text
stringlengths 0
4.99k
|
---|
loss_value = loss_fn(y, logits)
|
grads = tape.gradient(loss_value, model.trainable_weights)
|
optimizer.apply_gradients(zip(grads, model.trainable_weights))
|
train_acc_metric.update_state(y, logits)
|
return loss_value
|
Let's do the same with the evaluation step:
|
@tf.function
|
def test_step(x, y):
|
val_logits = model(x, training=False)
|
val_acc_metric.update_state(y, val_logits)
|
Now, let's re-run our training loop with this compiled training step:
|
import time
|
epochs = 2
|
for epoch in range(epochs):
|
print("\nStart of epoch %d" % (epoch,))
|
start_time = time.time()
|
# Iterate over the batches of the dataset.
|
for step, (x_batch_train, y_batch_train) in enumerate(train_dataset):
|
loss_value = train_step(x_batch_train, y_batch_train)
|
# Log every 200 batches.
|
if step % 200 == 0:
|
print(
|
"Training loss (for one batch) at step %d: %.4f"
|
% (step, float(loss_value))
|
)
|
print("Seen so far: %d samples" % ((step + 1) * 64))
|
# Display metrics at the end of each epoch.
|
train_acc = train_acc_metric.result()
|
print("Training acc over epoch: %.4f" % (float(train_acc),))
|
# Reset training metrics at the end of each epoch
|
train_acc_metric.reset_states()
|
# Run a validation loop at the end of each epoch.
|
for x_batch_val, y_batch_val in val_dataset:
|
test_step(x_batch_val, y_batch_val)
|
val_acc = val_acc_metric.result()
|
val_acc_metric.reset_states()
|
print("Validation acc: %.4f" % (float(val_acc),))
|
print("Time taken: %.2fs" % (time.time() - start_time))
|
Start of epoch 0
|
Training loss (for one batch) at step 0: 0.6483
|
Seen so far: 64 samples
|
Training loss (for one batch) at step 200: 0.5966
|
Seen so far: 12864 samples
|
Training loss (for one batch) at step 400: 0.5951
|
Seen so far: 25664 samples
|
Training loss (for one batch) at step 600: 1.3830
|
Seen so far: 38464 samples
|
Training loss (for one batch) at step 800: 0.2758
|
Seen so far: 51264 samples
|
Training acc over epoch: 0.8756
|
Validation acc: 0.8955
|
Time taken: 1.18s
|
Start of epoch 1
|
Training loss (for one batch) at step 0: 0.4447
|
Seen so far: 64 samples
|
Training loss (for one batch) at step 200: 0.3794
|
Seen so far: 12864 samples
|
Training loss (for one batch) at step 400: 0.4636
|
Seen so far: 25664 samples
|
Training loss (for one batch) at step 600: 0.3694
|
Seen so far: 38464 samples
|
Training loss (for one batch) at step 800: 0.2763
|
Seen so far: 51264 samples
|
Training acc over epoch: 0.8926
|
Validation acc: 0.9078
|
Time taken: 0.71s
|
Much faster, isn't it?
|
Low-level handling of losses tracked by the model
|
Layers & models recursively track any losses created during the forward pass by layers that call self.add_loss(value). The resulting list of scalar loss values are available via the property model.losses at the end of the forward pass.
|
If you want to be using these loss components, you should sum them and add them to the main loss in your training step.
|
Consider this layer, that creates an activity regularization loss:
|
class ActivityRegularizationLayer(layers.Layer):
|
def call(self, inputs):
|
self.add_loss(1e-2 * tf.reduce_sum(inputs))
|
return inputs
|
Let's build a really simple model that uses it:
|
inputs = keras.Input(shape=(784,), name="digits")
|
x = layers.Dense(64, activation="relu")(inputs)
|
# Insert activity regularization as a layer
|
x = ActivityRegularizationLayer()(x)
|
x = layers.Dense(64, activation="relu")(x)
|
outputs = layers.Dense(10, name="predictions")(x)
|
model = keras.Model(inputs=inputs, outputs=outputs)
|
Here's what our training step should look like now:
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.