20201120, 07:01  #34 
Einyen
Dec 2003
Denmark
6470_{8} Posts 

20201203, 15:52  #35 
Feb 2016
UK
1B9_{16} Posts 
Only just saw this, forgot this forum was here. Ycruncher would love as much ram as is needed, but in reality no consumer attainable system can possibly have enough ram for the bigger runs. We're talking well into the TB that not even high end servers can reach. And that's putting aside the cost of that much ram even if you could put it in a single system. So the practicality of it is, you have to use some form of swap as a less insane cost substitute, and that is where the optimisation needs to go.

20201203, 15:57  #36 
Aug 2002
10000100111100_{2} Posts 
To prove that you computed x digits of pi, couldn't you store only a checksum of all of the digits and keep the last digit "for fun"?

20201203, 16:32  #37 
Bamboozled!
"๐บ๐๐ท๐ท๐ญ"
May 2003
Down not across
10110011011111_{2} Posts 

20201205, 14:28  #38 
Aug 2002
213C_{16} Posts 

20201205, 16:58  #39 
6809 > 6502
"""""""""""""""""""
Aug 2003
101ร103 Posts
7·1,531 Posts 
The last 10 digits and a 128 bit checksum would be enough, I would suppose.

20201205, 17:10  #40 
Undefined
"The unspeakable one"
Jun 2006
My evil lair
2^{2}×17×97 Posts 
Digit extraction algorithms exist. So merely producing a few trailing digits wouldn't be enough to prove you computed all the digits up to that point.
A hash of all digits up to your claimed last digit would be suitable IMO. 
20201205, 18:08  #41  
"Robert Gerbicz"
Oct 2005
Hungary
3^{2}×5^{2}×7 Posts 
Quote:
Quote:
But even giving only the last few bits would enable to provide a fake proof, just give the exact bits from BBP and give a trash hash value. [notice that even giving say hundred consecutive bits of Pi is "easy"]. Much better: if you're claiming a world record then I would choose 1 million random positions and you should give the bits for each of these positions. The check: select say 2025 positions and verify the bits with BBP. You have an extremely small probability to fake me. This is assuming that when you need multiple bits of Pi then there is no faster method than to use the BBP formula for each position. 

20201207, 07:41  #42 
Romulan Interpreter
"name field"
Jun 2011
Thailand
10,093 Posts 
Group the bytes by 32 or 64 and compute a SHA256 or SHA512 of it. I don't believe anybody would contest that.

20201207, 14:05  #43  
"Robert Gerbicz"
Oct 2005
Hungary
3^{2}·5^{2}·7 Posts 
Quote:
Code:
a19a6c3a75783b6b5deee64777873ae207764837e769eedbe9b4c485d94b2986 Last fiddled with by R. Gerbicz on 20201207 at 14:05 Reason: typo 

20201208, 07:01  #44 
Romulan Interpreter
"name field"
Jun 2011
Thailand
10,093 Posts 
Yep. After I remake the calculus to see if I get the same value...
I assume somebody verifies this things, anyhow... Or not? Last fiddled with by LaurV on 20201208 at 07:03 
Thread Tools  
Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
operation trillion digits?  mersenneNoob  Operation Billion Digits  11  20210602 07:37 
Google Cloud Compute 31.4 Trillion Digits of Pi  Mysticial  ycruncher  30  20191011 14:45 
Sum of Digits  davar55  Puzzles  36  20151218 15:47 
How many digits?  kokakola  Information & Answers  23  20091103 05:08 
15M Digits  Just For Fun  storm5510  Math  7  20090908 04:14 