def Rt_to_matrix4x4(R: Tensor, t: Tensor) -> Tensor:
    r"""Combine 3x3 rotation matrix R and 1x3 translation vector t into 4x4 extrinsics.

    Args:
        R: Rotation matrix, :math:`(B, 3, 3).`
        t: Translation matrix :math:`(B, 3, 1)`.

    Returns:
        the extrinsics :math:`(B, 4, 4)`.

    Example:
        >>> R, t = torch.eye(3)[None], torch.ones(3).reshape(1, 3, 1)
        >>> Rt_to_matrix4x4(R, t)
        tensor([[[1., 0., 0., 1.],
                 [0., 1., 0., 1.],
                 [0., 0., 1., 1.],
                 [0., 0., 0., 1.]]])

    """
    KORNIA_CHECK_SHAPE(R, ["B", "3", "3"])
    KORNIA_CHECK_SHAPE(t, ["B", "3", "1"])
    Rt = concatenate([R, t], dim=2)
    return convert_affinematrix_to_homography3d(Rt)
Combine 3x3 rotation matrix R and 1x3 translation vector t into 4x4 extrinsics.

    Args:
        R: Rotation matrix, :math:`(B, 3, 3).`
        t: Translation matrix :math:`(B, 3, 1)`.

    Returns:
        the extrinsics :math:`(B, 4, 4)`.

    Example:
        >>> R, t = torch.eye(3)[None], torch.ones(3).reshape(1, 3, 1)
        >>> Rt_to_matrix4x4(R, t)
        tensor([[[1., 0., 0., 1.],
                 [0., 1., 0., 1.],
                 [0., 0., 1., 1.],
                 [0., 0., 0., 1.]]])

    
kornia/geometry/conversions.py