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Re: standard floating point arithmetic in Mathematica?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg132484] Re: standard floating point arithmetic in Mathematica?
  • From: "Nasser M. Abbasi" <nma at 12000.org>
  • Date: Fri, 28 Mar 2014 03:31:10 -0400 (EDT)
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  • Reply-to: nma at 12000.org

On 3/27/2014 4:00 AM, Alan wrote:
> I would like to illustrate some limitations with floating point calculations.
>Can I force Mathematica to do floating point computations
>at a standard float size and the display the full results (as the same size float)?
>
> E.g., if I enter
> 0.1+0.2
> I would like to see
> 0.30000000000000004
>
> Thanks,
> Alan Isaac
>

This particular result already does that. Use InputForm to see it:

0.1 + 0.2
     0.3

InputForm[%]
     0.30000000000000004

But in general, to force all computation in $MachinePrecision, one
way is:

Block[{
   $MinPrecision=$MachinePrecision,$MaxPrecision = $MachinePrecision},

     ... do computation floating point computation here
     .... in $MachinePrecision
]


--Nasser




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