I'm trying to convert PyTorch FOMM model to TorchScript. As soon as I started to annotate some classes with @torch.jit.script
I've got an error:
OSError: Can't get source for <class 'collections.deque'>. TorchScript requires source access in order to carry out compilation, make sure original .py files are available.
As I understand that class implemented in CPython therefore cannot be read by TorchScript compiler. I failed to find any pure-Python implementation. How can I overcome this issue?
Here is the class I'm trying to annotate:
import queue
import collections
import threading
import torch
@torch.jit.script
class SyncMaster(object):
"""An abstract `SyncMaster` object.
- During the replication, as the data parallel will trigger an callback of each module, all slave devices should
call `register(id)` and obtain an `SlavePipe` to communicate with the master.
- During the forward pass, master device invokes `run_master`, all messages from slave devices will be collected,
and passed to a registered callback.
- After receiving the messages, the master device should gather the information and determine to message passed
back to each slave devices.
"""
def __init__(self, master_callback):
"""
Args:
master_callback: a callback to be invoked after having collected messages from slave devices.
"""
self._master_callback = master_callback
self._queue = queue.Queue()
self._registry = collections.OrderedDict()
self._activated = False
def __getstate__(self):
return {'master_callback': self._master_callback}
def __setstate__(self, state):
self.__init__(state['master_callback'])
def register_slave(self, identifier):
"""
Register an slave device.
Args:
identifier: an identifier, usually is the device id.
Returns: a `SlavePipe` object which can be used to communicate with the master device.
"""
if self._activated:
assert self._queue.empty(), 'Queue is not clean before next initialization.'
self._activated = False
self._registry.clear()
future = FutureResult()
self._registry[identifier] = _MasterRegistry(future)
return SlavePipe(identifier, self._queue, future)
def run_master(self, master_msg):
"""
Main entry for the master device in each forward pass.
The messages were first collected from each devices (including the master device), and then
an callback will be invoked to compute the message to be sent back to each devices
(including the master device).
Args:
master_msg: the message that the master want to send to itself. This will be placed as the first
message when calling `master_callback`. For detailed usage, see `_SynchronizedBatchNorm` for an example.
Returns: the message to be sent back to the master device.
"""
self._activated = True
intermediates = [(0, master_msg)]
for i in range(self.nr_slaves):
intermediates.append(self._queue.get())
results = self._master_callback(intermediates)
assert results[0][0] == 0, 'The first result should belongs to the master.'
for i, res in results:
if i == 0:
continue
self._registry[i].result.put(res)
for i in range(self.nr_slaves):
assert self._queue.get() is True
return results[0][1]
@property
def nr_slaves(self):
return len(self._registry)
Switched TorchScript generation method from torch.jit.script
to torch.jit.trace
and it worked, no need in annotating anything. Alternatively torch.onnx.export
works sometimes.