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Forum: And now for something completely different 2022-05-20, 15:34
Replies: 109
Views: 4,881
Posted By R. Gerbicz
Btw what the current code is doing is already an...

Btw what the current code is doing is already an overshoot, though not that much, in nt.c:

int cm_nt_is_prime (mpz_t a)

{
return (mpz_probab_prime_p (a, 0) > 0);
}

Because with that you...
Forum: And now for something completely different 2022-05-19, 00:46
Replies: 109
Views: 4,881
Posted By R. Gerbicz
With a newer gcc-10.3.0 using that it is worked,...

With a newer gcc-10.3.0 using that it is worked, thank you all! Of course quickly proved that 1k, with a 4k:

gerbicz@gerbicz-MS-7972:~/cmexp3/cm-0.4.1dev/src$ mpirun ecpp-mpi -v -g -n...
Forum: And now for something completely different 2022-05-18, 22:38
Replies: 109
Views: 4,881
Posted By R. Gerbicz
I have Ubuntu 18.10. And this one? ...

I have Ubuntu 18.10.

And this one?

root@gerbicz-MS-7972:/home/gerbicz/cmexp3/cm-0.4.1dev/src# mpirun --version
HYDRA build details:
Version: 3.3a2
...
Forum: And now for something completely different 2022-05-18, 20:27
Replies: 109
Views: 4,881
Posted By R. Gerbicz
On my oldish core i7 6700, I can only get this...

On my oldish core i7 6700, I can only get this quickly:

gerbicz@gerbicz-MS-7972:~/cmexp3/cm-0.4.1dev/src$ mpirun -np 4 ecpp-mpi -g -n '10^1000+453' -c -f cert-1000
MPI with 3 workers initialised,...
Forum: And now for something completely different 2022-05-18, 16:27
Replies: 109
Views: 4,881
Posted By R. Gerbicz
It gives: ...

It gives:
root@gerbicz-MS-7972:/home/gerbicz/cmexp3/cm-0.4.1dev# mpirun --bind-to core ecpp-mpi
MPI with 0 workers initialised, of which 0 are local....
Forum: And now for something completely different 2022-05-18, 13:13
Replies: 109
Views: 4,881
Posted By R. Gerbicz
Some progress, but now "MPI with 0 workers...

Some progress, but now
"MPI with 0 workers initialised, of which 0 are local."
which is quite few, but surprisingly all 8 threads are running, but no screen/file output (after 20 minutes killed...
Forum: And now for something completely different 2022-05-17, 21:28
Replies: 109
Views: 4,881
Posted By R. Gerbicz
Used ./configure then make install I have only...

Used ./configure then make install
I have only ecpp in src library, what I can nicely run, using one thread.
Why the ecpp.mpi is not compiled??
Forum: And now for something completely different 2022-05-15, 17:13
Replies: 109
Views: 4,881
Posted By R. Gerbicz
Yeah. One very "trivial" improvement would come...

Yeah. One very "trivial" improvement would come to call a faster prp routine, so not call the gmp's built-in mpz_probab_prime_p function. Maybe use pfgw, or directly using the gw library. Notice that...
Forum: Factoring 2022-04-20, 23:46
Replies: 27
Views: 1,243
Posted By R. Gerbicz
False, another way is to show a 1<d<n divisor,...

False, another way is to show a 1<d<n divisor, say an algebraic divisor, and then (easily) prove that d or n/d is composite, then n is not semiprime. What is also a possible case in this sequence of...
Forum: Puzzles 2022-04-17, 20:33
Replies: 3
Views: 698
Posted By R. Gerbicz
All non-negative integers are reachable! ...

All non-negative integers are reachable!
consider the following 9 ways of reductions, the first number is always the starter, then we show each following numbers in the routine:
8*N+1 -> 24*N+3 ->...
Forum: Dobri 2022-04-11, 15:47
Replies: 16
Views: 1,179
Posted By R. Gerbicz
On quantum computer we already have the...

On quantum computer we already have the polynomial time factorization Shor's algorithm.
I'd say it is quite unlikely that the quad binary approach would be in polynomial time using quantum [because...
Forum: Dobri 2022-04-11, 15:09
Replies: 16
Views: 1,179
Posted By R. Gerbicz
And of course this is not a simplification of the...

And of course this is not a simplification of the problem, because it is a quadratic optimization problem using binary integers.
And I'd prefer this (known) form:

min{0 : x*y=n, x>=2, y>=2, x and...
Forum: Miscellaneous Math 2022-04-10, 22:37
Replies: 14
Views: 972
Posted By R. Gerbicz
Recommending 6 (six) more problems what you could...

Recommending 6 (six) more problems what you could easily attack: https://en.wikipedia.org/wiki/Millennium_Prize_Problems
all of them worth 1 million bucks (USD).
Forum: GMP-ECM 2022-04-01, 16:17
Replies: 24
Views: 1,839
Posted By R. Gerbicz
I've needed also: sudo apt-get install...

I've needed also:

sudo apt-get install libtool
Forum: Lounge 2022-03-15, 18:58
Replies: 169
Views: 32,609
Posted By R. Gerbicz
Recent video about William Shanks, who hold the...

Recent video about William Shanks, who hold the record computation of pi for almost a century: https://www.youtube.com/watch?v=DmfxIhmGPP4
And a follow up video to find the first 100 digits of pi by...
Forum: Puzzles 2022-02-23, 15:17
Replies: 13
Views: 1,292
Posted By R. Gerbicz
Yes, you're right.

Yes, you're right.
Forum: Puzzles 2022-02-22, 16:09
Replies: 13
Views: 1,292
Posted By R. Gerbicz
That is a very nice puzzle, complete solution...

That is a very nice puzzle, complete solution (with little maths):

Work mod 5, since there are 5 different things that Penn and Teller can choose, say they have chosen x on the left and y on the...
Forum: Puzzles 2022-02-21, 12:41
Replies: 14
Views: 1,176
Posted By R. Gerbicz
Hm, it is even faster: static inline bool...

Hm, it is even faster:

static inline bool issquare(uint64_t x)
{
uint64_t sqr = 0.5+sqrt(x);
return sqr * sqr == x;
}

and gives correct answer for the full [0,2^64) range (for the same...
Forum: Puzzles 2022-02-20, 21:13
Replies: 14
Views: 1,176
Posted By R. Gerbicz
It is easier: uint64_t sqr = sqrtl(x); return...

It is easier:
uint64_t sqr = sqrtl(x);
return sqr * sqr == x;

if you call it for 64 bits number, so 0<=x<2^64, then 0<=sqr<2^32, so it couldn't report a nonsquare number as a square, because in...
Forum: Puzzles 2022-02-20, 20:57
Replies: 14
Views: 1,176
Posted By R. Gerbicz
Using one core that is true, and it is almost...

Using one core that is true, and it is almost true for many cores/threads, because we're testing res values in increasing order, just check a%M values.



Good question, but it seems that the...
Forum: Puzzles 2022-02-20, 17:50
Replies: 14
Views: 1,176
Posted By R. Gerbicz
OK, but testing smaller trivial ranges is also...

OK, but testing smaller trivial ranges is also not that bad, because those contain many solutions so it is easier and quicker to find a problem, when observed that the code needs 64|M I've justed...
Forum: Puzzles 2022-02-19, 22:35
Replies: 14
Views: 1,176
Posted By R. Gerbicz
OK, (almost) completely new approach. Using...

OK, (almost) completely new approach.

Using M=100800 with t=8 threads done a=1..8000000, found 126 solutions in 1627 sec.

Roughly seven times faster what could be your code, and 20 or so times...
Forum: Puzzles 2022-02-18, 22:12
Replies: 14
Views: 1,176
Posted By R. Gerbicz
Replace the worker with the following: void...

Replace the worker with the following:

void *worker(void *data)
{
uint64_t a;
uint64_t b;
uint64_t c;

(void)data;
Forum: MattcAnderson 2022-02-15, 22:31
Replies: 15
Views: 415
Posted By R. Gerbicz
For Mathematica: "PrimeQ first tests for...

For Mathematica:
"PrimeQ first tests for divisibility using small primes, then uses the Miller–Rabin strong pseudoprime test base 2 and base 3, and then uses a Lucas test."
ref....
Forum: MattcAnderson 2022-02-15, 17:51
Replies: 15
Views: 415
Posted By R. Gerbicz
On the given link: "It returns false if n is...

On the given link: "It returns false if n is shown to be composite within one strong pseudo-primality test and one Lucas test. It returns true otherwise."

Likely they are doing some trial...
Showing results 1 to 25 of 1000

 
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