# Happy Pi(e) day…

What are your plans for today, 3,14 ?

Mine are to do a stress test. (and survive)

( As if interacting with 10 Cents isn’t stressful enough… )

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## Author: G.D.

I'm from Pensyltucky. Can trace my ancestry directly to whom the present day national anthem of Poland is written about.

## 9 thoughts on “Happy Pi(e) day…”

1. I just isn’t on the radar the way it was three years ago.   Today is a work day, filled with work stuff.

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2. There are a number of curious things about the decimal expansion of π.  The digits closely follow the statistics expected for a uniform distribution (each digit appears with equal probability) and pass a wide variety of tests for randomness, but π has never been proved to be a normal number.  The decimal expansion of  π contains a sequence of six consecutive nines starting at decimal place 762.  This is also the first occurrence of four and five consecutive identical digits.  The probability of six identical digits appearing in a random decimal sequence this short is just 0.686%.   The sequence of seven consecutive nines does not appear until decimal place 1,722,776.

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3. I am for Pi because it is a RAT-i-o.

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4. I think I’ll estimate the value of Pi on the Analytical Engine.

When I was in elementary school, I read that you could approximate Pi by dropping a needle “randomly” on a paper with parallel lines and using the lengths and distances and the count of the number of times the needle touched one of the lines*.  I was in the library with my head over the paper for about a half hour very carefully doing this when the Librarian came up and said she thought I was sick and was going to send me to the nurse.  It was all I could do to convince her that I was doing a real experiment.

These days, I don’t have an analytical engine, but have a cluster of 4 Raspberry Pi  (small, cheap computer not much bigger than a credit card) that can do it in parallel.

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5. How many Raspberry Pi users are there here? Why do you like them? Are they better than  a tablet?

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6. 10 Cents:
How many Raspberry Pi users are there here? Why do you like them?

I have one.  I bought it to prototype a much cheaper and more reliable fourth-generation HotBits generator but ended up pressing it into service as a Global Consciousness Project “EGG” node when the H-P laptop which ran it died last November.  The random event generator is connected to the Pi via a USB to serial port adapter.

One terrific thing about the Raspberry Pi is that it comes with a free full copy of Wolfram Mathematica, which costs €345 for a personal desktop license for other machines.  When I want to use Mathematica, I just ssh into my Pi from my regular development machine and run it from there.

I use the “Raspbian” Linux distribution, which is based on the same Debian core as the Xubuntu system I use on my laptops, so the administration is essentially identical.

A Raspberry Pi is not a substitute or competitor to a tablet.  It is essentially a very tiny desktop machine which you use with a USB keyboard and mouse and HDMI monitor.  It excels for embedded and control applications and is often run “headless” and administered from other machines.  (Although mine has a keyboard, mouse, and monitor, I don’t think I’ve used them in over a year.)

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7. How many Raspberry Pi users are there here? Why do you like them? Are they better than  a tablet?

There are a lot of Raspberry Pi users out there.  It was originally developed for educational purposes, so young people are still the focus of a lot of the attention.

Although you can build it into a tablet, there is no real comparison.  It is a cheap (about \$35) and small single board computer that has the capabilities of the first mainframe computer I worked on in terms of computing power and memory.  As it comes, there is no keyboard or display, but it can be hooked up to them.  Because of its low cost, it is used in a lot of applications where the keyboard and display are not needed – called headless.  It typically runs various versions of Linux, so is a cheap way to learn the different distributions if you are interested.

I have been interested in cluster computing for a long time, but the Raspberry Pi made it much more affordable to play with.  I have a “tower” with 4 boards in it that I can access (using SSH, a secure computer to computer protocol) from my laptop over wireless.  That is the setup that does a distributed calculation of Pi.

Because it was an early entrant into this market and is so popular, there are a lot of add on products for it.  Adafruit is one of the more popular vendors.  You can see here what sort of things are available – https://www.adafruit.com/index.php?main_page=category&cPath=105

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8. WillowSpring:
…approximate Pi by dropping a needle “randomly” on a paper with parallel lines and using the lengths and distances and the count of the number of times the needle touched one of the lines*.

I did this.   We had a regular board floor with narrow boards.   I cut 40 toothpicks to length and dropped them.   After I had recorded the results for 2000 drops, I found that it worked amazingly well.   I got an accuracy that was greater than anything I had to measure with.

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