The primary tool used for computation is Microsoft
Excel. This program has the benefit of being widely available
in academic, governmental and industrial institutions. It is
often updated by Microsoft to take advantage of increased power
in personal and networked computers. It is available for both
Windows and Apple operating systems. At has a variety of built-in
functions including several for financial applications. It includes
a powerful programming language called Visual Basic for Applications,
VBA. The VBA language has been used extensively by the author
to program add-ins to
Excel that implement many of the computational procedures covered
by this course as well as a variety of other topics related to
Operations Research, Operations Management and Industrial Engineering.
We assume students of this course have command
of the common procedures used in Excel, so we do not provide
instruction in this area. The site often provides screen shots
of worksheets to illustrate the methods and concepts of the course.
Screen shots are from the author's MacIntosh computer running
Mac Excel 2004. Although there are some differences with the
Windows version, they are minimal. The add-ins used have been
tested on Windows Excel 2013 but should also work with Windows Excel 2016 and Mac Excel 2011 (but not Mac Excel 2016). Although not tested in
every case, most add-ins will run on earlier versions of Excel. The instructions for the add-ins
are designed for Excel 2003 and 2004, but Excel 2013 has a different
menu structure. Click the link below for
a discussion of the changes in Excel 2007.
This section provides discussions of aspects of
Excel and Excel add-ins that may not be familiar to students.
More complete discussions are provided on the ORMM and OMIE sites.
There are links to relevant portions of these sites on this page
and throughout the instructional materials.
Excel add-ins are files with the ".xla" suffix.
This is in contrast to a data file that has the suffix ".xls" or ".xlsx".
This is important because although data files are opened by
double clicking their file icons or names or opening the file
through the File/Open command of Excel, add-in files
should not be opened in this way. An attempt to open an add-in
file will probably result in a security message from the operating
system because add-ins contain macros. Macros are VBA
programs that create worksheets, perform the algorithms and evaluate
the functions of the add-in. The system might ask for a password
when an add-in is opened incorrectly. If installed correctly,
the add-ins do not require a password. For a discussion about
installing and using add-ins see the Using
Add-ins section of the ORMM site. Click the tree
icon to open that site.
Add-ins must be installed to obtain their functionality.
Install an add-in by choosing the "Add-Ins..." command
from the Excel Tools menu. The add-in dialog similar
to the one below is presented. The dialog shows add-ins immediately
available. They can be installed by checking the adjacent box.
If the desired add-in does not appear in the list click the Select button
(the button is labeled Browse on Windows). This button
allows the user to browse to the location where the add-in is
Add-ins for the
Several add-ins are used in the
course from the OM/IE and ORMM collections. Rather than attempt
to explain them here, we provide links to the Jensen Add-in materials.
are listed in the order of use. The lessons explain the particular
features of the add-ins that are necessary for this course. In
the table below the first column opens a separate window to the
instructions for the add-in. The second column downloads an Excel
.xls file that is the demonstration file for the add-in. The
third column downloads a zipped file that holds the .xla file
that contains the add-in programs. The zip files must be un-zipped
before using. Most computers do this automatically. The download
processor may ask where the downloaded files should be placed.
Any convenient location on the hard drive can be used to store
the downloaded files, but it is most convenient if the add-in
and demo files are all stored in the same folder.
Before opening a demo file, install the add-in
as described above. To install an add-in through the Tools menu,
you must browse to the folder that holds the add-ins. Open
a demo file by double clicking the file or through
the Excel File/Open dialog.
Although you do not need to use them, the Add
OMIE and Add
are handy for installing other add-ins.
Add-ins are available for many topics in Operations
Research, Operations Management and Industrial Engineering. The
links below open pages where the add-ins are available
for download. You can download the entire collection of Jensen
add-ins by clicking the archive link at the bottom of the ORMM
Menus and Functions
Once an add-in is installed, a new
menu appears on the Excel menu bar as shown at the
left. The Economics add-in
is in the OM/IE collection, so the add-in commands
are listed under that title. Add-ins in the ORMM collection
are listed under an ORMM menu item. Note that the
word Economics is
checked in the list. Clicking on that item removes the check
and the menu items immediately below disappear. This is useful
to shrink the length of the menu when several add-ins are installed.
Clicking Economics again makes the items reappear.
The items prefaced with the underline, "_", call
various algorithms associated with the add-in. Not all the
items on the menu are used in the course. The lessons point
out the necessary ones.
Functions and Buttons
When user-defined functions
or buttons are
used in a workbook, they are linked to the add-in that provides
the function. No problem occurs when the workbook is subsequently
opened on the same computer. If a workbook created on one computer
is opened on another the linking problem must be addressed because
each function or button will still be linked to the computer
that created it. The Economics, Estimate and Project
Management add-ins have a Links command that simplifies
the problem. The command removes all functions and buttons before
a file is saved and later replaces the functions and buttons
when the file is reopened. All the demo files are saved with
the links removed. Click the icon below to see how this command
works for the Economics add-in.
Similar commands are provided for the Estimate and Project
All homework submitted for grading should have
the links removed using the Links command.
The Random Variables add-in has slightly
different method for handling the linking problem. When a file
with links opens, a message from Excel alerts the user. Always
respond by Canceling the dialog. Use the Relink
Functions command from the add-in to solve the problem.
Excel provides the Edit/Links command
that corrects all links reliably. Click the icon to open a window
describing the command.
Excel add-ins programmed in VBA extend the capacity
of Excel. They are used extensively in industry and are part of
this course. It may take a little effort to get started, but the
effort will be rewarded.
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