Reference for ultralytics/engine/model.py

class Model(torch.nn.Module):
    """A base class for implementing YOLO models, unifying APIs across different model types.

    This class provides a common interface for various operations related to YOLO models, such as training, validation,
    prediction, exporting, and benchmarking. It handles different types of models, including those loaded from local
    files, Ultralytics HUB, or Triton Server.

    Attributes:
        callbacks (dict): A dictionary of callback functions for various events during model operations.
        predictor (BasePredictor): The predictor object used for making predictions.
        model (torch.nn.Module): The underlying PyTorch model.
        trainer (BaseTrainer): The trainer object used for training the model.
        ckpt (dict): The checkpoint data if the model is loaded from a *.pt file.
        cfg (str): The configuration of the model if loaded from a *.yaml file.
        ckpt_path (str): The path to the checkpoint file.
        overrides (dict): A dictionary of overrides for model configuration.
        metrics (dict): The latest training/validation metrics.
        session (HUBTrainingSession): The Ultralytics HUB session, if applicable.
        task (str): The type of task the model is intended for.
        model_name (str): The name of the model.

    Methods:
        __call__: Alias for the predict method, enabling the model instance to be callable.
        _new: Initialize a new model based on a configuration file.
        _load: Load a model from a checkpoint file.
        _check_is_pytorch_model: Ensure that the model is a PyTorch model.
        reset_weights: Reset the model's weights to their initial state.
        load: Load model weights from a specified file.
        save: Save the current state of the model to a file.
        info: Log or return information about the model.
        fuse: Fuse Conv2d and BatchNorm2d layers for optimized inference.
        predict: Perform object detection predictions.
        track: Perform object tracking.
        val: Validate the model on a dataset.
        benchmark: Benchmark the model on various export formats.
        export: Export the model to different formats.
        train: Train the model on a dataset.
        tune: Perform hyperparameter tuning.
        _apply: Apply a function to the model's tensors.
        add_callback: Add a callback function for an event.
        clear_callback: Clear all callbacks for an event.
        reset_callbacks: Reset all callbacks to their default functions.

    Examples:
        >>> from ultralytics import YOLO
        >>> model = YOLO("yolo11n.pt")
        >>> results = model.predict("image.jpg")
        >>> model.train(data="coco8.yaml", epochs=3)
        >>> metrics = model.val()
        >>> model.export(format="onnx")
    """

    def __init__(
        self,
        model: str | Path | Model = "yolo11n.pt",
        task: str | None = None,
        verbose: bool = False,
    ) -> None:
        """Initialize a new instance of the YOLO model class.

        This constructor sets up the model based on the provided model path or name. It handles various types of model
        sources, including local files, Ultralytics HUB models, and Triton Server models. The method initializes several
        important attributes of the model and prepares it for operations like training, prediction, or export.

        Args:
            model (str | Path | Model): Path or name of the model to load or create. Can be a local file path, a model
                name from Ultralytics HUB, a Triton Server model, or an already initialized Model instance.
            task (str, optional): The specific task for the model. If None, it will be inferred from the config.
            verbose (bool): If True, enables verbose output during the model's initialization and subsequent operations.

        Raises:
            FileNotFoundError: If the specified model file does not exist or is inaccessible.
            ValueError: If the model file or configuration is invalid or unsupported.
            ImportError: If required dependencies for specific model types (like HUB SDK) are not installed.
        """
        if isinstance(model, Model):
            self.__dict__ = model.__dict__  # accepts an already initialized Model
            return
        super().__init__()
        self.callbacks = callbacks.get_default_callbacks()
        self.predictor = None  # reuse predictor
        self.model = None  # model object
        self.trainer = None  # trainer object
        self.ckpt = {}  # if loaded from *.pt
        self.cfg = None  # if loaded from *.yaml
        self.ckpt_path = None
        self.overrides = {}  # overrides for trainer object
        self.metrics = None  # validation/training metrics
        self.session = None  # HUB session
        self.task = task  # task type
        self.model_name = None  # model name
        model = str(model).strip()

        # Check if Ultralytics HUB model from https://hub.ultralytics.com
        if self.is_hub_model(model):
            from ultralytics.hub import HUBTrainingSession

            # Fetch model from HUB
            checks.check_requirements("hub-sdk>=0.0.12")
            session = HUBTrainingSession.create_session(model)
            model = session.model_file
            if session.train_args:  # training sent from HUB
                self.session = session

        # Check if Triton Server model
        elif self.is_triton_model(model):
            self.model_name = self.model = model
            self.overrides["task"] = task or "detect"  # set `task=detect` if not explicitly set
            return

        # Load or create new YOLO model
        __import__("os").environ["CUBLAS_WORKSPACE_CONFIG"] = ":4096:8"  # to avoid deterministic warnings
        if str(model).endswith((".yaml", ".yml")):
            self._new(model, task=task, verbose=verbose)
        else:
            self._load(model, task=task)

        # Delete super().training for accessing self.model.training
        del self.training

@property
def names(self) -> dict[int, str]:
    """Retrieve the class names associated with the loaded model.

    This property returns the class names if they are defined in the model. It checks the class names for validity
    using the 'check_class_names' function from the ultralytics.nn.autobackend module. If the predictor is not
    initialized, it sets it up before retrieving the names.

    Returns:
        (dict[int, str]): A dictionary of class names associated with the model, where keys are class indices and
            values are the corresponding class names.

    Raises:
        AttributeError: If the model or predictor does not have a 'names' attribute.

    Examples:
        >>> model = YOLO("yolo11n.pt")
        >>> print(model.names)
        {0: 'person', 1: 'bicycle', 2: 'car', ...}
    """
    from ultralytics.nn.autobackend import check_class_names

    if hasattr(self.model, "names"):
        return check_class_names(self.model.names)
    if not self.predictor:  # export formats will not have predictor defined until predict() is called
        predictor = self._smart_load("predictor")(overrides=self.overrides, _callbacks=self.callbacks)
        predictor.setup_model(model=self.model, verbose=False)  # do not mess with self.predictor.model args
        return predictor.model.names
    return self.predictor.model.names

@property
def device(self) -> torch.device:
    """Get the device on which the model's parameters are allocated.

    This property determines the device (CPU or GPU) where the model's parameters are currently stored. It is
    applicable only to models that are instances of torch.nn.Module.

    Returns:
        (torch.device): The device (CPU/GPU) of the model.

    Raises:
        AttributeError: If the model is not a torch.nn.Module instance.

    Examples:
        >>> model = YOLO("yolo11n.pt")
        >>> print(model.device)
        device(type='cuda', index=0)  # if CUDA is available
        >>> model = model.to("cpu")
        >>> print(model.device)
        device(type='cpu')
    """
    return next(self.model.parameters()).device if isinstance(self.model, torch.nn.Module) else None

@property
def transforms(self):
    """Retrieve the transformations applied to the input data of the loaded model.

    This property returns the transformations if they are defined in the model. The transforms typically include
    preprocessing steps like resizing, normalization, and data augmentation that are applied to input data before it
    is fed into the model.

    Returns:
        (object | None): The transform object of the model if available, otherwise None.

    Examples:
        >>> model = YOLO("yolo11n.pt")
        >>> transforms = model.transforms
        >>> if transforms:
        ...     print(f"Model transforms: {transforms}")
        ... else:
        ...     print("No transforms defined for this model.")
    """
    return self.model.transforms if hasattr(self.model, "transforms") else None

@property
def task_map(self) -> dict:
    """Provide a mapping from model tasks to corresponding classes for different modes.

    This property method returns a dictionary that maps each supported task (e.g., detect, segment, classify) to a
    nested dictionary. The nested dictionary contains mappings for different operational modes (model, trainer,
    validator, predictor) to their respective class implementations.

    The mapping allows for dynamic loading of appropriate classes based on the model's task and the desired
    operational mode. This facilitates a flexible and extensible architecture for handling various tasks and modes
    within the Ultralytics framework.

    Returns:
        (dict[str, dict[str, Any]]): A dictionary mapping task names to nested dictionaries. Each nested dictionary
            contains mappings for 'model', 'trainer', 'validator', and 'predictor' keys to their respective class
            implementations for that task.

    Examples:
        >>> model = Model("yolo11n.pt")
        >>> task_map = model.task_map
        >>> detect_predictor = task_map["detect"]["predictor"]
        >>> segment_trainer = task_map["segment"]["trainer"]
    """
    raise NotImplementedError("Please provide task map for your model!")

def __call__(
    self,
    source: str | Path | int | Image.Image | list | tuple | np.ndarray | torch.Tensor = None,
    stream: bool = False,
    **kwargs: Any,
) -> list:
    """Alias for the predict method, enabling the model instance to be callable for predictions.

    This method simplifies the process of making predictions by allowing the model instance to be called directly
    with the required arguments.

    Args:
        source (str | Path | int | PIL.Image | np.ndarray | torch.Tensor | list | tuple): The source of the image(s)
            to make predictions on. Can be a file path, URL, PIL image, numpy array, PyTorch tensor, or a list/tuple
            of these.
        stream (bool): If True, treat the input source as a continuous stream for predictions.
        **kwargs (Any): Additional keyword arguments to configure the prediction process.

    Returns:
        (list[ultralytics.engine.results.Results]): A list of prediction results, each encapsulated in a Results
            object.

    Examples:
        >>> model = YOLO("yolo11n.pt")
        >>> results = model("https://ultralytics.com/images/bus.jpg")
        >>> for r in results:
        ...     print(f"Detected {len(r)} objects in image")
    """
    return self.predict(source, stream, **kwargs)

def __getattr__(self, name):
    """Enable accessing model attributes directly through the Model class.

    This method provides a way to access attributes of the underlying model directly through the Model class
    instance. It first checks if the requested attribute is 'model', in which case it returns the model from
    the module dictionary. Otherwise, it delegates the attribute lookup to the underlying model.

    Args:
        name (str): The name of the attribute to retrieve.

    Returns:
        (Any): The requested attribute value.

    Raises:
        AttributeError: If the requested attribute does not exist in the model.

    Examples:
        >>> model = YOLO("yolo11n.pt")
        >>> print(model.stride)  # Access model.stride attribute
        >>> print(model.names)  # Access model.names attribute
    """
    return self._modules["model"] if name == "model" else getattr(self.model, name)

def _apply(self, fn) -> Model:
    """Apply a function to model tensors that are not parameters or registered buffers.

    This method extends the functionality of the parent class's _apply method by additionally resetting the
    predictor and updating the device in the model's overrides. It's typically used for operations like moving the
    model to a different device or changing its precision.

    Args:
        fn (Callable): A function to be applied to the model's tensors. This is typically a method like to(), cpu(),
            cuda(), half(), or float().

    Returns:
        (Model): The model instance with the function applied and updated attributes.

    Raises:
        AssertionError: If the model is not a PyTorch model.

    Examples:
        >>> model = Model("yolo11n.pt")
        >>> model = model._apply(lambda t: t.cuda())  # Move model to GPU
    """
    self._check_is_pytorch_model()
    self = super()._apply(fn)
    self.predictor = None  # reset predictor as device may have changed
    self.overrides["device"] = self.device  # was str(self.device) i.e. device(type='cuda', index=0) -> 'cuda:0'
    return self

def _check_is_pytorch_model(self) -> None:
    """Check if the model is a PyTorch model and raise TypeError if it's not.

    This method verifies that the model is either a PyTorch module or a .pt file. It's used to ensure that certain
    operations that require a PyTorch model are only performed on compatible model types.

    Raises:
        TypeError: If the model is not a PyTorch module or a .pt file. The error message provides detailed
            information about supported model formats and operations.

    Examples:
        >>> model = Model("yolo11n.pt")
        >>> model._check_is_pytorch_model()  # No error raised
        >>> model = Model("yolo11n.onnx")
        >>> model._check_is_pytorch_model()  # Raises TypeError
    """
    pt_str = isinstance(self.model, (str, Path)) and str(self.model).rpartition(".")[-1] == "pt"
    pt_module = isinstance(self.model, torch.nn.Module)
    if not (pt_module or pt_str):
        raise TypeError(
            f"model='{self.model}' should be a *.pt PyTorch model to run this method, but is a different format. "
            f"PyTorch models can train, val, predict and export, i.e. 'model.train(data=...)', but exported "
            f"formats like ONNX, TensorRT etc. only support 'predict' and 'val' modes, "
            f"i.e. 'yolo predict model=yolo11n.onnx'.\nTo run CUDA or MPS inference please pass the device "
            f"argument directly in your inference command, i.e. 'model.predict(source=..., device=0)'"
        )

def _load(self, weights: str, task=None) -> None:
    """Load a model from a checkpoint file or initialize it from a weights file.

    This method handles loading models from either .pt checkpoint files or other weight file formats. It sets up the
    model, task, and related attributes based on the loaded weights.

    Args:
        weights (str): Path to the model weights file to be loaded.
        task (str, optional): The task associated with the model. If None, it will be inferred from the model.

    Raises:
        FileNotFoundError: If the specified weights file does not exist or is inaccessible.
        ValueError: If the weights file format is unsupported or invalid.

    Examples:
        >>> model = Model()
        >>> model._load("yolo11n.pt")
        >>> model._load("path/to/weights.pth", task="detect")
    """
    if weights.lower().startswith(("https://", "http://", "rtsp://", "rtmp://", "tcp://")):
        weights = checks.check_file(weights, download_dir=SETTINGS["weights_dir"])  # download and return local file
    weights = checks.check_model_file_from_stem(weights)  # add suffix, i.e. yolo11n -> yolo11n.pt

    if str(weights).rpartition(".")[-1] == "pt":
        self.model, self.ckpt = load_checkpoint(weights)
        self.task = self.model.task
        self.overrides = self.model.args = self._reset_ckpt_args(self.model.args)
        self.ckpt_path = self.model.pt_path
    else:
        weights = checks.check_file(weights)  # runs in all cases, not redundant with above call
        self.model, self.ckpt = weights, None
        self.task = task or guess_model_task(weights)
        self.ckpt_path = weights
    self.overrides["model"] = weights
    self.overrides["task"] = self.task
    self.model_name = weights

def _new(self, cfg: str, task=None, model=None, verbose=False) -> None:
    """Initialize a new model and infer the task type from model definitions.

    Creates a new model instance based on the provided configuration file. Loads the model configuration, infers the
    task type if not specified, and initializes the model using the appropriate class from the task map.

    Args:
        cfg (str): Path to the model configuration file in YAML format.
        task (str, optional): The specific task for the model. If None, it will be inferred from the config.
        model (torch.nn.Module, optional): A custom model instance. If provided, it will be used instead of creating
            a new one.
        verbose (bool): If True, displays model information during loading.

    Raises:
        ValueError: If the configuration file is invalid or the task cannot be inferred.
        ImportError: If the required dependencies for the specified task are not installed.

    Examples:
        >>> model = Model()
        >>> model._new("yolo11n.yaml", task="detect", verbose=True)
    """
    cfg_dict = yaml_model_load(cfg)
    self.cfg = cfg
    self.task = task or guess_model_task(cfg_dict)
    self.model = (model or self._smart_load("model"))(cfg_dict, verbose=verbose and RANK == -1)  # build model
    self.overrides["model"] = self.cfg
    self.overrides["task"] = self.task

    # Below added to allow export from YAMLs
    self.model.args = {**DEFAULT_CFG_DICT, **self.overrides}  # combine default and model args (prefer model args)
    self.model.task = self.task
    self.model_name = cfg

@staticmethod
def _reset_ckpt_args(args: dict[str, Any]) -> dict[str, Any]:
    """Reset specific arguments when loading a PyTorch model checkpoint.

    This method filters the input arguments dictionary to retain only a specific set of keys that are considered
    important for model loading. It's used to ensure that only relevant arguments are preserved when loading a model
    from a checkpoint, discarding any unnecessary or potentially conflicting settings.

    Args:
        args (dict): A dictionary containing various model arguments and settings.

    Returns:
        (dict): A new dictionary containing only the specified include keys from the input arguments.

    Examples:
        >>> original_args = {"imgsz": 640, "data": "coco.yaml", "task": "detect", "batch": 16, "epochs": 100}
        >>> reset_args = Model._reset_ckpt_args(original_args)
        >>> print(reset_args)
        {'imgsz': 640, 'data': 'coco.yaml', 'task': 'detect'}
    """
    include = {"imgsz", "data", "task", "single_cls"}  # only remember these arguments when loading a PyTorch model
    return {k: v for k, v in args.items() if k in include}

def _smart_load(self, key: str):
    """Intelligently load the appropriate module based on the model task.

    This method dynamically selects and returns the correct module (model, trainer, validator, or predictor) based
    on the current task of the model and the provided key. It uses the task_map dictionary to determine the
    appropriate module to load for the specific task.

    Args:
        key (str): The type of module to load. Must be one of 'model', 'trainer', 'validator', or 'predictor'.

    Returns:
        (object): The loaded module class corresponding to the specified key and current task.

    Raises:
        NotImplementedError: If the specified key is not supported for the current task.

    Examples:
        >>> model = Model(task="detect")
        >>> predictor_class = model._smart_load("predictor")
        >>> trainer_class = model._smart_load("trainer")
    """
    try:
        return self.task_map[self.task][key]
    except Exception as e:
        name = self.__class__.__name__
        mode = inspect.stack()[1][3]  # get the function name.
        raise NotImplementedError(f"'{name}' model does not support '{mode}' mode for '{self.task}' task.") from e

def add_callback(self, event: str, func) -> None:
    """Add a callback function for a specified event.

    This method allows registering custom callback functions that are triggered on specific events during model
    operations such as training or inference. Callbacks provide a way to extend and customize the behavior of the
    model at various stages of its lifecycle.

    Args:
        event (str): The name of the event to attach the callback to. Must be a valid event name recognized by the
            Ultralytics framework.
        func (Callable): The callback function to be registered. This function will be called when the specified
            event occurs.

    Raises:
        ValueError: If the event name is not recognized or is invalid.

    Examples:
        >>> def on_train_start(trainer):
        ...     print("Training is starting!")
        >>> model = YOLO("yolo11n.pt")
        >>> model.add_callback("on_train_start", on_train_start)
        >>> model.train(data="coco8.yaml", epochs=1)
    """
    self.callbacks[event].append(func)

def benchmark(self, data=None, format="", verbose=False, **kwargs: Any):
    """Benchmark the model across various export formats to evaluate performance.

    This method assesses the model's performance in different export formats, such as ONNX, TorchScript, etc. It
    uses the 'benchmark' function from the ultralytics.utils.benchmarks module. The benchmarking is configured using
    a combination of default configuration values, model-specific arguments, method-specific defaults, and any
    additional user-provided keyword arguments.

    Args:
        data (str): Path to the dataset for benchmarking.
        verbose (bool): Whether to print detailed benchmark information.
        format (str): Export format name for specific benchmarking.
        **kwargs (Any): Arbitrary keyword arguments to customize the benchmarking process. Common options include:
            - imgsz (int | list[int]): Image size for benchmarking.
            - half (bool): Whether to use half-precision (FP16) mode.
            - int8 (bool): Whether to use int8 precision mode.
            - device (str): Device to run the benchmark on (e.g., 'cpu', 'cuda').

    Returns:
        (dict): A dictionary containing the results of the benchmarking process, including metrics for different
            export formats.

    Raises:
        AssertionError: If the model is not a PyTorch model.

    Examples:
        >>> model = YOLO("yolo11n.pt")
        >>> results = model.benchmark(data="coco8.yaml", imgsz=640, half=True)
        >>> print(results)
    """
    self._check_is_pytorch_model()
    from ultralytics.utils.benchmarks import benchmark

    from .exporter import export_formats

    custom = {"verbose": False}  # method defaults
    args = {**DEFAULT_CFG_DICT, **self.model.args, **custom, **kwargs, "mode": "benchmark"}
    fmts = export_formats()
    export_args = set(dict(zip(fmts["Argument"], fmts["Arguments"])).get(format, [])) - {"batch"}
    export_kwargs = {k: v for k, v in args.items() if k in export_args}
    return benchmark(
        model=self,
        data=data,  # if no 'data' argument passed set data=None for default datasets
        imgsz=args["imgsz"],
        device=args["device"],
        verbose=verbose,
        format=format,
        **export_kwargs,
    )

def clear_callback(self, event: str) -> None:
    """Clear all callback functions registered for a specified event.

    This method removes all custom and default callback functions associated with the given event. It resets the
    callback list for the specified event to an empty list, effectively removing all registered callbacks for that
    event.

    Args:
        event (str): The name of the event for which to clear the callbacks. This should be a valid event name
            recognized by the Ultralytics callback system.

    Examples:
        >>> model = YOLO("yolo11n.pt")
        >>> model.add_callback("on_train_start", lambda: print("Training started"))
        >>> model.clear_callback("on_train_start")
        >>> # All callbacks for 'on_train_start' are now removed

    Notes:
        - This method affects both custom callbacks added by the user and default callbacks
          provided by the Ultralytics framework.
        - After calling this method, no callbacks will be executed for the specified event
          until new ones are added.
        - Use with caution as it removes all callbacks, including essential ones that might
          be required for proper functioning of certain operations.
    """
    self.callbacks[event] = []

def embed(
    self,
    source: str | Path | int | list | tuple | np.ndarray | torch.Tensor = None,
    stream: bool = False,
    **kwargs: Any,
) -> list:
    """Generate image embeddings based on the provided source.

    This method is a wrapper around the 'predict()' method, focusing on generating embeddings from an image
    source. It allows customization of the embedding process through various keyword arguments.

    Args:
        source (str | Path | int | list | tuple | np.ndarray | torch.Tensor): The source of the image for generating
            embeddings. Can be a file path, URL, PIL image, numpy array, etc.
        stream (bool): If True, predictions are streamed.
        **kwargs (Any): Additional keyword arguments for configuring the embedding process.

    Returns:
        (list[torch.Tensor]): A list containing the image embeddings.

    Examples:
        >>> model = YOLO("yolo11n.pt")
        >>> image = "https://ultralytics.com/images/bus.jpg"
        >>> embeddings = model.embed(image)
        >>> print(embeddings[0].shape)
    """
    if not kwargs.get("embed"):
        kwargs["embed"] = [len(self.model.model) - 2]  # embed second-to-last layer if no indices passed
    return self.predict(source, stream, **kwargs)

def eval(self):
    """Sets the model to evaluation mode.

    This method changes the model's mode to evaluation, which affects layers like dropout and batch normalization
    that behave differently during training and evaluation. In evaluation mode, these layers use running statistics
    rather than computing batch statistics, and dropout layers are disabled.

    Returns:
        (Model): The model instance with evaluation mode set.

    Examples:
        >>> model = YOLO("yolo11n.pt")
        >>> model.eval()
        >>> # Model is now in evaluation mode for inference
    """
    self.model.eval()
    return self

def export(
    self,
    **kwargs: Any,
) -> str:
    """Export the model to a different format suitable for deployment.

    This method facilitates the export of the model to various formats (e.g., ONNX, TorchScript) for deployment
    purposes. It uses the 'Exporter' class for the export process, combining model-specific overrides, method
    defaults, and any additional arguments provided.

    Args:
        **kwargs (Any): Arbitrary keyword arguments for export configuration. Common options include:
            - format (str): Export format (e.g., 'onnx', 'engine', 'coreml').
            - half (bool): Export model in half-precision.
            - int8 (bool): Export model in int8 precision.
            - device (str): Device to run the export on.
            - workspace (int): Maximum memory workspace size for TensorRT engines.
            - nms (bool): Add Non-Maximum Suppression (NMS) module to model.
            - simplify (bool): Simplify ONNX model.

    Returns:
        (str): The path to the exported model file.

    Raises:
        AssertionError: If the model is not a PyTorch model.
        ValueError: If an unsupported export format is specified.
        RuntimeError: If the export process fails due to errors.

    Examples:
        >>> model = YOLO("yolo11n.pt")
        >>> model.export(format="onnx", dynamic=True, simplify=True)
        'path/to/exported/model.onnx'
    """
    self._check_is_pytorch_model()
    from .exporter import Exporter

    custom = {
        "imgsz": self.model.args["imgsz"],
        "batch": 1,
        "data": None,
        "device": None,  # reset to avoid multi-GPU errors
        "verbose": False,
    }  # method defaults
    args = {**self.overrides, **custom, **kwargs, "mode": "export"}  # highest priority args on the right
    return Exporter(overrides=args, _callbacks=self.callbacks)(model=self.model)

def fuse(self) -> None:
    """Fuse Conv2d and BatchNorm2d layers in the model for optimized inference.

    This method iterates through the model's modules and fuses consecutive Conv2d and BatchNorm2d layers into a
    single layer. This fusion can significantly improve inference speed by reducing the number of operations and
    memory accesses required during forward passes.

    The fusion process typically involves folding the BatchNorm2d parameters (mean, variance, weight, and
    bias) into the preceding Conv2d layer's weights and biases. This results in a single Conv2d layer that
    performs both convolution and normalization in one step.

    Examples:
        >>> model = Model("yolo11n.pt")
        >>> model.fuse()
        >>> # Model is now fused and ready for optimized inference
    """
    self._check_is_pytorch_model()
    self.model.fuse()

def info(self, detailed: bool = False, verbose: bool = True):
    """Display model information.

    This method provides an overview or detailed information about the model, depending on the arguments
    passed. It can control the verbosity of the output and return the information as a list.

    Args:
        detailed (bool): If True, shows detailed information about the model layers and parameters.
        verbose (bool): If True, prints the information. If False, returns the information as a list.

    Returns:
        (list[str]): A list of strings containing various types of information about the model, including model
            summary, layer details, and parameter counts. Empty if verbose is True.

    Examples:
        >>> model = Model("yolo11n.pt")
        >>> model.info()  # Prints model summary
        >>> info_list = model.info(detailed=True, verbose=False)  # Returns detailed info as a list
    """
    self._check_is_pytorch_model()
    return self.model.info(detailed=detailed, verbose=verbose)

@staticmethod
def is_hub_model(model: str) -> bool:
    """Check if the provided model is an Ultralytics HUB model.

    This static method determines whether the given model string represents a valid Ultralytics HUB model
    identifier.

    Args:
        model (str): The model string to check.

    Returns:
        (bool): True if the model is a valid Ultralytics HUB model, False otherwise.

    Examples:
        >>> Model.is_hub_model("https://hub.ultralytics.com/models/MODEL")
        True
        >>> Model.is_hub_model("yolo11n.pt")
        False
    """
    from ultralytics.hub import HUB_WEB_ROOT

    return model.startswith(f"{HUB_WEB_ROOT}/models/")

@staticmethod
def is_triton_model(model: str) -> bool:
    """Check if the given model string is a Triton Server URL.

    This static method determines whether the provided model string represents a valid Triton Server URL by parsing
    its components using urllib.parse.urlsplit().

    Args:
        model (str): The model string to be checked.

    Returns:
        (bool): True if the model string is a valid Triton Server URL, False otherwise.

    Examples:
        >>> Model.is_triton_model("http://localhost:8000/v2/models/yolo11n")
        True
        >>> Model.is_triton_model("yolo11n.pt")
        False
    """
    from urllib.parse import urlsplit

    url = urlsplit(model)
    return url.netloc and url.path and url.scheme in {"http", "grpc"}

def load(self, weights: str | Path = "yolo11n.pt") -> Model:
    """Load parameters from the specified weights file into the model.

    This method supports loading weights from a file or directly from a weights object. It matches parameters by
    name and shape and transfers them to the model.

    Args:
        weights (str | Path): Path to the weights file or a weights object.

    Returns:
        (Model): The instance of the class with loaded weights.

    Raises:
        AssertionError: If the model is not a PyTorch model.

    Examples:
        >>> model = Model()
        >>> model.load("yolo11n.pt")
        >>> model.load(Path("path/to/weights.pt"))
    """
    self._check_is_pytorch_model()
    if isinstance(weights, (str, Path)):
        self.overrides["pretrained"] = weights  # remember the weights for DDP training
        weights, self.ckpt = load_checkpoint(weights)
    self.model.load(weights)
    return self

def predict(
    self,
    source: str | Path | int | Image.Image | list | tuple | np.ndarray | torch.Tensor = None,
    stream: bool = False,
    predictor=None,
    **kwargs: Any,
) -> list[Results]:
    """Perform predictions on the given image source using the YOLO model.

    This method facilitates the prediction process, allowing various configurations through keyword arguments. It
    supports predictions with custom predictors or the default predictor method. The method handles different types
    of image sources and can operate in a streaming mode.

    Args:
        source (str | Path | int | PIL.Image | np.ndarray | torch.Tensor | list | tuple): The source of the image(s)
            to make predictions on. Accepts various types including file paths, URLs, PIL images, numpy arrays, and
            torch tensors.
        stream (bool): If True, treats the input source as a continuous stream for predictions.
        predictor (BasePredictor, optional): An instance of a custom predictor class for making predictions. If
            None, the method uses a default predictor.
        **kwargs (Any): Additional keyword arguments for configuring the prediction process.

    Returns:
        (list[ultralytics.engine.results.Results]): A list of prediction results, each encapsulated in a Results
            object.

    Examples:
        >>> model = YOLO("yolo11n.pt")
        >>> results = model.predict(source="path/to/image.jpg", conf=0.25)
        >>> for r in results:
        ...     print(r.boxes.data)  # print detection bounding boxes

    Notes:
        - If 'source' is not provided, it defaults to the ASSETS constant with a warning.
        - The method sets up a new predictor if not already present and updates its arguments with each call.
        - For SAM-type models, 'prompts' can be passed as a keyword argument.
    """
    if source is None:
        source = "https://ultralytics.com/images/boats.jpg" if self.task == "obb" else ASSETS
        LOGGER.warning(f"'source' is missing. Using 'source={source}'.")

    is_cli = (ARGV[0].endswith("yolo") or ARGV[0].endswith("ultralytics")) and any(
        x in ARGV for x in ("predict", "track", "mode=predict", "mode=track")
    )

    custom = {"conf": 0.25, "batch": 1, "save": is_cli, "mode": "predict", "rect": True}  # method defaults
    args = {**self.overrides, **custom, **kwargs}  # highest priority args on the right
    prompts = args.pop("prompts", None)  # for SAM-type models

    if not self.predictor:
        self.predictor = (predictor or self._smart_load("predictor"))(overrides=args, _callbacks=self.callbacks)
        self.predictor.setup_model(model=self.model, verbose=is_cli)
    else:  # only update args if predictor is already setup
        self.predictor.args = get_cfg(self.predictor.args, args)
        if "project" in args or "name" in args:
            self.predictor.save_dir = get_save_dir(self.predictor.args)
    if prompts and hasattr(self.predictor, "set_prompts"):  # for SAM-type models
        self.predictor.set_prompts(prompts)
    return self.predictor.predict_cli(source=source) if is_cli else self.predictor(source=source, stream=stream)

def reset_callbacks(self) -> None:
    """Reset all callbacks to their default functions.

    This method reinstates the default callback functions for all events, removing any custom callbacks that were
    previously added. It iterates through all default callback events and replaces the current callbacks with the
    default ones.

    The default callbacks are defined in the 'callbacks.default_callbacks' dictionary, which contains predefined
    functions for various events in the model's lifecycle, such as on_train_start, on_epoch_end, etc.

    This method is useful when you want to revert to the original set of callbacks after making custom
    modifications, ensuring consistent behavior across different runs or experiments.

    Examples:
        >>> model = YOLO("yolo11n.pt")
        >>> model.add_callback("on_train_start", custom_function)
        >>> model.reset_callbacks()
        # All callbacks are now reset to their default functions
    """
    for event in callbacks.default_callbacks.keys():
        self.callbacks[event] = [callbacks.default_callbacks[event][0]]

def reset_weights(self) -> Model:
    """Reset the model's weights to their initial state.

    This method iterates through all modules in the model and resets their parameters if they have a
    'reset_parameters' method. It also ensures that all parameters have 'requires_grad' set to True, enabling them
    to be updated during training.

    Returns:
        (Model): The instance of the class with reset weights.

    Raises:
        AssertionError: If the model is not a PyTorch model.

    Examples:
        >>> model = Model("yolo11n.pt")
        >>> model.reset_weights()
    """
    self._check_is_pytorch_model()
    for m in self.model.modules():
        if hasattr(m, "reset_parameters"):
            m.reset_parameters()
    for p in self.model.parameters():
        p.requires_grad = True
    return self

def save(self, filename: str | Path = "saved_model.pt") -> None:
    """Save the current model state to a file.

    This method exports the model's checkpoint (ckpt) to the specified filename. It includes metadata such as the
    date, Ultralytics version, license information, and a link to the documentation.

    Args:
        filename (str | Path): The name of the file to save the model to.

    Raises:
        AssertionError: If the model is not a PyTorch model.

    Examples:
        >>> model = Model("yolo11n.pt")
        >>> model.save("my_model.pt")
    """
    self._check_is_pytorch_model()
    from copy import deepcopy
    from datetime import datetime

    from ultralytics import __version__

    updates = {
        "model": deepcopy(self.model).half() if isinstance(self.model, torch.nn.Module) else self.model,
        "date": datetime.now().isoformat(),
        "version": __version__,
        "license": "AGPL-3.0 License (https://ultralytics.com/license)",
        "docs": "https://docs.ultralytics.com",
    }
    torch.save({**self.ckpt, **updates}, filename)

def track(
    self,
    source: str | Path | int | list | tuple | np.ndarray | torch.Tensor = None,
    stream: bool = False,
    persist: bool = False,
    **kwargs: Any,
) -> list[Results]:
    """Conduct object tracking on the specified input source using the registered trackers.

    This method performs object tracking using the model's predictors and optionally registered trackers. It handles
    various input sources such as file paths or video streams, and supports customization through keyword arguments.
    The method registers trackers if not already present and can persist them between calls.

    Args:
        source (str | Path | int | list | tuple | np.ndarray | torch.Tensor, optional): Input source for object
            tracking. Can be a file path, URL, or video stream.
        stream (bool): If True, treats the input source as a continuous video stream.
        persist (bool): If True, persists trackers between different calls to this method.
        **kwargs (Any): Additional keyword arguments for configuring the tracking process.

    Returns:
        (list[ultralytics.engine.results.Results]): A list of tracking results, each a Results object.

    Examples:
        >>> model = YOLO("yolo11n.pt")
        >>> results = model.track(source="path/to/video.mp4", show=True)
        >>> for r in results:
        ...     print(r.boxes.id)  # print tracking IDs

    Notes:
        - This method sets a default confidence threshold of 0.1 for ByteTrack-based tracking.
        - The tracking mode is explicitly set in the keyword arguments.
        - Batch size is set to 1 for tracking in videos.
    """
    if not hasattr(self.predictor, "trackers"):
        from ultralytics.trackers import register_tracker

        register_tracker(self, persist)
    kwargs["conf"] = kwargs.get("conf") or 0.1  # ByteTrack-based method needs low confidence predictions as input
    kwargs["batch"] = kwargs.get("batch") or 1  # batch-size 1 for tracking in videos
    kwargs["mode"] = "track"
    return self.predict(source=source, stream=stream, **kwargs)

def train(
    self,
    trainer=None,
    **kwargs: Any,
):
    """Train the model using the specified dataset and training configuration.

    This method facilitates model training with a range of customizable settings. It supports training with a custom
    trainer or the default training approach. The method handles scenarios such as resuming training from a
    checkpoint, integrating with Ultralytics HUB, and updating model and configuration after training.

    When using Ultralytics HUB, if the session has a loaded model, the method prioritizes HUB training arguments and
    warns if local arguments are provided. It checks for pip updates and combines default configurations,
    method-specific defaults, and user-provided arguments to configure the training process.

    Args:
        trainer (BaseTrainer, optional): Custom trainer instance for model training. If None, uses default.
        **kwargs (Any): Arbitrary keyword arguments for training configuration. Common options include:
            - data (str): Path to dataset configuration file.
            - epochs (int): Number of training epochs.
            - batch (int): Batch size for training.
            - imgsz (int): Input image size.
            - device (str): Device to run training on (e.g., 'cuda', 'cpu').
            - workers (int): Number of worker threads for data loading.
            - optimizer (str): Optimizer to use for training.
            - lr0 (float): Initial learning rate.
            - patience (int): Epochs to wait for no observable improvement for early stopping of training.
            - augmentations (list[Callable]): List of augmentation functions to apply during training.

    Returns:
        (dict | None): Training metrics if available and training is successful; otherwise, None.

    Examples:
        >>> model = YOLO("yolo11n.pt")
        >>> results = model.train(data="coco8.yaml", epochs=3)
    """
    self._check_is_pytorch_model()
    if hasattr(self.session, "model") and self.session.model.id:  # Ultralytics HUB session with loaded model
        if any(kwargs):
            LOGGER.warning("using HUB training arguments, ignoring local training arguments.")
        kwargs = self.session.train_args  # overwrite kwargs

    checks.check_pip_update_available()

    if isinstance(kwargs.get("pretrained", None), (str, Path)):
        self.load(kwargs["pretrained"])  # load pretrained weights if provided
    overrides = YAML.load(checks.check_yaml(kwargs["cfg"])) if kwargs.get("cfg") else self.overrides
    custom = {
        # NOTE: handle the case when 'cfg' includes 'data'.
        "data": overrides.get("data") or DEFAULT_CFG_DICT["data"] or TASK2DATA[self.task],
        "model": self.overrides["model"],
        "task": self.task,
    }  # method defaults
    args = {**overrides, **custom, **kwargs, "mode": "train", "session": self.session}  # prioritizes rightmost args
    if args.get("resume"):
        args["resume"] = self.ckpt_path

    self.trainer = (trainer or self._smart_load("trainer"))(overrides=args, _callbacks=self.callbacks)
    if not args.get("resume"):  # manually set model only if not resuming
        self.trainer.model = self.trainer.get_model(weights=self.model if self.ckpt else None, cfg=self.model.yaml)
        self.model = self.trainer.model

    self.trainer.train()
    # Update model and cfg after training
    if RANK in {-1, 0}:
        ckpt = self.trainer.best if self.trainer.best.exists() else self.trainer.last
        self.model, self.ckpt = load_checkpoint(ckpt)
        self.overrides = self._reset_ckpt_args(self.model.args)
        self.metrics = getattr(self.trainer.validator, "metrics", None)  # TODO: no metrics returned by DDP
    return self.metrics