Hello. I am training a NN classifier and everything seems to work fine. Except that my model isn’t updating(the losses aren’t dropping from the beginning).
class NN(nn.Module):
def __init__(self,width = 128):
super().__init__()
self.fc1 = nn.Sequential(
nn.Linear(50,512),
nn.ReLU(),
nn.Linear(512,512),
nn.ReLU(),
nn.Linear(512,512),
nn.ReLU(),
nn.Linear(512,256),
nn.ReLU(),
nn.Linear(256,256),
nn.ReLU(),
nn.Linear(256,128),
nn.ReLU(),
nn.Linear(128,64),
nn.ReLU(),
nn.Linear(64,32),
nn.ReLU(),
nn.Linear(32,16),
nn.ReLU(),
nn.Linear(16,4),
nn.Softmax(dim = 1)
)
def forward(self, x):
out = self.fc1(x)
return out
net = NN().to(device)
loss_function = nn.CrossEntropyLoss(weight=weight)
optimizer = optim.Adam(net.parameters(),lr = 0.001)
plot_loss = []
for epoch in range(3): # 3 full passes over the data
for data in trainset: # `data` is a batch of data
X, y = data # X is the batch of features, y is the batch of targets.
X = X.to(device)
y = y.to(device)
net.zero_grad() # sets gradients to 0 before loss calc. You will do this likely every step.
output = net(X.view(-1,50)) # pass in the reshaped batch (recall they are 28x28 atm)
loss = loss_function(output, y.flatten()) # calc and grab the loss value
loss.backward() # apply this loss backwards thru the network's parameters
optimizer.step() # attempt to optimize weights to account for loss/gradients
plot_loss.append(loss)
print(loss) # print loss. We hope loss (a measure of wrong-ness) declines!
the loss after 3 epoch:
Thanks in advance for any help.
