Sun Woong Kim, Steven G. Heeringa and Peter W. Solenberger
To take the advantages of the power of modern computing, we have developed a public use SAS-based software called the SOCSLP (Software for Optimal Controlled Selection Linear Programming) for our algorithm to solve controlled selection problems with two-way stratification. The recent version may be downloaded from the URL: http://www.isr.umich.edu/src/smp/socslp.
In using the software, there are no restrictions on the number of all possible arrays that can be considered for the solution. The number of those arrays and the number of constraints that can be solved depend on the memory capacity and the available disk space of the computer.
The two-phase revised simplex method, implemented using SAS/OR LP Procedure, simply “PROC LP”, is employed to solve the LP problem. A unique optimal solution to the LP problem is obtained when the objective function is minimized under the given constraints (6.7) through phase 1 and 2 of PROC LP, with the assumption that all unknown variables are nonnegative (6.8).
The software produces much information including the solution set to the controlled selection problem. Also, by choosing a simple option in the software, one array can be randomly selected from the solution set, completing the controlled selection. The SOCSLP is currently available for personal computers, and the details are provided through the User Guide on the website.