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12/6/2019 7:27:02 PM
Posted: 3/14/2005 7:05:16 PM EST
[Last Edit: 3/14/2005 7:06:25 PM EST by MadMardigan]
The Good Will Hunting question



1) Find the adjacency matrix A of the graph G

2) Find the matrix giving the number of 3 step walks in G.

3) Find the generating function for walks from point i to j.

4) Find the generating function for walks from points 1 to 3.

The adjacency matrix L encodes the graph. The entry Lij is equal to k if there are k connections between node i and j. Otherwise, the entry is zero. Problem 2 asks to find the matrix which encodes all possible paths of length 3.

Generating function. To a graph one can assign for pair of nodes i,j a series , where an(ij) is the number of walks from i to j with n steps. Problem 3) asks for a formula for f(z) and in problem 4) an explicit expression in the case i=1,j=3.

If you want to cheat, here is where I got the question from......



http://www.math.harvard.edu/archive/21b_fall_03/goodwill/
Link Posted: 3/14/2005 7:24:41 PM EST
I agree.
Link Posted: 3/14/2005 7:25:48 PM EST
42.
Link Posted: 3/14/2005 7:26:10 PM EST
The numbers add up to 10.
Link Posted: 3/14/2005 7:26:33 PM EST
Name one real world application for this problem?

Not trying to be an assclown, I just don't get it's relevance to anything in my world.
Link Posted: 3/14/2005 7:35:35 PM EST
graphs are used in data structures in programming.
Link Posted: 3/14/2005 8:07:47 PM EST
I don't know about you big city folks, but where I come from a man's adjacency matrix is something he keeps to himself. Besides, I would want you to feel insecure after I shared mine with you.
Link Posted: 3/14/2005 8:12:16 PM EST
Link Posted: 3/14/2005 8:47:10 PM EST
Don't scare me like that! Got my stochastic modeling midterm tomorrow! Currently studying my ass off -- with intermittent ar15.com breaks of course.
Link Posted: 3/14/2005 9:02:58 PM EST
If I had any understanding at all of anything in the first post I'd be happy to answer. Since I know something of everything important in the universe and nothing of this question it is therefore useless and irrelevant. You sir are hereby banned from all further posting on this or any other website. I say gooday to you.
Link Posted: 3/14/2005 9:16:09 PM EST
the real answer is 2, not 3 nor 4, but 2, doesn't matter what bs the org site said, it's 2
Link Posted: 3/15/2005 1:07:37 AM EST
Link Posted: 3/15/2005 1:14:46 AM EST
adjacency matrix

Is that the sequel or prequel?
Link Posted: 3/15/2005 2:47:09 PM EST

Originally Posted By threefiftynone:
Eleventy billion +.9bar.

Your coat's in the mail. Should be there tomorrow.



Thanks 350, you the man, and king of bump
Link Posted: 3/15/2005 2:50:15 PM EST

Originally Posted By 4xys2xxs:
Name one real world application for this problem?

Not trying to be an assclown, I just don't get it's relevance to anything in my world.



You can impress chicks with your knowledge at bars
Link Posted: 3/15/2005 3:01:43 PM EST

Originally Posted By MadMardigan:
The Good Will Hunting question

www.math.harvard.edu/archive/21b_fall_03/goodwill/img/graph.gif

1) Find the adjacency matrix A of the graph G

2) Find the matrix giving the number of 3 step walks in G.

3) Find the generating function for walks from point i to j.

4) Find the generating function for walks from points 1 to 3.

The adjacency matrix L encodes the graph. The entry Lij is equal to k if there are k connections between node i and j. Otherwise, the entry is zero. Problem 2 asks to find the matrix which encodes all possible paths of length 3.

Generating function. To a graph one can assign for pair of nodes i,j a series www.math.harvard.edu/archive/21b_fall_03/goodwill/img/01.gif, where an(ij) is the number of walks from i to j with n steps. Problem 3) asks for a formula for f(z) and in problem 4) an explicit expression in the case i=1,j=3.

If you want to cheat, here is where I got the question from......



http://www.math.harvard.edu/archive/21b_fall_03/goodwill/




ohhh god, I just had to withdraw from my math class this semester. Linear functions and matirx operations. This thread gave me flashbacks, and I'll probably have nightmares tonight
Link Posted: 3/15/2005 3:03:20 PM EST
Pretty colors.
Link Posted: 3/15/2005 3:08:15 PM EST
I dont know about that shit but 10 clicks up from my 200 yard zero puts me dead on at 300 yards!!



1/4 min clicks
Link Posted: 3/15/2005 4:05:29 PM EST
Ahhhh, yes.....but the real question is what round is needed to kill it.


On second thought, wasn't that the graph thingy that Pacino had in that one movie?
Link Posted: 3/15/2005 4:11:03 PM EST
I'm going with D. All of the Above..........
Link Posted: 3/15/2005 5:03:01 PM EST
Oh, no! Another forty-two thousand years!
Link Posted: 3/15/2005 5:11:35 PM EST
After further thought, you can't get there from here.
Link Posted: 3/15/2005 7:02:39 PM EST
[Last Edit: 3/15/2005 7:03:16 PM EST by mattja]
That brings back bad memories.

I took graph theory as part of the CS program at a local college. The professor had a PhD from Berkeley and worked at Lawrence Livermore Labs on the SDI program. I think the project he was in was called "smart pebbles" or “brilliant pebbles.” The guy had torn, shabby cloths, matted stringy hair, drove a POS VW bus and had an IQ or at least 200. The focker had the most intense blue eyes I have ever seen. Kind of a mad scientist type.

I hated that shit! Other than sparse matrices, I have never used any of that stuff in 20 years of programming.

Of course, it can be useful for minimum spanning trees, shortest path algorithms, etc.
Link Posted: 3/15/2005 7:24:43 PM EST
Ive had engineering math in the past, Calc 1 and 2, the bad part is, my prof. wrote the books, actually wrote 23 books, and probally has written some more. This guy had 5 degrees when I was in college, and was working on another one. 1 PhD, 2 Masters, and 2 BS. I thought this would be a good one since that .999 ~ 1 thread awhile back.
Link Posted: 3/15/2005 7:25:40 PM EST

Originally Posted By Zack3g:
42.



Agreed.
Link Posted: 3/15/2005 7:27:46 PM EST
It goes to eleven.
Link Posted: 3/15/2005 7:29:14 PM EST
False
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