Exchange Matrix

thornahawk · Posted: 20 Aug 2008 11:26:36 am Post subject:

Write a program that, without using matrix variables except Ans for storage, will generate an N×N exchange matrix given N in Ans.

My attempt was at 41 bytes plus program name.

thornahawk

DarkerLine · Posted: 20 Aug 2008 11:47:37 am Post subject:

Exchange matrix - a "reversed" identity matrix with the 1s along the other diagonal.

Also, I've got 37 bytes.

Ed H · Member Joined: 30 Nov 2007 Posts: 138

I've also got 37. You started with the identity matrix and then rowswapped, right?

Weregoose · Posted: 20 Aug 2008 08:25:35 pm Post subject:

I also have 37 bytes.

thornahawk · Posted: 20 Aug 2008 08:55:02 pm Post subject:

It turns out what I had was optimizable to the 37 bytes the rest of you got. :o

(edit: Whoops, I goofed. Back to the drawing board.)

thornahawk

alexrudd · Posted: 21 Aug 2008 12:32:14 am Post subject:

If you let me output to the homescreen instead of a matrix variable...

I can get 36 bytes, including program name.

DarkerLine · Posted: 21 Aug 2008 09:50:15 am Post subject:

Ah, but if you let me output to the graph screen using black pixels to represent 1 and white pixels to represent 0...

I can get 29 bytes plus the length of the name.

Weregoose · Posted: 21 Aug 2008 10:29:48 am Post subject:

AxesOff
ZInteger
Line(Ans,Ans,1,1

22 bytes. Totally valid.

[EDIT]

Sure, you could add in FnOff, PlotsOff, and GridOff...

DarkerLine · Posted: 21 Aug 2008 11:02:35 am Post subject:

I was thinking with the matrix starting from the top left corner. But that works too.

alexrudd · Posted: 21 Aug 2008 05:07:16 pm Post subject:

With your methods, how do I know that you don't have a matrix the size of the screen with a bit that looks like the exchange matrix in the middle?

Anyway, mine's fairly easy. I forgot that my name was >1 character, so it's 34 bytes with a one-byte name.