import tensorflow as tf


        # Item memories a query
        self._cur_item = self.item_memory(self.input_items)
        self._cur_item_negative = self.item_memory(self.input_items_negative)

    def _construct_placeholders(self):
        self.input_users = tf.placeholder(tf.int32, [None], 'UserID')
        self.input_items = tf.placeholder(tf.int32, [None], 'ItemID')
        self.input_items_negative = tf.placeholder(tf.int32, [None], 'NegativeItemID')

        # Add our placeholders
        add_to_collection(GraphKeys.PLACEHOLDER, [self.input_users,
