a periodic_stats

from .nearly_even_split import nearly_even_split

from .geometry import ElipsoidTriangulation 

from .template_subs import discoverKeys, templateFiller

from .periodic_stats import periodic_stats

from .periodic_stats import periodic_stats, periodic_centroid

#from import .grep

#import .intervalls

import numpy as np

def periodic_stats(alpha,deg=False) :

def periodic_stats(alpha) :

   """ statistics of a periodic alpha (radiants)

   If alpha is a vector of angles (radiants) find the average number and the std deviation avoiding the problem of the switch between -180,180 or 360 and 0

   #

   return np.arctan2(rr[1],rr[0]), np.nanvar(np.arctan2(vp,up))**0.5

def periodic_centroid(alpha) :

   """ centroid of a periodic alpha (radiants)

   If alpha is a vector of angles (radiants) find the average number and the std deviation avoiding the problem of the switch between -180,180 or 360 and 0

   example: alpha=np.array([-180,180]) 

   """

   u=np.cos(alpha)

   v=np.sin(alpha)

   #

   rr=np.array([np.nanmean(u),np.nanmean(v)])

   rr=rr/rr.dot(rr)**0.5

   #

   up=rr[0]*u+rr[1]*v ;

   vp=-rr[1]*u+rr[0]*v

   return np.array([up,vp]).T

if __name__=='__main__' :

   print("Test1")

   alpha=np.arange(350,371)