Method cat

detectron2/structures/boxes.py:281–306

Concatenates a list of Boxes into a single Boxes Arguments: boxes_list (list[Boxes]) Returns: Boxes: the concatenated Boxes

(cls, boxes_list: List["Boxes"])

    @classmethod
    def cat(cls, boxes_list: List["Boxes"]) -> "Boxes":
        """
        Concatenates a list of Boxes into a single Boxes

        Arguments:
            boxes_list (list[Boxes])

        Returns:
            Boxes: the concatenated Boxes
        """
        if torch.jit.is_scripting():
            # https://github.com/pytorch/pytorch/issues/18627
            # 1. staticmethod can be used in torchscript, But we can not use
            # `type(boxes).staticmethod` because torchscript only supports function
            # `type` with input type `torch.Tensor`.
            # 2. classmethod is not fully supported by torchscript. We explicitly assign
            # cls to Box as a workaround to get torchscript support.
            cls = Boxes
        assert isinstance(boxes_list, (list, tuple))
        if len(boxes_list) == 0:
            return cls(torch.empty(0))
        assert all([isinstance(box, Boxes) for box in boxes_list])

        # use torch.cat (v.s. layers.cat) so the returned boxes never share storage with input
        cat_boxes = cls(torch.cat([b.tensor for b in boxes_list], dim=0))
        return cat_boxes

    @property
    def device(self) -> device: