Talk:Primes whose sum of digits is 25: Difference between revisions
Talk:Primes whose sum of digits is 25 (view source)
Revision as of 13:35, 29 March 2021
, 3 years ago→The limit of primes that do not contain zeroes: Added a comment about C++ time.
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: Correct, stretch goal updated. If zeroes were allowed there would be an infinite number of them. It will need reasonably decent bignum handling and a fast prime number checker. I expect this is not really do-able in asm, etc. I would put a reasonable (soft) upper limit of say 30 mins runtime on this and not be too critical of anything around that, certainly not if it actually manages to get all the way to 1.5e6 in that timeframe, and I'll be proper impressed if anyone ever manages a sub-10s, on any box in any lang. The Phix algorithm generates 1.65e7 potential candidates (without testing for primality that takes just 7.7s) as opposed (it is rather daft to test even numbers for primality!) to +2 generating 5.55e24 candidates which at that same (test-less) rate would take around 8 billion years. --[[User:Petelomax|Pete Lomax]] ([[User talk:Petelomax|talk]]) 12:34, 21 March 2021 (UTC)
:: <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)
== Perhaps the syntax of the task title could be normalized ? ==
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