Top 12 OR Linear Programming Simplex Method Terms You Need To Know

1. Standard Form:       A LPP in which all constraints are written in equalities.

2. Slack Variable:        A variable added to the LHS of “less than or equal to” constraint to convert the convert the constraint into an equality. Value of slack variable indicates unused resources.

3. Surplus Variable:     A variable subtracted from the LHS of “more than or equal to” constraint to convert the convert the constraint into an equality. Value of surplus variable indicates consumption over & above minimum requirements.

4. Simplex Tableau:     A table used to keep record of the calculation made at each iteration.

5. Basis:           The set of variables which are not restricted to equal zero in the current basic solution. The variables which make up the basis are called Basic variables. The remaining are called non-basic variables.

6. Iteration:     The steps performed in simplex method to progress form one feasible solution to another.

7. Cj Row:       A row in the simplex table which contains the coefficients (unit profit) of the variables in the Objective function.

8. Zj Row:       A row in the simplex tables whose elements represent the increase / decrease in the value of objective function; if one unit of that variable is brought into the solution.

9. Zj – Cj Row (Index Row): A row in the simplex table whose elements represent net contribution / loss per unit if one unit of that variable is brought into the solution.

10. Key column:          The column with the largest positive / negative index number. It indicates the Entering variable in the Basis.

11. Key row:   The row with the smallest positive ratio found by dividing Quantity column values by Key column values for each row. It indicates the Exiting variable from the Basis.

12. Key element:         The element at the intersection of Key row & Key column.