def dePeriod(arr):
    """make an array of periodic angles increase linearly"""
    diff= arr-nu.roll(arr,1,axis=1)
    w= diff < -6.
    addto= nu.cumsum(w.astype(int),axis=1)
    return arr+_TWOPI*addto
def dePeriod ( arr ) : diff = arr - nu . roll ( arr , 1 , axis = 1 ) w = diff < - 6. addto = nu . cumsum ( w . astype ( int ) , axis = 1 ) return arr + _TWOPI * addto
make an array of periodic angles increase linearly