Code to perform density field reconstruction given an object catalog and two random files. The goal of density field reconstruction is to sharpen the baryon acoustic oscillation feature for measuring distances. This code implements the standard, lowest-order algorithm presented in Eisenstein et al. (2007) with periodic boundary conditions using a multigrid relaxation technique with a full multigrid V-cycle based on damped Jacobi iteration. Inputs are a catalog of objects and two random catalogs which serve to specify the selection function and act as the "shifted" fields. Output are `shifted' versions of the object and second random catalogs.