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Re: Floating-Point Computing

  • To: mathgroup at smc.vnet.net
  • Subject: [mg93931] Re: Floating-Point Computing
  • From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
  • Date: Fri, 28 Nov 2008 07:12:02 -0500 (EST)
  • Organization: Uni Leipzig
  • References: <ggofnk$rsh$1@smc.vnet.net>
  • Reply-to: kuska at informatik.uni-leipzig.de

Hi,

Sum[Sqrt[n], {n, 1, 1000000000}]

NSum[Sqrt[n], {n, 1, 1000000000}]  ??

Regards
   Jens


Antonio wrote:
> Dear List,
> 
> I came across this Sun article on floating point:
> http://developers.sun.com/solaris/articles/fp_errors.html
> 
> which calculates the following code:
> 
> main()
> {
>  register i;
>  double f=0.0;
>  double sqrt();
> 
>  for(i=0;i<=1000000000;i++)
>  {
>     f+=sqrt( (double) i);
>  }
>  printf("Finished %20.14f\n",f);
> }
> 
> whose correct answer using Euler-Maclaurin formula is:
> f=21081851083600.37596259382529338
> 
> Tried to implement in mathematica, just for fun, so that later I could
> play with precision, but the kernel has no more memory and shuts down.
> 
> N[Total[Sqrt[Range[1000000000]]]]
> 
> Any ideas?
> 
> ANtonio
> 
> 
> 


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