def variation(a, axis=0):
 (a, axis) = _chk_asarray(a, axis)
 return (a.std(axis) / a.mean(axis))

def variation ( a , axis = 0 ) : ( a , axis ) = _chk_asarray ( a , axis ) return ( a . std ( axis ) / a . mean ( axis ) )
computes the coefficient of variation .