title: TensorFlow: “Attempting to use uninitialized value” in variable initialization
body: <p>Here's my code.</p>
  
  <pre><code>import tensorflow as tf
  
  a=tf.Variable(tf.constant([0,1,2],dtype=tf.int32))
  b=tf.Variable(tf.constant([1,1,1],dtype=tf.int32))
  recall=tf.metrics.recall(b,a)
  
  init=tf.global_variables_initializer()
  with tf.Session() as sess:
      sess.run(init)
      rec=sess.run(recall)
      print(rec)
  </code></pre>
  
  <p>I tried to test tf.metrics.precision and got the following error message.</p>
  
  <pre><code>FailedPreconditionError (see above for traceback): Attempting to use uninitialized value recall/true_positives/count
       [[Node: recall/true_positives/count/read = Identity[T=DT_FLOAT, _class=["loc:@recall/true_positives/count"], _device="/job:localhost/replica:0/task:0/gpu:0"](recall/true_positives/count)]]
       [[Node: recall/value/_15 = _Recv[client_terminated=false, recv_device="/job:localhost/replica:0/task:0/cpu:0", send_device="/job:localhost/replica:0/task:0/gpu:0", send_device_incarnation=1, tensor_name="edge_73_recall/value", tensor_type=DT_FLOAT, _device="/job:localhost/replica:0/task:0/cpu:0"]()]]
  </code></pre>