import tensorflow as tf

        truncated_learning_rate = tf.maximum(learning_rate, tf.constant(params['end_learning_rate'], dtype=learning_rate.dtype), name='learning_rate')
        tf.summary.scalar('lr', truncated_learning_rate)

        optimizer = tf.train.MomentumOptimizer(learning_rate=truncated_learning_rate,
                                                momentum=params['momentum'])

