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Quick Update from the Computer Lab

Chet — Wed, 16 Nov 2011 02:26:27 +0000

Cornell Engineering is incredibly difficult, so I don’t write much. There is, however, much to tell on the recruiting front as I have seen some amazing offices and companies. I will update my readers in December or January.

Book Sale

Chet — Sat, 01 Oct 2011 17:16:37 +0000

I actually really love used books. The Ithaca Library System was having their annual sale and it’s quite something. I picked up Edward Tufte’s ‘Visual Display of Quantitative Information’ for $4.50 and a couple volumes of Plato and Virgil as well.

Rubik’s

Chet — Tue, 20 Sep 2011 03:34:53 +0000

I solved my first couple Rubik’s cubes this week, obviously while staring at algorithms for them, but hopefully I can commit these to memory at some point.

Cornell

Chet — Fri, 09 Sep 2011 20:00:27 +0000

Well, I’ve been a few weeks here at Cornell’s M.Eng program and I’m loving it. It’s amazing actually being with some of the smartest an innovative engineers in one place. We have so many great resources here to use too.

I’m currently taking AI, which I think will be good to brush up on my algorithms and searching, and I never had that in undergrad. I’m also in an Info Retrieval course which is doing some interesting stuff with text searching and MapReduce. Software Engineering is primarily about project management tasks, but involves building a substantial project. Finally, I’m taking statistics because I’m trying to keep my math sharp mostly, and there weren’t any other CS courses that fit well into my strategy and schedule.

Euclidean Algorithm

Chet — Sat, 04 Jul 2009 03:46:41 +0000

One of my favorite algorithms is the simple, elegant Euclidean algorithm for finding the greatest common denominator of two numbers. In ML or another functional language it really is beautiful:

1 2	fun gcd(a, 0) = a \| gcd(a, b) = gcd(b, a mod b);

Of course, the same can be done in Java iteratively:

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public int gcd(int a, int b){
int c;
while (b>0){
c = a;
a = b;
b = c%b;
}
return a;
}

Or recursively:

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public int gcd(int a, int b){
if(b==0){
return a;
}else{
return gcd(b, a%b);
}
}

Recursive Fibonacci

Chet — Sat, 04 Jul 2009 03:40:28 +0000

Here are two recursive fibonacci functions in ML I did for CS243. Can you tell which one is more efficient?

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fun fibonacci(n) =
let
fun fib((a, b), i)=
if i=0 then b
else fib((b, a + b), i-1);
in
fib((0, 1), n)
end;

fun fibonacci(0) = 1
| fibonacci(1) = 1
| fibonacci(n) = fibonacci(n-1) + fibonacci(n-2);

Circle Calculator

Chet — Sat, 04 Jul 2009 03:26:57 +0000

For my first code post I thought it might be appropriate to put the first code from the first lab of my first computer science class at Wheaton.

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import java.util.Scanner;
public class Circle {
public static void main(String[] args) {
Scanner keyboard = new Scanner(System.in); // input from keyboard
System.out.print("Please enter the radius-->");
double radius = keyboard.nextDouble(); // radius to work with
double diameter = radius*2;
System.out.println("The diameter is " + diameter);
double circumference = Math.PI*2*radius;
System.out.println("The circumference is " + circumference);
double area = Math.PI * Math.pow(radius, 2);
System.out.println("The area is " + area);
double volume = (4.0 / 3.0) * Math.PI * Math.pow(radius, 3);
System.out.println("The volume of a sphere is " + volume);
double surfaceArea = Math.PI * 4 * Math.pow(radius, 2);
System.out.println("The surface area of a sphere is " + surfaceArea);
}
}