As Murray points out, there are indeed faster means
of computing Riemann's zeta function.

Carl Siegel found the formula now known as the
Riemann-Siegel formula when working through some
of Riemann's hard to decipher handwritten notes.
That formula is (I believe) the basis of modern
numerical computations of the zeta function.

  http://en.wikipedia.org/wiki/Riemann–Siegel_formula

There's a wonderful book by H.M. Edwards with
(almost) everything you wanted to ask about the
zeta function.

        -Dan

On 9 Mar 2014, at 12:25, Dan Abell wrote:

> so
> 
>    zeta =: [:+/(%@^~>:@i.)
> 
> then
> 
>   2 zeta 2e5
> 1.64493
>   3 zeta 1e5
> 1.20206
> 
> this also works for non-integer arguments:
> 
>   3.5 zeta 1e5
> 1.12673
>   3.5j0.5 zeta 1e5
> 1.11256j_0.053509
> 
> Cheers,
>       -Dan
> 
> On 9 Mar 2014, at 11:54, Aai wrote:
> 
>> in fact something like:
>> 
>>  2 +/@:(%@^~) 1+i.100000
>> 1.64492
>> 
>> -- 
>> Met vriendelijke groet,
>> @@i = Arie Groeneveld
>> 
>> ----------------------------------------------------------------------
>> For information about J forums see http://www.jsoftware.com/forums.htm
> 
> 
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm

--
Dan T. Abell :: dabell at txcorp dot com :: 303.444.2452
Tech-X Corp., 5621 Arapahoe Ave, Ste A, Boulder CO 80303
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