def inference(model,
data_loader,
dataset_name,
device,
output_folder=None,
use_cached=False,
**kwargs):
dataset = data_loader.dataset
logger = logging.getLogger("SSD.inference")
logger.info("Evaluating {} dataset({} images):".format(
dataset_name, len(dataset)))
predictions_path = os.path.join(output_folder, 'predictions.pth')
if use_cached and os.path.exists(predictions_path):
predictions = torch.load(predictions_path, map_location='cpu')
else:
predictions = compute_on_dataset(model, data_loader, device)
synchronize()
predictions = _accumulate_predictions_from_multiple_gpus(predictions)
if not is_main_process():
return
if output_folder:
torch.save(predictions, predictions_path)
return evaluate(dataset=dataset,
predictions=predictions,
output_dir=output_folder,
**kwargs)
def cache_url(url, model_dir=None, progress=True):
r"""Loads the Torch serialized object at the given URL.
If the object is already present in `model_dir`, it's deserialized and
returned. The filename part of the URL should follow the naming convention
``filename-<sha256>.ext`` where ``<sha256>`` is the first eight or more
digits of the SHA256 hash of the contents of the file. The hash is used to
ensure unique names and to verify the contents of the file.
The default value of `model_dir` is ``$TORCH_HOME/models`` where
``$TORCH_HOME`` defaults to ``~/.torch``. The default directory can be
overridden with the ``$TORCH_MODEL_ZOO`` environment variable.
Args:
url (string): URL of the object to download
model_dir (string, optional): directory in which to save the object
progress (bool, optional): whether or not to display a progress bar to stderr
Example:
>>> cached_file = maskrcnn_benchmark.utils.model_zoo.cache_url('https://s3.amazonaws.com/pytorch/models/resnet18-5c106cde.pth')
"""
if model_dir is None:
torch_home = os.path.expanduser(os.getenv("TORCH_HOME", "~/.torch"))
model_dir = os.getenv("TORCH_MODEL_ZOO",
os.path.join(torch_home, "models"))
if not os.path.exists(model_dir):
os.makedirs(model_dir)
parts = urlparse(url)
filename = os.path.basename(parts.path)
if filename == "model_final.pkl":
# workaround as pre-trained Caffe2 models from Detectron have all the same filename
# so make the full path the filename by replacing / with _
filename = parts.path.replace("/", "_")
cached_file = os.path.join(model_dir, filename)
if not os.path.exists(cached_file) and is_main_process():
sys.stderr.write('Downloading: "{}" to {}\n'.format(url, cached_file))
hash_prefix = HASH_REGEX.search(filename)
if hash_prefix is not None:
hash_prefix = hash_prefix.group(1)
# workaround: Caffe2 models don't have a hash, but follow the R-50 convention,
# which matches the hash PyTorch uses. So we skip the hash matching
# if the hash_prefix is less than 6 characters
if len(hash_prefix) < 6:
hash_prefix = None
download_url_to_file(url, cached_file, hash_prefix, progress=progress)
synchronize()
return cached_file
def _accumulate_predictions_from_multiple_gpus(predictions_per_gpu):
all_predictions = dist_util.all_gather(predictions_per_gpu)
if not dist_util.is_main_process():
return
# merge the list of dicts
predictions = {}
for p in all_predictions:
predictions.update(p)
# convert a dict where the key is the index in a list
image_ids = list(sorted(predictions.keys()))
if len(image_ids) != image_ids[-1] + 1:
logger = logging.getLogger("SSD.inference")
logger.warning(
"Number of images that were gathered from multiple processes is not "
"a contiguous set. Some images might be missing from the evaluation"
)
# convert to a list
predictions = [predictions[i] for i in image_ids]
return predictions
