Maximilian Hasler on Sat, 29 Dec 2012 22:16:47 +0100

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Re: Square of an unsigned integer without products.

It would be nice if you could be a little less cryptic to save time
(needed to understand), to all those which receive this message.

I hope no computer uses
sum(i=1,2  (some other sum independent of i)  )
to compute twice that other sum, by doing all the calculation two
times ; while multiplication by 2 is achieved with nearly zero
computational complexity by binary left shift.

Why do you want to avoid "multiplication", do you think it is more
expensive than a triple nested sum ? This is certainly not the case.
(cf. e.g.

As a side note (since you post this on a PARI list, which is maybe not
really the best place for such a question),
the " my(i,j,k); " statement leads to a useless duplicate of the
summation variables.
(They are automatically declared as local variable by the for(..) statement.)

Best regards,


On Sat, Dec 29, 2012 at 3:05 PM, Remy José Cano Ramírez
<> wrote:
> Greetings,
> About the following:
> ----------------------------------------------------------------------------------------
> /*
>    Please review and comment if at certain low level the computers today
> already
>    make such calculations with the method shown below.
> */
> uisqr(x)={my(i,j,k); x+sum(i=1,2,sum(j=1,(x-1),sum(k=(j+1),x,1)))};
> ----------------------------------------------------------------------------------------
> (Also available at:
> Regards,
> Remy