Types of restrictions
A restriction is a goal or requirement that two individuals either be assigned to the same roster or not be assigned to the same roster. To force several individuals all to be assigned to distinct rosters (so that each roster contains at most one of the individuals), you need to insert one restriction for each pair of individuals. To force several individuals all to be assigned to the same roster, you can again enter one restriction for each pair, but it may be sufficient to enter just enough restrictions that everyone is connected to everyone else through a chain of restrictions. For instance, suppose that Moe, Larry, Curly and Shemp should all be on the same roster. It might be enough to enter three restrictions (Moe and Larry together, Larry and Curly together, Curly and Shemp together). This is particularly true when the restrictions are mandatory, rather than just goals. On the other hand, if you experience problems finding solutions that keep them together, adding additional restrictions (Moe and Curly together, Larry and Shemp together, etc.) may help push Parity Builder in the right direction.
One other thing to note is how Parity Builder interprets restrictions when it is not mandatory that all individuals be assigned to a roster. If Dan and John are restricted to being together, Parity Builder considers that restriction satisfied if neither of them is assigned to a roster, but not satisfied if Dan is assigned and John is unassigned. On the other hand, if they are restricted to being kept apart, Parity Builder considers the restriction satisfied if neither is assigned and also if Dan is assigned and John is unassigned.
Adding restrictions in the tutorial
Click on the Restrictions tab, which initially is empty. Angelina and Antoinette are twins, and, twins being twins, have to do everything together, so it is essential they be on the same team. Click the Restrictions menu, then Add restriction. Select Angelina in the first drop-down list and Antoinette in the second. (The order you pick them does not matter.) Leave the restriction type TOGETHER and select the Mandatory? check box. Notice that this disables the priority input slider. Click Accept/Continue. The dialog will not change, but the restriction has indeed been added. You will see it appear in the Restrictions tab.
Cameron and Gideon are siblings, and their parents would like them assigned together (to simply transportation arrangements). Keeping them together is important but not critical. Select them in the two drop-down lists, keep the type TOGETHER, but remove the check in the Mandatory? box. Instead, use the priority slider to give this restriction a high priority (90 or better). Again, click Accept/Continue.
Emanuel and Kenton perpetually get into mischief when they are together. For the sanity of the adults concerned, it would be best if they were assigned to different teams. Pick them, change the restriction type to APART, make the restriction optional with a high priority (85 or so), and click Accept/Continue.
Finally, Joseph and Patrick absolutely must be kept apart. Enter a mandatory restriction of type APART for them. Since this is the last restriction, click Accept/Done. Confirm on the Restrictions tab that the four restrictions were properly entered and then save the file.
At any time when working on a project, you can edit restrictions by clicking in any cell of the table. With the restrictions entered for this project, we are ready to build the model.
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