November 2010
<<October November December>>
November's challenge is dedicated to IBM Fellow Benoît Mandelbrot, who died on October 14, 2010, at the age of 85.
Let's define a function f on five variables (i, j, k, l, and m) as follows:
If (i-m)*(j-m) is zero then
f(i,j,k,l,m) ← ((abs(j-(1-k+l)*m)-m+1)* (abs(i-(k+l)*m)-m+1))
else
f(i,j,k,l,m) ← f(i mod m,
j mod m,
int(((i^j)&((m*l)^i))/m)^l^k^int(i/m),
int(((i^j)&((m*k)^i))/m)^l,
m/2)
Where
x^y means bitwise xor (exclusive or)
x&y means bitwise and (conjunction)
abs is the absolute value
mod is the modulo function
int means truncating downwards to an integer
What should be the input to the function f, and how do you need to interpret its output to associate it with Professor Mandelbrot?
Update: November 5th: We are *not* looking for his age.
Update: December 1st: m is a power of 2.
We will post the names of those who submit a correct, original solution! If you don't want your name posted then please include such a statement in your submission!
We invite visitors to our website to submit an elegant solution. Send your submission to the ponder@il.ibm.com.
If you have any problems you think we might enjoy, please send them in. All replies should be sent to: ponder@il.ibm.com
Challenge:
11/02/2010 @ 10:30 AM EST
Solution:
List Updated:
11/02/2010 @ 10:30 AM EST
People who answered correctly:
Mark Mixer (11/02/2010 08:32 PM EDT)
John Tromp (11/02/2010 11:50 PM EDT)
John T. Robinson (11/11/2010 03:16 PM EDT)
Sylvain Becker (11/11/2010 08:22 PM EDT)
Piet Orye (11/15/2010 10:34 AM EDT)
Tim Tran (12/05/2010 04:31 AM EDT)
Luke Pebody (12/06/2010 04:00 PM EDT)
Attention: If your name is posted here and you wish it removed please send email to the ponder@il.ibm.com.