

In [12]:

    
import tensorflow as tf

with tf.device('/gpu:2'):
    a = tf.constant([1.0, 2.0, 3.0, 4.0, 5.0, 6.0], shape=[2, 3], name='a')
    b = tf.constant([1.0, 2.0, 3.0, 4.0, 5.0, 6.0], shape=[3, 2], name='b')
    c = tf.matmul(a, b)
    sess = tf.Session(config=tf.ConfigProto(log_device_placement=True))
    print sess.run(c)









    



---------------------------------------------------------------------------
InvalidArgumentError                      Traceback (most recent call last)
<ipython-input-12-93f4e247b504> in <module>()
      6     c = tf.matmul(a, b)
      7     sess = tf.Session(config=tf.ConfigProto(log_device_placement=True))
----> 8     print sess.run(c)

/Users/lipingzhang/anaconda/lib/python2.7/site-packages/tensorflow/python/client/session.pyc in run(self, fetches, feed_dict, options, run_metadata)
    765     try:
    766       result = self._run(None, fetches, feed_dict, options_ptr,
--> 767                          run_metadata_ptr)
    768       if run_metadata:
    769         proto_data = tf_session.TF_GetBuffer(run_metadata_ptr)

/Users/lipingzhang/anaconda/lib/python2.7/site-packages/tensorflow/python/client/session.pyc in _run(self, handle, fetches, feed_dict, options, run_metadata)
    963     if final_fetches or final_targets:
    964       results = self._do_run(handle, final_targets, final_fetches,
--> 965                              feed_dict_string, options, run_metadata)
    966     else:
    967       results = []

/Users/lipingzhang/anaconda/lib/python2.7/site-packages/tensorflow/python/client/session.pyc in _do_run(self, handle, target_list, fetch_list, feed_dict, options, run_metadata)
   1013     if handle is None:
   1014       return self._do_call(_run_fn, self._session, feed_dict, fetch_list,
-> 1015                            target_list, options, run_metadata)
   1016     else:
   1017       return self._do_call(_prun_fn, self._session, handle, feed_dict,

/Users/lipingzhang/anaconda/lib/python2.7/site-packages/tensorflow/python/client/session.pyc in _do_call(self, fn, *args)
   1033         except KeyError:
   1034           pass
-> 1035       raise type(e)(node_def, op, message)
   1036 
   1037   def _extend_graph(self):

InvalidArgumentError: Cannot assign a device to node 'MatMul_6': Could not satisfy explicit device specification '/device:GPU:2' because no devices matching that specification are registered in this process; available devices: /job:localhost/replica:0/task:0/cpu:0
	 [[Node: MatMul_6 = MatMul[T=DT_FLOAT, transpose_a=false, transpose_b=false, _device="/device:GPU:2"](a_9, b_6)]]

Caused by op u'MatMul_6', defined at:
  File "/Users/lipingzhang/anaconda/lib/python2.7/runpy.py", line 174, in _run_module_as_main
    "__main__", fname, loader, pkg_name)
  File "/Users/lipingzhang/anaconda/lib/python2.7/runpy.py", line 72, in _run_code
    exec code in run_globals
  File "/Users/lipingzhang/anaconda/lib/python2.7/site-packages/ipykernel_launcher.py", line 16, in <module>
    app.launch_new_instance()
  File "/Users/lipingzhang/anaconda/lib/python2.7/site-packages/traitlets/config/application.py", line 658, in launch_instance
    app.start()
  File "/Users/lipingzhang/anaconda/lib/python2.7/site-packages/ipykernel/kernelapp.py", line 477, in start
    ioloop.IOLoop.instance().start()
  File "/Users/lipingzhang/anaconda/lib/python2.7/site-packages/zmq/eventloop/ioloop.py", line 177, in start
    super(ZMQIOLoop, self).start()
  File "/Users/lipingzhang/anaconda/lib/python2.7/site-packages/tornado/ioloop.py", line 888, in start
    handler_func(fd_obj, events)
  File "/Users/lipingzhang/anaconda/lib/python2.7/site-packages/tornado/stack_context.py", line 277, in null_wrapper
    return fn(*args, **kwargs)
  File "/Users/lipingzhang/anaconda/lib/python2.7/site-packages/zmq/eventloop/zmqstream.py", line 440, in _handle_events
    self._handle_recv()
  File "/Users/lipingzhang/anaconda/lib/python2.7/site-packages/zmq/eventloop/zmqstream.py", line 472, in _handle_recv
    self._run_callback(callback, msg)
  File "/Users/lipingzhang/anaconda/lib/python2.7/site-packages/zmq/eventloop/zmqstream.py", line 414, in _run_callback
    callback(*args, **kwargs)
  File "/Users/lipingzhang/anaconda/lib/python2.7/site-packages/tornado/stack_context.py", line 277, in null_wrapper
    return fn(*args, **kwargs)
  File "/Users/lipingzhang/anaconda/lib/python2.7/site-packages/ipykernel/kernelbase.py", line 283, in dispatcher
    return self.dispatch_shell(stream, msg)
  File "/Users/lipingzhang/anaconda/lib/python2.7/site-packages/ipykernel/kernelbase.py", line 235, in dispatch_shell
    handler(stream, idents, msg)
  File "/Users/lipingzhang/anaconda/lib/python2.7/site-packages/ipykernel/kernelbase.py", line 399, in execute_request
    user_expressions, allow_stdin)
  File "/Users/lipingzhang/anaconda/lib/python2.7/site-packages/ipykernel/ipkernel.py", line 196, in do_execute
    res = shell.run_cell(code, store_history=store_history, silent=silent)
  File "/Users/lipingzhang/anaconda/lib/python2.7/site-packages/ipykernel/zmqshell.py", line 533, in run_cell
    return super(ZMQInteractiveShell, self).run_cell(*args, **kwargs)
  File "/Users/lipingzhang/anaconda/lib/python2.7/site-packages/IPython/core/interactiveshell.py", line 2717, in run_cell
    interactivity=interactivity, compiler=compiler, result=result)
  File "/Users/lipingzhang/anaconda/lib/python2.7/site-packages/IPython/core/interactiveshell.py", line 2821, in run_ast_nodes
    if self.run_code(code, result):
  File "/Users/lipingzhang/anaconda/lib/python2.7/site-packages/IPython/core/interactiveshell.py", line 2881, in run_code
    exec(code_obj, self.user_global_ns, self.user_ns)
  File "<ipython-input-12-93f4e247b504>", line 6, in <module>
    c = tf.matmul(a, b)
  File "/Users/lipingzhang/anaconda/lib/python2.7/site-packages/tensorflow/python/ops/math_ops.py", line 1855, in matmul
    a, b, transpose_a=transpose_a, transpose_b=transpose_b, name=name)
  File "/Users/lipingzhang/anaconda/lib/python2.7/site-packages/tensorflow/python/ops/gen_math_ops.py", line 1454, in _mat_mul
    transpose_b=transpose_b, name=name)
  File "/Users/lipingzhang/anaconda/lib/python2.7/site-packages/tensorflow/python/framework/op_def_library.py", line 763, in apply_op
    op_def=op_def)
  File "/Users/lipingzhang/anaconda/lib/python2.7/site-packages/tensorflow/python/framework/ops.py", line 2395, in create_op
    original_op=self._default_original_op, op_def=op_def)
  File "/Users/lipingzhang/anaconda/lib/python2.7/site-packages/tensorflow/python/framework/ops.py", line 1264, in __init__
    self._traceback = _extract_stack()

InvalidArgumentError (see above for traceback): Cannot assign a device to node 'MatMul_6': Could not satisfy explicit device specification '/device:GPU:2' because no devices matching that specification are registered in this process; available devices: /job:localhost/replica:0/task:0/cpu:0
	 [[Node: MatMul_6 = MatMul[T=DT_FLOAT, transpose_a=false, transpose_b=false, _device="/device:GPU:2"](a_9, b_6)]]