Binary Integer Programming Solver Help

**OnlyAntony** · 12-08-2017, 04:19 PM

Hi,

I am working through developing a binary integer programming exersie in excel and using OpenSolver (because there are more than 200 variables) to solve it. My problem is that I have no idea what I am doing, as the solver is not treating the variables as binary. This is what I have developed already
yMi3hIk.png.

The book has provided the algebra for this problem:
172RAup.png

This is the problem for reference:
yZ8zEvj.jpg
Using the decision variables I should be able to draw the paths like this (after adding a load of constraints of course)
zRTqyvC.png

Could someone help me out with implementing the decision variables as I don't think I've done it correct, possibly over complicated it. This first step is preventing me with the rest of the problem.

Thank you all

**Alf** · 12-09-2017, 03:55 AM

As I'm not that familiar with model building in OpenSolver I build my model using the excel solver but run the model using OpenSolver. Have you tried that?

As for why your model is ignoring the binary constraint I can't tell by just looking at images. You better upload a file with your model.

Your problem is certainly solvable as all homework's are, still there is the forum rule specifying that members my help by giving hints on how to solve the homework problem but they should no do the homework.

Alf

**OnlyAntony** · 12-09-2017, 07:17 AM

Hi thanks for getting back,

I should of been more clear, I am using the built-in solver to build the model and using OpenSolver to solve it.
I can understand this rule, I just need a little help with the variables because I can't add the constraints when they are not working. Here is my file: https://www.dropbox.com/s/7ljyk0pkg1...size.xlsx?dl=0

Thanks for your help

**JeteMc** · 12-11-2017, 01:14 PM

Hello OnlyAntony and Welcome to Excel Forum.
I am attaching the file contained in the dropbox link as many contributors will not or can not (due to company firewalls etc.) get files from a link that is offsite.
In the future please attach a sample workbook by clicking on the GO ADVANCED button below the Quick Reply window and then scrolling down to Manage Attachments to open the upload window.
Let us know if you have any questions.