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Groups > comp.lang.c++ > #91459

Re: Sieve of Eratosthenes

From Bonita Montero <Bonita.Montero@gmail.com>
Newsgroups comp.lang.c++
Subject Re: Sieve of Eratosthenes
Date 2023-08-28 18:47 +0200
Organization A noiseless patient Spider
Message-ID <ucij2p$1pe53$1@dont-email.me> (permalink)
References (4 earlier) <56146f63-17d7-40cc-8c42-4f29c922a8c4n@googlegroups.com> <874jkknizq.fsf@bsb.me.uk> <4f7eeaa9-47d5-4782-864b-476746654325n@googlegroups.com> <uci8ta$1nj3p$1@dont-email.me> <1872f8f6-4f5a-4059-b717-b40e8b9c5f3cn@googlegroups.com>

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Am 28.08.2023 um 18:03 schrieb Öö Tiib:

> Quite likely Ben's "naive" is better algorithm. Pasted your algorithm to
> Apple M1 Max (that is 3.2  GHz):
>     
> sieving 18.1471 seconds.
> counting 1.8121 seconds.
> 203280221 primes.

I'd like to know how this code performs on a Apple
silicon Mac. That's while the M1 Max has a memory
bandwidh slightly below 300GB/s.

#include <iostream>
#include <vector>
#include <charconv>
#include <string_view>
#include <algorithm>
#include <fstream>
#include <cctype>
#include <cstring>
#include <bit>

#if defined(_MSC_VER)
	#pragma warning(disable: 26495) // uninitialized member
#endif

using namespace std;

int main( int argc, char **argv )
{
	constexpr size_t BUF_SIZE = 0x100000;
	try
	{
		size_t end;
		if( argc < 2 )
			return EXIT_FAILURE;
		char const *sizeStr = argv[1];
		bool hex = sizeStr[0] == '0' && (sizeStr[1] == 'x' || sizeStr[1] == 'X');
		sizeStr += 2 * hex;
		if( from_chars_result fcr = from_chars( sizeStr, sizeStr + strlen( 
sizeStr ), end, !hex ? 10 : 16 ); (bool)fcr.ec || *fcr.ptr )
			return EXIT_FAILURE;
		if( !++end )
			throw bad_alloc();
		using word_t = uint64_t;
		constexpr size_t BITS = sizeof(word_t) * 8;
		size_t bEnd = (end + BITS - 1) & -(ptrdiff_t)BITS;
		if( bEnd < end )
			throw bad_alloc();
		using bit_vec = vector<word_t>;
		using bit_it = bit_vec::iterator;
		bit_vec sieve( (end + BITS - 1) / BITS, -1 );
		ofstream ofs;
		union ndi_t { char c; ndi_t() {} };
		using ndi_vec = vector<ndi_t>;
		using ndi_vec_it = ndi_vec::iterator;
		constexpr size_t AHEAD = 32;
		ndi_vec printBuf;
		ndi_vec_it bufBegin, bufEnd, bufFlush;
		if( argc < 3 || *argv[2] )
		{
			ofs.exceptions( ofstream::failbit | ofstream::badbit );
			ofs.open( argc >= 3 ? argv[2] : "primes.txt", ofstream::trunc );
			printBuf.resize( BUF_SIZE + AHEAD - 1 );
			bufBegin = printBuf.begin();
			bufEnd = bufBegin;
			bufFlush = bufBegin + BUF_SIZE;
		}
		auto print = [&]() { ofs << string_view( &to_address( bufBegin )->c, 
&to_address( bufEnd )->c ); };
		for( size_t p = 2; p < end; )
		{
			bit_it
				pSieve = sieve.begin(),
				pSieveEnd = sieve.end();
			if( size_t m = 2 * p; m < end )
				if( p >= BITS )
				{
					word_t mask = ~((word_t)1 << m % BITS);
					do
						pSieve[m / BITS] &= mask,
						mask = rotl( mask, (int)p % BITS ),
						m += p;
					while( m < end );
				}
				else
				{
					pSieve += m / BITS;
					word_t newMask = ~((word_t)1 << m % BITS);
					do
					{
						word_t word = *pSieve, mask;
						do
							mask = newMask,
							word &= mask,
							newMask = rotl( mask, (int)p );
						while( newMask < mask );
						*pSieve = word;
					} while( ++pSieve != pSieveEnd );
				}
			if( ++p == end ) [[unlikely]]
				break;
			word_t mask = (word_t)1 << p % BITS;
			pSieve = sieve.begin() + p / BITS;
			do
			{
				word_t word = *pSieve;
				do
					if( word & mask ) [[unlikely]]
						goto foundNext;
					else
						++p,
						mask = rotl( mask, 1 );
				while( mask != 1 );
			} while( ++pSieve != pSieveEnd );
		foundNext:
			if( p >= end ) [[unlikely]]
				break;
			if( !ofs.is_open() )
				continue;
			auto [ptr, ec] = to_chars( &bufEnd->c, &to_address( bufEnd + (AHEAD - 
1) )->c, p );
			if( (bool)ec ) [[unlikely]]
				throw system_error( (int)ec, generic_category(), "converson failed" );
			bufEnd = ptr - &bufBegin->c + bufBegin; // NOP
			bufEnd++->c = '\n';
			if( bufEnd >= bufFlush )
				print(),
				bufEnd = bufBegin;
		}
		print();
		return EXIT_SUCCESS;
	}
	catch( bad_alloc const & )
	{
		cout << "out of memory" << endl;
	}
	catch( ios_base::failure const & )
	{
		cout << "I/O error" << endl;
	}
	catch( system_error const &se )
	{
		cout << se.what() << endl;
	}
}

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Thread

Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-16 15:37 +0200
  Re: Sieve of Eratosthenes wij <wyniijj5@gmail.com> - 2023-08-16 10:57 -0700
    Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-16 20:21 +0200
      Re: Sieve of Eratosthenes wij <wyniijj5@gmail.com> - 2023-08-16 12:17 -0700
    Re: Sieve of Eratosthenes Paavo Helde <eesnimi@osa.pri.ee> - 2023-08-16 21:44 +0300
      Re: Sieve of Eratosthenes wij <wyniijj5@gmail.com> - 2023-08-16 12:09 -0700
  Re: Sieve of Eratosthenes "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2023-08-16 23:17 +0200
    Re: Sieve of Eratosthenes "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2023-08-16 23:21 +0200
    Re: Sieve of Eratosthenes "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2023-08-16 23:39 +0200
      Re: Sieve of Eratosthenes "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2023-08-16 23:59 +0200
        Re: Sieve of Eratosthenes "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-08-16 16:27 -0700
    Re: Sieve of Eratosthenes red floyd <no.spam.here@its.invalid> - 2023-08-16 18:06 -0700
      Re: Sieve of Eratosthenes Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-08-16 19:26 -0700
        Re: Sieve of Eratosthenes Öö Tiib <ootiib@hot.ee> - 2023-08-27 12:26 -0700
          Re: Sieve of Eratosthenes Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-08-28 00:49 +0100
            Re: Sieve of Eratosthenes Öö Tiib <ootiib@hot.ee> - 2023-08-27 23:23 -0700
              Re: Sieve of Eratosthenes "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2023-08-28 15:53 +0200
                Re: Sieve of Eratosthenes Öö Tiib <ootiib@hot.ee> - 2023-08-28 09:03 -0700
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-28 18:47 +0200
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-30 13:01 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-30 15:38 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-30 18:31 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-31 08:22 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-31 11:00 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-31 15:23 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-31 17:28 +0200
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-31 11:52 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-31 15:22 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-31 17:32 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-31 15:44 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-31 17:50 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-09-01 10:26 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-09-01 12:59 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-09-01 12:30 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-09-01 15:33 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-09-01 13:49 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-09-01 15:59 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-09-01 14:03 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-09-01 16:15 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-09-01 14:39 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-09-01 16:59 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-09-01 15:01 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-09-01 17:05 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-09-01 15:08 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-09-01 17:15 +0200
                Re: Sieve of Eratosthenes Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-08-31 21:33 +0100
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-09-01 05:35 +0200
                Re: Sieve of Eratosthenes scott@slp53.sl.home (Scott Lurndal) - 2023-08-31 14:43 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-31 16:57 +0200
                Re: Sieve of Eratosthenes scott@slp53.sl.home (Scott Lurndal) - 2023-08-31 16:10 +0000
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-31 15:25 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-31 17:33 +0200
                Re: Sieve of Eratosthenes scott@slp53.sl.home (Scott Lurndal) - 2023-08-31 16:12 +0000
                Re: Sieve of Eratosthenes Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-08-28 23:08 +0100
            Re: Sieve of Eratosthenes Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-08-28 15:15 -0700
              Re: Sieve of Eratosthenes Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-08-28 23:41 +0100
                Re: Sieve of Eratosthenes Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-08-30 17:45 -0700
                Re: Sieve of Eratosthenes Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-08-31 03:18 +0100
          Re: Sieve of Eratosthenes Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-08-28 15:08 -0700
      Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-17 08:42 +0200
        Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-17 11:38 +0200
          Re: Sieve of Eratosthenes "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2023-08-17 12:50 +0200
            Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-17 13:10 +0200
            Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-17 17:47 +0200
            Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-21 11:00 +0200
              Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-21 17:19 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-21 19:50 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-21 18:12 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-21 20:22 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-21 19:01 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-22 05:27 +0200
                Re: Sieve of Eratosthenes Öö Tiib <ootiib@hot.ee> - 2023-08-21 23:25 -0700
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-22 11:23 +0200
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-22 11:59 +0200
                Re: Sieve of Eratosthenes Öö Tiib <ootiib@hot.ee> - 2023-08-22 05:15 -0700
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-22 14:23 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-22 06:56 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-22 11:27 +0200
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-22 11:34 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-22 14:13 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-22 16:17 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-22 14:27 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-22 16:48 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-22 14:57 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-22 17:00 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-22 17:56 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-22 20:13 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-22 18:18 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-22 20:50 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-23 06:51 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-23 09:59 +0200
                Re: Sieve of Eratosthenes Richard Damon <Richard@Damon-Family.org> - 2023-08-23 07:52 -0400
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-23 14:40 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-23 14:24 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-23 16:30 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-23 14:36 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-23 16:38 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-23 14:43 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-23 16:45 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-23 17:49 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-23 20:05 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-24 17:18 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-24 19:20 +0200
                Re: Sieve of Eratosthenes Daniel <danielaparker@gmail.com> - 2023-08-23 11:13 -0700
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-23 20:17 +0200
                Re: Sieve of Eratosthenes "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-08-23 11:20 -0700
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-23 20:24 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-24 17:25 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-24 19:29 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-24 17:40 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-24 19:49 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-25 16:07 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-25 18:10 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-25 16:15 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-25 18:18 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-26 08:03 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-26 10:16 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-26 08:27 +0000
                Re: Sieve of Eratosthenes Daniel <danielaparker@gmail.com> - 2023-08-23 11:37 -0700
                Re: Sieve of Eratosthenes "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-08-26 15:33 -0700
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-23 14:20 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-23 16:32 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-23 14:41 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-23 16:47 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-23 17:51 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-23 20:09 +0200
                Re: Sieve of Eratosthenes scott@slp53.sl.home (Scott Lurndal) - 2023-08-23 18:51 +0000
                Re: Sieve of Eratosthenes "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-08-24 11:25 -0700
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-24 17:22 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-24 19:27 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-24 17:37 +0000
                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-24 19:52 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-25 16:07 +0000
                Re: Sieve of Eratosthenes Daniel <danielaparker@gmail.com> - 2023-08-23 08:00 -0700
                Re: Sieve of Eratosthenes scott@slp53.sl.home (Scott Lurndal) - 2023-08-22 15:49 +0000
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-22 17:58 +0000
                Re: Sieve of Eratosthenes scott@slp53.sl.home (Scott Lurndal) - 2023-08-22 18:24 +0000
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-23 06:50 +0000
    Re: Sieve of Eratosthenes wij <wyniijj5@gmail.com> - 2023-08-17 13:43 -0700
      Re: Sieve of Eratosthenes "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2023-08-18 02:00 +0200
        Re: Sieve of Eratosthenes wij <wyniijj5@gmail.com> - 2023-08-18 05:01 -0700
          Re: Sieve of Eratosthenes wij <wyniijj5@gmail.com> - 2023-08-18 17:02 -0700
  Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-28 06:15 +0200
  Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-28 09:43 +0200
  Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-29 20:34 +0200
    Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-30 19:02 +0200

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