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From: <ben...@id...> - 2004-05-25 07:46:25
|
Dear Open Source developer I am doing a research project on "Fun and Software Development" in which I kindly invite you to participate. You will find the online survey under http://fasd.ethz.ch/qsf/. The questionnaire consists of 53 questions and you will need about 15 minutes to complete it. With the FASD project (Fun and Software Development) we want to define the motivational significance of fun when software developers decide to engage in Open Source projects. What is special about our research project is that a similar survey is planned with software developers in commercial firms. This procedure allows the immediate comparison between the involved individuals and the conditions of production of these two development models. Thus we hope to obtain substantial new insights to the phenomenon of Open Source Development. With many thanks for your participation, Benno Luthiger PS: The results of the survey will be published under http://www.isu.unizh.ch/fuehrung/blprojects/FASD/. We have set up the mailing list fa...@we... for this study. Please see http://fasd.ethz.ch/qsf/mailinglist_en.html for registration to this mailing list. _______________________________________________________________________ Benno Luthiger Swiss Federal Institute of Technology Zurich 8092 Zurich Mail: benno.luthiger(at)id.ethz.ch _______________________________________________________________________ |
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From: Drew N. <dre...@ho...> - 2003-10-06 17:44:57
|
Hi Erik,
Thanks for starting this up again...
Indeed Karva notation does represent expression trees. There's a =
one-to-one mapping between Karva string and expression string. I'll =
read into this Koza stuff further.
The main benefit of the Karva notation is that mutation and crossover =
always lead to syntactically correct expression trees.
The main areas I'd like to tackle next fit together nicely. The first =
is allowing variable-length genomes. The second is to introduce a =
penalty tactic whereby smaller genomes (arguably more elegant solutions) =
are favoured. In my experience, penalties are trickly and delicate =
parameters for GAs.
Drew
----- Original Message -----=20
From: Erik Doernenburg=20
To: dn...@th...=20
Cc: inf...@li...=20
Sent: Monday, October 06, 2003 10:15 AM
Subject: [Infinitemonkeys-devel] GA/GP (was: Re: Infinite Monkeys)
Hi Drew,
let's continue this on the infinitemonkeys list...
Doing this kind of functional optimisation is probably the most common =
problem for GAs. That said, it could get you to solve the fist infinite =
monkeys problem quite easily.
Rather than Karva notation have you considered using a tree-based =
notation for your expressions, somewhat like Koza proposes?
http://www.geneticprogramming.com/Tutorial/
There are problems with this approach (Most notably: deep trees which =
you can't prune because the important nodes are down near the leaves) =
but it has its advantages.
cheers
erik
Drew Noakes
18/09/2003 08:18
To: Mike Mason/UK/ThoughtWorks@ThoughtWorks
cc: Adam Murdoch/OZ/ThoughtWorks@ThoughtWorks, Ahmed M =
Hassan/Corporate/ThoughtWorks/US@ThoughtWorks, Amit =
Rathore/India/ThoughtWorks@ThoughtWorks, Anand =
Vishwanath/India/ThoughtWorks@ThoughtWorks, Ashok =
Subramanian/India/ThoughtWorks@ThoughtWorks, Aslak =
Hellesoy/UK/ThoughtWorks@ThoughtWorks, Brett =
Dargan/OZ/ThoughtWorks@ThoughtWorks, Brilly =
Tsang/Corporate/ThoughtWorks/US@ThoughtWorks, Chris =
Stevenson/UK/ThoughtWorks@ThoughtWorks, Chris =
Tarttelin/UK/ThoughtWorks@ThoughtWorks, Darrell =
Deboer/OZ/ThoughtWorks@ThoughtWorks, Dragos =
Manolescu/US/ThoughtWorks@ThoughtWorks, Ed =
Turnock/UK/ThoughtWorks@ThoughtWorks, Erik =
Doernenburg/UK/ThoughtWorks@ThoughtWorks, Ian =
Bourke/UK/ThoughtWorks@ThoughtWorks, Ivan =
Moore/UK/ThoughtWorks@ThoughtWorks, James E =
Weaver/Corporate/ThoughtWorks/US@ThoughtWorks, Jason C =
Yip/Corporate/ThoughtWorks/US@ThoughtWorks, Jeremy =
Stell-Smith/Corporate/ThoughtWorks/US@ThoughtWorks, Joe =
Walnes/UK/ThoughtWorks@ThoughtWorks, Jon =
Tirs=E9n/UK/ThoughtWorks@ThoughtWo
rks, Lakshminarasimhan Sudarshan/India/ThoughtWorks@ThoughtWorks, =
Luke T Maxon/Corporate/ThoughtWorks/US@ThoughtWorks, Manoj K =
Bharadwaj/Corporate/ThoughtWorks/US@ThoughtWorks, Martin =
Andrews/OZ/ThoughtWorks@ThoughtWorks, Matthew P =
Foemmel/Corporate/ThoughtWorks/US@ThoughtWorks, Michael L =
Royle/Corporate/ThoughtWorks/US@ThoughtWorks, Mike =
Roberts/UK/ThoughtWorks@ThoughtWorks, Neil =
Fletcher/UK/ThoughtWorks@ThoughtWorks, Owen =
Rogers/Canada/ThoughtWorks@ThoughtWorks, Patrick B =
Sarnacke/Corporate/ThoughtWorks/US@TWorks, Paul =
Hammant/UK/ThoughtWorks@ThoughtWorks, Rajeev M =
Bhat/Corporate/ThoughtWorks/US@ThoughtWorks, Rebecca J =
Parsons/Corporate/ThoughtWorks/US@ThoughtWorks, Roger =
Marlow/UK/ThoughtWorks@ThoughtWorks, Sri Harsha K. =
M./India/ThoughtWorks@ThoughtWorks, Stacy =
Curl/UK/ThoughtWorks@ThoughtWorks, Steve =
Purcell/UK/ThoughtWorks@ThoughtWorks, Tim =
Bacon/UK/ThoughtWorks@ThoughtWorks, Tim =
Mackinnon/UK/ThoughtWorks@ThoughtWorks, William E =
Caputo/Corporate/ThoughtWorks/US@Thought
Works, Xiao Guo/Corporate/ThoughtWorks/US@ThoughtWorks, Yasser M =
Helmi/Corporate/ThoughtWorks/US@ThoughtWorks
Subject: Re: Infinite Monkeys
Hi All,
I've only just picked up this thread -- being home ill all of =
yesterday.
This topic is near to my heart. I've been working with GAs for the =
last six months of my free time, and have come up with some interesting =
results. The framework I've been writing is in .NET, and can evolve a =
wide range of problem cases. The case I've solved which is closest to =
the goal of this project involves discovering mathematical expressions =
to fit known data points.
A side-project that spawned from this covers parsing, notation, =
recombination and evaluation of expressions. Evaluation is performed in =
a variety of ways, but the snappiest uses System.Reflection.Emit to =
generate types at runtime from dynamically generated bytecode.
For example, with a target dataset for function f(x,y) =3D z...
x =3D 3, y =3D 4, z =3D 5
x =3D 1, y =3D 2, z =3D 2.236
x =3D 1.414, y =3D 1.414, z =3D 1.414
...and a random initial population of expressions, using these =
elements (reduced to characters for simplified presentation only -- each =
is an IExpressionElement object as a gene):
+ (addition)
* (multiplication)
Q (square root)
x (parameter)
y (parameter)
At the moment, I'm using a PostFix notation (the most common notation =
is InFix) in which expression 'a + b' is written as 'ab+', and 'Sqrt( =
(a*a) + (b*b) )' is written as 'aa*bb*+Q'. I'm currently working on =
support for Karva notation, which guarantees valid expressions (as with =
PostFix notation, crossover and mutation will mostly generate noisy =
expressions, such as '+a+bbQ' which can only be evalulated as =
'Sqrt(b)').
The above sample data is from Pythagorus' theorem, and the GA =
successfully evolves a solution about 50% of the time. Through using =
Karva notation, a new set of mutation functions and variable length =
genomes (I'm currently only using fixed length genomes) I'm hoping to =
get even better results.
Whilst this work deals with mathematical expressions, the general =
approach could be extended to work with higher-level procedural code =
trees. Graph reduction theory and sub-genome (gene) sharing techniques =
bring to mind method/variable extraction.
I've also coded solutions (well, GAs are non-deterministic, so I don't =
know if you call them 'solutions') to other non-programming problems, =
such as the travelling salesman problem (a GA classic), the napsack =
problem, mastermind (the board game), the Chinese Hat problem, and =
functional optimisation (maximising or minimising a functional value, =
exemplified most easily on 3D functions with many local max/minima, and =
a single global max/minimum).
Some reading:
http://web.media.mit.edu/~lieber/PBE/
=
http://www.testdriven.com/modules/newbb/viewtopic.php?viewmode=3Dflat&top=
ic_id=3D206&forum=3D6
(Aaargg! There's a site out there by a =
Fowler/Gamma/Jeffries/Beck/someone on this, but I can't find it...)
I was going to hold a session on this at the away day -- it's a shame =
I didn't go through with the idea. I'd really like to bounce these =
ideas off some people. Anyone fancy meeting up at Peek House sometime?
Drew Noakes
ThoughtWorks, Inc. UK
-------------------------------------------------------
This sf.net email is sponsored by:ThinkGeek
Welcome to geek heaven.
http://thinkgeek.com/sf
_______________________________________________
Infinitemonkeys-devel mailing list
Inf...@li...
https://lists.sourceforge.net/lists/listinfo/infinitemonkeys-devel
|
|
From: Erik D. <er...@th...> - 2003-10-06 09:16:34
|
Hi Drew,
let's continue this on the infinitemonkeys list...
Doing this kind of functional optimisation is probably the most common problem for GAs. That said, it could get you to solve the fist infinite monkeys problem quite easily.
Rather than Karva notation have you considered using a tree-based notation for your expressions, somewhat like Koza proposes?
http://www.geneticprogramming.com/Tutorial/
There are problems with this approach (Most notably: deep trees which you can't prune because the important nodes are down near the leaves) but it has its advantages.
cheers
erik
Drew Noakes
18/09/2003 08:18
To: Mike Mason/UK/ThoughtWorks@ThoughtWorks
cc: Adam Murdoch/OZ/ThoughtWorks@ThoughtWorks, Ahmed M Hassan/Corporate/ThoughtWorks/US@ThoughtWorks, Amit Rathore/India/ThoughtWorks@ThoughtWorks, Anand Vishwanath/India/ThoughtWorks@ThoughtWorks, Ashok Subramanian/India/ThoughtWorks@ThoughtWorks, Aslak Hellesoy/UK/ThoughtWorks@ThoughtWorks, Brett Dargan/OZ/ThoughtWorks@ThoughtWorks, Brilly Tsang/Corporate/ThoughtWorks/US@ThoughtWorks, Chris Stevenson/UK/ThoughtWorks@ThoughtWorks, Chris Tarttelin/UK/ThoughtWorks@ThoughtWorks, Darrell Deboer/OZ/ThoughtWorks@ThoughtWorks, Dragos Manolescu/US/ThoughtWorks@ThoughtWorks, Ed Turnock/UK/ThoughtWorks@ThoughtWorks, Erik Doernenburg/UK/ThoughtWorks@ThoughtWorks, Ian Bourke/UK/ThoughtWorks@ThoughtWorks, Ivan Moore/UK/ThoughtWorks@ThoughtWorks, James E Weaver/Corporate/ThoughtWorks/US@ThoughtWorks, Jason C Yip/Corporate/ThoughtWorks/US@ThoughtWorks, Jeremy Stell-Smith/Corporate/ThoughtWorks/US@ThoughtWorks, Joe Walnes/UK/ThoughtWorks@ThoughtWorks, Jon Tirsén/UK/ThoughtWorks@ThoughtWorks, Lakshminarasimhan Sudarshan/India/ThoughtWorks@ThoughtWorks, Luke T Maxon/Corporate/ThoughtWorks/US@ThoughtWorks, Manoj K Bharadwaj/Corporate/ThoughtWorks/US@ThoughtWorks, Martin Andrews/OZ/ThoughtWorks@ThoughtWorks, Matthew P Foemmel/Corporate/ThoughtWorks/US@ThoughtWorks, Michael L Royle/Corporate/ThoughtWorks/US@ThoughtWorks, Mike Roberts/UK/ThoughtWorks@ThoughtWorks, Neil Fletcher/UK/ThoughtWorks@ThoughtWorks, Owen Rogers/Canada/ThoughtWorks@ThoughtWorks, Patrick B Sarnacke/Corporate/ThoughtWorks/US@TWorks, Paul Hammant/UK/ThoughtWorks@ThoughtWorks, Rajeev M Bhat/Corporate/ThoughtWorks/US@ThoughtWorks, Rebecca J Parsons/Corporate/ThoughtWorks/US@ThoughtWorks, Roger Marlow/UK/ThoughtWorks@ThoughtWorks, Sri Harsha K. M./India/ThoughtWorks@ThoughtWorks, Stacy Curl/UK/ThoughtWorks@ThoughtWorks, Steve Purcell/UK/ThoughtWorks@ThoughtWorks, Tim Bacon/UK/ThoughtWorks@ThoughtWorks, Tim Mackinnon/UK/ThoughtWorks@ThoughtWorks, William E Caputo/Corporate/ThoughtWorks/US@ThoughtWorks, Xiao Guo/Corporate/ThoughtWorks/US@ThoughtWorks, Yasser M Helmi/Corporate/ThoughtWorks/US@ThoughtWorks
Subject: Re: Infinite Monkeys
Hi All,
I've only just picked up this thread -- being home ill all of yesterday.
This topic is near to my heart. I've been working with GAs for the last six months of my free time, and have come up with some interesting results. The framework I've been writing is in .NET, and can evolve a wide range of problem cases. The case I've solved which is closest to the goal of this project involves discovering mathematical expressions to fit known data points.
A side-project that spawned from this covers parsing, notation, recombination and evaluation of expressions. Evaluation is performed in a variety of ways, but the snappiest uses System.Reflection.Emit to generate types at runtime from dynamically generated bytecode.
For example, with a target dataset for function f(x,y) = z...
x = 3, y = 4, z = 5
x = 1, y = 2, z = 2.236
x = 1.414, y = 1.414, z = 1.414
...and a random initial population of expressions, using these elements (reduced to characters for simplified presentation only -- each is an IExpressionElement object as a gene):
+ (addition)
* (multiplication)
Q (square root)
x (parameter)
y (parameter)
At the moment, I'm using a PostFix notation (the most common notation is InFix) in which expression 'a + b' is written as 'ab+', and 'Sqrt( (a*a) + (b*b) )' is written as 'aa*bb*+Q'. I'm currently working on support for Karva notation, which guarantees valid expressions (as with PostFix notation, crossover and mutation will mostly generate noisy expressions, such as '+a+bbQ' which can only be evalulated as 'Sqrt(b)').
The above sample data is from Pythagorus' theorem, and the GA successfully evolves a solution about 50% of the time. Through using Karva notation, a new set of mutation functions and variable length genomes (I'm currently only using fixed length genomes) I'm hoping to get even better results.
Whilst this work deals with mathematical expressions, the general approach could be extended to work with higher-level procedural code trees. Graph reduction theory and sub-genome (gene) sharing techniques bring to mind method/variable extraction.
I've also coded solutions (well, GAs are non-deterministic, so I don't know if you call them 'solutions') to other non-programming problems, such as the travelling salesman problem (a GA classic), the napsack problem, mastermind (the board game), the Chinese Hat problem, and functional optimisation (maximising or minimising a functional value, exemplified most easily on 3D functions with many local max/minima, and a single global max/minimum).
Some reading:
http://web.media.mit.edu/~lieber/PBE/
http://www.testdriven.com/modules/newbb/viewtopic.php?viewmode=flat&topic_id=206&forum=6
(Aaargg! There's a site out there by a Fowler/Gamma/Jeffries/Beck/someone on this, but I can't find it...)
I was going to hold a session on this at the away day -- it's a shame I didn't go through with the idea. I'd really like to bounce these ideas off some people. Anyone fancy meeting up at Peek House sometime?
Drew Noakes
ThoughtWorks, Inc. UK
|
