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Student Support Forum: 'How is $MaxMachineInteger determined?' topicStudent Support Forum > General > "How is $MaxMachineInteger determined?"

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David Nicholus
07/16/12 5:35pm

After loading the developer package, $MaxMachineInteger gives 2147483647 = 2^31-1 for my computer system. My research involves dealing with integers >2^31-1. Thus, I notice a large drop in the speed of my algorithms when I use integers >2^31-1. This doesn't surprise me, as $MaxMachineInteger tells me integers >2^31-1 are not machine.

However, I am working on a Mac Pro, which has a 64-bit processor and 64-bit path and registry. Furthermore, $SystemWordLength gives 64. Thus, I have 2 questions.

1) Why is $MaxMachineInteger returning 2^31-1?

2) What specifically determines the magnitude of what Mathematica considers a machine integer? The documentation tells me that my machine determines it, but with a 64-bit processor, 64-bit path and registry, and 64-bit system word length, why would $MaxMachineInteger give only 2^31-1?

Basically, I want to raise the maximum integer that Mathematica considers "machine" on my computer so that my algorithms do not decrease so drastically in speed when I go over this maximum.

Thank you very much for your attention!

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Subject (listing for 'How is $MaxMachineInteger determined?')
Author Date Posted
How is $MaxMachineInteger determined? David Nicholus 07/16/12 5:35pm
Re: How is $MaxMachineInteger determined? Forum Modera... 07/16/12 7:37pm
Re: Re: How is $MaxMachineInteger determined? David 07/16/12 7:49pm
Re: Re: Re: How is $MaxMachineInteger determined? Forum Modera... 07/18/12 2:06pm
Re: Re: How is $MaxMachineInteger determined? David nicholus 07/17/12 2:35pm
Re: Re: Re: How is $MaxMachineInteger determined? Forum Modera... 07/18/12 2:26pm
Re: Re: Re: Re: How is $MaxMachineInteger deter... David Nicholus 07/18/12 11:20pm
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