Hi,

I was wondering what the equivlent in pytorch of the following tensor flow is:

```
def compute_apply_gradients(model, x, optimizer):
with tf.GradientTape() as tape:
loss = compute_loss(model, x)
gradients = tape.gradient(loss, model.trainable_variables)
optimizer.apply_gradients(zip(gradients, model.trainable_variables))
```

many thanks,

chaslie