marginalization implementation in CeresPhotometricBundleAdjustment

[ShuiXianhua]

Hi, this is really a very good work, thank you. I encountered a little problem when I was studying. Does CeresPhotometricBundleAdjustment use marginalization factors? The marginalization factor was implemented in EigenPhotometricBundleAdjustment, but I did not see the relevant code in CeresPhotometricBundleAdjustment.