How can I fix this NotImplementedError in python class module while working in pytorch framework? - class

Question

Hello everyone I am working on CIFAR10 dataset using pytorch. I have developed a model which works absolutely fine but the main problem occurrs while runing the following code:
import time
start_time=time.time()
epochs=5
train_losses=[]
test_losses=[]
train_correct=[]
test_correct=[]
for i in range(epochs):
tsn_corr=0
tst_corr=0
for b, (X_train,y_train) in enumerate(train_loader):
b+=1
y_pred=model(X_train)
loss=criterion(y_pred,y_train)
#Tally the number of correct predictions
predicted= torch.max(y_pred.data, 1)[1]
batch_corr=(predicted==y_train).sum()
tsn_corr += batch_corr
#optimize paramters
optimizer.zero_grad()
loss.backward()
optimizer.step()
#print interim results
if b%600 == 0:
print(f"epochs: {i}, batch: {b}, loss: {loss.item():10.8f}")
loss=loss.detach().numpy()
train_losses.append(loss)
train_correct.append(tsn_corr)
#Running the test_batches
with torch.no_grad():
for b, (X_test,y_test) in enumerate(test_loader):
b+=1
y_val=model(X_test)
#TALLY THE NUMBER OF CORRECT PREDICTIONS
predicted=torch.max(y_val.data, 1)[1]
batch_corr= (predicted==y_test).sum()
tst_corr += batch_corr
loss=criterion(y_val,y_test)
loss=loss.detach().numpy()
test_losses.append(loss)
test_correct.append(tst_corr)
the following error occurrs while running the following code:
NotImplementedError Traceback (most recent call last)
<ipython-input-43-48e21e83e9f7> in <module>
15 b+=1
16
---> 17 y_pred=model(X_train)
18 loss=criterion(y_pred,y_train)
19
~\Anaconda3\lib\site-packages\torch\nn\modules\module.py in _call_impl(self, *input, **kwargs)
887 result = self._slow_forward(*input, **kwargs)
888 else:
--> 889 result = self.forward(*input, **kwargs)
890 for hook in itertools.chain(
891 _global_forward_hooks.values(),
~\Anaconda3\lib\site-packages\torch\nn\modules\module.py in _forward_unimplemented(self, *input)
199 registered hooks while the latter silently ignores them.
200 """
--> 201 raise NotImplementedError
202
203
NotImplementedError:
Can someone tell me what can I do to fix this code. Apart from this previous all codes work fine and the model which I made using ConvolutionalNeural-Networks also runs successfully meaning that there is no problem with the model. I guess this detail might help. It might be noted that this code works just fine on MNIST dataset. I dont know what is the problem with CIFAR datasets

Answer 1

Your model class needs to implement a forward method. See the PyTorch Example on Subclassing to see an example.