LoÃc Grenià on Sun, 14 Oct 2012 23:07:52 +0200

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Re: iterators, sums and products

2012/10/14 Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr>:
> On Thu, Oct 11, 2012 at 10:14:17PM +0200, LoÃc Grenià wrote:
>>     Hi pari developers,
>>     what do you think of the following idea ? Does it look interesting
>>   and feasible ?
>>     We have a forprime iterator. I've always wished I could sum over
>>   primes.
>>     My idea is to introduce a new pari type t_ITERATOR which
>>   could wrap some iterators (forprime, forsubgroup, forell, etc). For each
>>   iterator there would be an initializer. There would also be some
>>   users of those iterators: foriter, sumiter, proditer and (why not)
>>   vectoriter. Usage:
> I miss two things:
> sumprime()
> and a function that return the sum of the element of a vector.

    For the last one, I've the attached patch (vecsum and vecprod).
  For moderately long vectors, sum(i=1,#v,v[i]) is not so bad...


Attachment: vecsum.diff
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