So, I’m generating a SQL database of the first million primes as part of one of those random side tangents that I go off on occasionally. So far I’m up to half a million, and I’ve made several optimizations. I don’t know that my primefinder is actually valid, so I’m including it for you all to critique:<\/p>\n
#!\/usr\/bin\/perl<\/p>\n # version: 0.06 use DBI; $dbh = DBI->connect(“dbi:mysql:db=primes”,undef,undef) || die “Failed to connect to database”;<\/p>\n $SIG{INT} = \\&shutdown;<\/p>\n # first, locate our current position<\/p>\n ($current) = $dbh->selectrow_array(“SELECT loc FROM current_location”);<\/p>\n $counter = $current;<\/p>\n #$lastprime = 1;<\/p>\n ($lastprime) = $dbh->selectrow_array(“SELECT MAX(prime_number) FROM primes”);<\/p>\n $counter = ($lastprime + 1) if($lastprime > $counter);<\/p>\n while(1) {<\/p>\n if(is_prime($counter)) { if(! ($counter % 1000)) { $counter++;<\/p>\n }<\/p>\n sub is_prime {<\/p>\n my $number = shift;<\/p>\n # could use much improvement<\/p>\n return 0 if ($number == 1); # $maxprime = (int($number \/ 2) + 1); # test against all known primes thus far<\/p>\n $sth = $dbh->prepare(“SELECT prime_number FROM primes WHERE prime_number < $maxprime\");\n $sth->execute();<\/p>\n while(($pp) = $sth->fetchrow_array()) { $sth->finish();<\/p>\n return 1; sub log_prime { $dbh->do(“INSERT INTO primes VALUES (NULL,$number,$span,now())”); sub shutdown {<\/p>\n $dbh->do(“UPDATE current_location SET loc = $counter, ts = now()”); So, I’m generating a SQL database of the first million primes as part of one of those random side tangents that I go off on occasionally. So far I’m up to half a million, and I’ve made several optimizations. I don’t know that my primefinder is actually valid, so I’m including it for you all […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"_links":{"self":[{"href":"https:\/\/www.sheer.us\/weblogs\/wp-json\/wp\/v2\/posts\/1776"}],"collection":[{"href":"https:\/\/www.sheer.us\/weblogs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.sheer.us\/weblogs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.sheer.us\/weblogs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.sheer.us\/weblogs\/wp-json\/wp\/v2\/comments?post=1776"}],"version-history":[{"count":0,"href":"https:\/\/www.sheer.us\/weblogs\/wp-json\/wp\/v2\/posts\/1776\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.sheer.us\/weblogs\/wp-json\/wp\/v2\/media?parent=1776"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.sheer.us\/weblogs\/wp-json\/wp\/v2\/categories?post=1776"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.sheer.us\/weblogs\/wp-json\/wp\/v2\/tags?post=1776"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\n$debug = 1;<\/p>\n
\nuse Time::Local;<\/p>\n
\n $span = $counter – $lastprime;
\n $lastprime = $counter;
\n log_prime($counter, $span);
\n print “$counter ($span)\\n” if($debug);
\n }<\/p>\n
\n $dbh->do(“UPDATE current_location SET loc = $counter, ts = now()”);
\n }<\/p>\n
\n return 0 if (($number != 2) && (($number % 2) == 0));<\/p>\n
\n $maxprime = (int(sqrt($number)) + 1);<\/p>\n
\n# return 0 if(($number != $pp) && (int($number \/ $pp)) == ($number \/ $pp));
\n return 0 if(($number != $pp) && (($number % $pp) == 0));
\n }<\/p>\n
\n}<\/p>\n
\n my $number = shift;
\n my $span = shift;<\/p>\n
\n}<\/p>\n
\n exit(0);
\n}
\n<\/lj-CUT><\/p>\n","protected":false},"excerpt":{"rendered":"