Forum: Factoring
2022-06-12, 22:58
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Replies: 21
Views: 1,054
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Forum: And now for something completely different
2022-06-01, 20:48
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Replies: 184
Views: 11,547
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Forum: And now for something completely different
2022-05-31, 13:51
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Replies: 184
Views: 11,547
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Forum: And now for something completely different
2022-05-29, 12:01
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Replies: 184
Views: 11,547
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Forum: And now for something completely different
2022-05-28, 21:24
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Replies: 184
Views: 11,547
For those who has big guns.
I believe this...
For those who has big guns.
I believe this could be faster, for that runs where the current code spends a lot of time on trial division comparing to the the total running time [big N value with a...
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Forum: And now for something completely different
2022-05-20, 15:34
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Replies: 184
Views: 11,547
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Forum: And now for something completely different
2022-05-19, 00:46
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Replies: 184
Views: 11,547
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Forum: And now for something completely different
2022-05-18, 22:38
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Replies: 184
Views: 11,547
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Forum: And now for something completely different
2022-05-18, 20:27
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Replies: 184
Views: 11,547
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,...
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Forum: And now for something completely different
2022-05-18, 16:27
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Replies: 184
Views: 11,547
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....
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Forum: And now for something completely different
2022-05-18, 13:13
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Replies: 184
Views: 11,547
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...
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Forum: And now for something completely different
2022-05-17, 21:28
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Replies: 184
Views: 11,547
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Forum: And now for something completely different
2022-05-15, 17:13
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Replies: 184
Views: 11,547
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...
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Forum: Factoring
2022-04-20, 23:46
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Replies: 30
Views: 1,865
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...
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Forum: Puzzles
2022-04-17, 20:33
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Replies: 3
Views: 940
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 ->...
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Forum: Dobri
2022-04-11, 15:47
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Replies: 16
Views: 1,511
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...
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Forum: Dobri
2022-04-11, 15:09
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Replies: 16
Views: 1,511
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Forum: Miscellaneous Math
2022-04-10, 22:37
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Replies: 14
Views: 1,325
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Forum: GMP-ECM
2022-04-01, 16:17
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Replies: 24
Views: 2,217
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Forum: Lounge
2022-03-15, 18:58
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Replies: 169
Views: 33,232
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...
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Forum: Puzzles
2022-02-23, 15:17
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Replies: 13
Views: 1,880
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Forum: Puzzles
2022-02-22, 16:09
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Replies: 13
Views: 1,880
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...
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Forum: Puzzles
2022-02-21, 12:41
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Replies: 14
Views: 1,318
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...
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Forum: Puzzles
2022-02-20, 21:13
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Replies: 14
Views: 1,318
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...
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Forum: Puzzles
2022-02-20, 20:57
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Replies: 14
Views: 1,318
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...
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