The LP Procedure

The Reduced Costs, Dual Activities, and Current Tableau

The evaluation of reduced costs and the dual activities is independent of problem structure. For a basic solution, let  b be the matrix composed of the basic columns of  a and let  n be the matrix composed of the nonbasic columns of  a. The reduced cost associated with the  ith variable is

 (c^t - c^t_b b^{-1} a)_i
and the dual activity of the  jth row is
 (c^t_b b^{-1})_j

The Current Tableau is a section displayed when you specify either the TABLEAUPRINT option in the PROC LP statement or the TABLEAU option in the PRINT statement. The output contains a row for each basic variable and a column for each nonbasic variable. In addition, there is a row for the reduced costs and a column for the product

 b^{-1} b
This column is labeled INV(B)*R. The body of the tableau contains the matrix
 b^{-1} n

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