forprime to parforprime - Page 2

WraithX · 2023-08-16, 10:13

When you start PARI/GP, you should see a line similar to the following:

Code:

parisize = 8000000, primelimit = 500000, nbthreads = 24

If you don't see "nbthreads", then you do not have a multithread capable PARI/GP.

I'm sure you have other examples to work with, but here is one I just created:

Code:

spawn_thread_work(a, b) = {
  print(a+b);
}

calculate_unique_var(i) = {
  return(i);
}

do_parallel_work(num_threads, first_n, last_n) = {
  my(i);
  default(nbthreads, num_threads);
  parfor(i = first_n, last_n,
    my(myvar = calculate_unique_var(i));
    spawn_thread_work(myvar, i);
  );
}

\\ the following line is needed so all threads can have their own copy of functions
export(calculate_unique_var, spawn_thread_work);

\\ now you can call "do_parallel_work" and it should spawn multiple threads
do_parallel_work(4, 1, 1000) \\ 4 threads in this case

paulunderwood · 2023-08-16, 12:17

Thanks for that.

Code:

/usr/local/bin/gp
Reading GPRC: /etc/gprc
GPRC Done.

                                  GP/PARI CALCULATOR Version 2.15.1 (released)
                          amd64 running linux (x86-64/GMP-6.2.1 kernel) 64-bit version
                      compiled: Aug 16 2023, gcc version 10.2.1 20210110 (Debian 10.2.1-6)
                                            threading engine: single
                               (readline not compiled in, extended help enabled)

                                     Copyright (C) 2000-2022 The PARI Group

PARI/GP is free software, covered by the GNU General Public License, and comes WITHOUT ANY WARRANTY WHATSOEVER.

Type ? for help, \q to quit.
Type ?18 for how to get moral (and possibly technical) support.

parisize = 8000000, primelimit = 500000

Code:

/usr/bin/gp-2.13 
Reading GPRC: /etc/gprc
GPRC Done.

                                  GP/PARI CALCULATOR Version 2.13.1 (released)
                          amd64 running linux (x86-64/GMP-6.2.1 kernel) 64-bit version
                      compiled: Jan 25 2021, gcc version 10.2.1 20210110 (Debian 10.2.1-6)
                                           threading engine: pthread
                                 (readline v8.1 enabled, extended help enabled)

                                     Copyright (C) 2000-2020 The PARI Group

PARI/GP is free software, covered by the GNU General Public License, and comes WITHOUT ANY WARRANTY WHATSOEVER.

Type ? for help, \q to quit.
Type ?17 for how to get moral (and possibly technical) support.

parisize = 8000000, primelimit = 500000, nbthreads = 128
? 

Goodbye!

This is useful because now parforprime works and I need pthreads to check an ECPP cert.

science_man_88 · 2023-08-16, 13:10

Quote:

Originally Posted by paulunderwood

This is useful because now parforprime works and I need pthreads to check an ECPP cert.

Glad to hear. Still think single pass logic might be good. Don't know default precidence or proper symbol for single pass logic but I'd bet it can still go faster...