Calculate the separation in magnitude-magnitude space between points and isochrone. Uses a dense sampling of the isochrone and calculates the metric distance from any isochrone sample point.

        Parameters:
        -----------
        mag_1 : The magnitude of the test points in the first band
        mag_2 : The magnitude of the test points in the second band
        steps : Number of steps to sample the isochrone

        Returns:
        --------
        sep : Minimum separation between test points and isochrone sample

def raw_separation(self,mag_1,mag_2,steps=10000):
        """ 
        Calculate the separation in magnitude-magnitude space between points and isochrone. Uses a dense sampling of the isochrone and calculates the metric distance from any isochrone sample point.

        Parameters:
        -----------
        mag_1 : The magnitude of the test points in the first band
        mag_2 : The magnitude of the test points in the second band
        steps : Number of steps to sample the isochrone

        Returns:
        --------
        sep : Minimum separation between test points and isochrone sample
        """
     
        # http://stackoverflow.com/q/12653120/
        mag_1 = np.array(mag_1,copy=False,ndmin=1)
        mag_2 = np.array(mag_2,copy=False,ndmin=1)
     
        init,pdf,act,iso_mag_1,iso_mag_2 = self.sample(mass_steps=steps)
        iso_mag_1+=self.distance_modulus
        iso_mag_2+=self.distance_modulus
     
        iso_cut = (iso_mag_1<np.max(mag_1))&(iso_mag_1>np.min(mag_1)) | \
                  (iso_mag_2<np.max(mag_2))&(iso_mag_2>np.min(mag_2))
        iso_mag_1 = iso_mag_1[iso_cut]
        iso_mag_2 = iso_mag_2[iso_cut]
         
        dist_mag_1 = mag_1[:,np.newaxis]-iso_mag_1
        dist_mag_2 = mag_2[:,np.newaxis]-iso_mag_2
        
        return np.min(np.sqrt(dist_mag_1**2 + dist_mag_2**2),axis=1)