Displaying post-solution information

For post-solution information, the Interactive Optimizer supports these options.

After an optimal solution is found, CPLEX can provide many different kinds of information for you to view and analyze the results. You access this information by means of the display command and by certain write commands.

Information about the following features of a solution is available with the display solution command:

• objective function value;

• solution values;

• numerical quality of the solution;

• slack values;

• reduced costs;

• dual values (shadow prices);

• basic rows and columns.

For information about the write commands, see Writing problem and solution files. Sensitivity analysis can also be performed in analyzing results, as explained in Performing sensitivity analysis.

For example, to view the optimal value of each variable, enter the command:

display solution variables -

In response, the list of variable names with the solution value for each variable is displayed, like this:

Variable Name    Solution Value
x1                    40.000000
x2                    17.500000
x3                    42.500000

To view the slack values of each constraint, enter the command:

display solution slacks - 

The resulting message indicates that for this problem the slack variables are all zero.

All slacks in the range 1-2 are 0.

To view the dual values (sometimes called shadow prices) for each constraint, enter the command:

display solution dual - 

The list of constraint names with the solution value for each constraint appears, like this:

Constraint Name     Dual Price
c1                    2.750000
c2                    0.250000

display solution identifier