Can't create more than one instance of MTCNN class

[lshostenko]

Creating another instance of MTCNN causes a tensorflow error. Seems like they are trying to share the same tf session:

from mtcnn.mtcnn import MTCNN

detector_1 = MTCNN(steps_threshold=(.2, .7, .7))  # ok
detector_2 = MTCNN(steps_threshold=(.1, .7, .5))  # error

ValueError                                Traceback (most recent call last)
<ipython-input-3-62d11dc62821> in <module>()
----> 1 detector_2 = MTCNN(steps_threshold=(.1, .7, .5))

~/py/ocean/test/env/lib/python3.6/site-packages/mtcnn/mtcnn.py in __init__(self, weights_file, min_face_size, steps_threshold, scale_factor)
    191
    192         weights = np.load(weights_file).item()
--> 193         self.__pnet = PNet(self.__session, False)
    194         self.__pnet.set_weights(weights['PNet'])
    195

~/py/ocean/test/env/lib/python3.6/site-packages/mtcnn/network.py in __init__(self, session, trainable)
     42
     43         with tf.variable_scope(self.__class__.__name__.lower()):
---> 44             self._config()
     45
     46     def _config(self):

~/py/ocean/test/env/lib/python3.6/site-packages/mtcnn/mtcnn.py in _config(self)
     53         layer_factory.new_feed(name='data', layer_shape=(None, None, None, 3))
     54         layer_factory.new_conv(name='conv1', kernel_size=(3, 3), channels_output=10, stride_size=(1, 1),
---> 55                                padding='VALID', relu=False)
     56         layer_factory.new_prelu(name='prelu1')
     57         layer_factory.new_max_pool(name='pool1', kernel_size=(2, 2), stride_size=(2, 2))

~/py/ocean/test/env/lib/python3.6/site-packages/mtcnn/layer_factory.py in new_conv(self, name, kernel_size, channels_output, stride_size, padding, group, biased, relu, input_layer_name)
    121
    122         with tf.variable_scope(name) as scope:
--> 123             kernel = self.__make_var('weights', shape=[kernel_size[1], kernel_size[0], channels_input // group, channels_output])
    124
    125             output = convolve(input_layer, kernel)

~/py/ocean/test/env/lib/python3.6/site-packages/mtcnn/layer_factory.py in __make_var(self, name, shape)
     76         :return: created TF variable.
     77         """
---> 78         return tf.get_variable(name, shape, trainable=self.__network.is_trainable())
     79
     80     def new_feed(self, name: str, layer_shape: tuple):

~/py/ocean/test/env/lib/python3.6/site-packages/tensorflow/python/ops/variable_scope.py in get_variable(name, shape, dtype, initializer, regularizer, trainable, collections, caching_device, partitioner, validate_shape, use_resource, custom_getter, constraint)
   1315       partitioner=partitioner, validate_shape=validate_shape,
   1316       use_resource=use_resource, custom_getter=custom_getter,
-> 1317       constraint=constraint)
   1318 get_variable_or_local_docstring = (
   1319     """%s

~/py/ocean/test/env/lib/python3.6/site-packages/tensorflow/python/ops/variable_scope.py in get_variable(self, var_store, name, shape, dtype, initializer, regularizer, reuse, trainable, collections, caching_device, partitioner, validate_shape, use_resource, custom_getter, constraint)
   1077           partitioner=partitioner, validate_shape=validate_shape,
   1078           use_resource=use_resource, custom_getter=custom_getter,
-> 1079           constraint=constraint)
   1080
   1081   def _get_partitioned_variable(self,

~/py/ocean/test/env/lib/python3.6/site-packages/tensorflow/python/ops/variable_scope.py in get_variable(self, name, shape, dtype, initializer, regularizer, reuse, trainable, collections, caching_device, partitioner, validate_shape, use_resource, custom_getter, constraint)
    423           caching_device=caching_device, partitioner=partitioner,
    424           validate_shape=validate_shape, use_resource=use_resource,
--> 425           constraint=constraint)
    426
    427   def _get_partitioned_variable(

~/py/ocean/test/env/lib/python3.6/site-packages/tensorflow/python/ops/variable_scope.py in _true_getter(name, shape, dtype, initializer, regularizer, reuse, trainable, collections, caching_device, partitioner, validate_shape, use_resource, constraint)
    392           trainable=trainable, collections=collections,
    393           caching_device=caching_device, validate_shape=validate_shape,
--> 394           use_resource=use_resource, constraint=constraint)
    395
    396     if custom_getter is not None:

~/py/ocean/test/env/lib/python3.6/site-packages/tensorflow/python/ops/variable_scope.py in _get_single_variable(self, name, shape, dtype, initializer, regularizer, partition_info, reuse, trainable, collections, caching_device, validate_shape, use_resource, constraint)
    731                          "reuse=tf.AUTO_REUSE in VarScope? "
    732                          "Originally defined at:\n\n%s" % (
--> 733                              name, "".join(traceback.format_list(tb))))
    734       found_var = self._vars[name]
    735       if not shape.is_compatible_with(found_var.get_shape()):

ValueError: Variable pnet/conv1/weights already exists, disallowed. Did you mean to set reuse=True or reuse=tf.AUTO_REUSE in VarScope? Originally defined at:

  File "/Users/erizo/py/ocean/test/env/lib/python3.6/site-packages/mtcnn/layer_factory.py", line 78, in __make_var
    return tf.get_variable(name, shape, trainable=self.__network.is_trainable())
  File "/Users/erizo/py/ocean/test/env/lib/python3.6/site-packages/mtcnn/layer_factory.py", line 123, in new_conv
    kernel = self.__make_var('weights', shape=[kernel_size[1], kernel_size[0], channels_input // group, channels_output])
  File "/Users/erizo/py/ocean/test/env/lib/python3.6/site-packages/mtcnn/mtcnn.py", line 55, in _config
    padding='VALID', relu=False)

[ipazc]

This is the cause of the issue #6

[ipazc]

Fixed