Fix tensor devices for DARTS Trial (#2273)

* Update architect.py

[email protected]

Signed-off-by: Chen Pin-Han <72907153+sifa1024​@users.noreply.github.com>

* Update run_trial.py

[email protected]

Signed-off-by: Chen Pin-Han <72907153+sifa1024​@users.noreply.github.com>

* Update architect.py

[email protected]

Signed-off-by: Chen Pin-Han <72907153+sifa1024​@users.noreply.github.com>

---------

Signed-off-by: Chen Pin-Han <72907153+sifa1024​@users.noreply.github.com>

Author: sifa1024

examples/v1beta1/trial-images/darts-cnn-cifar10/architect.py

@@ -20,11 +20,12 @@ class Architect():
     """" Architect controls architecture of cell by computing gradients of alphas
     """
 
-    def __init__(self, model, w_momentum, w_weight_decay):
+    def __init__(self, model, w_momentum, w_weight_decay, device):
         self.model = model
         self.v_model = copy.deepcopy(model)
         self.w_momentum = w_momentum
         self.w_weight_decay = w_weight_decay
+        self.device = device
 
     def virtual_step(self, train_x, train_y, xi, w_optim):
         """
@@ -43,17 +44,21 @@ def virtual_step(self, train_x, train_y, xi, w_optim):
         # Forward and calculate loss
         # Loss for train with w. L_train(w)
         loss = self.model.loss(train_x, train_y)
+
         # Compute gradient
         gradients = torch.autograd.grad(loss, self.model.getWeights())
-
+        
         # Do virtual step (Update gradient)
         # Below operations do not need gradient tracking
         with torch.no_grad():
             # dict key is not the value, but the pointer. So original network weight have to
             # be iterated also.
             for w, vw, g in zip(self.model.getWeights(), self.v_model.getWeights(), gradients):
                 m = w_optim.state[w].get("momentum_buffer", 0.) * self.w_momentum
-                vw.copy_(w - torch.FloatTensor(xi) * (m + g + self.w_weight_decay * w))
+                if(self.device == 'cuda'):
+                    vw.copy_(w - torch.cuda.FloatTensor(xi) * (m + g + self.w_weight_decay * w))
+                elif(self.device == 'cpu'):
+                    vw.copy_(w - torch.FloatTensor(xi) * (m + g + self.w_weight_decay * w))
 
             # Sync alphas
             for a, va in zip(self.model.getAlphas(), self.v_model.getAlphas()):
@@ -71,7 +76,7 @@ def unrolled_backward(self, train_x, train_y, valid_x, valid_y, xi, w_optim):
         # Calculate unrolled loss
         # Loss for validation with w'. L_valid(w')
         loss = self.v_model.loss(valid_x, valid_y)
-
+        
         # Calculate gradient
         v_alphas = tuple(self.v_model.getAlphas())
         v_weights = tuple(self.v_model.getWeights())
@@ -85,7 +90,10 @@ def unrolled_backward(self, train_x, train_y, valid_x, valid_y, xi, w_optim):
         # Update final gradient = dalpha - xi * hessian
         with torch.no_grad():
             for alpha, da, h in zip(self.model.getAlphas(), dalpha, hessian):
-                alpha.grad = da - torch.FloatTensor(xi) * h
+                if(self.device == 'cuda'):
+                    alpha.grad = da - torch.cuda.FloatTensor(xi) * h
+                elif(self.device == 'cpu'):
+                    alpha.grad = da - torch.cpu.FloatTensor(xi) * h
 
     def compute_hessian(self, dws, train_x, train_y):
         """

examples/v1beta1/trial-images/darts-cnn-cifar10/run_trial.py

@@ -140,7 +140,7 @@ def main():
         num_epochs,
         eta_min=w_lr_min)
 
-    architect = Architect(model, w_momentum, w_weight_decay)
+    architect = Architect(model, w_momentum, w_weight_decay, device)
 
     # Start training
     best_top1 = 0.