Category Archives: Programming

More Mandelbrot

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I just recently revisited the M-Set code from my Perl Snippets post. The code I had was pretty ugly, so I decided to rewrite it in Python. The result is not only a lot cleaner and easier to understand, but it’s also a lot faster:

$ time python mandel.py > \dev\null
real	0m0.051s
user	0m0.036s
sys	0m0.010s
$ time perl mandel.pl > \dev\null
real	0m3.518s
user	0m3.463s
sys	0m0.029s

You can find the code here.

This script works well for zooms, as long as you stay below a few thousand iterations. The following picture was generated with x=-1.1887204, y=-0.3032472, width=0.01 and 150 iterations.

Perl Snippets

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I’ve been getting into a mood lately that makes me fiddle around with fun Perl stuff, but sadly school’s picking up to the point that writing anything up isn’t going to happen. However, I have a couple short scripts that I’m just dying to share.

Just Another Perl Hacker

I figured that it was about time in my hacking career (read: I was bored enough) that I should make a japh script. After a couple attempts I came up with this:

#!/usr/bin/perl
while(){
 	for (map{ord($_)-33}split ''){
		$__++;
		$_||(print(chr($__+19))&&($__=0));
	}
}

print "\n";

__END__
                   /|                        |\
      !            ; :                        : :
                  | Y,                      ,P |
     !             |  Yb.        __        ,dP  |
                  l\  YMMb,_ _,/  \,_ _,dMMP  /f
  !                 j;  `YMMP'  `--'  `YMMP'  ;j
                   : \   YP`-._    _.-'YP   / ;
  !            !      \ `\,  _,\_    _/,_  ,/' /
                     `,_,   \`o>  

Download.


I'll let you go ahead and figure it out on your own. It's not super-hard, but it's fun.


Mandelbrot


In another fit of boredom I decided that it was finally time to create a mandelbrot set renderer. I originally tried to make one of these in basic, long before I had the math to do so. I was proud that I got the real axis to render, and figured it was time to complexify it. To keep things simple I decided to make it render an ASCII-art version of the set that would fit in a terminal window. The output looks like this:


                        ...............................:::::oo@@@@o::::..........
                      ...............................::::::O@@@@@@@@o:::::.......
                     .............................::::::::oO@@@@@@@@o::::::::....
                   ...........................::::OOO8ooO@O88@@@@@@8@O8o::::Oo:..
                  .......................:::::::::o8@@@@@@@@@@@@@@@@@@@@OO@@@@::.
                 ...................:::::::::::::oOO@@@@@@@@@@@@@@@@@@@@@@@@@o:::
                ................:::::::::::::::o@@@@@@@@@@@@@@@@@@@@@@@@@@@@Oo:::
               ..............::::@oo::oOoo:::ooo@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@8o:
               ...........:::::::oO@@@O@@8@OooO8@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@O::
              ..........:::::::::oO@@@@@@@@@@88@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@::
              ........:::::::8ooO8@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@o::
              .:::::::::::::oO@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@o:::
              @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@Oo::::
              .:::::::::::::oO@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@o:::
              ........:::::::8ooO8@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@o::
              ..........:::::::::oO@@@@@@@@@@88@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@::
               ...........:::::::oO@@@O@@8@OooO8@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@O::
               ..............::::@oo::oOoo:::ooo@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@8o:
                ................:::::::::::::::o@@@@@@@@@@@@@@@@@@@@@@@@@@@@Oo:::
                 ...................:::::::::::::oOO@@@@@@@@@@@@@@@@@@@@@@@@@o:::
                  .......................:::::::::o8@@@@@@@@@@@@@@@@@@@@OO@@@@::.
                   ...........................::::OOO8ooO@O88@@@@@@8@O8o::::Oo:..
                     .............................::::::::oO@@@@@@@@o::::::::....
                      ...............................::::::O@@@@@@@@o:::::.......
                        ...............................:::::oo@@@@o::::..........


The code's far from polished and not what I like to publish, but it's a fun thing to look at and offers you some neat abilities to poke things around and fix some pesky problems that just need clear thinking applied to them. It's available here.

Genetic Algorithms in Perl

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Inspired by recent genetic algorithms floating around, I decided to try my hand at implementing one in perl. I’d thought for a long time that it would be quite difficult, but really it’s quite easy. My biggest hangup was dealing with data structures, but once I did that, it turns out that all you really need is a few functions:

  • A fitness function, that determines which individuals are most fit to reproduce
  • A mutate function, that will add random chance into each generation
  • A breed function that allows the best individuals to reproduce.

I ended up implementing a very simple algorithm, but it’s fairly fast and very generic โ€“ it can be easily adapted to just about any task. Sadly, I have no fascinating application just yet, but if I stumble across one, I’ll be sure to post about it.

After the jump, I’ll put up some of the code I used and a link to the script, all for your viewing pleasure.
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Fast and Simple Stock Quotes Using Perl

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One of the things that makes perl so powerful and fascinating is the huge number of modules that are available online, especially through the CPAN repository. Today I stumbled upon one called Finance::Quote, which does one thing, very simply: it retrieves stock (or mutual fund) quotes. You feed it a ticker symbol and it gives back a hash with all sorts of information, but most importantly, the price. I’m going to show how to use this to create a command line tool that will grab an up-to-the minute stock quote for any ticker symbol you give it.

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