Displaying a Problem

Now that you have entered a problem using ILOG CPLEX, you must verify that the problem was entered correctly. To do so, use the display command. At the CPLEX> prompt type:

  display

A list of the items that can be displayed then appears. Some of the options display parts of the problem description, while others display parts of the problem solution. Options about the problem solution are not available until after the problem has been solved. The list looks like this: 

Display Options:



iis           display infeasibility diagnostics (IIS constraints)

problem       display problem characteristics

sensitivity   display sensitivity analysis

settings      display parameter settings

solution      display existing solution



Display what:

If you type problem in reply to that prompt, that option will list a set of problem characteristics, like this: 

Display Problem Options:



all              display entire problem

binaries         display binary variables

bounds           display a set of bounds

constraints      display a set of constraints or node supply/demand values

generals         display general integer variables

histogram        display a histogram of row or column counts

integers         display integer variables

names            display names of variables or constraints

qpvariables      display quadratic variables

semi-continuous  display semi-continuous and semi-integer variables

sos              display special ordered sets

stats            display problem statistics

variable         display a column of the constraint matrix



Display which problem characteristic:

Enter the option all to display the entire problem. 

Maximize

 obj: x1 + 2 x2 + 3 x3

Subject To

 c1: - x1 +   x2 +   x3 <= 20

 c2:  x1 - 3 x2 +   x3 <= 30

Bounds

 0 <= x1 <= 40

All other variables are >= 0.

The default names obj, c1, c2, are provided by ILOG CPLEX.

If that is what you want, you are ready to solve the problem. If there is a mistake, you must use the change command to modify the problem. The change command is described in Changing a Problem on page 56.

Summary

Display problem characteristics by entering the command:

  display problem
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