How to get gradients from GradientTape

TensorFlow General Discussion
1

I wanted to get the gradients from the gradient tape so in tf version 1 I used something like -

grads = model.optimizer.get_gradients(model.total_loss, model.trainable_weights)
symb_inputs = (model._feed_inputs + model._feed_targets + model._feed_sample_weights)

Now for tf v2 I want to get gradients so I used -

grads = tf.GradientTape(model.total_loss, model.trainable_weights)
symb_inputs = (model.feed_inputs + model.feed_targets + model.feed_sample_weights)

It is not working, I got errors like feed_inputs or feed_targets are not there.

3

Hi @Shashank_Priyadarshi, TensorFlow records relevant operations executed inside the context of a tf.GradientTape. TensorFlow then uses that tape to compute the gradients of a recorded computation using reverse mode differentiation. To get gradients from a model,

layer = tf.keras.layers.Dense(2, activation='relu')
x = tf.constant([[1., 2., 3.]])

with tf.GradientTape() as tape:
  y = layer(x)
  loss = tf.reduce_mean(y**2)

grad = tape.gradient(loss, layer.trainable_variables)

for var, g in zip(layer.trainable_variables, grad):
  print(f'{var.name}, gradients: {g}')

Thank You!

4

Hi @Kiran_Sai_Ramineni Thank you for the reply, I wanted to do something like this - python - How to obtain the gradients in keras? - Stack Overflow

5

Closing this as I fixed the issue