| 1. Introduction | 2. Example | 3. Main Menu | 4. Printing | 5. Graphs | 6. Modules |
As with linear and integer programs any mixed integer linear program is defined by the number of variables and the number of constraints. Do not count the non-negativity restrictions as constraints.
Consider the following example
maximize 30x + 33y + 50z
subject to 23x+ 43y + 16z<= 1000
32x + 33y + 25z <= 2500
43x + 53y + 26z <= 1500
x, y, z >= 0
x integer,
z 0/1
The components are identical to linear and integer programming except that there is one extra row of information that needs to be given indicating the type of each variable (real, integer or 0/1).
Objective function. The choice of minimization or maximization is made in the usual way at the time of problem creation but it can be changed on the data screen using the objective box above the data.
Objective function coefficients. The coefficients (typically referred to as cj) are entered as numerical values.
Constraint coefficients. The main body of information are the constraint coefficients which typically are called the aijs. These coefficients may be positive or negative.
The constraint sign. This can be entered in one of two ways. It is permissible to press the [<] key, the [>] key or the [=] key. When you go to a cell with the constraint sign then a drop down arrow appears in the cell.
Right hand side coefficients. The values on the right hand side of the constraints are entered here. These are also termed the bis. They must be nonnegative.
The variable type. This is a dropdown box which will change the variable type from "integer", to "real" to "0/1". You can change all at once by clicking on the leftmost column.
The variable types and their values are displayed.
In addition, the iterations can be displayed.
Note: Integer programs can be entered as mixed integer programs without any loss of results. The
same is not true for linear programs. They will be solved but the range table and linear
programming iterations will not be available.
| 1. Introduction | 2. Example | 3. Main Menu | 4. Printing | 5. Graphs | 6. Modules |
 |
©
Prentice-Hall, Inc. A Simon & Schuster Company Upper Saddle River, New Jersey 07458 |