grids.py 文件源码

def _di(scalararray):
    """Return the difference scalararray(i+1) - scalararray(i).

    A priori, for internal use only.

    Parameters
    ----------
    scalararray : xarray.DataArray
        xarray that should be differentiated.

    Returns
    -------
    di : xarray.DataArray
       xarray of difference, defined at point i+1/2
    """
    di = scalararray.shift(x=-1) - scalararray
    return di