我是 TensorFlow 的新手,我正在尝试在 v2 中实现简单的协同过滤。我一次训练整个训练集没有问题,但是当我尝试批量训练时遇到问题。具体来说,在计算
grads
时,输出梯度为 [None, None]
。完整尝试的 colab 文件可以在here.中找到
with tf.GradientTape() as tape:
tape.watch(user_embedding)
tape.watch(item_embedding)
## Compute the predicted ratings
predicted_ratings = tf.reduce_sum(user_batch * item_batch, axis=1)
## Compute loss
true_ratings = tf.cast(train_batch_st.values, tf.float32)
loss = tf.losses.mean_squared_error(true_ratings, predicted_ratings) # batch loss
# Cumulative epoch loss (across all batches)
epoch_loss += loss
## Compute gradients of loss with respect to user and item embeddings
grads = tape.gradient(loss, [user_embedding, item_embedding])
print(grads) # grads None, None thus causing error below
# Apply gradients
optimizer.apply_gradients(zip(grads, [user_embedding, item_embedding]))
感谢您的帮助!