def skewvR(self,R,romberg=False,nsigma=None,phi=0.):
        """
        NAME:

           skewvR

        PURPOSE:

           calculate skew in vR at R by marginalizing over velocity

        INPUT:

           R - radius at which to calculate <vR> (can be Quantity)

        OPTIONAL INPUT:

           nsigma - number of sigma to integrate the velocities over

        KEYWORDS:

           romberg - if True, use a romberg integrator (default: False)

        OUTPUT:

           skewvR

        HISTORY:

           2011-12-07 - Written - Bovy (NYU)

        """
        surfmass= self.surfacemass(R,romberg=romberg,nsigma=nsigma,
                                   use_physical=False)
        vr= self._vmomentsurfacemass(R,1,0,romberg=romberg,nsigma=nsigma)\
            /surfmass
        vr2= self._vmomentsurfacemass(R,2,0,romberg=romberg,nsigma=nsigma)\
            /surfmass
        vr3= self._vmomentsurfacemass(R,3,0,romberg=romberg,nsigma=nsigma)\
            /surfmass
        s2= vr2-vr**2.
        return (vr3-3.*vr*vr2+2.*vr**3.)*s2**(-1.5)
def skewvR ( self , R , romberg = False , nsigma = None , phi = 0. ) : surfmass = self . surfacemass ( R , romberg = romberg , nsigma = nsigma , use_physical = False ) vr = self . _vmomentsurfacemass ( R , 1 , 0 , romberg = romberg , nsigma = nsigma ) / surfmass vr2 = self . _vmomentsurfacemass ( R , 2 , 0 , romberg = romberg , nsigma = nsigma ) / surfmass vr3 = self . _vmomentsurfacemass ( R , 3 , 0 , romberg = romberg , nsigma = nsigma ) / surfmass s2 = vr2 - vr ** 2. return ( vr3 - 3. * vr * vr2 + 2. * vr ** 3. ) * s2 ** ( - 1.5 )
NAME:

           skewvR

        PURPOSE:

           calculate skew in vR at R by marginalizing over velocity

        INPUT:

           R - radius at which to calculate <vR> (can be Quantity)

        OPTIONAL INPUT:

           nsigma - number of sigma to integrate the velocities over

        KEYWORDS:

           romberg - if True, use a romberg integrator (default: False)

        OUTPUT:

           skewvR

        HISTORY:

           2011-12-07 - Written - Bovy (NYU)