A SAS Macro for Implementing the Generalized RAS Algorithm for Constraining Matrices of Mixed Sign

The problem of constraining matrices of mixed sign to controls of possibly mixed sign arises in input-output matrices in economics and net migration in demography. The recently developed Generalized RAS (GRAS) algorithm is presented to solve these problems. The GRAS algorithm produces a unique solution that minimizes an entropy-like function. The algorithm is applied to a well-known example and compared to the solution originally obtained using a generalization of the Akers-Siegel procedure.