  For an in invertible quasihomogeneous singularity $w$ we prove an all-genus
mirror theorem establishing an isomorphism between two cohomological field
theories. On the $B$-side it is the Saito-Givental theory given by a certain
choice of a primitive form. On the $A$-side, it is the reduced matrix
factorization CohFT for the dual singularity $w^T$ with the maximal diagonal
symmetry group.
