurgutlu/deeplearning/blob/master/avazu/FAST.AI%20Binary%20Classification%20-%20Kaggle%20Avazu%20CTR.ipynb

**kcturgutlu**(Kerem Turgutlu) #53

Thanks for the reminder, I’ve changed the link. I am working on DSBOWL 2018 and USCF simultaneously right now since task is very similar:) But I will probably be able to optimize the work and polish it as you recommend in couple of days and let you know. Thank you so much !

SIDE NOTE: I didn’t realize how computationally expensive encoder decoder CNNs are before actually running one