## Pi Day and an Interview With a Pi Researcher 188 188

JoshuaInNippon writes

*"In honor of Pi Day, March 14 (or 3.14 for those who may need a hint), readers may be interested in reading an interview with Professor Daisuke Takahashi, the Japanese researcher who found 2.5 trillion digits of Pi back in August, before being apparently being edged out in December by a French computer programmer looking to prove his efficient coding abilities. Professor Takahashi's interview gives some unique insight into one man who truly marvels at the number that has driven people to ever greater lengths to find more digits for centuries."*Plant Kingdom adds*"There have been a number of proposals for alternatives to March 14 (see the Wikipedia page for Pi Day). Here's mine: when the Earth has gone through 1/pi-th of its orbit, as measured from Winter Solstice to Winter Solstice. I've put together a web site to make the case."*
## I don't get it (Score:5, Informative)

Huh? Pi isn't 14.3 or 14/3.

## Re:US-centricity (Score:3, Informative)

TFA suggests Archimedes' approximation of 22/7

## Celebration (Score:1, Informative)

## Re:I don't get it (Score:1, Informative)

idiot american system of month.day instead of day.month

## Re:Ellipse != Circle (Score:4, Informative)

Pi is relevant to the circumference of circles. The earth has an elliptical orbit. http://en.wikipedia.org/wiki/Circumference [wikipedia.org]

Um...pi is relevant to a lot of things, including ellipses. And besides, the orbit of the Earth has very low eccentricity, meaning it is very close to a circle. Who modded the parent "informative"?

## Re:a French computer programmer? (Score:4, Informative)

OTOH, reading Bellard's FAQ [bellard.org] on his latest result does seem like he was interested more in fast algorithms and not in Pi. So I stand corrected. Still.. he's not some random programmer to us. :P Following links from his FAQ, I found two cool books:

## Re:I don't get it (Score:3, Informative)

Huh? Pi isn't 14.3 or 14/3.No, but it's close to 22nd July.

## Re:Stupid (Score:4, Informative)

Bad form replying to one's self but this is interesting: http://en.wikipedia.org/wiki/File:Date.png [wikipedia.org]

The number of countries using the US system is pretty small. It's basically the US and a few random places like Palau and Micronesia.

But - there are quite a few variations on date format, more than I thought :)

## Re:Ellipse != Circle (Score:3, Informative)

Who modded the parent "informative"?This is Slashdot, in case you hadn't noticed. Only on Slashdot is pointing out the trivially obvious considered "Informative."

## Re:Efficient coding abilities? (Score:3, Informative)

If the doubling time of computational power is N hours (a bastardization of Moore's law, approximately 17500 hours.. or two years), then it never makes sense to start a calculation that will take more than 2N hours.

For easy visualization of this concept, lets suppose you have a program that will take 6 years to complete if run on todays fastest hardware, and you begin it March 14th, 2010

But you have an adversary who wants to beat you to the punch and announce the programs output before you do. He can wait until March 14th, 2012, exactly two years later than your start date, and at that time buy the fastest hardware of that time period. On March 14th, 2014 his program will overtake yours, and it will finish on March 14th, 2015.

He beat you by 1 year even though he started 2 years later than you did. As you see, it is a futile waste to perform such very long calculations as long as moore's law holds.

A similar concept was introduced to me in a space-ship through experiment. Humanity builds its first set of inter-galactic space ships which can achieve 50% the speed of light, and these ships set off to explore the universe. Surprisingly those first explorers all arive at stars populated by human beings, humans who themselves set off exploring AFTER they did, because inter-galactic drives improved to 98% the speed of light after only a few more years of development.

## Re:What's the significance of 1/pi? (Score:3, Informative)

For every pi proportioality the reciprocal relation is a 1/pi proportionality, so it's every bit a significant. For a near-circular Earth orbit 1/pi of a year is the time when the earth has passed the equivalent of the diameter of it's orbit and swept an area the size of of a rectangle made from it's major and minor axis.