import tensorflow as tf

        opt_momentum = knobs['opt_momentum'] # Momentum optimizer momentum
        grad_clip_norm = knobs['grad_clip_norm'] # L2 norm to clip gradients by

        # Compute learning rate, gradients
        tf_trainable_vars = tf.trainable_variables()
        lr = self._get_learning_rate(step, **knobs)
        grads = tf.gradients(loss, tf_trainable_vars)
        self._mark_for_monitoring('lr', lr)
