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Search: Posts Made By: paulunderwood
Forum: Homework Help 2021-12-08, 11:26
Replies: 14
Views: 367
Posted By paulunderwood
The pipsqueak can more than double the speed of...

The pipsqueak can more than double the speed of my code by making a couple of changes. I am not going to say how.

With a little more re-factoring of the code a 3 times speed up can be had. Still...
Forum: Software 2021-12-07, 21:24
Replies: 161
Sticky: Prime95 30.7
Views: 14,137
Posted By paulunderwood
My Xeon Phi barfs at P-1. I am running 32 workers...

My Xeon Phi barfs at P-1. I am running 32 workers with 16GB RAM. It would be nice to have the option to grab P-1-less tasks, assuming there is a great effort to do tons of P-1 by others at the...
Forum: Miscellaneous Math 2021-12-07, 20:37
Replies: 52
Views: 2,617
Posted By paulunderwood
After making a fool of myself on the pari-users...

After making a fool of myself on the pari-users list server, I was told, and with further experimentation, that something like

a || b && c || d

should be interpreted as

((a || b) && c) || d.
Forum: Miscellaneous Math 2021-12-07, 16:15
Replies: 52
Views: 2,617
Posted By paulunderwood
So logical operators are right associative now. I...

So logical operators are right associative now. I have posted on pari-users the discrepancy with the documentation. :smile:

Edit that might be left associativity. :redface: What Dr S wrote and...
Forum: Miscellaneous Math 2021-12-07, 07:35
Replies: 52
Views: 2,617
Posted By paulunderwood
Retro-fitting my compilers etc. to deal with old...

Retro-fitting my compilers etc. to deal with old gp's is not worth the salt :grin: I'll just take your word for the parse change.
Forum: Miscellaneous Math 2021-12-07, 06:38
Replies: 52
Views: 2,617
Posted By paulunderwood
Similarly with your example you get 1 3 5 7 9. ...

Similarly with your example you get 1 3 5 7 9.

You have to wait for the web content payload transfer from headquarters and then everything is okay.


? version
%1 = [2, 13, 3, 26039,...
Forum: Miscellaneous Math 2021-12-07, 02:09
Replies: 52
Views: 2,617
Posted By paulunderwood
n=2^44497-1;if(1==0&&Mod(3,n)^n==3) is...

n=2^44497-1;if(1==0&&Mod(3,n)^n==3)

is instant.
Forum: Miscellaneous Math 2021-12-06, 19:41
Replies: 52
Views: 2,617
Posted By paulunderwood
Apart from parenthesis and operator precedence,...

Apart from parenthesis and operator precedence, things are parsed left to right, except for a few like "=" and "^" in Pari/GP (https://pari.math.u-bordeaux.fr/dochtml/html-stable/operators.html)...
Forum: Homework Help 2021-12-06, 18:31
Replies: 14
Views: 367
Posted By paulunderwood
Thumbs down :redface:

:redface:
Forum: Homework Help 2021-12-06, 11:21
Replies: 14
Views: 367
Posted By paulunderwood
c=0;forprime(p=3,10^8,V=digits(p,3);W=[0,0,0];for(...

c=0;forprime(p=3,10^8,V=digits(p,3);W=[0,0,0];for(v=1,#V,W[V[v]+1]++);if(W[3]==W[2]+W[1],c++));c
187914
Forum: Miscellaneous Math 2021-12-06, 01:14
Replies: 10
Views: 196
Posted By paulunderwood
To fool these "semi Euler" PRP tests, find a...

To fool these "semi Euler" PRP tests, find a prime number with kronecker(2,n)==-1 and kronecker(-1,n)==-1 respectively....

The first:
T(q)={Wq=3*2^2-1;S0=2^3;S=S0;print("q=...
Forum: Miscellaneous Math 2021-12-05, 22:42
Replies: 10
Views: 196
Posted By paulunderwood
Nor Riesel ...

Nor Riesel

q=4;Wq=557*2^q-1;S0=2^557;print(q," ",Wq);print(Mod(S0,Wq));S=S0;for(i=1,q,S=Mod(S^2,Wq);print(S))
4 8911 ...
Forum: Miscellaneous Math 2021-12-05, 22:19
Replies: 10
Views: 196
Posted By paulunderwood
q=4;Wq=35*2^q+1;S0=2^35;print(q,"...

q=4;Wq=35*2^q+1;S0=2^35;print(q," ",Wq);print(Mod(S0,Wq));S=S0;for(i=1,q,S=Mod(S^2,Wq);print(S));print(S==S0)
4 561 ...
Forum: Miscellaneous Math 2021-12-05, 21:52
Replies: 10
Views: 196
Posted By paulunderwood
q=1;Wq=80*7^1+1;S0=7^80;print(q,"...

q=1;Wq=80*7^1+1;S0=7^80;print(q," ",Wq);print(Mod(S0,Wq));S=S0;for(i=1,q,S=Mod(S^7,Wq);print(S));print(S==S0)
1 561 ...
Forum: Riesel Prime Search 2021-12-03, 22:50
Replies: 74
Views: 28,176
Posted By paulunderwood
A slightly smaller one: 69* 2^14977631 - 1...

A slightly smaller one: 69* 2^14977631 - 1 (https://primes.utm.edu/primes/page.php?id=133013) :banana:
Forum: And now for something completely different 2021-11-28, 22:16
Replies: 17
Views: 7,804
Posted By paulunderwood
Another way to do it with Pari-GP is...

Another way to do it with Pari-GP is 2^89\10^2%10^21 where the infix operator \ gives the quotient.
Forum: Miscellaneous Math 2021-11-28, 14:42
Replies: 435
Views: 41,880
Posted By paulunderwood
Sorry for the confusion. I was just referring to...

Sorry for the confusion. I was just referring to Tucker's blunder in general.
Forum: Miscellaneous Math 2021-11-28, 08:07
Replies: 435
Views: 41,880
Posted By paulunderwood
Gender populations are not 50::50. Most forumites...

Gender populations are not 50::50. Most forumites here happen to be male. Some people like to identify as non-binary gender. "Dobri" is mainly a man's name. Like your guess at 168Mb for the next...
Forum: And now for something completely different 2021-11-28, 07:50
Replies: 82
Views: 26,628
Posted By paulunderwood
Welcome back to the fold. I should be...

Welcome back to the fold.



I should be continuing these shortly into the new year :devil:

I can do the Mersenne cofactor Ryan reserved about a year ago too. Ryan?
Forum: And now for something completely different 2021-11-28, 07:42
Replies: 17
Views: 7,804
Posted By paulunderwood
Playing the sleuth, I think I can answer this....

Playing the sleuth, I think I can answer this. Putting "Gleit kommarechnerheizgerät" in to google translate gives "Sliding comma computer heater". The German people often concatenate their written...
Forum: Hardware 2021-11-27, 21:34
Replies: 224
Views: 38,208
Posted By paulunderwood
Thumbs up Formidable power. I had toyed with getting such a...

Formidable power. I had toyed with getting such a system. The potential noise put me off. It would draw about 1400w running flat out. One would need a garage or basement to house it. I think it is...
Forum: Math 2021-11-27, 09:22
Replies: 13
Views: 622
Posted By paulunderwood
It is not so great since (3/2)^2-2 = 1/4 which is...

It is not so great since (3/2)^2-2 = 1/4 which is already known.

Just as (3)^((Mp - 1)/2) == -1 mod Mp for Mersenne primes, we have (-7)^((Wq - 1)/2) == 1 mod Wq for Wagstaff PRPs. The latter can...
Forum: Math 2021-11-26, 23:49
Replies: 13
Views: 622
Posted By paulunderwood
More on the seed 3/2 for Wagstaff numbers. ...

More on the seed 3/2 for Wagstaff numbers.

Mod(Mod(x,W),x^2-3/2*x+1) is at the heart because S = S0 = 3/2 = x+1/x which leads to the recurrence S=S^2-2 mod W

The solution for x is ( 3/2 +-...
Forum: Math 2021-11-26, 22:38
Replies: 13
Views: 622
Posted By paulunderwood
I just found this works for (2/3)^-1 ...

I just found this works for (2/3)^-1

wag(q)=W=(2^q+1)/3;S0=S=Mod(3/2,W);for(i=2,q,S=S^2-2);S==S0;

So maybe there is some relationship between inverse seeds for Mersenne and Wagstaff. I.e if S0...
Forum: Miscellaneous Math 2021-11-26, 21:22
Replies: 64
Views: 20,697
Posted By paulunderwood
I don't know about what you are driving at, but...

I don't know about what you are driving at, but isn't a bit like "Goldbach" -- strong numerical evidence but no proof?

Anyway here is an interesting youtube video on prime gaps which sounds...
Showing results 1 to 25 of 1000

 
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