A recipe for beating the record of most-calculated digits of pi

Editor’s note: Today, March 14, is Pi Day (3.14). Here at
Google, we’re celebrating the day with a new milestone: A team at
Google has broken the
Guinness World RecordsTMtitle
for most accurate value of
pi.

Whether or not you realize it, pi is everywhere you look. It’s
the ratio of the circumference of a circle to its diameter, so the
next time you check your watch or see the turning wheels of a
vehicle go by, you’re looking at pi. And since pi is an
irrational number, there’s no end to how many of its digits can
be calculated. You might know it as 3.14, but math and science pros
are constantly working to calculate more and more digits of pi, so
they can test supercomputers (and have a bit of healthy
competition, too).

While I’ve been busy thinking about which flavor of pie I’m
going to enjoy later today, Googler Emma Haruka Iwao has been busy
using Google Compute Engine, powered by Google Cloud, to calculate
the most accurate value of pi—ever. That’s 31,415,926,535,897
digits, to be exact. Emma used the power of the cloud for the task,
making this the first time the cloud has been used for a pi
calculation of this magnitude.

Here’s Emma’s recipe for what started out as a
pie-in-the-sky idea to break a Guinness World Records title:

Step 1: Find inspiration for your calculation.

When Emma was 12 years old, she became fascinated with pi. “Pi
seems simple—it starts with 3.14. When I was a kid, I downloaded
a program to calculate pi on my computer,” she says. “At the
time, the world record holders were Yasumasa Kanada and Daisuke
Takahashi, who are Japanese, so it was really relatable for me
growing up in Japan.”

Later on, when Emma was in college, one of her professors was
Dr. Daisuke Takahashi, then the record holder for calculating the
most accurate value of pi using a supercomputer. “When I told him
I was going to start this project, he shared his advice and some
technical strategies with me.”

Step 2: Combine your ingredients.

To calculate pi, Emma used an application called y-cruncher on 25
Google Cloud virtual
machines
. “The biggest challenge with pi is that it requires
a lot of storage and memory to calculate,” Emma says. Her
calculation required 170 terabytes of data to complete—that’s
roughly equivalent to the amount of data in the entire Library of
Congress print collections.

Emma
Step 3: Bake for four months.

Emma’s calculation took the virtual machines about 121 days to
complete. During that whole time, the Google Cloud infrastructure
kept the servers going. If there’d been any failures or
interruptions, it would’ve disrupted the calculation. When Emma
checked to see if her end result was correct, she felt relieved
when the number checked out. “I started to realize it was an
exciting accomplishment for my team,” she says.

Step 4: Share a slice of your achievement.

Emma thinks there are a lot of mathematical problems out there
to solve, and we’re just at the beginning of exploring how cloud
computing can play a role. “When I was a kid, I didn’t have
access to supercomputers. But even if you don’t work for Google,
you can apply for various scholarships and programs to access
computing resources,” she says. “I was very fortunate that
there were Japanese world record holders that I could relate to.
I’m really happy to be one of the few women in computer science
holding the record, and I hope I can show more people who want to
work in the industry what’s possible.”

At Google, Emma is a Cloud Developer Advocate, focused on
high-performance computing and programming language communities.
Her job is to work directly with developers, helping them to do
more with the cloud and share information about how products work.
And now, she’s also sharing her calculations: Google Cloud has

published
the computed digits entirely as disk snapshots, so
they’re available to anyone who wants to access them. This means
anyone can copy the snapshots, work on the results and use the
computation resources in less than an hour. Without the cloud, the
only way someone could access such a large dataset would be to ship
physical hard drives. 

Today, though, Emma and her team are taking a moment to
celebrate the new world record. And maybe a piece of pie, too.
Emma’s favorite flavor? “I like apple pie—not too
sweet.”

For the technical details on how Emma used Google Compute Engine
to calculate pi, head over to the Google Cloud Platform
blog
.

Source: FS – Social Media Blogs 2
A recipe for beating the record of most-calculated digits of pi