import torch


def get_ja(arr):
    """
    calculates jaw aperture (euclidean distance between UL / J (LI)):
        pertinent indexes:
        Jx : 6, ULx: 10, Jy : 7, ULy : 11
    """
    return torch.sqrt((arr[:,6]-arr[:,10])**2+(arr[:,7]-arr[:,11])**2)