Em Sex, 2008-11-14 às 05:06 -0800, Harald Schilly escreveu:
> On Nov 14, 9:26 am, Jason Grout <[EMAIL PROTECTED]> wrote:
> > > sage: sum(2^i for i in range(n+1))
>
> > sum(i for i in (1..oo))
>
> They look nice, but i doubt if they could work. e.g. think of more
> than one variable and relationships between them (e.g. for all i,j in
> N where i>j and i mod 7 == 0 and so on) Therefore, I think a new kind
> of object to represent the set over which the sum is made must be
> created. This set could be created by various constructors and returns
> "information" about itself (not a black box).
> A = sumset(vars=[i,j], start=[0,0], constraint={ i>j , mod(i,7)==0},
> intersect=sumset_B, union=sumset_C)
> and then things like: values = A.getGenerator() ; A.isInfinite(i) ->
> true ; j_vals_sumset = A.getSet(i=fixed_value)
No need to complicate with another object.
Something like that would be nicer (if possible):
sum(sum([f(j%7) for j in (0..oo) if j>k]) for k in (0..oo)]))
using j and k, since i is parsed as the complex constant.
Ronan Paixão
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