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Forum: Chess 2021-01-17, 12:50
Replies: 2
Views: 140
Posted By R. Gerbicz
See:...

See: https://chess.stackexchange.com/questions/4490/maximum-possible-movement-in-a-turn
Forum: Puzzles 2021-01-04, 20:50
Replies: 13
Views: 544
Posted By R. Gerbicz
We need for a given x>0 that...

We need for a given x>0 that x=a+..+(a+b)=(2*a+b)*(b+1)/2 with a,b>0

So: 2*x=(2*a+b)*(b+1)
Notice that 2*a+b and b+1 has different parity, hence if x is a power of two
then this equation has no...
Forum: Forum Feedback 2020-12-26, 16:25
Replies: 4
Views: 383
Posted By R. Gerbicz
Also this thread??

Also this thread??
Forum: Programming 2020-12-25, 18:54
Replies: 37
Views: 8,868
Posted By R. Gerbicz
That is way slower than my brain, it is...

That is way slower than my brain, it is irreducible with Eisenstein's criterion using p=2, ref:
https://en.wikipedia.org/wiki/Eisenstein%27s_criterion
Forum: Math 2020-12-15, 00:53
Replies: 16
Views: 635
Posted By R. Gerbicz
The reason: 2^(E*2*p)==1 mod 2^p-1.

The reason: 2^(E*2*p)==1 mod 2^p-1.
Forum: Tales From the Crypt(o) 2020-12-13, 19:55
Replies: 7
Views: 570
Posted By R. Gerbicz
Probably not found, all of them looks like...

Probably not found, all of them looks like gibberish, but here it is:
using a wordlist of size=9027 [basically a 10k list, but deleted all words with length<4 that was not in a 4k list]. All...
Forum: y-cruncher 2020-12-08, 12:25
Replies: 49
Views: 25,504
Posted By R. Gerbicz
False, I've written this: "if you're claiming a...

False, I've written this:
"if you're claiming a world record then I would choose 1 million random positions and you should give the bits for each of these positions. The check: select say 20-25...
Forum: y-cruncher 2020-12-08, 10:59
Replies: 49
Views: 25,504
Posted By R. Gerbicz
That's why your suggested methods is just not...

That's why your suggested methods is just not working (needs to repeat the whole computation), but my proposed way is using much less time.
For comparison in this record size the BBP takes less than...
Forum: y-cruncher 2020-12-07, 14:05
Replies: 49
Views: 25,504
Posted By R. Gerbicz
So you would accept any(?) hash value as a proof,...

So you would accept any(?) hash value as a proof, say claiming 256T digits of Pi, and giving only sha256 as:

a19a6c3a75783b6b5deee64777873ae207764837e769eedbe9b4c485d94b2986
Forum: y-cruncher 2020-12-05, 18:08
Replies: 49
Views: 25,504
Posted By R. Gerbicz
There is no BBP type formula for Pi in base ten...

There is no BBP type formula for Pi in base ten [though there could be], https://en.wikipedia.org/wiki/Bailey%E2%80%93Borwein%E2%80%93Plouffe_formula .
But even giving only the last few bits would...
Forum: Programming 2020-11-29, 00:33
Replies: 37
Views: 8,868
Posted By R. Gerbicz
Try x^720-1. On an older Chrome it is just...

Try x^720-1. On an older Chrome it is just crashing, on Firefox after some computation it has given: "index out of bounds", the 2nd run is still computing and it is in the: "Computing LLL in matrix...
Forum: Puzzles 2020-11-26, 20:58
Replies: 34
Views: 1,529
Posted By R. Gerbicz
For Q2 the optimal is 9 terms (using 4 pieces of...

For Q2 the optimal is 9 terms (using 4 pieces of 13 and 5 pieces 666):

13-(666-(666+666)*(666+13*(13+13)))/666

and for Q1 the optimal is the above 8 terms.
Assuming that we would use "only"...
Forum: GpuOwl 2020-11-22, 16:04
Replies: 195
Views: 12,485
Posted By R. Gerbicz
In that P1(5.5M) the 5.5M is the first stage...

In that P1(5.5M) the 5.5M is the first stage limit in the P-1 method.
The product of prime powers up to that limit has roughly 5.5*10^6/ln(2)=7934822 bits.
And there was no P-1 method inside the...
Forum: And now for something completely different 2020-11-13, 18:44
Replies: 9
Views: 682
Posted By R. Gerbicz
Exactly. There is a not hard pattern for these...

Exactly. There is a not hard pattern for these factors: if additionally you remove all lower exponents factors then for the remaining p prime factors what divides polcyclo(n,x) we have p%n=1. You...
Forum: FermatSearch 2020-11-07, 19:53
Replies: 32
Views: 1,734
Posted By R. Gerbicz
Actually for large n it is better to do a Proth...

Actually for large n it is better to do a Proth test, which takes the same amount of time, but you could discover million+ digit prime (that is not divide any Fermat number).
And if it is prime then...
Forum: Software 2020-11-02, 21:32
Replies: 46
Views: 8,878
Posted By R. Gerbicz
You shouldn't see such slowdown due to the...

You shouldn't see such slowdown due to the checking. See what gpuowl is using L=400 or L=1000 with that the slowdown is "only" 2/L part of the total running time. p95 is using a not fixed L, changing...
Forum: GPU Computing 2020-11-01, 19:33
Replies: 0
Views: 1,041
Posted By R. Gerbicz
Better error correction

With a probably restarted computation the task is to compute base^(2^n) mod N, so here we can have that base is "big". As usual the standard setup, let:

x[t]=base^(2^(t*L)) mod N...
Forum: Information & Answers 2020-10-26, 00:11
Replies: 12
Views: 1,313
Posted By R. Gerbicz
Not checked, but do you reward also the p-1 work...

Not checked, but do you reward also the p-1 work when it is hidden in the prp test during the (new) gpuowl 7 run?
Forum: Miscellaneous Math 2020-10-22, 11:58
Replies: 6
Views: 790
Posted By R. Gerbicz
Combined Theorem 1 is enough from...

Combined Theorem 1 is enough from https://primes.utm.edu/prove/prove3_3.html
with F1=1, F2=10^8668.
Forum: Software 2020-10-18, 22:55
Replies: 46
Views: 8,878
Posted By R. Gerbicz
Basically in the algorithm there is "almost" only...

Basically in the algorithm there is "almost" only squarings and very few multplications (at the stuff for error computation).

For N=(k*b^n+c)/d using a^d as "base" with Fermat's little theorem if...
Forum: GpuOwl 2020-10-11, 15:16
Replies: 20
Views: 2,978
Posted By R. Gerbicz
What processor bug you would detect with my error...

What processor bug you would detect with my error check, actually it would not give any "correct or incorrect" answer because in a non-random FFT implementation it would not pass the error check with...
Forum: Miscellaneous Math 2020-10-10, 15:59
Replies: 18
Views: 1,762
Posted By R. Gerbicz
On page 39: "The Euler Phi Function is useful...

On page 39:
"The Euler Phi Function is useful since for all a
a^(1+φ(n)) ≡ a (mod n)."

This is very false, a small counter-example is a=2, n=4.
Forum: Math 2020-10-09, 20:12
Replies: 8
Views: 840
Posted By R. Gerbicz
Really not read, in general I know the shortest...

Really not read, in general I know the shortest proofs. Another way:
If 2^(2^m)==-1 mod d then for n>m taking this to the 2^(n-m)-th power:
2^(2^n)==1 mod d from this F(n)==2 mod d and the rest is...
Forum: Math 2020-10-09, 08:52
Replies: 8
Views: 840
Posted By R. Gerbicz
I've learnt in this nice way:...

I've learnt in this nice way: F(n)=2+F(0)*F(1)*F(2)*...*F(n-1), so if we have a common divisor d of F(n) and F(m), where m<n then d|2, hence d=1 because all F(k) is odd.
Forum: FermatSearch 2020-10-06, 22:39
Replies: 324
Views: 49,908
Posted By R. Gerbicz
As I can remember pfgw is doing this (or...

As I can remember pfgw is doing this (or something like that, the constant=50 is not that interesting,
we'd catch all known factors if n is not small: n>50): let N=k*2^n+1 and
r(u)=u^(2^(n-50)) mod...
Showing results 1 to 25 of 1000

 
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