This is LinPro for Macintosh, a linear programming optimizer operating on a Macintosh computer and using the simplex method. The purpose of this application is to provide a linear programming optimizer for students, particularly for those in Operations Research courses. This software is really easy to use because all you have to do is to enter the linear programming model in a text window then optimize it. The solution appears in a new window that can be saved, printed, or copied entirely to the clipboard and used in another program (like a spreadsheet). You do not have to learn lot of commands, only a few keywords.
Limitations
First of all, this version only works on a PowerPC Macintosh. This version currently supports models as large as 100 variables and 100 constraints. The objective function and all constraints must be in linear forms. Actually, LinPro for Macintosh does not support the explicit use of binary and integer variables, but if funding is sufficient (that means if people pay their shareware fees) I will develop a new version supporting binary and integer programming.
How to use LinPro for Macintosh
When you start the application, a new empty window will appear. You can start to enter your model in that window. To enter a model, just write the model in the model window as it appears in your book: write the keyword "min" or "max" (or "minimize" or "maximize", capital letters are not significant so it is okay to write "Min" or "MIN"), a space then the objective function. When the objective function is complete, make a return with the return key, type the keyword "subject to", then type each of your constraints. Do not write the non-negative constraints because they are implicit in the application. Here is an example of a linear programming model:
Max 66X1+84X2
subject to
3X1+4X2<=4200
X1+3X2<=2250
2X1+2X2<=2600
X1<=1100
That's it! You are ready to optimize your linear programming model! Just go to the "Model" menu and choose "Optimize" or type Command-G.
When you write a less-than-or-equal constraint, you can use "<=", "<", or "≤".
When you write a more-than-or-equal constraint, you can use ">=", ">", or "≥".
Some options
You can go to the "Model" menu and check some options before optimizing the model. Options you can choose are: displaying the sensitivity analysis results for the objective coefficients, displaying the sensitivity analysis results for the constraints, displaying the final simplex tableau. Just check the box of your choice.
You can insert comments in your model by using the letter "!". When the application meets the letter "!", it simply ignores all the following characters until the end of line. So feel free to comment your model. Here is an example:
Max 66X1+84X2
subject to
3X1+4X2<=4200 ! number of available hours at work center 1
X1+3X2<=2250 ! number of available hours at work center 2
2X1+2X2<=2600 ! number of available hours at work center 3
X1<=1100 ! maximum quantity of product 1 to produce
Variable names
When you write a linear programming model in the model window, you can use whatever name for each of the variables in the model. You can name a variable "x1", or "X1", or "ProductA", or "PRODA". Use a name that is meaningful but not too long.
Open and Save
LinPro for Macintosh can open text files and its own files. When you write a model in LinPro for Macintosh and save it, it will be a LinPro for Macintosh file. A solution window is always a LinPro for Macintosh file. But you can write a model with another application, save it as a text file, then open it with LinPro for Macintosh.
Bug report
Report bugs you encountered to: plyonnais@videotron.ca
