a periodic_stats

src/yapsut/__init__.py

@@ -13,7 +13,7 @@ from .DummyCLI import DummyCLI
 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

src/yapsut/periodic_stats.py

@@ -2,7 +2,7 @@
 
 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
@@ -23,6 +23,24 @@ def periodic_stats(alpha,deg=False) :
    #
    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)