def split_params(sym, params):
"""Helper function to split params dictionary into args and aux params
Parameters
----------
sym : :class:`~mxnet.symbol.Symbol`
MXNet symbol object
params : dict of ``str`` to :class:`~mxnet.ndarray.NDArray`
Dict of converted parameters stored in ``mxnet.ndarray.NDArray`` format
Returns
-------
arg_params : dict of ``str`` to :class:`~mxnet.ndarray.NDArray`
Dict of converted parameters stored in ``mxnet.ndarray.NDArray`` format
aux_params : dict of ``str`` to :class:`~mxnet.ndarray.NDArray`
Dict of converted parameters stored in ``mxnet.ndarray.NDArray`` format
"""
arg_params = {}
aux_params = {}
for args in sym.list_arguments():
if args in params:
arg_params.update({args: nd.array(params[args])})
for aux in sym.list_auxiliary_states():
if aux in params:
aux_params.update({aux: nd.array(params[aux])})
return arg_params, aux_params
def from_onnx(self, graph):
"""Construct symbol from onnx graph.
Parameters
----------
graph : onnx protobuf object
The loaded onnx graph
Returns
-------
sym :symbol.Symbol
The returned mxnet symbol
params : dict
A dict of name: nd.array pairs, used as pretrained weights
"""
# get input, output shapes
self.model_metadata = self.get_graph_metadata(graph)
# parse network inputs, aka parameters
for init_tensor in graph.initializer:
if not init_tensor.name.strip():
raise ValueError("Tensor's name is required.")
self._params[init_tensor.name] = self._parse_array(init_tensor)
# converting GraphProto message
for i in graph.input:
if i.name in self._params:
# i is a param instead of input
self._nodes[i.name] = symbol.Variable(name=i.name,
shape=self._params[i.name].shape)
else:
self._nodes[i.name] = symbol.Variable(name=i.name)
# constructing nodes, nodes are stored as directed acyclic graph
# converting NodeProto message
for node in graph.node:
op_name = node.op_type
node_name = node.name.strip()
node_name = node_name if node_name else None
onnx_attr = self._parse_attr(node.attribute)
inputs = [self._nodes[i] for i in node.input]
mxnet_sym = self._convert_operator(node_name, op_name, onnx_attr, inputs)
for k, i in zip(list(node.output), range(len(mxnet_sym.list_outputs()))):
self._nodes[k] = mxnet_sym[i]
# splitting params into args and aux params
for args in mxnet_sym.list_arguments():
if args in self._params:
self.arg_dict.update({args: nd.array(self._params[args])})
for aux in mxnet_sym.list_auxiliary_states():
if aux in self._params:
self.aux_dict.update({aux: nd.array(self._params[aux])})
# now return the outputs
out = [self._nodes[i.name] for i in graph.output]
if len(out) > 1:
out = symbol.Group(out)
else:
out = out[0]
return out, self.arg_dict, self.aux_dict
def _prepare_image(img, nrow=8, padding=2, square_image=False):
"""Given an image of format HW, CHW, or NCHW, returns a image of format HWC.
If the input is a batch of images, a grid of images is made by stitching them together.
If data type is float, values must be in the range [0, 1], and then they are rescaled to
range [0, 255]. If data type is 'uint8`, values are unchanged.
"""
if isinstance(img, np.ndarray):
img = nd.array(img, dtype=img.dtype, ctx=current_context())
if not isinstance(img, NDArray):
raise TypeError('expected MXNet NDArray or numpy.ndarray, '
'while received type {}'.format(str(type(img))))
assert img.ndim == 2 or img.ndim == 3 or img.ndim == 4
if img.dtype == np.uint8:
return make_image_grid(
img, nrow=nrow, padding=padding, square_image=square_image).transpose((1, 2, 0))
elif img.dtype == np.float32 or img.dtype == np.float64:
min_val = img.min().asscalar()
max_val = img.max().asscalar()
if min_val < 0.0:
raise ValueError('expected non-negative min value from img, '
'while received {}'.format(min_val))
if max_val > 1.0:
raise ValueError('expected max value from img not greater than 1, '
'while received {}'.format(max_val))
img = make_image_grid(img, nrow=nrow, padding=padding, square_image=square_image) * 255.0
return img.astype(np.uint8).transpose((1, 2, 0))
else:
raise ValueError('expected input image dtype is one of uint8, float32, '
'and float64, received dtype {}'.format(str(img.dtype)))
def _parse_array(self, tensor_proto):
"""Grab data in TensorProto and convert to numpy array."""
try:
from onnx.numpy_helper import to_array
except ImportError:
raise ImportError("Onnx and protobuf need to be installed. "
+ "Instructions to install - https://github.com/onnx/onnx")
if len(tuple(tensor_proto.dims)) > 0:
np_array = to_array(tensor_proto).reshape(tuple(tensor_proto.dims))
else:
# If onnx's params are scalar values without dims mentioned.
np_array = np.array([to_array(tensor_proto)])
return nd.array(np_array)
def _make_sprite_image(images, save_path):
"""Given an NDArray as a batch images, make a sprite image out of it following the rule
defined in
https://www.tensorflow.org/programmers_guide/embedding
and save it in sprite.png under the path provided by the user."""
if isinstance(images, np.ndarray):
images = nd.array(images, dtype=images.dtype, ctx=current_context())
elif not isinstance(images, (NDArray, np.ndarray)):
raise TypeError('images must be an MXNet NDArray or numpy.ndarray,'
' while received type {}'.format(str(type(images))))
assert isinstance(images, NDArray)
shape = images.shape
nrow = int(np.ceil(np.sqrt(shape[0])))
_save_image(images, os.path.join(save_path, 'sprite.png'), nrow=nrow, padding=0)