The Project Worksheet contains a button
labeled Build LP/IP model. Pressing this button shows
the dialog below.
Three options are available. The first
produces a linear programming model with variables for the production
level of each product. It computes the optimum product mix with
constraints on the total resources used.
The second is also a linear programming
model that adds to the production variables, variables that
specify the time on each resource and the amounts of each raw
material. It includes constraints on the amounts of raw materials
and the amounts of resources available. It determines the optimum
product mix with these added constraints.
The third is a mixed integer-linear programming
model that also includes integer variables for the number of
each resource type (machine type). It computes the optimum number
of resources (machines) that should used for the system.
The objective in each case is to maximize
the net income. The solutions obtained by solving the mathematical
programming model are automatically placed on the Project worksheet.
The models use the Math Programming add-in, so that add-in
must be installed to proceed. A solver add-in must also be available,
either the Excel Solver or the Jensen LP/IP solver that is available
from this site. The solver is chosen on the Linear Model dialog
which appears after clicking the OK button on the dialog above.
If the Excel Solver is used, be sure to connect to the Solver
by selecting Solver from the Tools menu before trying to create
a model. This establishes a connection to the add-in. Modeling
will fail if the connection is not established.
Click the links at the left to learn about the three models.