Talk:Primes whose sum of digits is 25: Difference between revisions

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Peak moved page Talk:Primes which sum of digits is 25 to Talk:Primes whose sum of digits is 25: acceptable English

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Revision as of 13:35, 29 March 2021 (view source) PureFox (talk \| contribs) (→‎The limit of primes that do not contain zeroes: Added a comment about C++ time.) ← Older edit		Latest revision as of 05:36, 24 September 2021 (view source) Peak (talk \| contribs) m (Peak moved page Talk:Primes which sum of digits is 25 to Talk:Primes whose sum of digits is 25: acceptable English)
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Line 6: :: <u>I'll be proper impressed if anyone ever manages a sub-10s</u> is reached.Generating the numbers for sum of digits = 25 is < 0.5 s.But on Win64 my old gmp.dll is very slow -> 7s => 15s [[User:Horsth\|Horsth]] 13:06, 29 March 2021 (UTC) :::On my machine, the C++ entry compiled with g++ is ~~also~~ coming in at 9.17 seconds so also (just) qualifies for 'proper impression' :) --[[User:PureFox\|PureFox]] ([[User talk:PureFox\|talk]]) 13:35, 29 March 2021 (UTC) :::I am indeed proper impressed and I take my hat off to you, good sir. I've also spotted the Pascal entry does it in 6s! --[[User:Petelomax\|Pete Lomax]] ([[User talk:Petelomax\|talk]]) 17:35, 29 March 2021 (UTC) ::::Incidentally, the C++ version was written by Simonjsaunders using a similar approach to Phix and Go. No surprise that it's a lot faster than Go which is handicapped by the overhead of Cgo when using the GMP wrapper but is still significantly faster than Go's native big.Int. --[[User:PureFox\|PureFox]] ([[User talk:PureFox\|talk]]) 18:31, 29 March 2021 (UTC) :Have just played with the Pascal entry on tio, and found the answer to ''I don't know why there is one more probably prime'': 1 and 2 fail but mpz_probab_prime_p(z,3) gets the right answer. C++ might benefit from 25->3 too. Left it to you lot to update your own entries & times. --[[User:Petelomax\|Pete Lomax]] ([[User talk:Petelomax\|talk]]) 17:58, 29 March 2021 (UTC) ::Using a certainty level of 3, both the Go and C++ examples still give the same answer (1,525,141 primes) though, surprisingly, the difference in timings was negligible. --[[User:PureFox\|PureFox]] ([[User talk:PureFox\|talk]]) 18:49, 29 March 2021 (UTC) :::testing the false checked primes.<br><Lang pascal>procedure OUT_FalsePrime(n:NativeINt); Begin writeln('false checked ',CS,' after ',n,' rounds'); end; procedure CheckPrime; begin mpz_set_str(z,CS,10); // if mpz_probab_prime_p(z,0)>0 then inc(PrimeCount); if mpz_probab_prime_p(z,0)>0 then if mpz_probab_prime_p(z,1)= 0 then OUT_FalsePrime(1) else if mpz_probab_prime_p(z,2)= 0 then OUT_FalsePrime(2) else if mpz_probab_prime_p(z,3)= 0 then OUT_FalsePrime(3) else if mpz_probab_prime_p(z,5)= 0 then OUT_FalsePrime(5) else inc(PrimeCount) end;</lang> {{out}} <pre>GMP-Version 6.1.2 false checked 2194111141 after 1 rounds false checked 128124151 after 1 rounds false checked 1134342151 after 1 rounds false checked 11973121 after 1 rounds false checked 12941161 after 1 rounds false checked 15614161 after 1 rounds false checked 132641521 after 1 rounds false checked 26157121 after 1 rounds false checked 41581321 after 1 rounds false checked 12731461 after 1 rounds false checked 1281661 after 1 rounds false checked 4411681 after 1 rounds false checked 1432242241 after 1 rounds false checked 237224311 after 1 rounds false checked 25292131 after 1 rounds false checked 12225841 after 1 rounds false checked 31294231 after 1 rounds false checked 18342241 after 1 rounds false checked 1722913 after 1 rounds false checked 14555221 after 1 rounds false checked 34124641 after 1 rounds false checked 1943521 after 3 rounds <========== astonishing small number false checked 1235851 after 1 rounds false checked 1132657 after 1 rounds false checked 64343311 after 1 rounds false checked 1584133 after 1 rounds false checked 1357441 after 1 rounds false checked 5354611 after 1 rounds false checked 28213333 after 1 rounds false checked 4922413 after 1 rounds false checked 3255271 after 1 rounds false checked 1372453 after 1 rounds false checked 5423713 after 1 rounds false checked 3542533 after 1 rounds PrimeCount of generated numbers with digits sum of 25 are 16499120 Propably primes 1525141</pre> TIO.RUN uses GMP-Version 6.1.2 too, with same results.<BR>[[User:Horsth\|Horsth]] 18:31, 30 March 2021 (UTC) ::::Intalled GMP 6.2.1 and now a certainty level of 0 "if mpz_probab_prime_p(z,0)>0 then .." suffices to find 1525141 Propably primes <BR>The runtime is lifted to 11.2 s :-( ;-)<BR>[[User:Horsth\|Horsth]] 05:52, 31 March 2021 (UTC) == Perhaps the syntax of the task title could be normalized ? == For example, something like "''Primes with decimal digits summing to 25''" ? [[User:Hout\|Hout]] ([[User talk:Hout\|talk]]) 11:18, 29 March 2021 (UTC) :Or just "Sum25 primes"? --[[User:Petelomax\|Pete Lomax]] ([[User talk:Petelomax\|talk]]) 12:25, 29 March 2021 (UTC) :: Or   ''Two-bit primes''?           For right-ponders and elsewhere, that's slang for   <big>25¢,</big>   or a quarter of a (US) dollar.     -- [[User:Gerard Schildberger\|Gerard Schildberger]] ([[User talk:Gerard Schildberger\|talk]]) 13:23, 24 April 2021 (UTC)