# British Association for the Advancement of Science: Home-made computer cuts bigger slice of pi

A MATHEMATICAL problem that has dogged thinkers for 4,000 years has come close to being solved by two New York brothers on their home-made computer writes Steve Connor.

David and Gregory Chudnovsky have worked out the value of the mathematical constant pi - the ratio of a circle's circumference to its diameter - to 2.16 billion decimal places, a number long enough to fill 20 encyclopaedias.

Their computer, built at a cost of dollars 70,000 with the help of money from their wives and a grant from Columbia University, has 25 fans to prevent it melting when number crunching.

Although it is a world record for computing the value of pi, mathematicians believe that it is not the end of the story that began 2,000 years ago in Babylonia. Peter Webster, a mathematician at the University of Sheffield, told the British Association's annual meeting yesterday that the exact value of pi, which is about 3.14, will be the subject of intrigue for years to come.

For thousands of years, mathematicians came gradually closer to calculating the precise value of pi, Archimedes setting the standard in 240BC.

The constant did not have a universally recognised name until a Welshman, William Jones, wrote a mathematical treatise and referred to the number as pi. 'The book was on the top-selling list for year after year. Jones was like Stephen Hawking in his popularity,' Dr Webster said.

In 1840, a German boy, Johann Dase, calculated pi to 200 decimal places in his head. Dr Webster said his computing genius earned him a considerable reputation. 'He was a human calculator.'

Other attempts at mentally calculating the exact value of pi were quickly superseded by the first electronic attempt on the ENIAC computer in 1949.

Two French mathematicians calculated it to a million decimal places in the early Seventies. In 1989, a Japanese managed to break through the billion decimal place barrier.

Dr Webster is adamant that the latest attempt will not be the end of the matter. The continuing saga of calculating pi 'is to be continued'.

Suggested Topics
News

### 'He's worth idolising'

peopleSusan Sarandon reveals more on her David Bowie romance
Sport

football
Sport

### Look who's back

sportDidier Drogba returns to Chelsea on one-year deal
Arts and Entertainment

film
PROMOTED VIDEO
News

### Robert Fisk on Israel: The Obama Years

ebookA unique anthology of reporting and analysis of a crucial period of history
Life and Style

### Rihanna, Kim Kardashian and me

fashionHow Olivier Rousteing is revitalising the house of Balmain
News

### Former QPR teammates Barton and Benayoun clash over Gaza conflict

people
Arts and Entertainment

### Not in front of the kids!

filmFifty Shades of Grey trailer provokes moral outrage in US
News

### Wolf in sheep’s clothing

peopleForget Paxman - what will Evan Davis be like on Newsnight?
Life and Style

### Primark forced to remove skinny mannequin

fashionCustomer complained about the visibly protruding ribs
Voices

### 'The economy may be back on track, but ordinary people are being left behind'

voicesJames Moore: As the Tories rub their hands together, the average voter will be asking why they're not getting a piece of the action
Sport

sport
News

### Nobody’s laughing

newsComedy club forced to apologise as maggots eating a dead pigeon fall out of air-conditioning
Arts and Entertainment

### 'X Factor and BGT wheel on people with mental health problems'

tvJo Brand says shows encourage people to laugh at the vulnerable
Life and Style

life
News

people
Sport

### Welsh hurdles champion Rhys Williams suspended over doping charge

commonwealth games
News

i100
Sport

### Five things we’ve learned so far about Man United under Louis van Gaal

football
Arts and Entertainment

### Captivating Nicolas Cage is no ordinary Joe

filmReview: Actor delivers astonishing performance in low budget drama
Independent
Travel Shop
Up to 70% off luxury travel
on city breaks Find out more
Up to 70% off luxury travel
on chic beach resorts Find out more
Up to 70% off luxury travel
on country retreats Find out more
##### Independent Dating
and

By clicking 'Search' you
are agreeing to our

### Senior Risk Manager - Banking - London - £650

£600 - £650 per day: Orgtel: Conduct Risk Liaison Manager - Banking - London -...

### Commercial Litigation Associate

Highly Attractive Package: Austen Lloyd: CITY - COMMERCIAL LITIGATION - GLOBAL...

### Systems Manager - Dynamics AX

£65000 - £75000 per annum + Benefits: Progressive Recruitment: The client is a...

### Service Delivery Manager (Software Development, Testing)

£40000 - £45000 per annum: Ashdown Group: A well-established software house ba...

## The BBC’s wolf in sheep’s clothing

What will Evan Davis be like on Newsnight?

## Finding the names for America’s shame

The immigrants crossing the US-Mexico border without documents who never make it past the Arizona desert

## Inside a church for Born Again Christians

As Britain's Anglican church struggles to establish its modern identity, one branch of Christianity is booming

## Olivier Rousteing is revitalising the house of Balmain

Parisian couturier Pierre Balmain made his name dressing the mid-century jet set. Today, Olivier Rousteing – heir to the house Pierre built – is celebrating their 21st-century equivalents. The result? Nothing short of Balmania

## Incredible survival story of David Tovey

Tovey went from cooking for the Queen to rifling through bins for his supper. His is a startling story of endurance against the odds – and of a social safety net failing at every turn

## Bribery and abuses of power soar in China

The bribery is fuelled by the surge in China's economy but the rules of corruption are subtle and unspoken, finds Evan Osnos, as he learns the dark arts from a master

## Highland terriers steal the show at opening ceremony

Gillian Orr explores why a dog loved by film stars and presidents is finally having its day

## Brewing the fat from artwork angers widow of sculptor

Part of Joseph Beuys' 1982 sculpture 'Fettecke' used to distil schnapps

## BBC takes viewers back down memory lane

The Secret History of Our Streets, which returns with three films looking at Scottish streets, is the inverse of Benefits Street - delivering warmth instead of cynicism

## Nicolas Cage shines in low-budget drama Joe

Cage plays an ex-con in David Gordon Green's independent drama, which has been adapted from a novel by Larry Brown

## Make your own ice lollies and frozen yoghurt

Think outside the cool box for this summer's tempting frozen treats

## Fiesta is UK's most popular car of all-time

Sales have topped 4.1 million since 1976. To celebrate this milestone, four Independent writers recall their Fiestas with pride

## Heaven scent: 10 best reed diffusers

Keep your rooms smelling summery and fresh with one of these subtle but distinctive home fragrances that’ll last you months

## Female boxers set to compete at Commonwealth Games for first time

There’s no favourites and with no headguards anything could happen

## Five things we’ve learned so far about United under Van Gaal

It’s impossible to avoid the impression that the Dutch manager is playing to the gallery a little