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-   -   50 Trillion Digits of Pi (https://www.mersenneforum.org/showthread.php?t=25155)

Mysticial 2020-01-30 18:56

50 Trillion Digits of Pi
 
So when Google set the record of 31.4 trillion digits last year, I gave it a 50/50 chance that record would fall before the end of the year.

Didn't quite work out that way. This latest computation suffered about a month of setbacks that pushed it all the way through January. But it is finally complete and passes verification.

Congrats to Timothy Mullican for setting the new record for the most digits of Pi!

His Blog: [url]https://blog.timothymullican.com/calculating-pi-my-attempt-breaking-pi-record[/url]


Compared to the Google's record last year, Tim used a 4-socket Ivy Bridge machine with a 48-drive array. The computation ran for 10 months starting from April and ending yesterday.

The computation of the binary digits of Pi actually completed early in December and matched the results of BBP spot check. But the base conversion (which takes 2 weeks and has no checkpoints) took several attempts before completing successfully.

--------------------

This base conversion has been an issue in 3 or the last 4 Pi records due to it being ~10% of the total time and having no checkpoints at all. 10% run-time of these computations of this size equates to multiple weeks - which is also comparable to the MTTF of the systems that are used.

Why don't I have checkpoints in the base conversion? The algorithm is largely in-place and destructive. That's not to say it's impossible to checkpoint, but I just haven't figured out a good way to do it yet.

Xyzzy 2020-01-30 20:44

:bow:

mackerel 2020-02-01 11:49

Reading this I almost want to have a go. Almost... That storage requirement is scary...

LaurV 2020-02-02 08:21

Very nice, congrats!

How do you make the base switch "in place"? I have some ideas how to transform from base 2 to base 10 quite fast and also have some checkpoints, but you would need more storage space (it can't really be done "in place"), and I don't believe this is new, for sure somebody else was thinking to it before. I "invented" it long time ago and used it in my programs in the past, but never for such large inputs.

jwaltos 2020-02-05 04:19

Just finished reading the blog...impressive home build.

Xyzzy 2020-02-06 13:09

[QUOTE=jwaltos;536711]Just finished reading the blog...impressive home build.[/QUOTE]It certainly causes one to reflect about how big 5E19 is!

:mike:

paulunderwood 2020-02-06 13:15

[QUOTE=Xyzzy;536877]It certainly causes one to reflect about how big 5E19 is!

:mike:[/QUOTE]

5E19? I think it is 5E13. :whack:

For those who can recite many digits of pi.. How long would it take to recite the first 50 trillion digits given that you hold them in your brain?

mart_r 2020-02-06 18:44

[QUOTE=paulunderwood;536878]For those who can recite many digits of pi.. How long would it take to recite the first 50 trillion digits given that you hold them in your brain?[/QUOTE]

For a fast speaker who can recite ten digits per second, and disregard any needs intrinsic to the human nature (including death), about 158,000 years. (That is, by the current measurement of years.)
(I've calculated this on my Casio calculator watch, so please correct me if I'm wrong)

retina 2020-02-06 18:54

[QUOTE=mart_r;536901]For a fast speaker who can recite ten digits per second ...[/QUOTE]In what language is that? Surely not in English. No one can speak English numbers that quickly and still be understood.

You might need a tonal language specially constructed for the task. All words can be 'ah' and just vary the tone. So basically just singing notes to the tune of Pi. Even then it would be extremely difficult. I'd like to hear someone try.

Uncwilly 2020-02-06 19:02

[QUOTE=retina;536902]In what language is that? Surely not in English. No one can speak English numbers that quickly and still be understood.[/QUOTE]655 words per minute. And since digits are short words, it is doable.


[url]https://www.guinnessworldrecords.com/world-records/358936-fastest-talker[/url]

retina 2020-02-06 19:04

[QUOTE=Uncwilly;536903]655 words per minute. And since digits are short words, it is doable.


[url]https://www.guinnessworldrecords.com/world-records/358936-fastest-talker[/url][/QUOTE]Amazing!


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