## New Pi Computation Record Using a Desktop PC 204

Posted
by
kdawson

from the more-digits-than-you dept.

from the more-digits-than-you dept.

hint3 writes

*"Fabrice Bellard has calculated Pi to about 2.7 trillion decimal digits, besting the previous record by over 120 billion digits. While the improvement may seem small, it is an outstanding achievement because only a single desktop PC, costing less than $3,000, was used — instead of a multi-million dollar supercomputer as in the previous records."*
## Re:So... umm... (Score:4, Insightful)

Could someone fill me in what purpose that may be?

Because.

## Re:One thing to say (Score:1, Insightful)

Interesting, but it didn't really answer the question.

## Re:silly (Score:4, Insightful)

There is an algorithm now for calculating the nth digit of Pi at a whim.

The algorithm [wikipedia.org] only works for hexadecimal digits. There is no known formula or algorithm for calculating the n-th decimal digit directly.

Having said that, the existence or non-existence of an n-th digit algorithm does not have any relevance on the silliness or non-silliness of computing trillions of digits of pi, unless the algorithm is

extremelytrivial (i.e. computing the digit takes less CPU time than a byte of I/O), which is not the case here.## Re:One thing to say (Score:5, Insightful)

In another thread someone had posted that there was no reason for any modern CPUs; the idea being that anything one could reasonably want to do with a computer was possible with decade old hardware.

This.. *This* article is why I enjoy the breakneck pace of processor speed improvements. The thought of being able to do some pretty serious computing on a relatively inexpensive bit of hardware -- even if it takes half a year to get results -- does what the printing press did. It allows the unwashed masses (of which I am one) a chance to do things that were once only the realm of researchers in academia or the corporate world. Sure, all that you need to do some serious mathematics is a pen and paper, but more and more discoveries occur using methods that can only be performed with a computer.

There's always the argument that cheap computers and cheap access to powerful software pollutes the space with hacks and dilletantes. People have said this about desktop publishing, ray tracing, and even the growth of Linux. But it's this ability to do some amazing things with computers that makes it all worthwhile.

## Re:So... umm... (Score:0, Insightful)

although unfortunately he says he doesn't plan to release the code (somewhat unusual, since most of his projects are free software).

More than unusual - it also means that for all practical purposes, his record is worthless. If we cannot look at the program he used to calculate these digits and verify (i.e., prove) that it's actually correct, what have we actually gained?

Without the program OR the data, all we really have is one guy's claim that he set a new world record, in secret, with the result not even available.

Now, I have no reason to distrust Bellard, and I don't really doubt he really did what he claims to have done; make no mistake about that. I don't think he's lying or anything, but I'd like to be able to verify what he did for myself, or at least have the possibility to. That's what science works like.

## Would have been nice to see some code. (Score:2, Insightful)

I don't think many people will be running his program that takes 116 days to complete to get as far as he did. Would have been nice to at least see how the code worked.

## Re:this guy has a pretty impressive track record (Score:2, Insightful)

## Re:Verification (Score:1, Insightful)

But the fact that the algorithm runs is the best proof of it working.

And it is also an exercise in practicality; the author notes in the PDF that there was a high probability of a random bit error during the 100+ day computation period. It is in a way important to show that yes, long computations can be done and verified on ordinary hardware without ECC.

## Re:One thing to say (Score:3, Insightful)

Pi is interesting in that regard -- there are algorithms that can compute the Nth digit without needing to compute the intermediate digits. If you want to compute all digits from 0 to N, however, there are more efficient algorithms.

## Re:Finally! (Score:3, Insightful)

I think you'll find you don't need anywhere near that level of precision of pi to find the radius of the Universe in Planck lengths. 50 digits is sufficient.