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Re: Not sure this limit is right...

  • To: mathgroup at smc.vnet.net
  • Subject: [mg131113] Re: Not sure this limit is right...
  • From: Bill Rowe <readnews at sbcglobal.net>
  • Date: Wed, 12 Jun 2013 05:38:32 -0400 (EDT)
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On 6/11/13 at 2:32 AM, bernardsarman at gmail.com (Bernard Sarman)
wrote:

>Yes, that's what I meant.
>
>I have another, related question: 9^-9^9 seems to explode on my
>machine. The memory jumps to over 1 GB, and I have to abort the
>evaluation. I have no idea why Mathematica would require so much
>memory to evaluate this expression.

9^9 evaluates to 387420489. That is you are computing an *exact*
value with a bit less than 400 million digits. You should expect
each digit to take require at least 4 bytes (assumes 32 bit
integers). So the number you are computing requires around 1 GB
to store.

Perhaps you want to compute

9^-9^9.

Notice the decimal point with tells Mathematica to use a machine
precision value. That expression will evaluate quickly and not
require much storage at all.




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