Talk:Rare numbers: Difference between revisions

== F# tweaks ==

Kudos to Nigel Galloway for the F# version. I don't know the language well, but was able to cut a few corners to improve performance slightly and add some stats:

{{out|Output at [https://tio.run/##pVXfb9s2EH73X3EwEIdsJEVSgjZ2LAHd1g0DXC@YC/RBMApWohmiEqWK1BSv7d/eHSnZsYu9lS/ikce777tf2mk/r1v@/XvdcAWbvTa8mpzsgz//OhN/k0yoWhuZ68nk@notBS/hD1aWdc/28LoTnTYQ3ZrHwIM4jO6A/Mpaw7VkCpq2Lrrc0EnJDeQPoESy4Z@DXV0Wv7D8E9l1ChQIP812dQvqEqSVixqsKJworLiXvCzwfrEQl1uKZiDLtlsLB36XqgBEA3@zloPqqo@81dBL8wgMCimk0QGcg17AhjdIDTUhujsAnwdA3vWcfeKFuw8gjlUxQG/XwJIJ4LKS/PdhAyIRSVP3CohU5uUtecvQ0OZza8iurJkhguKC@PiINZ4aHkThCgjzI@phRLKBWhauguDlantviX@wvDPm3wQB8WMaBNH2EIPMn6Pi3QrJH9Ekow3W@NHq3oVOjRZiayFCCyxN02crhByBKOqTU1QK1SndwvV1Np@jtXD17GlIXsUa6RInQY2JE9ZdxZ7A2ghXvkKPFR7NUZxb8ehYvDjzJq23K6KuBD25kNT78eioK8706JYe0WHyE7kDNpvNoiQE88ht8SjgpeZggbMGqxohIOcsO0Qpi@5vbFysBZ2cOrQRo3S5XCrn4ufXEAHtaXqSvTJRX1PXE7I0vB06wk/Pwh2TFxSxDnq6q1xbpOFqNrOVaCttuEJVwtM0fxjlvFY5M4OrZ43Rw6EPrUyUJygQdemJS@qnGHy7vUKBYjq9cIUtR3@E6R75qUhZMwKxOaMT1zC6hwQ2pm56ZnLsC4MjYc17MrRT1Rn2seSQ151Ca6gauvOmxV7aYI5Mv3jHn8z7VuI1JTttPI29mGBZQs@hVuUeeqYMmBo05zbZ@EW@BZiuKbkHTdlp0HWF54YZDQyvMOcVM0Yq4WIyel/64@YqcsemD5xfMv0SevE3@BJ70XyhQtzdeK@@QaWn3vjCG4F5ug/elKzRvHgry1IOUDTGIlu@UabdP9RILN0O5Bmmj7XiHxgmiiO9UzBVOLLG5WbZ2s0yK/LBtoVcITvDi6l7aouYuVbHRo9utzgqj7Xargmj8DV1pW/DSEZH0wsG00Ok6VH/COMivtEXrwrkiacXcTGF6RT@nyAw9zy0aWm56VokZpvKcIHA@ZPEoV8X@Kv5Dw Tio.run (linked)]}}

<pre>nth Rare Number elapsed completed

1 65 139 ms

173 ms 2

181 ms 3

182 ms 4

200 ms 5

2 621,770 210 ms

211 ms 6

216 ms 7

383 ms 8

3 281,089,082 405 ms

449 ms 9

4 2,022,652,202 988 ms

5 2,042,832,002 1690 ms

3858 ms 10

5424 ms 11

6 872,546,974,178 33467 ms

7 872,568,754,178 34525 ms

</pre>Of course, it can't get too far in the 60 second timeout window. Sometimes it doesn't get past the 5th number, due to poor luck at Tio.run.

{{out|Output on a i7 core (Visual Studio Console App)}}

<pre>nth Rare Number elapsed completed

1 65 22 ms

24 ms 2

26 ms 3

27 ms 4

28 ms 5

2 621,770 31 ms

31 ms 6

34 ms 7

68 ms 8

3 281,089,082 74 ms

83 ms 9

4 2,022,652,202 292 ms

5 2,042,832,002 429 ms

964 ms 10

1340 ms 11

6 872,546,974,178 6562 ms

7 872,568,754,178 6758 ms

8 868,591,084,757 10261 ms

13375 ms 12

9 6,979,302,951,885 18419 ms

21481 ms 13

10 20,313,693,904,202 184922 ms

11 20,313,839,704,202 185490 ms

12 20,331,657,922,202 196893 ms

13 20,331,875,722,202 198502 ms

14 20,333,875,702,202 202160 ms

15 40,313,893,704,200 386972 ms

16 40,351,893,720,200 388014 ms

452668 ms 14</pre>Checking up to 14 digit numbers in under 8 minutes. Given more time, it can get the correct 17th number (first 15 digit number), but has problems after that. Not sure if it's the memory requirements, or perhaps I pared down Nigel's original program too much for valid output after 14 digits.<br/>

I added this here in the discussion and did not post the revised code on the main codepage out of respect for Nigel's original contribution. All I did was tweak it, and did not add any core improvements.<br/><br/>

I've been trying to figure out how to put some limits on the permutation of numbers generated, but don't know F# well enough to do it effectively. And when I work in languages I am familiar with, the performance is decades of magnitude worse.--[[User:Enter your username|Enter your username]] ([[User talk:Enter your username|talk]]) 18:37, 22 September 2019 (UTC)