Before you can try out the examples below, you must install xyzOPT on your computer: You need a computer with Windows 11. Download the xyzOPT installation file from the download area of this website and run this file for installation.

Example 1: a machine scheduling problem

Problem description
Let's take a company that manufactures toilet paper. The company has a number of machines to produce the paper. Each machine can operate in one or more of the following modes: two-ply paper, three-ply paper, four-ply paper. If the mode of a machine is changed, a pause of one time step must be scheduled. The company now receives a certain demand for the different types of paper. The aim of the optimization is to produce the necessary quantity of paper as quickly as possible to meet the demand.

Download the example
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Download the folder, copy to desktop and unzip

The downloaded folder contains two files: machineschedulingproblem.xls and machineschedulingproblem.xml

Have a look at machineschedulingproblem.xls
The file machineschedulingproblem.xls can be opened in a table calculation program of your choice. The sheet schedules contains two tables (problem1 and problem2), in which the results of the calculations of xyzOPT shall be inserted later on. 



Problem1 is an instance of the machine scheduling problem, in which the company has three machines: machine1 can work in the modes two-ply or three-ply, machine2 can work in the modes three-ply or four-ply and machine3 can work in the mode three-ply.

Problem2 is another instance of the machine scheduling problem, in which the company has two machines: machine1 can work in the modes two-ply or four-ply, machine2 can work in the modes two-ply or three-ply or four-ply.

Now we want to use xyzOPT to calculate an optimal schedule for each of the two problems, that means to calculate a schedule which minimizes the timesteps needed to produce a given demand (which will be entered in xyzOPT) and fullfill the side conditions, that a machine can only work in one mode at a time and needs to pause for one timestep, in case the machine is switching to a new mode. For this purpos, first of all, please close the file machineschedulingproblem.xls. 

Calculate the two optimal schedules with xyzOPT
For this purpos please start xyzOPT and open the model machineschedulingproblem.xml.



The sheet with the name schedule links input data and results of the two problems between the .xls-spreadsheet and xyzOPT. This link needs to be adjusted: double-click on schedule; a dialog opens; select folder and choose the path to the machineschedlungproblem.xls-file on your system and confirm.

Calculate an optimal schedule for problem1
For the given exmaple the problem structure as well as the input data is already configured for problem1: Within the model tree on the left hand side you can see the structure of the problem and by clicking the items in the grid, the data of the chosen item is displayed in the data box on the right hand side. For problem1, especially the demands for the different type of papers and for each mode, the amount of paper which is produced by the machine per timestep, in case the machine is working in this mode in the timestep, are given.

Now please select problem1 within the choicebox in the top of the application and press the run button next to the choicebox: the optimization of problem1 is carried out by xyzOPT; the run-dialog opens and informs on the progress of the optimization. In case everything worked out fine, you should end up with the following result:


If you open the file machineschedulingprobelm.xls again, you should see the following result:


Calculate an optimal schedule for problem2
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