Source code for detectron2.export.api

# Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
import copy
import logging
import os
import torch
from caffe2.proto import caffe2_pb2
from torch import nn

from detectron2.config import CfgNode as CN

from .caffe2_export import export_caffe2_detection_model
from .caffe2_export import export_onnx_model as export_onnx_model_impl
from .caffe2_export import run_and_save_graph
from .caffe2_inference import ProtobufDetectionModel
from .caffe2_modeling import META_ARCH_CAFFE2_EXPORT_TYPE_MAP, convert_batched_inputs_to_c2_format
from .shared import get_pb_arg_vali, get_pb_arg_vals, save_graph

__all__ = [
    "add_export_config",
    "export_caffe2_model",
    "Caffe2Model",
    "export_onnx_model",
    "Caffe2Tracer",
]


[docs]def add_export_config(cfg): """ Args: cfg (CfgNode): a detectron2 config Returns: CfgNode: an updated config with new options that will be used by :class:`Caffe2Tracer`. """ is_frozen = cfg.is_frozen() cfg.defrost() cfg.EXPORT_CAFFE2 = CN() cfg.EXPORT_CAFFE2.USE_HEATMAP_MAX_KEYPOINT = False if is_frozen: cfg.freeze() return cfg
[docs]class Caffe2Tracer: """ Make a detectron2 model traceable with caffe2 style. An original detectron2 model may not be traceable, or cannot be deployed directly after being traced, due to some reasons: 1. control flow in some ops 2. custom ops 3. complicated pre/post processing This class provides a traceable version of a detectron2 model by: 1. Rewrite parts of the model using ops in caffe2. Note that some ops do not have GPU implementation. 2. Define the inputs "after pre-processing" as inputs to the model 3. Remove post-processing and produce raw layer outputs More specifically about inputs: all builtin models take two input tensors. (1) NCHW float "data" which is an image (usually in [0, 255]) (2) Nx3 float "im_info", each row of which is (height, width, 1.0) After making a traceable model, the class provide methods to export such a model to different deployment formats. The class currently only supports models using builtin meta architectures. """
[docs] def __init__(self, cfg, model, inputs): """ Args: cfg (CfgNode): a detectron2 config, with extra export-related options added by :func:`add_export_config`. model (nn.Module): a model built by :func:`detectron2.modeling.build_model`. inputs: sample inputs that the given model takes for inference. Will be used to trace the model. """ assert isinstance(cfg, CN), cfg assert isinstance(model, torch.nn.Module), type(model) if "EXPORT_CAFFE2" not in cfg: cfg = add_export_config(cfg) # will just the defaults self.cfg = cfg self.model = model self.inputs = inputs
def _get_traceable(self): # TODO how to make it extensible to support custom models C2MetaArch = META_ARCH_CAFFE2_EXPORT_TYPE_MAP[self.cfg.MODEL.META_ARCHITECTURE] traceable_model = C2MetaArch(self.cfg, copy.deepcopy(self.model)) traceable_inputs = traceable_model.get_caffe2_inputs(self.inputs) return traceable_model, traceable_inputs
[docs] def export_caffe2(self): """ Export the model to Caffe2's protobuf format. The returned object can be saved with `.save_protobuf()` method. The result can be loaded and executed using Caffe2 runtime. Returns: Caffe2Model """ model, inputs = self._get_traceable() predict_net, init_net = export_caffe2_detection_model(model, inputs) return Caffe2Model(predict_net, init_net)
[docs] def export_onnx(self): """ Export the model to ONNX format. Note that the exported model contains custom ops only available in caffe2, therefore it cannot be directly executed by other runtime. Post-processing or transformation passes may be applied on the model to accommodate different runtimes. Returns: onnx.ModelProto: an onnx model. """ model, inputs = self._get_traceable() return export_onnx_model_impl(model, (inputs,))
[docs] def export_torchscript(self): """ Export the model to a `torch.jit.TracedModule` by tracing. The returned object can be saved to a file by ".save()". Returns: torch.jit.TracedModule: a torch TracedModule """ model, inputs = self._get_traceable() logger = logging.getLogger(__name__) logger.info("Tracing the model with torch.jit.trace ...") with torch.no_grad(): return torch.jit.trace(model, (inputs,), optimize=True)
[docs]def export_caffe2_model(cfg, model, inputs): """ Export a detectron2 model to caffe2 format. Args: cfg (CfgNode): a detectron2 config, with extra export-related options added by :func:`add_export_config`. model (nn.Module): a model built by :func:`detectron2.modeling.build_model`. It will be modified by this function. inputs: sample inputs that the given model takes for inference. Will be used to trace the model. Returns: Caffe2Model """ return Caffe2Tracer(cfg, model, inputs).export_caffe2()
[docs]def export_onnx_model(cfg, model, inputs): """ Export a detectron2 model to ONNX format. Note that the exported model contains custom ops only available in caffe2, therefore it cannot be directly executed by other runtime. Post-processing or transformation passes may be applied on the model to accommodate different runtimes. Args: cfg (CfgNode): a detectron2 config, with extra export-related options added by :func:`add_export_config`. model (nn.Module): a model built by :func:`detectron2.modeling.build_model`. It will be modified by this function. inputs: sample inputs that the given model takes for inference. Will be used to trace the model. Returns: onnx.ModelProto: an onnx model. """ return Caffe2Tracer(cfg, model, inputs).export_onnx()
[docs]class Caffe2Model(nn.Module): """ A wrapper around the traced model in caffe2's pb format. """ def __init__(self, predict_net, init_net): super().__init__() self.eval() # always in eval mode self._predict_net = predict_net self._init_net = init_net self._predictor = None @property def predict_net(self): """ Returns: core.Net: the underlying caffe2 predict net """ return self._predict_net @property def init_net(self): """ Returns: core.Net: the underlying caffe2 init net """ return self._init_net __init__.__HIDE_SPHINX_DOC__ = True
[docs] def save_protobuf(self, output_dir): """ Save the model as caffe2's protobuf format. Args: output_dir (str): the output directory to save protobuf files. """ logger = logging.getLogger(__name__) logger.info("Saving model to {} ...".format(output_dir)) os.makedirs(output_dir, exist_ok=True) with open(os.path.join(output_dir, "model.pb"), "wb") as f: f.write(self._predict_net.SerializeToString()) with open(os.path.join(output_dir, "model.pbtxt"), "w") as f: f.write(str(self._predict_net)) with open(os.path.join(output_dir, "model_init.pb"), "wb") as f: f.write(self._init_net.SerializeToString())
[docs] def save_graph(self, output_file, inputs=None): """ Save the graph as SVG format. Args: output_file (str): a SVG file inputs: optional inputs given to the model. If given, the inputs will be used to run the graph to record shape of every tensor. The shape information will be saved together with the graph. """ if inputs is None: save_graph(self._predict_net, output_file, op_only=False) else: size_divisibility = get_pb_arg_vali(self._predict_net, "size_divisibility", 0) device = get_pb_arg_vals(self._predict_net, "device", b"cpu").decode("ascii") inputs = convert_batched_inputs_to_c2_format(inputs, size_divisibility, device) inputs = [x.cpu().numpy() for x in inputs] run_and_save_graph(self._predict_net, self._init_net, inputs, output_file)
[docs] @staticmethod def load_protobuf(dir): """ Args: dir (str): a directory used to save Caffe2Model with :meth:`save_protobuf`. The files "model.pb" and "model_init.pb" are needed. Returns: Caffe2Model: the caffe2 model loaded from this directory. """ predict_net = caffe2_pb2.NetDef() with open(os.path.join(dir, "model.pb"), "rb") as f: predict_net.ParseFromString(f.read()) init_net = caffe2_pb2.NetDef() with open(os.path.join(dir, "model_init.pb"), "rb") as f: init_net.ParseFromString(f.read()) return Caffe2Model(predict_net, init_net)
[docs] def __call__(self, inputs): """ An interface that wraps around a caffe2 model and mimics detectron2's models' input & output format. This is used to compare the outputs of caffe2 model with its original torch model. Due to the extra conversion between torch/caffe2, this method is not meant for benchmark. """ if self._predictor is None: self._predictor = ProtobufDetectionModel(self._predict_net, self._init_net) return self._predictor(inputs)