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New Pi Computation Record Using a Desktop PC

Posted by kdawson on 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."

5 of 204 comments (clear)

  1. Verification by Tukz · · Score: 3, Interesting

    I didn't read the article, only the summery but it made me wonder.

    Do they verify these numbers somehow?
    Anyone can write down a series of a numbers and claim it's a specific sequence.

    Not saying these numbers aren't correct, just a thought.

    --
    - Don't do what I do, it's probably not healthy nor safe. -
    1. Re:Verification by David+Jao · · Score: 4, Interesting

      I didn't read the article, only the summery but it made me wonder.

      Do they verify these numbers somehow? Anyone can write down a series of a numbers and claim it's a specific sequence.

      Not saying these numbers aren't correct, just a thought.

      Perhaps this is why you should read the article. The press release answers this question directly.

      The binary result was verified with a formula found by the author with the Bailey-Borwein-Plouffe algorithm which directly gives the n'th hexadecimal digits of Pi. With this algorithm, the last 50 hexadecimal digits of the binary result were checked. A checksum modulo a 64 bit prime number done in the last multiplication of the Chudnovsky formula evaluation ensured a negligible probability of error.

      The conversion from binary to base 10 was verified with a checksum modulo a 64 bit prime number.

  2. Re:Wow... by MichaelSmith · · Score: 3, Interesting

    Plain html is a wonderful thing. And as he points out, it would be easy to write a cgi script which returns a specified block of digits.

    I wonder if he has checked for the circle?

    --
    http://michaelsmith.id.au
  3. Re:One thing to say by PinkyGigglebrain · · Score: 4, Interesting

    An answer is a reply but a reply is not always an answer.

  4. Re:One thing to say by HateBreeder · · Score: 3, Interesting

    I would assume he only needs to verify the last 120 billion digits.

    Assuming his algorithm can support serialization of its state into a check-point, he can simply recalculate the last 120 billion digits a couple of times and compare.

    Assuming linear time to compute each digit: 120e9/2.7e12 * 116 =~ 5 days. not too bad.

    --
    Sigs are for the weak.