Update stats.py to include extension_radial parameter in supplement()

Part 1 of an improvement to use the full posterior when calculating the azimuthally-averaged (radial) extension.

This fix specifically adds extension_radial to the class method supplement(), part of the Samples class

ugali/utils/stats.py

@@ -299,7 +299,14 @@ def supplement(self,coordsys='gal'):
                 names = ['position_angle_gal','position_angle_cel']
                 arrs = [pa_gal,pa_cel]
                 out = recfuncs.append_fields(out,names,arrs,**kwargs).view(Samples)
-
+
+            if ('extension' in out.names) and ('ellipticity' in out.names):
+                ext = out.extension
+                ellipticity = out.ellipticity
+                rext = ext * np.sqrt(1-ellipticity)
+
+                out = recfuncs.append_fields(out,['extension_radial'], [rext]).view(Samples)
+
         return out
 
     def get(self, names=None, burn=None, clip=None):