Model Loading Error

Traceback (most recent call last):
  File "/u/nlp/anaconda/main/anaconda3/envs/fresh/lib/python3.6/site-packages/tensorflow/python/client/session.py", line 1334, in _do_call
    return fn(*args)
  File "/u/nlp/anaconda/main/anaconda3/envs/fresh/lib/python3.6/site-packages/tensorflow/python/client/session.py", line 1319, in _run_fn
    options, feed_dict, fetch_list, target_list, run_metadata)
  File "/u/nlp/anaconda/main/anaconda3/envs/fresh/lib/python3.6/site-packages/tensorflow/python/client/session.py", line 1407, in _call_tf_sessionrun
    run_metadata)
tensorflow.python.framework.errors_impl.FailedPreconditionError: Attempting to use uninitialized value eval_metrics/mean/count
         [[{{node eval_metrics/mean/AssignAdd_1}} = AssignAdd[T=DT_FLOAT, use_locking=false, _device="/job:localhost/replica:0/task:0/device:GPU:0"](eval_metrics/mean/count, eval_metrics/mean/ToFloat, ^add_8)]]

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "evaluate_save.py", line 42, in <module>
    model.evaluate(test_batch_generator, evaluator) # inference on test data
  File "/juicier/scr126/scr/hnf035/fresh/SMRCToolkit/sogou_mrc/model/bert_coqa.py", line 356, in evaluate
    Trainer._evaluate(self, batch_generator, evaluator)
  File "/juicier/scr126/scr/hnf035/fresh/SMRCToolkit/sogou_mrc/train/trainer.py", line 153, in _evaluate
    output = Trainer._eval_sess(model, batch_generator, eval_num_steps, None)
  File "/juicier/scr126/scr/hnf035/fresh/SMRCToolkit/sogou_mrc/train/trainer.py", line 48, in _eval_sess
    _, output = model.session.run([model.eval_update_metrics, model.output_variable_dict], feed_dict=feed_dict)
  File "/u/nlp/anaconda/main/anaconda3/envs/fresh/lib/python3.6/site-packages/tensorflow/python/client/session.py", line 929, in run
    run_metadata_ptr)
  File "/u/nlp/anaconda/main/anaconda3/envs/fresh/lib/python3.6/site-packages/tensorflow/python/client/session.py", line 1152, in _run
    feed_dict_tensor, options, run_metadata)
  File "/u/nlp/anaconda/main/anaconda3/envs/fresh/lib/python3.6/site-packages/tensorflow/python/client/session.py", line 1328, in _do_run
    run_metadata)
  File "/u/nlp/anaconda/main/anaconda3/envs/fresh/lib/python3.6/site-packages/tensorflow/python/client/session.py", line 1348, in _do_call
    raise type(e)(node_def, op, message)
tensorflow.python.framework.errors_impl.FailedPreconditionError: Attempting to use uninitialized value eval_metrics/mean/count
         [[node eval_metrics/mean/AssignAdd_1 (defined at /juicier/scr126/scr/hnf035/fresh/SMRCToolkit/sogou_mrc/model/bert_coqa.py:199)  = AssignAdd[T=DT_FLOAT, use_locking=false, _device="/job:localhost/replica:0/task:0/device:GPU:0"](eval_metrics/mean/count, eval_metrics/mean/ToFloat, ^add_8)]]

Caused by op 'eval_metrics/mean/AssignAdd_1', defined at:
  File "evaluate_save.py", line 38, in <module>
    model = BertCoQA(bert_dir=bert_dir,answer_verification=True)
  File "/juicier/scr126/scr/hnf035/fresh/SMRCToolkit/sogou_mrc/model/bert_coqa.py", line 25, in __init__
    self._build_graph()
  File "/juicier/scr126/scr/hnf035/fresh/SMRCToolkit/sogou_mrc/model/bert_coqa.py", line 199, in _build_graph
    'loss': tf.metrics.mean(self.loss)
  File "/u/nlp/anaconda/main/anaconda3/envs/fresh/lib/python3.6/site-packages/tensorflow/python/ops/metrics_impl.py", line 403, in mean
    update_count_op = state_ops.assign_add(count, num_values)
  File "/u/nlp/anaconda/main/anaconda3/envs/fresh/lib/python3.6/site-packages/tensorflow/python/ops/state_ops.py", line 188, in assign_add
    ref, value, use_locking=use_locking, name=name)
  File "/u/nlp/anaconda/main/anaconda3/envs/fresh/lib/python3.6/site-packages/tensorflow/python/ops/gen_state_ops.py", line 103, in assign_add
    "AssignAdd", ref=ref, value=value, use_locking=use_locking, name=name)
  File "/u/nlp/anaconda/main/anaconda3/envs/fresh/lib/python3.6/site-packages/tensorflow/python/framework/op_def_library.py", line 787, in _apply_op_helper
    op_def=op_def)
  File "/u/nlp/anaconda/main/anaconda3/envs/fresh/lib/python3.6/site-packages/tensorflow/python/util/deprecation.py", line 488, in new_func
    return func(*args, **kwargs)
  File "/u/nlp/anaconda/main/anaconda3/envs/fresh/lib/python3.6/site-packages/tensorflow/python/framework/ops.py", line 3274, in create_op
    op_def=op_def)
  File "/u/nlp/anaconda/main/anaconda3/envs/fresh/lib/python3.6/site-packages/tensorflow/python/framework/ops.py", line 1770, in __init__
    self._traceback = tf_stack.extract_stack()

FailedPreconditionError (see above for traceback): Attempting to use uninitialized value eval_metrics/mean/count
         [[node eval_metrics/mean/AssignAdd_1 (defined at /juicier/scr126/scr/hnf035/fresh/SMRCToolkit/sogou_mrc/model/bert_coqa.py:199)  = AssignAdd[T=DT_FLOAT, use_locking=false, _device="/job:localhost/replica:0/task:0/device:GPU:0"](eval_metrics/mean/count, eval_metrics/mean/ToFloat, ^add_8)]]