## Gigapixel Tapestries & Gigadecimal Pi 215

Posted
by
Hemos

from the welcome-to-the-machine dept.

from the welcome-to-the-machine dept.

RobotWisdom writes

*"The new New Yorker magazine has posted two long non-technical articles about the Chudnovsky brothers and their homebrew supercomputers. One is a 1992 article about how they calculated pi to over two billion decimal places using a $70,000 cluster with 16 nodes. The other is a brandnew piece about how they spent months creating a seamless multi-gigabyte image of a fifteenth century tapestry for New York's Metropolitan Museum of Art. Tapestries are essentially pixel-art on a non-rigid (cloth) matrix, so the manual labor of photographing it inch by inch had introduced many tiny deformations in the images, which they had to mathematically iron out. Old lo-res pix of the tapestries are on the Met's site, pix of the brothers are in the world brain."*
## If you're in New York (Score:5, Informative)

## The Cloisters at the Met (Score:5, Informative)

It's a fascinating structure, with excellent pieces for close inspection. I encourage anyone within a couple hours drive of Manhattan to take the trip to see these in person. It's at the north end of Manhattan at Fort Tryon Park (there's also one high-resolution picture in my gallery from the park).

## Re:Why? (Score:5, Informative)

## Re:Gigabyte, gigapixel artwork? (Score:2, Informative)

## Re:several months?? (Score:1, Informative)

Since the tapestry was "released" from its frame for the first time in 500 years, it started to slowly contract (sort of like a rubber band that has been released). Additionally, the photographers was in contact with the fabric when taking the pictures, which meant that they moved it ever so slightly.

What took these brothers several months to do was to undo these transformations of the individual fabrics through modelling them with a vector field. The actual stitching together took 24 hours.

## Re:Pi (Score:3, Informative)

Carl Sagan, dreamed long ago (through one of his characters) to find a "circle" pattern inside Pi (i.e another series of Pi inside).

Who knows, perhaps something interesting will be found.

## Re:Gigabyte, gigapixel artwork? (Score:4, Informative)

## Re:Why do you need to know Pi so accurately? (Score:2, Informative)

See the movie:

PI [imdb.com]

There are also several interesting books on the topic including The

History of PI, by Peter Beckmann.The Life of Piby Yann Martel, however, has nothing to do with the number.## Re:Billion Places Of Pi (Score:1, Informative)

## Re:Pi (Score:3, Informative)

Hooptie

## Re:If you're in New York (Score:2, Informative)

## Re:Billion Places Of Pi (Score:5, Informative)

pi^2 / 6 = Sum_{n=1}^{oo} 1/(n^2)

It is straightforward to prove this identity. (Just take Fourier coefficients on the function f(x) = x on the interval -pi to pi).

If you're looking for an experiment with 2 billion significant digits of accuracy, you're never going to find one. That's physically impossible, for several hundred reasons.

## Re:Pi Accuracy (Score:3, Informative)

## Re:Pi Accuracy (Score:3, Informative)

## Re:Film (Score:2, Informative)

Putting the actual tapestry through a large drum-scanner would be the ideal solution, but I bet the museum was looking for a slightly gentler process. Seems like the photo-mosaic approach was a decent compromise.

## Re:Pi Accuracy (Score:3, Informative)

## Re:Pi Accuracy (Score:3, Informative)