def iou_distance(atracks, btracks):
    """
    Compute cost based on IoU
    :type atracks: list[STrack]
    :type btracks: list[STrack]

    :rtype cost_matrix np.ndarray
    """

    if (len(atracks)>0 and isinstance(atracks[0], np.ndarray)) or (len(btracks) > 0 and isinstance(btracks[0], np.ndarray)):
        atlbrs = atracks
        btlbrs = btracks
    else:
        atlbrs = [track.tlbr for track in atracks]
        btlbrs = [track.tlbr for track in btracks]
    _ious = ious(atlbrs, btlbrs)
    cost_matrix = 1 - _ious

    return cost_matrix

    Compute cost based on IoU
    :type atracks: list[STrack]
    :type btracks: list[STrack]

    :rtype cost_matrix np.ndarray
    
trackers/byte_tracker/matching.py