At 06:51 PM 7/9/99 +0100, Brian J. Beesley wrote:
>For reasonably small multi-precision numbers, Head's method is
>actually very good, if you're working on a true RISC processor with
>no integer multiply instruction.
I started using Head's algorithm in 1981 on my Apple II. It was better
than
On 8 Jul 99, at 23:33, Lucas Wiman wrote:
> >That is going to be a *lot* slower than FFT convolution, for numbers the size
> >of the Mersenne numbers we're testing! FFT is O(n*log(n)) where n is the
> >number of limbs in the numbers being multiplied. Head's method is O(n^2),
> >with O being sli
Pierre Abbat writes:
>>> In the book _Primes and Programming_ Head's method of multiplying
>>> two numbers mod n is mentioned. Is this actually more efficient
>>> than simply multiplying the two numbers and taking the modulus?
>>
>> Look at it this way. Head's method is essentially binary long
>>
> Limbs? It is good to know that the world has many different literal meanings
> in many languages for "bits" - variety is good for us all. (The French word
> for "buffer" is also, I seem to remember, rather amusing).
"Limb" is the term used in gmp for a digit in a large base (such as 2147483648)
Hi folks
> > > In the book _Primes and Programming_ Head's method of multiplying
> > > two numbers mod n is mentioned. Is this actually more effiecient
> > > than simply multiplying the two numbers and taking the modulus?
> > Look at it this way. Head's method is essentially binary long
> > mult
At 08:11 PM 7/8/99 -0400, Pierre Abbat wrote:
>That is going to be a *lot* slower than FFT convolution, for numbers the size
>of the Mersenne numbers we're testing!
Head's algorithm is for getting x*y mod n when 0<=x,yM, where M is the largest integer you can store in a format
native to the com
On Thu, 08 Jul 1999, Brian J. Beesley wrote:
> On 8 Jul 99, at 6:19, Lucas Wiman wrote:
>
> > In the book _Primes and Programming_ Head's method of multiplying
> > two numbers mod n is mentioned. Is this actually more effiecient
> > than simply multiplying the two numbers and taking the modulus?
On 8 Jul 99, at 6:19, Lucas Wiman wrote:
> In the book _Primes and Programming_ Head's method of multiplying
> two numbers mod n is mentioned. Is this actually more effiecient
> than simply multiplying the two numbers and taking the modulus?
Look at it this way. Head's method is essentially bin
At 06:19 AM 7/8/99 -0400, you wrote:
>All,
>In the book _Primes and Programming_ Head's method of multiplying
>two numbers mod n is mentioned. Is this actually more effiecient
>than simply multiplying the two numbers and taking the modulus?
>
Yes, because it keeps the numbers smaller. It was ori
At 06:19 AM 7/8/99 -0400, Lucas Wiman wrote:
>In the book _Primes and Programming_ Head's method of multiplying
>two numbers mod n is mentioned. Is this actually more effiecient
>than simply multiplying the two numbers and taking the modulus?
No it is actually much less efficient, but you are mi
All,
In the book _Primes and Programming_ Head's method of multiplying
two numbers mod n is mentioned. Is this actually more effiecient
than simply multiplying the two numbers and taking the modulus?
If so, is it implemented in the various mersenne factoring programs
in use?
Thankyou,
Lucas Wim
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