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Re: precisions

  • To: mathgroup at
  • Subject: [mg56003] Re: precisions
  • From: Peter Pein <petsie at>
  • Date: Wed, 13 Apr 2005 01:10:40 -0400 (EDT)
  • References: <d3g92l$t1u$>
  • Sender: owner-wri-mathgroup at

Tun Myint Aung wrote:
> Hi All,
>     I am doing a calculation involving eigenvalues and eigenvectors for
> structural mechanics. I encountered with difficulties in numerical
> calculation which is very sensitive to precisions of numerical numbers.
> I used "SetPrecision[inputdata,100] for my input data. But after I got
> eigenvalues and eigenvectors, these numbers are "MachinePrecision". I
> tried to change the precision in "Eigenvalues", but there are no options
> for that. How can I set the precision for the whole notebook?
> With Regards,
> Tun Myint Aung (Graduate Student)
> Civil Engineering Department
> National University of Singapore
> E1A 02-18
> E-mail: g0202015 at (or) tma at
Maybe you misunderstood the functionality of SetPrecision. This function
_returns_ the input set to the desired precision (as the help tells us:
 "SetPrecision[expr, p] does not modify expr itself."):

511131541150948460400505...Rest of output left out}

Peter Pein

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