Drexel dragonThe Math ForumDonate to the Math Forum



Search All of the Math Forum:

Views expressed in these public forums are not endorsed by Drexel University or The Math Forum.


Math Forum » Discussions » Software » comp.soft-sys.math.mathematica

Topic: Low precision exponentiation
Replies: 5   Last Post: Feb 19, 2013 6:51 PM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
Bob Hanlon

Posts: 906
Registered: 10/29/11
Re: Low precision exponentiation
Posted: Feb 18, 2013 6:00 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

To avoid using machine precision enter exact numbers (Rationalize).
Exact result:

Rationalize[2.5]^125

2350988701644575015937473074444491355637331113544175043017503412556834518909454345703125/42535295865117307932921825928971026432

To a specified precision

N[%, 25]

5.527147875260444560247265192192255725514240233239`25.*^49


Bob Hanlon


On Sun, Feb 17, 2013 at 4:08 AM, Blaise F Egan <blaise@blaisefegan.me.uk> wrote:
> I am trying to evaluate 2.5^125 to high precision.
>
> R gives 5.527147875260445183346e+49 as the answer but Mathematica with N[2.5^125,30] gives 5.52715*10^49 and says that is to machine precision.
>
> I am inexperienced at Mathematica. Am I doing something silly?
>
> Blaise
>





Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© Drexel University 1994-2014. All Rights Reserved.
The Math Forum is a research and educational enterprise of the Drexel University School of Education.