Re: question on execution time for qfbsolve

Bill:

Thanks for the comment. I am doing millions of these qfbsolve(), but the 
numbers <= 1e6 in general, so I won't see much speed increase.

At least I can avoid an O^2 execution time bottle neck caused by 2 nest 
loops, in the brute force method I was using in the past.

Randall

On 7/3/25 00:20, Bill Allombert wrote:
> On Wed, Jul 02, 2025 at 08:14:09PM -0700, American Citizen wrote:
>> I ran over the first 100,000 integers
>>
>> ? for(i=1,100000,qfbsolve(Qfb(1,0,1),i,3))
>> cpu time = 3,394 ms, real time = 3,394 ms.
>> ? for(i=1,100000,qfbsolve(Qfb(1,0,1),[i,factor(i)],3))
>> cpu time = 3,348 ms, real time = 3,348 ms.
>>
>> so it is about the same, not much improvement, 46 milliseconds.
> Of course since you are including the time to factor i!
>
> The point is to avoid factoring i again when its factorization is already
> known.
>
> For example:
>
> ? #
> ? forfactored(i=1,1000000,qfbsolve(Qfb(1,0,1),i,3))
>    ***   last result computed in 2,767 ms.
> ? for(i=1,1000000,qfbsolve(Qfb(1,0,1),i,3))
>    ***   last result computed in 2,994 ms.
> ? for(i=1,1000000,qfbsolve(Qfb(1,0,1),[i,factor(i)],3))
>    ***   last result computed in 3,131 ms.
>
> Of course for small numbers, it should not make a lot of difference.
>
> Cheers,
> Bill.
>