Referentie voor ultralytics/nn/autobackend.py

class AutoBackend(nn.Module):
    """
    Handles dynamic backend selection for running inference using Ultralytics YOLO models.

    The AutoBackend class is designed to provide an abstraction layer for various inference engines. It supports a wide
    range of formats, each with specific naming conventions as outlined below:

        Supported Formats and Naming Conventions:
            | Format                | File Suffix      |
            |-----------------------|------------------|
            | PyTorch               | *.pt             |
            | TorchScript           | *.torchscript    |
            | ONNX Runtime          | *.onnx           |
            | ONNX OpenCV DNN       | *.onnx (dnn=True)|
            | OpenVINO              | *openvino_model/ |
            | CoreML                | *.mlpackage      |
            | TensorRT              | *.engine         |
            | TensorFlow SavedModel | *_saved_model    |
            | TensorFlow GraphDef   | *.pb             |
            | TensorFlow Lite       | *.tflite         |
            | TensorFlow Edge TPU   | *_edgetpu.tflite |
            | PaddlePaddle          | *_paddle_model   |
            | NCNN                  | *_ncnn_model     |

    This class offers dynamic backend switching capabilities based on the input model format, making it easier to deploy
    models across various platforms.
    """

    @torch.no_grad()
    def __init__(
        self,
        weights="yolov8n.pt",
        device=torch.device("cpu"),
        dnn=False,
        data=None,
        fp16=False,
        batch=1,
        fuse=True,
        verbose=True,
    ):
        """
        Initialize the AutoBackend for inference.

        Args:
            weights (str): Path to the model weights file. Defaults to 'yolov8n.pt'.
            device (torch.device): Device to run the model on. Defaults to CPU.
            dnn (bool): Use OpenCV DNN module for ONNX inference. Defaults to False.
            data (str | Path | optional): Path to the additional data.yaml file containing class names. Optional.
            fp16 (bool): Enable half-precision inference. Supported only on specific backends. Defaults to False.
            batch (int): Batch-size to assume for inference.
            fuse (bool): Fuse Conv2D + BatchNorm layers for optimization. Defaults to True.
            verbose (bool): Enable verbose logging. Defaults to True.
        """
        super().__init__()
        w = str(weights[0] if isinstance(weights, list) else weights)
        nn_module = isinstance(weights, torch.nn.Module)
        (
            pt,
            jit,
            onnx,
            xml,
            engine,
            coreml,
            saved_model,
            pb,
            tflite,
            edgetpu,
            tfjs,
            paddle,
            ncnn,
            triton,
        ) = self._model_type(w)
        fp16 &= pt or jit or onnx or xml or engine or nn_module or triton  # FP16
        nhwc = coreml or saved_model or pb or tflite or edgetpu  # BHWC formats (vs torch BCWH)
        stride = 32  # default stride
        model, metadata = None, None

        # Set device
        cuda = torch.cuda.is_available() and device.type != "cpu"  # use CUDA
        if cuda and not any([nn_module, pt, jit, engine, onnx]):  # GPU dataloader formats
            device = torch.device("cpu")
            cuda = False

        # Download if not local
        if not (pt or triton or nn_module):
            w = attempt_download_asset(w)

        # In-memory PyTorch model
        if nn_module:
            model = weights.to(device)
            if fuse:
                model = model.fuse(verbose=verbose)
            if hasattr(model, "kpt_shape"):
                kpt_shape = model.kpt_shape  # pose-only
            stride = max(int(model.stride.max()), 32)  # model stride
            names = model.module.names if hasattr(model, "module") else model.names  # get class names
            model.half() if fp16 else model.float()
            self.model = model  # explicitly assign for to(), cpu(), cuda(), half()
            pt = True

        # PyTorch
        elif pt:
            from ultralytics.nn.tasks import attempt_load_weights

            model = attempt_load_weights(
                weights if isinstance(weights, list) else w, device=device, inplace=True, fuse=fuse
            )
            if hasattr(model, "kpt_shape"):
                kpt_shape = model.kpt_shape  # pose-only
            stride = max(int(model.stride.max()), 32)  # model stride
            names = model.module.names if hasattr(model, "module") else model.names  # get class names
            model.half() if fp16 else model.float()
            self.model = model  # explicitly assign for to(), cpu(), cuda(), half()

        # TorchScript
        elif jit:
            LOGGER.info(f"Loading {w} for TorchScript inference...")
            extra_files = {"config.txt": ""}  # model metadata
            model = torch.jit.load(w, _extra_files=extra_files, map_location=device)
            model.half() if fp16 else model.float()
            if extra_files["config.txt"]:  # load metadata dict
                metadata = json.loads(extra_files["config.txt"], object_hook=lambda x: dict(x.items()))

        # ONNX OpenCV DNN
        elif dnn:
            LOGGER.info(f"Loading {w} for ONNX OpenCV DNN inference...")
            check_requirements("opencv-python>=4.5.4")
            net = cv2.dnn.readNetFromONNX(w)

        # ONNX Runtime
        elif onnx:
            LOGGER.info(f"Loading {w} for ONNX Runtime inference...")
            check_requirements(("onnx", "onnxruntime-gpu" if cuda else "onnxruntime"))
            if IS_RASPBERRYPI or IS_JETSON:
                # Fix error: module 'numpy.linalg._umath_linalg' has no attribute '_ilp64' when exporting to Tensorflow SavedModel on RPi and Jetson
                check_requirements("numpy==1.23.5")
            import onnxruntime

            providers = ["CUDAExecutionProvider", "CPUExecutionProvider"] if cuda else ["CPUExecutionProvider"]
            session = onnxruntime.InferenceSession(w, providers=providers)
            output_names = [x.name for x in session.get_outputs()]
            metadata = session.get_modelmeta().custom_metadata_map

        # OpenVINO
        elif xml:
            LOGGER.info(f"Loading {w} for OpenVINO inference...")
            check_requirements("openvino>=2024.0.0")
            import openvino as ov

            core = ov.Core()
            w = Path(w)
            if not w.is_file():  # if not *.xml
                w = next(w.glob("*.xml"))  # get *.xml file from *_openvino_model dir
            ov_model = core.read_model(model=str(w), weights=w.with_suffix(".bin"))
            if ov_model.get_parameters()[0].get_layout().empty:
                ov_model.get_parameters()[0].set_layout(ov.Layout("NCHW"))

            # OpenVINO inference modes are 'LATENCY', 'THROUGHPUT' (not recommended), or 'CUMULATIVE_THROUGHPUT'
            inference_mode = "CUMULATIVE_THROUGHPUT" if batch > 1 else "LATENCY"
            LOGGER.info(f"Using OpenVINO {inference_mode} mode for batch={batch} inference...")
            ov_compiled_model = core.compile_model(
                ov_model,
                device_name="AUTO",  # AUTO selects best available device, do not modify
                config={"PERFORMANCE_HINT": inference_mode},
            )
            input_name = ov_compiled_model.input().get_any_name()
            metadata = w.parent / "metadata.yaml"

        # TensorRT
        elif engine:
            LOGGER.info(f"Loading {w} for TensorRT inference...")
            try:
                import tensorrt as trt  # noqa https://developer.nvidia.com/nvidia-tensorrt-download
            except ImportError:
                if LINUX:
                    check_requirements("nvidia-tensorrt", cmds="-U --index-url https://pypi.ngc.nvidia.com")
                import tensorrt as trt  # noqa
            check_version(trt.__version__, "7.0.0", hard=True)  # require tensorrt>=7.0.0
            if device.type == "cpu":
                device = torch.device("cuda:0")
            Binding = namedtuple("Binding", ("name", "dtype", "shape", "data", "ptr"))
            logger = trt.Logger(trt.Logger.INFO)
            # Read file
            with open(w, "rb") as f, trt.Runtime(logger) as runtime:
                try:
                    meta_len = int.from_bytes(f.read(4), byteorder="little")  # read metadata length
                    metadata = json.loads(f.read(meta_len).decode("utf-8"))  # read metadata
                except UnicodeDecodeError:
                    f.seek(0)  # engine file may lack embedded Ultralytics metadata
                model = runtime.deserialize_cuda_engine(f.read())  # read engine

            # Model context
            try:
                context = model.create_execution_context()
            except Exception as e:  # model is None
                LOGGER.error(f"ERROR: TensorRT model exported with a different version than {trt.__version__}\n")
                raise e

            bindings = OrderedDict()
            output_names = []
            fp16 = False  # default updated below
            dynamic = False
            is_trt10 = not hasattr(model, "num_bindings")
            num = range(model.num_io_tensors) if is_trt10 else range(model.num_bindings)
            for i in num:
                if is_trt10:
                    name = model.get_tensor_name(i)
                    dtype = trt.nptype(model.get_tensor_dtype(name))
                    is_input = model.get_tensor_mode(name) == trt.TensorIOMode.INPUT
                    if is_input:
                        if -1 in tuple(model.get_tensor_shape(name)):
                            dynamic = True
                            context.set_input_shape(name, tuple(model.get_tensor_profile_shape(name, 0)[1]))
                            if dtype == np.float16:
                                fp16 = True
                    else:
                        output_names.append(name)
                    shape = tuple(context.get_tensor_shape(name))
                else:  # TensorRT < 10.0
                    name = model.get_binding_name(i)
                    dtype = trt.nptype(model.get_binding_dtype(i))
                    is_input = model.binding_is_input(i)
                    if model.binding_is_input(i):
                        if -1 in tuple(model.get_binding_shape(i)):  # dynamic
                            dynamic = True
                            context.set_binding_shape(i, tuple(model.get_profile_shape(0, i)[1]))
                        if dtype == np.float16:
                            fp16 = True
                    else:
                        output_names.append(name)
                    shape = tuple(context.get_binding_shape(i))
                im = torch.from_numpy(np.empty(shape, dtype=dtype)).to(device)
                bindings[name] = Binding(name, dtype, shape, im, int(im.data_ptr()))
            binding_addrs = OrderedDict((n, d.ptr) for n, d in bindings.items())
            batch_size = bindings["images"].shape[0]  # if dynamic, this is instead max batch size

        # CoreML
        elif coreml:
            LOGGER.info(f"Loading {w} for CoreML inference...")
            import coremltools as ct

            model = ct.models.MLModel(w)
            metadata = dict(model.user_defined_metadata)

        # TF SavedModel
        elif saved_model:
            LOGGER.info(f"Loading {w} for TensorFlow SavedModel inference...")
            import tensorflow as tf

            keras = False  # assume TF1 saved_model
            model = tf.keras.models.load_model(w) if keras else tf.saved_model.load(w)
            metadata = Path(w) / "metadata.yaml"

        # TF GraphDef
        elif pb:  # https://www.tensorflow.org/guide/migrate#a_graphpb_or_graphpbtxt
            LOGGER.info(f"Loading {w} for TensorFlow GraphDef inference...")
            import tensorflow as tf

            from ultralytics.engine.exporter import gd_outputs

            def wrap_frozen_graph(gd, inputs, outputs):
                """Wrap frozen graphs for deployment."""
                x = tf.compat.v1.wrap_function(lambda: tf.compat.v1.import_graph_def(gd, name=""), [])  # wrapped
                ge = x.graph.as_graph_element
                return x.prune(tf.nest.map_structure(ge, inputs), tf.nest.map_structure(ge, outputs))

            gd = tf.Graph().as_graph_def()  # TF GraphDef
            with open(w, "rb") as f:
                gd.ParseFromString(f.read())
            frozen_func = wrap_frozen_graph(gd, inputs="x:0", outputs=gd_outputs(gd))

        # TFLite or TFLite Edge TPU
        elif tflite or edgetpu:  # https://www.tensorflow.org/lite/guide/python#install_tensorflow_lite_for_python
            try:  # https://coral.ai/docs/edgetpu/tflite-python/#update-existing-tf-lite-code-for-the-edge-tpu
                from tflite_runtime.interpreter import Interpreter, load_delegate
            except ImportError:
                import tensorflow as tf

                Interpreter, load_delegate = tf.lite.Interpreter, tf.lite.experimental.load_delegate
            if edgetpu:  # TF Edge TPU https://coral.ai/software/#edgetpu-runtime
                LOGGER.info(f"Loading {w} for TensorFlow Lite Edge TPU inference...")
                delegate = {"Linux": "libedgetpu.so.1", "Darwin": "libedgetpu.1.dylib", "Windows": "edgetpu.dll"}[
                    platform.system()
                ]
                interpreter = Interpreter(model_path=w, experimental_delegates=[load_delegate(delegate)])
            else:  # TFLite
                LOGGER.info(f"Loading {w} for TensorFlow Lite inference...")
                interpreter = Interpreter(model_path=w)  # load TFLite model
            interpreter.allocate_tensors()  # allocate
            input_details = interpreter.get_input_details()  # inputs
            output_details = interpreter.get_output_details()  # outputs
            # Load metadata
            with contextlib.suppress(zipfile.BadZipFile):
                with zipfile.ZipFile(w, "r") as model:
                    meta_file = model.namelist()[0]
                    metadata = ast.literal_eval(model.read(meta_file).decode("utf-8"))

        # TF.js
        elif tfjs:
            raise NotImplementedError("YOLOv8 TF.js inference is not currently supported.")

        # PaddlePaddle
        elif paddle:
            LOGGER.info(f"Loading {w} for PaddlePaddle inference...")
            check_requirements("paddlepaddle-gpu" if cuda else "paddlepaddle")
            import paddle.inference as pdi  # noqa

            w = Path(w)
            if not w.is_file():  # if not *.pdmodel
                w = next(w.rglob("*.pdmodel"))  # get *.pdmodel file from *_paddle_model dir
            config = pdi.Config(str(w), str(w.with_suffix(".pdiparams")))
            if cuda:
                config.enable_use_gpu(memory_pool_init_size_mb=2048, device_id=0)
            predictor = pdi.create_predictor(config)
            input_handle = predictor.get_input_handle(predictor.get_input_names()[0])
            output_names = predictor.get_output_names()
            metadata = w.parents[1] / "metadata.yaml"

        # NCNN
        elif ncnn:
            LOGGER.info(f"Loading {w} for NCNN inference...")
            check_requirements("git+https://github.com/Tencent/ncnn.git" if ARM64 else "ncnn")  # requires NCNN
            import ncnn as pyncnn

            net = pyncnn.Net()
            net.opt.use_vulkan_compute = cuda
            w = Path(w)
            if not w.is_file():  # if not *.param
                w = next(w.glob("*.param"))  # get *.param file from *_ncnn_model dir
            net.load_param(str(w))
            net.load_model(str(w.with_suffix(".bin")))
            metadata = w.parent / "metadata.yaml"

        # NVIDIA Triton Inference Server
        elif triton:
            check_requirements("tritonclient[all]")
            from ultralytics.utils.triton import TritonRemoteModel

            model = TritonRemoteModel(w)

        # Any other format (unsupported)
        else:
            from ultralytics.engine.exporter import export_formats

            raise TypeError(
                f"model='{w}' is not a supported model format. "
                f"See https://docs.ultralytics.com/modes/predict for help.\n\n{export_formats()}"
            )

        # Load external metadata YAML
        if isinstance(metadata, (str, Path)) and Path(metadata).exists():
            metadata = yaml_load(metadata)
        if metadata:
            for k, v in metadata.items():
                if k in {"stride", "batch"}:
                    metadata[k] = int(v)
                elif k in {"imgsz", "names", "kpt_shape"} and isinstance(v, str):
                    metadata[k] = eval(v)
            stride = metadata["stride"]
            task = metadata["task"]
            batch = metadata["batch"]
            imgsz = metadata["imgsz"]
            names = metadata["names"]
            kpt_shape = metadata.get("kpt_shape")
        elif not (pt or triton or nn_module):
            LOGGER.warning(f"WARNING ⚠️ Metadata not found for 'model={weights}'")

        # Check names
        if "names" not in locals():  # names missing
            names = default_class_names(data)
        names = check_class_names(names)

        # Disable gradients
        if pt:
            for p in model.parameters():
                p.requires_grad = False

        self.__dict__.update(locals())  # assign all variables to self

    def forward(self, im, augment=False, visualize=False, embed=None):
        """
        Runs inference on the YOLOv8 MultiBackend model.

        Args:
            im (torch.Tensor): The image tensor to perform inference on.
            augment (bool): whether to perform data augmentation during inference, defaults to False
            visualize (bool): whether to visualize the output predictions, defaults to False
            embed (list, optional): A list of feature vectors/embeddings to return.

        Returns:
            (tuple): Tuple containing the raw output tensor, and processed output for visualization (if visualize=True)
        """
        b, ch, h, w = im.shape  # batch, channel, height, width
        if self.fp16 and im.dtype != torch.float16:
            im = im.half()  # to FP16
        if self.nhwc:
            im = im.permute(0, 2, 3, 1)  # torch BCHW to numpy BHWC shape(1,320,192,3)

        # PyTorch
        if self.pt or self.nn_module:
            y = self.model(im, augment=augment, visualize=visualize, embed=embed)

        # TorchScript
        elif self.jit:
            y = self.model(im)

        # ONNX OpenCV DNN
        elif self.dnn:
            im = im.cpu().numpy()  # torch to numpy
            self.net.setInput(im)
            y = self.net.forward()

        # ONNX Runtime
        elif self.onnx:
            im = im.cpu().numpy()  # torch to numpy
            y = self.session.run(self.output_names, {self.session.get_inputs()[0].name: im})

        # OpenVINO
        elif self.xml:
            im = im.cpu().numpy()  # FP32

            if self.inference_mode in {"THROUGHPUT", "CUMULATIVE_THROUGHPUT"}:  # optimized for larger batch-sizes
                n = im.shape[0]  # number of images in batch
                results = [None] * n  # preallocate list with None to match the number of images

                def callback(request, userdata):
                    """Places result in preallocated list using userdata index."""
                    results[userdata] = request.results

                # Create AsyncInferQueue, set the callback and start asynchronous inference for each input image
                async_queue = self.ov.runtime.AsyncInferQueue(self.ov_compiled_model)
                async_queue.set_callback(callback)
                for i in range(n):
                    # Start async inference with userdata=i to specify the position in results list
                    async_queue.start_async(inputs={self.input_name: im[i : i + 1]}, userdata=i)  # keep image as BCHW
                async_queue.wait_all()  # wait for all inference requests to complete
                y = np.concatenate([list(r.values())[0] for r in results])

            else:  # inference_mode = "LATENCY", optimized for fastest first result at batch-size 1
                y = list(self.ov_compiled_model(im).values())

        # TensorRT
        elif self.engine:
            if self.dynamic or im.shape != self.bindings["images"].shape:
                if self.is_trt10:
                    self.context.set_input_shape("images", im.shape)
                    self.bindings["images"] = self.bindings["images"]._replace(shape=im.shape)
                    for name in self.output_names:
                        self.bindings[name].data.resize_(tuple(self.context.get_tensor_shape(name)))
                else:
                    i = self.model.get_binding_index("images")
                    self.context.set_binding_shape(i, im.shape)
                    self.bindings["images"] = self.bindings["images"]._replace(shape=im.shape)
                    for name in self.output_names:
                        i = self.model.get_binding_index(name)
                        self.bindings[name].data.resize_(tuple(self.context.get_binding_shape(i)))

            s = self.bindings["images"].shape
            assert im.shape == s, f"input size {im.shape} {'>' if self.dynamic else 'not equal to'} max model size {s}"
            self.binding_addrs["images"] = int(im.data_ptr())
            self.context.execute_v2(list(self.binding_addrs.values()))
            y = [self.bindings[x].data for x in sorted(self.output_names)]

        # CoreML
        elif self.coreml:
            im = im[0].cpu().numpy()
            im_pil = Image.fromarray((im * 255).astype("uint8"))
            # im = im.resize((192, 320), Image.BILINEAR)
            y = self.model.predict({"image": im_pil})  # coordinates are xywh normalized
            if "confidence" in y:
                raise TypeError(
                    "Ultralytics only supports inference of non-pipelined CoreML models exported with "
                    f"'nms=False', but 'model={w}' has an NMS pipeline created by an 'nms=True' export."
                )
                # TODO: CoreML NMS inference handling
                # from ultralytics.utils.ops import xywh2xyxy
                # box = xywh2xyxy(y['coordinates'] * [[w, h, w, h]])  # xyxy pixels
                # conf, cls = y['confidence'].max(1), y['confidence'].argmax(1).astype(np.float32)
                # y = np.concatenate((box, conf.reshape(-1, 1), cls.reshape(-1, 1)), 1)
            elif len(y) == 1:  # classification model
                y = list(y.values())
            elif len(y) == 2:  # segmentation model
                y = list(reversed(y.values()))  # reversed for segmentation models (pred, proto)

        # PaddlePaddle
        elif self.paddle:
            im = im.cpu().numpy().astype(np.float32)
            self.input_handle.copy_from_cpu(im)
            self.predictor.run()
            y = [self.predictor.get_output_handle(x).copy_to_cpu() for x in self.output_names]

        # NCNN
        elif self.ncnn:
            mat_in = self.pyncnn.Mat(im[0].cpu().numpy())
            with self.net.create_extractor() as ex:
                ex.input(self.net.input_names()[0], mat_in)
                # WARNING: 'output_names' sorted as a temporary fix for https://github.com/pnnx/pnnx/issues/130
                y = [np.array(ex.extract(x)[1])[None] for x in sorted(self.net.output_names())]

        # NVIDIA Triton Inference Server
        elif self.triton:
            im = im.cpu().numpy()  # torch to numpy
            y = self.model(im)

        # TensorFlow (SavedModel, GraphDef, Lite, Edge TPU)
        else:
            im = im.cpu().numpy()
            if self.saved_model:  # SavedModel
                y = self.model(im, training=False) if self.keras else self.model(im)
                if not isinstance(y, list):
                    y = [y]
            elif self.pb:  # GraphDef
                y = self.frozen_func(x=self.tf.constant(im))
                if len(y) == 2 and len(self.names) == 999:  # segments and names not defined
                    ip, ib = (0, 1) if len(y[0].shape) == 4 else (1, 0)  # index of protos, boxes
                    nc = y[ib].shape[1] - y[ip].shape[3] - 4  # y = (1, 160, 160, 32), (1, 116, 8400)
                    self.names = {i: f"class{i}" for i in range(nc)}
            else:  # Lite or Edge TPU
                details = self.input_details[0]
                is_int = details["dtype"] in {np.int8, np.int16}  # is TFLite quantized int8 or int16 model
                if is_int:
                    scale, zero_point = details["quantization"]
                    im = (im / scale + zero_point).astype(details["dtype"])  # de-scale
                self.interpreter.set_tensor(details["index"], im)
                self.interpreter.invoke()
                y = []
                for output in self.output_details:
                    x = self.interpreter.get_tensor(output["index"])
                    if is_int:
                        scale, zero_point = output["quantization"]
                        x = (x.astype(np.float32) - zero_point) * scale  # re-scale
                    if x.ndim == 3:  # if task is not classification, excluding masks (ndim=4) as well
                        # Denormalize xywh by image size. See https://github.com/ultralytics/ultralytics/pull/1695
                        # xywh are normalized in TFLite/EdgeTPU to mitigate quantization error of integer models
                        x[:, [0, 2]] *= w
                        x[:, [1, 3]] *= h
                    y.append(x)
            # TF segment fixes: export is reversed vs ONNX export and protos are transposed
            if len(y) == 2:  # segment with (det, proto) output order reversed
                if len(y[1].shape) != 4:
                    y = list(reversed(y))  # should be y = (1, 116, 8400), (1, 160, 160, 32)
                y[1] = np.transpose(y[1], (0, 3, 1, 2))  # should be y = (1, 116, 8400), (1, 32, 160, 160)
            y = [x if isinstance(x, np.ndarray) else x.numpy() for x in y]

        # for x in y:
        #     print(type(x), len(x)) if isinstance(x, (list, tuple)) else print(type(x), x.shape)  # debug shapes
        if isinstance(y, (list, tuple)):
            return self.from_numpy(y[0]) if len(y) == 1 else [self.from_numpy(x) for x in y]
        else:
            return self.from_numpy(y)

    def from_numpy(self, x):
        """
        Convert a numpy array to a tensor.

        Args:
            x (np.ndarray): The array to be converted.

        Returns:
            (torch.Tensor): The converted tensor
        """
        return torch.tensor(x).to(self.device) if isinstance(x, np.ndarray) else x

    def warmup(self, imgsz=(1, 3, 640, 640)):
        """
        Warm up the model by running one forward pass with a dummy input.

        Args:
            imgsz (tuple): The shape of the dummy input tensor in the format (batch_size, channels, height, width)
        """
        warmup_types = self.pt, self.jit, self.onnx, self.engine, self.saved_model, self.pb, self.triton, self.nn_module
        if any(warmup_types) and (self.device.type != "cpu" or self.triton):
            im = torch.empty(*imgsz, dtype=torch.half if self.fp16 else torch.float, device=self.device)  # input
            for _ in range(2 if self.jit else 1):
                self.forward(im)  # warmup

    @staticmethod
    def _model_type(p="path/to/model.pt"):
        """
        This function takes a path to a model file and returns the model type. Possibles types are pt, jit, onnx, xml,
        engine, coreml, saved_model, pb, tflite, edgetpu, tfjs, ncnn or paddle.

        Args:
            p: path to the model file. Defaults to path/to/model.pt

        Examples:
            >>> model = AutoBackend(weights="path/to/model.onnx")
            >>> model_type = model._model_type()  # returns "onnx"
        """
        from ultralytics.engine.exporter import export_formats

        sf = list(export_formats().Suffix)  # export suffixes
        if not is_url(p) and not isinstance(p, str):
            check_suffix(p, sf)  # checks
        name = Path(p).name
        types = [s in name for s in sf]
        types[5] |= name.endswith(".mlmodel")  # retain support for older Apple CoreML *.mlmodel formats
        types[8] &= not types[9]  # tflite &= not edgetpu
        if any(types):
            triton = False
        else:
            from urllib.parse import urlsplit

            url = urlsplit(p)
            triton = bool(url.netloc) and bool(url.path) and url.scheme in {"http", "grpc"}

        return types + [triton]