Fix multiple GPUs fails in training Mask_RCNN

Test with:

Keras: 2.2.4
Python: 3.6.9
Tensorflow: 1.12.0

==================

Problem:

Using code from https://github.com/matterport/Mask_RCNN

When setting GPU_COUNT > 1

enconter this error:

RuntimeError: It looks like you are subclassing `Model` and you forgot to call `super(YourClass, self).__init__()`. Always start with this line.

Traceback (most recent call last):
  File "D:\Anaconda33\lib\site-packages\keras\engine\network.py", line 313, in __setattr__
    is_graph_network = self._is_graph_network
  File "parallel_model.py", line 46, in __getattribute__
    return super(ParallelModel, self).__getattribute__(attrname)
AttributeError: 'ParallelModel' object has no attribute '_is_graph_network'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "parallel_model.py", line 159, in <module>
    model = ParallelModel(model, GPU_COUNT)
  File "parallel_model.py", line 35, in __init__
    self.inner_model = keras_model
  File "D:\Anaconda33\lib\site-packages\keras\engine\network.py", line 316, in __setattr__
    'It looks like you are subclassing `Model` and you '
RuntimeError: It looks like you are subclassing `Model` and you forgot to call `super(YourClass, self).__init__()`. Always start with this line.

Solution 1:

changing code in mrcnn/parallel_model.py as the following:

class ParallelModel(KM.Model):
    def __init__(self, keras_model, gpu_count):
        """Class constructor.
        keras_model: The Keras model to parallelize
        gpu_count: Number of GPUs. Must be > 1
        """
        super(ParallelModel, self).__init__()
        self.inner_model = keras_model
        self.gpu_count = gpu_count
        merged_outputs = self.make_parallel()
        super(ParallelModel, self).__init__(inputs=self.inner_model.inputs,
                                            outputs=merged_outputs)

When getting this error:

asking for two arguments: inputs and outputs

Just upgrade your Keras to 2.2.4

When getting this error:

No node-device colocations were active during op 'tower_1/mask_rcnn/anchors/Variable/anchors/Variable/read_tower_1/mask_rcnn/anchors/Variable_0' creation.
Device assignments active during op 'tower_1/mask_rcnn/anchors/Variable/anchors/Variable/read_tower_1/mask_rcnn/anchors/Variable_0' creation:
with tf.device(/gpu:1): <M:\new\mrcnn\parallel_model.py:70>

No node-device colocations were active during op 'anchors/Variable' creation.
No device assignments were active during op 'anchors/Variable' creation.

Traceback (most recent call last):
  File "D:\Anaconda33\lib\site-packages\tensorflow\python\client\session.py", line 1334, in _do_call
    return fn(*args)
  File "D:\Anaconda33\lib\site-packages\tensorflow\python\client\session.py", line 1317, in _run_fn
    self._extend_graph()
  File "D:\Anaconda33\lib\site-packages\tensorflow\python\client\session.py", line 1352, in _extend_graph
    tf_session.ExtendSession(self._session)
tensorflow.python.framework.errors_impl.InvalidArgumentError: Cannot colocate nodes {{colocation_node tower_1/mask_rcnn/anchors/Variable/anchors/Variable/read_tower_1/mask_rcnn/anchors/Variable_0}} and {{colocation_node anchors/Variable}}: Cannot merge devices with incompatible ids: '/device:GPU:0' and '/device:GPU:1'
         [[{{node tower_1/mask_rcnn/anchors/Variable/anchors/Variable/read_tower_1/mask_rcnn/anchors/Variable_0}} = Identity[T=DT_FLOAT, _class=["loc:@anchors/Variable"], _device="/device:GPU:1"](tower_1/mask_rcnn/anchors/Variable/cond/Merge)]]

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "train_mul.py", line 448, in <module>
    "mrcnn_bbox", "mrcnn_mask"])
  File "M:\new\mrcnn\model.py", line 2132, in load_weights
    saving.load_weights_from_hdf5_group_by_name(f, layers)
  File "D:\Anaconda33\lib\site-packages\keras\engine\saving.py", line 1022, in load_weights_from_hdf5_group_by_name
    K.batch_set_value(weight_value_tuples)
  File "D:\Anaconda33\lib\site-packages\keras\backend\tensorflow_backend.py", line 2440, in batch_set_value
    get_session().run(assign_ops, feed_dict=feed_dict)
  File "D:\Anaconda33\lib\site-packages\keras\backend\tensorflow_backend.py", line 197, in get_session
    [tf.is_variable_initialized(v) for v in candidate_vars])
  File "D:\Anaconda33\lib\site-packages\tensorflow\python\client\session.py", line 929, in run
    run_metadata_ptr)
  File "D:\Anaconda33\lib\site-packages\tensorflow\python\client\session.py", line 1152, in _run
    feed_dict_tensor, options, run_metadata)
  File "D:\Anaconda33\lib\site-packages\tensorflow\python\client\session.py", line 1328, in _do_run
    run_metadata)
  File "D:\Anaconda33\lib\site-packages\tensorflow\python\client\session.py", line 1348, in _do_call
    raise type(e)(node_def, op, message)
tensorflow.python.framework.errors_impl.InvalidArgumentError: Cannot colocate nodes node tower_1/mask_rcnn/anchors/Variable/anchors/Variable/read_tower_1/mask_rcnn/anchors/Variable_0 (defined at M:\new\mrcnn\model.py:1936) having device Device assignments active during op 'tower_1/mask_rcnn/anchors/Variable/anchors/Variable/read_tower_1/mask_rcnn/anchors/Variable_0' creation:
  with tf.device(/gpu:1): <M:\new\mrcnn\parallel_model.py:70>  and node anchors/Variable (defined at M:\new\mrcnn\model.py:1936) having device No device assignments were active during op 'anchors/Variable' creation. : Cannot merge devices with incompatible ids: '/device:GPU:0' and '/device:GPU:1'
         [[node tower_1/mask_rcnn/anchors/Variable/anchors/Variable/read_tower_1/mask_rcnn/anchors/Variable_0 (defined at M:\new\mrcnn\model.py:1936)  = Identity[T=DT_FLOAT, _class=["loc:@anchors/Variable"], _device="/device:GPU:1"](tower_1/mask_rcnn/anchors/Variable/cond/Merge)]]

No node-device colocations were active during op 'tower_1/mask_rcnn/anchors/Variable/anchors/Variable/read_tower_1/mask_rcnn/anchors/Variable_0' creation.
Device assignments active during op 'tower_1/mask_rcnn/anchors/Variable/anchors/Variable/read_tower_1/mask_rcnn/anchors/Variable_0' creation:
  with tf.device(/gpu:1): <M:\new\mrcnn\parallel_model.py:70>

No node-device colocations were active during op 'anchors/Variable' creation.
No device assignments were active during op 'anchors/Variable' creation.

Caused by op 'tower_1/mask_rcnn/anchors/Variable/anchors/Variable/read_tower_1/mask_rcnn/anchors/Variable_0', defined at:
  File "train_mul.py", line 417, in <module>
    model_dir=MODEL_DIR)
  File "M:\new\mrcnn\model.py", line 1839, in __init__
    self.keras_model = self.build(mode=mode, config=config)
  File "M:\new\mrcnn\model.py", line 2064, in build
    model = ParallelModel(model, config.GPU_COUNT)
  File "M:\new\mrcnn\parallel_model.py", line 36, in __init__
    merged_outputs = self.make_parallel()
  File "M:\new\mrcnn\parallel_model.py", line 80, in make_parallel
    outputs = self.inner_model(inputs)
  File "D:\Anaconda33\lib\site-packages\keras\engine\base_layer.py", line 457, in __call__
    output = self.call(inputs, **kwargs)
  File "D:\Anaconda33\lib\site-packages\keras\engine\network.py", line 570, in call
    output_tensors, _, _ = self.run_internal_graph(inputs, masks)
  File "D:\Anaconda33\lib\site-packages\keras\engine\network.py", line 724, in run_internal_graph
    output_tensors = to_list(layer.call(computed_tensor, **kwargs))
  File "D:\Anaconda33\lib\site-packages\keras\layers\core.py", line 682, in call
    return self.function(inputs, **arguments)
  File "M:\new\mrcnn\model.py", line 1936, in <lambda>
    anchors = KL.Lambda(lambda x: tf.Variable(anchors), name="anchors")(input_image)
  File "D:\Anaconda33\lib\site-packages\tensorflow\python\ops\variables.py", line 183, in __call__
    return cls._variable_v1_call(*args, **kwargs)
  File "D:\Anaconda33\lib\site-packages\tensorflow\python\ops\variables.py", line 146, in _variable_v1_call
    aggregation=aggregation)
  File "D:\Anaconda33\lib\site-packages\tensorflow\python\ops\variables.py", line 125, in <lambda>
    previous_getter = lambda **kwargs: default_variable_creator(None, **kwargs)
  File "D:\Anaconda33\lib\site-packages\tensorflow\python\ops\variable_scope.py", line 2444, in default_variable_creator
    expected_shape=expected_shape, import_scope=import_scope)
  File "D:\Anaconda33\lib\site-packages\tensorflow\python\ops\variables.py", line 187, in __call__
    return super(VariableMetaclass, cls).__call__(*args, **kwargs)
  File "D:\Anaconda33\lib\site-packages\tensorflow\python\ops\variables.py", line 1329, in __init__
    constraint=constraint)
  File "D:\Anaconda33\lib\site-packages\tensorflow\python\ops\variables.py", line 1480, in _init_from_args
    self._initial_value),
  File "D:\Anaconda33\lib\site-packages\tensorflow\python\ops\variables.py", line 2177, in _try_guard_against_uninitialized_dependencies
    return self._safe_initial_value_from_tensor(initial_value, op_cache={})
  File "D:\Anaconda33\lib\site-packages\tensorflow\python\ops\variables.py", line 2195, in _safe_initial_value_from_tensor
    new_op = self._safe_initial_value_from_op(op, op_cache)
  File "D:\Anaconda33\lib\site-packages\tensorflow\python\ops\variables.py", line 2241, in _safe_initial_value_from_op
    name=new_op_name, attrs=op.node_def.attr)
  File "D:\Anaconda33\lib\site-packages\tensorflow\python\util\deprecation.py", line 488, in new_func
    return func(*args, **kwargs)
  File "D:\Anaconda33\lib\site-packages\tensorflow\python\framework\ops.py", line 3274, in create_op
    op_def=op_def)
  File "D:\Anaconda33\lib\site-packages\tensorflow\python\framework\ops.py", line 1770, in __init__
    self._traceback = tf_stack.extract_stack()

InvalidArgumentError (see above for traceback): Cannot colocate nodes node tower_1/mask_rcnn/anchors/Variable/anchors/Variable/read_tower_1/mask_rcnn/anchors/Variable_0 (defined at M:\new\mrcnn\model.py:1936) having device Device assignments active during op 'tower_1/mask_rcnn/anchors/Variable/anchors/Variable/read_tower_1/mask_rcnn/anchors/Variable_0' creation:
  with tf.device(/gpu:1): <M:\new\mrcnn\parallel_model.py:70>  and node anchors/Variable (defined at M:\new\mrcnn\model.py:1936) having device No device assignments were active during op 'anchors/Variable' creation. : Cannot merge devices with incompatible ids: '/device:GPU:0' and '/device:GPU:1'
         [[node tower_1/mask_rcnn/anchors/Variable/anchors/Variable/read_tower_1/mask_rcnn/anchors/Variable_0 (defined at M:\new\mrcnn\model.py:1936)  = Identity[T=DT_FLOAT, _class=["loc:@anchors/Variable"], _device="/device:GPU:1"](tower_1/mask_rcnn/anchors/Variable/cond/Merge)]]

No node-device colocations were active during op 'tower_1/mask_rcnn/anchors/Variable/anchors/Variable/read_tower_1/mask_rcnn/anchors/Variable_0' creation.
Device assignments active during op 'tower_1/mask_rcnn/anchors/Variable/anchors/Variable/read_tower_1/mask_rcnn/anchors/Variable_0' creation:
  with tf.device(/gpu:1): <M:\new\mrcnn\parallel_model.py:70>

No node-device colocations were active during op 'anchors/Variable' creation.
No device assignments were active during op 'anchors/Variable' creation.

Adding this line:

import keras.backend.tensorflow_backend as KTF

config = tf.ConfigProto()
config.allow_soft_placement=True
session = tf.Session(config=config)
KTF.set_session(session)

Solution 2:(not recommended)

downgrade Keras to 2.1.3:

conda install keras=2.1.3

(this works for someone but not works for me)

Reference:

https://github.com/matterport/Mask_RCNN/issues/921

https://github.com/tensorflow/tensorflow/issues/2285