Comments on: ruby inject and the Mandelbrot set

By: Javi Fontan

Javi Fontan — Wed, 27 May 2009 01:12:54 +0000

Simply lovely.

And now for some performance wars I changed the number of iterations from 50 to 1000 and ran it using ruby 1.8.6 (the one that comes with Leopard), ruby 1.9.1p0 (2009-01-30 revision 21907) and MacRuby 0.4:

ruby 1.8.6
real 0m54.405s
user 0m54.209s
sys 0m0.083s

ruby 1.9.1p0
real 0m10.758s
user 0m8.756s
sys 0m0.133s

MacRuby 0.4
real 1m7.342s
user 1m19.255s
sys 0m2.261s

By: Michael Fairchild

Michael Fairchild — Tue, 26 May 2009 23:02:28 +0000

This is awesome. Mad props.
Here is a screenshot from a run of the code.
http://img.skitch.com/20090526-jdss7n6f8hssmmywnsyiam3ycb.jpg

By: Matt Pulver

Matt Pulver — Tue, 26 May 2009 17:47:33 +0000

@Arya: The meaning of the word “appropriate” depends upon what the goals are. The first goal here is to illustrate use of ruby’s inject function. If you can suggest a nearly equally succinct way to write the function

def mandelbrot(a)
Array.new(50,a).inject(a) { |z,c| z*z+c }
end

which illustrates use of the inject function that doesn’t use a 50-element array of identical values, then I would consider your nit pick “appropriate”.

By: Arya Asemanfar

Arya Asemanfar — Tue, 26 May 2009 15:51:13 +0000

That’s pretty cool output!

One nit pick though, it seems your usage of inject isn’t appropriate because you’re creating an array of size 50 just to iterate over something 50 times.

It might be more appropriate to do something like:

def mandelbrot(a)
  z = 0
  50.times { z = z * z + a }
  z
end

That way, if you want to do some large number of iterations, you don’t end up creating and destroying huge arrays. But I guess it’s just preference

By: Eimantas

Eimantas — Mon, 25 May 2009 17:58:15 +0000

awsomeness at it’s best! one can expand it to use colors in console ,)

By: Dave Nolan

Dave Nolan — Mon, 25 May 2009 15:34:00 +0000

That is a thing of beauty. Cheers!

By: ruby inject and category breadcrumbs

ruby inject and category breadcrumbs — Wed, 05 Mar 2008 18:26:47 +0000

[...] addition to mapping out the Mandelbrot set, ruby’s inject method can also be used to easily find and/or create nested categories given a [...]

By: Nate Murray

Nate Murray — Tue, 26 Feb 2008 17:50:11 +0000

Fantastic! The code is succinct and the output is beautiful. Raganwald just wrote another interesting article on Ruby inject that could be interesting to everyone (http://weblog.raganwald.com/2008/02/1100inject.html). As our interview last week said, if these types of constructs (map, inject, etc) should be interesting to anyone who is in the business of programming.

Thanks for the insightful post!