The algebro geometric construction of all genus Landau Ginzburg model has been achieved via P fields and cosection localization. When there is a wall crossing between two LG models, by promoting the stability parameter to a field on the worldsheet, one constructs a master moduli space interpolating the two LG theories. In this talk we discuss the geometric constructions. An application is the proof of the Yamaguchi-Yau finite generation conjecture of quintic 3fold's. We also find that the R matrices of the MSP theory gives the same propagator in the Feymann graph sum which BCOV used to solve (physics') Holomorphic Anomaly Equation.