Luis Dias, January 2003
This is the on-line manual for IRIS v2.0. It is a Decision Support Software designed to address the problem of assigning a set of alternatives to predefined ordered categories, according to their performances at multiple criteria. It implements the Electre TRI method, adding the following characteristics:
To know more about the problem and the methodology implemented by IRIS, refer to the papers:
IRIS runs on Windows 95/98 computers. The monitor should be at least VGA (640x480) with 32 colors. It occupies very little space on disk and is not too demanding in terms of RAM (however, the more the better...). The program may run without a mouse, but becomes somewhat cumbersome to use. You should have a 2-button mouse to make the best use of this software. To read this on-line manual you need a browser (e.g. Microsoft Explorer or Netscape). To access it from IRIS you must have a default browser installed.
Example of an IRIS window
IRIS is a SDI (Single Document Interface) program, as for instance Microsoft Explorer. This means that you can work at a single document (problem) at a time. Of course, you can work on several problems at the same time if you run several instances of IRIS simultaneously.
The program runs on a single window and you can change its position, change its size, minimize it, etc. This window is divided in two areas. The left area of the screen is for inputs, whereas the right area of the screen is for outputs. Each area is organized according to a multi-page notebook metaphor with tabs to change pages. The space occupied by each area may be changed by clicking on the dividing line and dragging it to the left or to the right. The outputs will reflect the changes in input after the option Robust Assignments from the Results menu is chosen.
There are some grids associated with input and output pages. You can edit the height, width and font size of the grid elements by setting their values at the right top of the screen:
It may happen that the contents of some grid cells cannot be displayed in its entirety. In such cases, if you do not wish to enlarge the width of the cells, you only have to position the mouse over the cell so that its contents will be entirely displayed.
All of the input or output pages have pull-down menus associated with them. To access these menus just click on the right button of your mouse or select the pull-down menu key that is available in some of the recent keyboards. The last option in each menu (Help) leads you directly to the page of this manual related to the page you are in.
The inputs must be read from a file (and then may be changed)
or typed in by the user. To open an existing file (which should
have been created using IRIS) choose File|Open
(or button 
) and
locate the file. The default extension is .tri. To
create a new file choose File|New (or button
) and insert the number
of alternatives, the number of criteria, and the number of
categories for your problem. The program allows to add or delete
criteria, alternatives or categories later on. The caption of the
window indicates the name of the file that you are working on.
In the present version of the program there is a limit of 15 criteria. The number of alternatives is limited only by the amount of memory.
The inputs area may be enlarged or reduced (see the Interface organization section). This area contains four pages:
| Actions: | To edit the alternatives the performances of the alternatives at the criteria and (optionally) to set some assignment examples. Click here to know the editing details. |
| Fixed Par.: | To edit the performances that define category bounds (profiles) and to edit the thresholds associated with the criteria. Click here to know the editing details. |
| Bounds: | To edit the upper and lower bounds of the importance coefficients (weights) and the cutting level (lambda). Click here to know the editing details. |
| Constraints: | To edit the explicit constraints (other than bounds) on the parameter values. Note that the implicit constraints related to assignment examples are edited in the Actions page. Click here to know the editing details. |
To save the current file choose File|Save Data As (or
button 
), which
allow you to define the location and name of your file, or choose
File|Save Data to save it under its current name
and location.
After you have specified all of your input you may get some results. The Results menu offers some outputs that depend on the inputs:
The outputs area of the screen, updated after choosing the option Robust Assignments, may be enlarged or reduced (see the Interface organization section) and contains the following pages:
| Results: | Displays a grid with the inferred parameter values and assignments, as well as the range of possible assignments for each alternative. Click here to find out more. |
| Inferred constraints: | Displays the linear constraints corresponding to the assignment examples. |
| Infer.Prog.: | Displays the linear program corresponding to the inference problem, indicating which ones are violated when the constraints are inconsistent. Click here to find out more. |
| Indices: | Indicates the geometric mean of the number of possible assignments per alternative (when the constraints are consistent), and its variation relative to the previous computation. |
When the constraints are inconsistent, the menu option Inconsistency becomes available. This option activates the inconsistency analysis form. Click here to find out more.
You may produce a report (text file) on the outputs that you
presently have by selecting File|Report (or
button 
). Do not
supply an extension, since the program will automatically append
the extension .rep. This text file may then be formatted
as you wish in the word processor of your choice or may even be
read by a spreadsheet program. If you choose File|Print
form you will obtain a bitmap file that mirrors the
present contents of your IRIS window.
After changing any input the output pages the output pages become outdated. To show this, the Results and the Inferred constraints pages display their text in red color. The command Results|Robust Assignments must be selected again to make the outputs reflect the changes to the inputs.
The following picture depicts the menu for IRIS (The underlined characters are keyboard shortcuts Alt+Key):
New: Creates a new problem, asking for its dimensions.
Open: Opens a problem, reading the inputs from disk.
Report: Creates a file containing the computed results.
Save Data: Saves the current inputs on disk, considering the current file's name and location.
Save Data As: Saves the current inputs on disk, allowing the user to specify the file's name and location.
Print: Prints a copy of the IRIS window.
Print Setup: Allows the user to define the printer's settings.
Exit: Terminates the program.
Split: Splits a category (prompting the user to choose which one) into two categories. The user has to specify suitable profiles for the two categories.
Merge: Merges two consecutive categories (the user chooses the lower one) into a single one. The user does not need to edit the profiles, since the merged category inherits the lower bound of the lower category and the upper bound of the higher category..
Insert: Adds a new criterion.
Delete: Deletes a criterion (prompting the user to choose which one).
Insert: Adds a new alternative (action).
Delete: Deletes an alternative (action) (prompting the user to choose which one).
Erase Examples: Removes all the assignment examples (the alternatives are not deleted, only the constraints imposed on them).
Insert: Adds a new constraint.
Delete: Deletes a constraint (prompting the user to choose which one). Note that the constraint number "zero" ("norm") cannot be deleted.
Volume Computation: Provides an estimate of the volume of the polytope formed by the combinations of parameter values that respect all the constraints, bounds and assignment examples.
Robust Assignments: Updates the outputs, solving the inference problem and determining the assignment ranges (robustness analysis).
by Input Order: Sorts the alternatives by their input number.
by Variability Order: Sorts the alternatives by decreasing variability order.
This menu is available only when the constraints are inconsistent. It activates the inconsistency analysis form.
Online Manual: Opens this manual. A default browser must be installed.
How to Get Help: Briefly explains how to get help.
About...: Provides information on the IRIS version.
(These menus are accessible either using the right button of the mouse or using a special key (in some keyboards))
Actions page: A menu gives access to the options in the criteria and actions' menus (described just above) and an option for getting specific help.
Fixed Par. page: A menu gives access to the options in the criteria menu (described just above) and an option for getting specific help.
Bounds page: A menu gives access an option for getting specific help.
Constraints page: A menu gives access to the options in the constraints menu (described just above) and an option for getting specific help.
Results and Infer. Prog. pages: A menu gives access an option for getting specific help.
: Opens a
problem, reading the inputs from disk.
: Creates a new
problem, asking for its dimensions.
: Saves the
current inputs on disk.
: Creates a file
containing the results.
: Changes the
characteristics of the editing cells.