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According to this website, all Macs on OS X 10.5 or greater have a 64 bit operating system and a 64 bit processor, so if your Mac is from 2007 or later then you will probably be fine. If your Mac is from before 2007, you would need an earlier version of Cplex than the one that we require. Instructions to checking check which version of OS X you have are given in the first link.
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IBM ILOG CPLEX Optimization Studio V12.5 for Mac OS 10 Multilingual (CIC4UML)(is this 32 bit or 64 bit? There only seems to be one option...)
Scroll to the bottom and accept the licence agreement, then hit download. A java applet will pop up to manage the download. If you get an error in the applet saying your java is out of date and a second pop up, hit OK until the second pop up goes away then it Run anyway on the applet. Again, if you can't get the applet to work, just select Http Transfer instead of Download Director as the Download Method. The download could take as long as half an hour.
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