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 Showing results 1 to 25 of 1000 Search took 0.42 seconds. Search: Posts Made By: paulunderwood
 Forum: Homework Help 2020-08-13, 06:50 Replies: 55 Views: 9,837 Posted By paulunderwood Arbitrary precision arithmetic... Arbitrary precision arithmetic (https://en.wikipedia.org/wiki/Arbitrary-precision_arithmetic) is a solved problem.
 Forum: Information & Answers 2020-08-13, 06:47 Replies: 3 Views: 121 Posted By paulunderwood https://en.wikipedia.org/wiki/Decompiler https://en.wikipedia.org/wiki/Decompiler
 Forum: Math 2020-08-12, 18:58 Replies: 2 Views: 67 Posted By paulunderwood If N is the number to be proved then you need to... If N is the number to be proved then you need to factor N-1 or N+1 or a combination of N-1 and N+1 to 33.33%. This is dead easy for numbers of the form k*b^n+-1, much harder if not infeasible for...
 Forum: Miscellaneous Math 2020-08-11, 20:05 Replies: 27 Views: 806 Posted By paulunderwood Spot the difference Spot the difference
 Forum: Hardware 2020-08-08, 23:07 Replies: 1 Sticky: Official "Swap Meet" thread Views: 112 Posted By paulunderwood not free but dead cheap AMD 1090T w/ Original heatsink on ASUS board with 4GB RAM. Have two. £15 each. Pickup only from Gloucestershire, England. Job lot of:- 4x G34 6174 12 core (untested) 4x G34 6176 12 core...
 Forum: Software 2020-08-08, 15:36 Replies: 581 Views: 74,389 Posted By paulunderwood see:... see: https://mersenneforum.org/showpost.php?p=552855&postcount=177 Does it interest you?
 2020-08-08, 00:06 Replies: 13 Views: 2,830 Posted By paulunderwood Go to https://primes.utm.edu/bios/ and create a... Go to https://primes.utm.edu/bios/ and create a new prover account based on a "c" code for Primo if you don't already have one. Then you can submit your newly certified prime under the new code with...
 Forum: PARI/GP 2020-08-06, 05:28 Replies: 272 Views: 12,133 Posted By paulunderwood cat test.gp V=read("./myvec.txt"); ... cat test.gp V=read("./myvec.txt"); for(v=1,#V,print(V[v])) echo "[1,2,3,4]" > myvec.txt; gp -q < test.gp 1 2 3 4
 Forum: PARI/GP 2020-08-06, 04:45 Replies: 272 Views: 12,133 Posted By paulunderwood https://rosettacode.org/wiki/Parse_command-line_ar... https://rosettacode.org/wiki/Parse_command-line_arguments#PARI.2FGP "GP exists in a REPL (https://en.wikipedia.org/wiki/Read%E2%80%93eval%E2%80%93print_loop) and so it doesn't make sense to parse...
 Forum: GpuOwl 2020-08-06, 01:11 Replies: 2,393 Views: 135,943 Posted By paulunderwood https://www.thefreedictionary.com/cofactor ... https://www.thefreedictionary.com/cofactor "1. One of two or more contributing factors." :grin:
 Forum: GpuOwl 2020-08-05, 23:42 Replies: 2,393 Views: 135,943 Posted By paulunderwood It looks like the cofactor is given:... It looks like the cofactor is given: 765044109502655639249
 Forum: Math 2020-08-05, 15:06 Replies: 6 Views: 222 Posted By paulunderwood Yes. Addition and subtraction and mod 2^p-1 does... Yes. Addition and subtraction and mod 2^p-1 does not require FFT.
 Forum: Software 2020-08-05, 14:50 Replies: 9 Views: 278 Posted By paulunderwood Prime95/mprime is Intel/AMD X86/64 only. For ARM... Prime95/mprime is Intel/AMD X86/64 only. For ARM you need to run mlucas (https://www.mersenneforum.org/mayer/README.html). Basically: Download the asimd image. bunzip it. tune. communicate...
 Forum: Math 2020-08-05, 13:30 Replies: 6 Views: 222 Posted By paulunderwood You need a data structure to hold the numbers.... You need a data structure to hold the numbers. The simplest would be a one dimensional array (https://en.wikipedia.org/wiki/Array_data_structure#One-dimensional_arrays) and a byte or two indicating...
 Forum: Miscellaneous Math 2020-08-03, 19:36 Replies: 75 Views: 5,925 Posted By paulunderwood House of cards [n,b] = [79786523, 2982537] is a counterexample to the test given in post #74 where r=1. This was overlooked because of the same programming error indicated in post #75. The only thing to be lifted...
 Forum: Miscellaneous Math 2020-08-03, 14:20 Replies: 75 Views: 5,925 Posted By paulunderwood 1+1 selfridges Here is a 1+1 selfridges algorithm: Given a non-square n find b: kronecker(b,n)==1 kronecker(1-b,n)==-1 gcd(4-b,n)==1 gcd(4-2*b,n)==1
 Forum: Miscellaneous Math 2020-08-02, 09:15 Replies: 75 Views: 5,925 Posted By paulunderwood Second draft :book: :mooc:
 Forum: Proth Prime Search 2020-07-31, 22:23 Replies: 158 Views: 35,603 Posted By paulunderwood Congratulations for a top 20 prime! Congratulations for a top 20 prime!
 Forum: Programming 2020-07-31, 11:03 Replies: 53 Views: 8,320 Posted By paulunderwood Here is a gwnum program that tests... Here is a gwnum program that tests Euler+Frobenius as per https://mersenneforum.org/showpost.php?p=552286&postcount=74. :fish1: power_quadratic.c tests over x^2-2*x-2^s which arguably safer than...
 Forum: PARI/GP 2020-07-30, 13:56 Replies: 12 Views: 431 Posted By paulunderwood ?solve solve(X=a,b,expr): real root of... ?solve solve(X=a,b,expr): real root of expression expr (X between a and b), where expr(a)*expr(b)<=0. For logarithmic equations use pen and paper and an internet search engine.
 Forum: Miscellaneous Math 2020-07-30, 01:10 Replies: 75 Views: 5,925 Posted By paulunderwood Answer and warning Apart form the ill-formed question, writing b=s^2 (and found by trial and error) the answer is: (x*(1-s^2))^((n+1)/2) == s*(1-s^2)*kronecker(2*(1-s),n) (mod n, x^2-2*x+s^2), Warning: this...
 Forum: Linux 2020-07-29, 04:04 Replies: 13 Views: 569 Posted By paulunderwood This looks like a problem with unattended... This looks like a problem with unattended upgrades. Remove it (https://ostechnix.com/how-to-disable-unattended-upgrades-on-ubuntu/) with sudo apt remove unattended-upgrades or disable it via sudo...
 Forum: Linux 2020-07-29, 03:31 Replies: 13 Views: 569 Posted By paulunderwood This... This (https://serverfault.com/questions/884597/how-to-find-reason-for-system-reboot-or-shutdown-in-ubuntu-16-04-system) says run the command egrep -ir "(shut|reboot)" /var/log/*
 Forum: Linux 2020-07-29, 02:58 Replies: 13 Views: 569 Posted By paulunderwood Freshly installed Debian has to be coaxed into... Freshly installed Debian has to be coaxed into not suspending (https://wiki.debian.org/Suspend#Disable_suspend_and_hibernation) etc after ~20 minutes with a mask command. I wonder if your problem is...
 Forum: Miscellaneous Math 2020-07-28, 18:53 Replies: 75 Views: 5,925 Posted By paulunderwood Simplification Recap: The solutions to x^2-2^r*x+b=0 are x=2^(r-1)+-sqrt(4^(r-1)-b). Let r=1. Then the solutions are to the equation x^2-2*x+b=0 which are x=1+-sqrt(1-b) We have to have kronecker(1-b,n)==-1,...
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