about life, the universe, and everything
Yesterday the Pan-Mass Challenge presented a check for $26 million, 99% of the funds raised this year, to the Jimmy Fund in support of the Dana-Farber Cancer Institute, bringing the PMC’s 27-year total contribution to $171 million.
posted @ 11:28 PM EST
One of the interesting things about Cyberduck, an FTP client for Mac OS X, is that it is written in Java using Cocoa; certainly a rarity. It’s an open source project with web access to the Subversion code repository, so you can browse the implementation.
posted @ 08:03 AM EST
After a long hiatus I’ve added some bits to fnPad: hexadecimal and octal numbers, bitwise operations on integers, and functions that return hexadecimal and octal strings. Note that I used “$” for the “exclusive or” operator since I’d already taken “^” for exponentiation. I think that both of these make more graphical sense than the choice made in Java.
posted @ 11:44 AM EST
Here’s fnPad code to calculate the modular inverse.
// calculate the modular inverse
a = 5; b = 93
i = modi(a,b); i ≈ 56
i*a%b == 1 ≈ true // show that i is the modular inverse
// modular inverse of a mod b
modi(a,b) = mode(egcd(a,b),b)
// modular inverse given extended GCD (GCD must be 1)
mode(e,b) = ( e[1] == 1 ) ? e[2]%b + ( ( e[2] < 0 ) ? b : 0 ) : NaN
// extended greatest common divisor
egcd(a,b) = ( b == 0 ) ? { a, 1, 1 } : dcge(egcd(b,a%b),a/b)
// unwind from GCD; recurrence relation makes e[1] = e[2]*a + e[3]*b
dcge(e,q) = { e[1], e[3], e[2]-e[3]*q }
posted @ 07:39 AM EST
Here’s a reference for the algorithm used in the previously posted fnPad code that calculates the modular inverse. It looks to me as though there’s a bug in the pseudocode wherein the first returned vector should be { 1, 1 }.
posted @ 07:53 PM EST
The table of data below, released by the Pan-Mass Challenge, shows how unusual that event is in contributing 99% of funds raised to the charity it benefits.
| Event | Raised | Participants | Contributed |
| Pan-Mass Challenge | $26,000,000 | 4,271 | 99% |
| Nike Women’s Marathon | $12,000,000 | 15,000 | 70% |
| MS 150, Texas | $8,360,000 | 13,000 | 76% |
| 5 Livestrong Rides in US | $7,500,000 | 10,000 | 75% |
posted @ 08:16 PM EST
2006 Pan-Mass Challenge Team Dolben:
Hank Dolben, Don Dolben, Al Murphy, Martha Dolben, Deane Dolben, Sue Prakken, Mike Prakken, Dana Pope, and Drew Dolben.
posted @ 12:20 AM EST
This site routinely gets search hits for examples of use of the quadratic formula. See the calculation of the golden ratio for one of my favorites.
In fnPad the result might look this:
φ = (1+sqrt(5))/2
φ ≈ 1.618
posted @ 11:30 AM EST
About a year ago, I stuck my neck out at work and persuaded the software team and management to make a switch to Subversion for version control. It turned out to be a great choice as the system is the best I’ve seen—does everything you’d want, and is rock-solid. There, we do software development in Windows XP and use a Linux server for the repository.
For personal projects I like to use Xcode in Mac OS X where I’ve built Subversion from source without any difficulty, but recently took advantage of the convenience of a binary package made available by Martin Ott to update to the latest version.
posted @ 12:09 PM EST
Resonating strongly with my own view, in Team of Rivals, Doris Kearns Goodwin says:
Like the ancient Greeks, Lincoln seemed to believe that “ideas of a person’s worth are tied to the way others, both contemporaries and future generations, perceive him.” Unable to find comfort in the idea of a literal afterlife in heaven, he found consolation in the conviction that in the memories of others, some part of us remains alive.
[Today is the anniversary of Lincoln’s Gettysburg address.]
posted @ 08:38 AM EST
