import tensorflow as tf

    def _build_net(self):  # we use parameter sharing among agents
        with tf.variable_scope(self.name):
            # ------------------ all inputs ------------------------
            self.S = tf.placeholder(tf.float32, [None, self.num_global_s], name='S')  # input Global State
            self.s = tf.placeholder(tf.float32, [None, self.num_s], name='s1')  # input state for agent1
            self.S_ = tf.placeholder(tf.float32, [None, self.num_global_s], name='S_')  # input Next Global State
