Once an optimal solution is found, ILOG CPLEX can provide many different kinds of information for viewing and analyzing the results. This information is accessed via the display command and via some write commands.

Information about the following is available with the display solution command:

• objective function value;
• solution values;
• slack values;
• reduced costs;
• dual values (shadow prices);
• basic rows and columns.

For information on the write commands, see Writing Problem and Solution Files on page 47. Sensitivity analysis can also be performed in analyzing results, as described in Performing Sensitivity Analysis on page 46.

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 characteristics by entering a command with the syntax:

display solution identifier