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Search found 14 results on 1 pages for 'psych'.

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• How to fix "ruby installation is missing psych (for YAML output)." on CentOS?

  - by ohho

  After rvm installation on CentOS 5.8: [rails@localhost ~]$ rvm -v rvm 1.16.17 [rails@localhost ~]$ which ruby ~/.rvm/rubies/ruby-1.9.3-p286/bin/ruby [rails@localhost ~]$ ruby -v ruby 1.9.3p286 (2012-10-12 revision 37165) [i686-linux] [rails@localhost ~]$ which gem ~/.rvm/rubies/ruby-1.9.3-p286/bin/gem there is a warning: $ gem -v /home/rails/.rvm/rubies/ruby-1.9.3-p286/lib/ruby/1.9.1/yaml.rb:56:in `<top (required)>': It seems your ruby installation is missing psych (for YAML output). To eliminate this warning, please install libyaml and reinstall your ruby. 1.8.24 I followed some advice: $ rvm pkg install libyaml Fetching yaml-0.1.4.tar.gz to /home/rails/.rvm/archives Extracting yaml-0.1.4.tar.gz to /home/rails/.rvm/src Prepare yaml in /home/rails/.rvm/src/yaml-0.1.4. Configuring yaml in /home/rails/.rvm/src/yaml-0.1.4. Compiling yaml in /home/rails/.rvm/src/yaml-0.1.4. Installing yaml to /home/rails/.rvm/usr Please note that it's required to reinstall all rubies: rvm reinstall all --force and then: $ rvm reinstall all --force Removing /home/rails/.rvm/src/ruby-1.8.7-p371... Removing /home/rails/.rvm/rubies/ruby-1.8.7-p371... No binary rubies available for: centos/5.8/i386/ruby-1.8.7-p371. Continuing with compilation. Please read 'rvm mount' to get more information on binary rubies. Installing Ruby from source to: /home/rails/.rvm/rubies/ruby-1.8.7-p371, this may take a while depending on your cpu(s)... ruby-1.8.7-p371 - #downloading ruby-1.8.7-p371, this may take a while depending on your connection... ruby-1.8.7-p371 - #extracting ruby-1.8.7-p371 to /home/rails/.rvm/src/ruby-1.8.7-p371 ruby-1.8.7-p371 - #extracted to /home/rails/.rvm/src/ruby-1.8.7-p371 Applying patch /home/rails/.rvm/patches/ruby/1.8.7/stdout-rouge-fix.patch Applying patch /home/rails/.rvm/patches/ruby/1.8.7/no_sslv2.diff ruby-1.8.7-p371 - #configuring ruby-1.8.7-p371 - #compiling ruby-1.8.7-p371 - #installing Removing old Rubygems files... Installing rubygems-1.8.24 for ruby-1.8.7-p371 ... Installation of rubygems completed successfully. Saving wrappers to '/home/rails/.rvm/bin'. ruby-1.8.7-p371 - #adjusting #shebangs for (gem irb erb ri rdoc testrb rake). ruby-1.8.7-p371 - #importing default gemsets (/home/rails/.rvm/gemsets/) Install of ruby-1.8.7-p371 - #complete Please be aware that you just installed a ruby that requires 2 patches just to be compiled on up to date linux system. This may have known and unaccounted for security vulnerabilities. Please consider upgrading to Ruby 1.9.3-286 which will have all of the latest security patches. Making gemset ruby-1.8.7-p371 pristine. Making gemset ruby-1.8.7-p371@global pristine. Removing /home/rails/.rvm/src/ruby-1.9.3-p286... Removing /home/rails/.rvm/rubies/ruby-1.9.3-p286... No binary rubies available for: centos/5.8/i386/ruby-1.9.3-p286. Continuing with compilation. Please read 'rvm mount' to get more information on binary rubies. Installing Ruby from source to: /home/rails/.rvm/rubies/ruby-1.9.3-p286, this may take a while depending on your cpu(s)... ruby-1.9.3-p286 - #downloading ruby-1.9.3-p286, this may take a while depending on your connection... ruby-1.9.3-p286 - #extracting ruby-1.9.3-p286 to /home/rails/.rvm/src/ruby-1.9.3-p286 ruby-1.9.3-p286 - #extracted to /home/rails/.rvm/src/ruby-1.9.3-p286 ruby-1.9.3-p286 - #configuring ruby-1.9.3-p286 - #compiling ruby-1.9.3-p286 - #installing Removing old Rubygems files... Installing rubygems-1.8.24 for ruby-1.9.3-p286 ... Installation of rubygems completed successfully. Saving wrappers to '/home/rails/.rvm/bin'. ruby-1.9.3-p286 - #adjusting #shebangs for (gem irb erb ri rdoc testrb rake). ruby-1.9.3-p286 - #importing default gemsets (/home/rails/.rvm/gemsets/) Install of ruby-1.9.3-p286 - #complete Making gemset ruby-1.9.3-p286 pristine. Making gemset ruby-1.9.3-p286@global pristine. Too bad, the warning is still there: $ gem -v /home/rails/.rvm/rubies/ruby-1.9.3-p286/lib/ruby/1.9.1/yaml.rb:56:in `<top (required)>': It seems your ruby installation is missing psych (for YAML output). To eliminate this warning, please install libyaml and reinstall your ruby. 1.8.24 How can I get rid of the warning? UPDATE: (applying rvm reinstall 1.9.3 --movable) $ rvm reinstall 1.9.3 --movable Removing /home/rails/.rvm/src/ruby-1.9.3-p286... Removing /home/rails/.rvm/rubies/ruby-1.9.3-p286... Fetching yaml-0.1.4.tar.gz to /home/rails/.rvm/archives Extracting yaml-0.1.4.tar.gz to /home/rails/.rvm/src Prepare yaml in /home/rails/.rvm/src/yaml-0.1.4. Configuring yaml in /home/rails/.rvm/src/yaml-0.1.4. Compiling yaml in /home/rails/.rvm/src/yaml-0.1.4. Installing yaml to /home/rails/.rvm/rubies/ruby-1.9.3-p286 Installing Ruby from source to: /home/rails/.rvm/rubies/ruby-1.9.3-p286, this may take a while depending on your cpu(s)... ruby-1.9.3-p286 - #downloading ruby-1.9.3-p286, this may take a while depending on your connection... ruby-1.9.3-p286 - #extracting ruby-1.9.3-p286 to /home/rails/.rvm/src/ruby-1.9.3-p286 ruby-1.9.3-p286 - #extracted to /home/rails/.rvm/src/ruby-1.9.3-p286 Applying patch /home/rails/.rvm/patches/ruby/1.9.3/ruby-multilib.patch Error running 'patch -F 25 -p1 -N -f -i /home/rails/.rvm/patches/ruby/1.9.3/ruby-multilib.patch', please read /home/rails/.rvm/log/ruby-1.9.3-p286/patch.apply.ruby-multilib.log There has been an error applying the specified patches. Halting the installation. Making gemset ruby-1.9.3-p286 pristine. Making gemset ruby-1.9.3-p286@global pristine.

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• rails g migration error

  - by user1506183

  I don't know what to do. Try to use command $ rails g migration vacancy but this command give me error: invoke active_record /home/proger/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/psych.rb:203:in `parse': (<unknown>): mapping values are not allowed in this context at line 21 column 11 (Psych::SyntaxError) from /home/proger/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/psych.rb:203:in `parse_stream' from /home/proger/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/psych.rb:151:in `parse' ... There are many rows in error code I don't know how to fix that Thanks

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• how to properly credit authors of MIT license program

  - by kon psych

  Although I have found similar questions on this site they were not what I was looking for. I have modified the source code of an MIT licensed project, and I have added new classes to it as well. Please correct me if I am wrong, but I think that it is legal to add my copyright notice above the license and remove the other one. But how should I attribute the contribution of the previous authors? Should I use a separate file? There are also some html files with no license or copyright notice in them which I also modified. Do I have to handle them differently? My question is different than this question in that I have also modified some of the files of the project I am extending.

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• Error whilst starting rails server

  - by Sajeer

  I am new to rails and the bundle install works fine for the project. but when I start the rails server errors are shown.The shown errors are attached herewith. Exiting C:/Ruby193/lib/ruby/1.9.1/psych.rb:203:in `parse': (): could not find e xpected ':' while scanning a simple key at line 27 column 3 (Psych::SyntaxError) from C:/Ruby193/lib/ruby/1.9.1/psych.rb:203:in `parse_stream' from C:/Ruby193/lib/ruby/1.9.1/psych.rb:151:in `parse' from C:/Ruby193/lib/ruby/1.9.1/psych.rb:127:in `load' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/railties-3.2.2/lib/rails/applic ation/configuration.rb:115:in database_configuration' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/activerecord-3.2.2/lib/active_r ecord/railtie.rb:75:inblock (2 levels) in ' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_ support/lazy_load_hooks.rb:36:in instance_eval' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_ support/lazy_load_hooks.rb:36:inexecute_hook' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_ support/lazy_load_hooks.rb:26:in on_load' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/activerecord-3.2.2/lib/active_r ecord/railtie.rb:74:inblock in ' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/railties-3.2.2/lib/rails/initia lizable.rb:30:in instance_exec' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/railties-3.2.2/lib/rails/initia lizable.rb:30:inrun' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/railties-3.2.2/lib/rails/initia lizable.rb:55:in block in run_initializers' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/railties-3.2.2/lib/rails/initia lizable.rb:54:ineach' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/railties-3.2.2/lib/rails/initia lizable.rb:54:in run_initializers' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/railties-3.2.2/lib/rails/applic ation.rb:136:ininitialize!' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/railties-3.2.2/lib/rails/railti e/configurable.rb:30:in method_missing' from D:/ROR/appmallserver/config/environment.rb:22:in' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_ support/dependencies.rb:251:in require' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_ support/dependencies.rb:251:inblock in require' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_ support/dependencies.rb:236:in load_dependency' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_ support/dependencies.rb:251:inrequire' from D:/ROR/appmallserver/config.ru:4:in block in <main>' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/rack-1.4.1/lib/rack/builder.rb: 51:ininstance_eval' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/rack-1.4.1/lib/rack/builder.rb: 51:in initialize' from D:/ROR/appmallserver/config.ru:1:innew' from D:/ROR/appmallserver/config.ru:1:in <main>' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/rack-1.4.1/lib/rack/builder.rb: 40:ineval' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/rack-1.4.1/lib/rack/builder.rb: 40:in parse_file' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/rack-1.4.1/lib/rack/server.rb:2 00:inapp' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/railties-3.2.2/lib/rails/comman ds/server.rb:46:in app' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/rack-1.4.1/lib/rack/server.rb:3 01:inwrapped_app' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/rack-1.4.1/lib/rack/server.rb:2 52:in start' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/railties-3.2.2/lib/rails/comman ds/server.rb:70:instart' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/railties-3.2.2/lib/rails/comman ds.rb:55:in block in <top (required)>' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/railties-3.2.2/lib/rails/comman ds.rb:50:intap' from C:/Ruby193/lib/ruby/gems/1.9.1/gems/railties-3.2.2/lib/rails/comman ds.rb:50:in <top (required)>' from script/rails:21:inrequire' from script/rails:21:in `'

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• How to concatenate multiple lines of log file into single variable in batch file?

  - by psych

  I have a log file containing a stack trace split over a number of lines. I need to read this file into a batch file and remove all of the lines breaks. As a first step, I tried this: if exist "%log_dir%\Log.log" ( for /F "tokens=*" %%a in ("%log_dir%\Log.log") do @echo %%a ) My expectation was that this would echo out each line of the log file. I was then planning to concatenate these lines together and set that value in a variable. However, this code doesn't do what I would expect. I have tried changing the value of the options for delims and tokens, but the only output I can get is the absolute path to the log file and nothing from the contents of this file. How can I set a variable to be equal to the lines of text in a file with the line breaks removed?

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• Why is YAML installing to my home directory instead of its proper directory?

  - by Zack Shapiro

  I keep getting the following error when installing Ruby 1.9.3-p125: It seems your ruby installation is missing psych (for YAML output). To eliminate this warning, please install libyaml and reinstall your ruby. I've tried installing LibYAML and for some reason it's installing in my home directory on OS X Lion where the Documents, Music, Pictures, etc. folders are. Any idea how I can get rid of this error, properly install YAML and never have to deal with this again?

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• Reinstall ruby (or just yaml lib)

  - by Christian Sciberras

  I've installed ruby 1.9 from source, and tried installing gem 'bundler': < gem install bundler > /usr/local/lib/ruby/1.9.1/yaml.rb:56:in `<top (required)>': > It seems your ruby installation is missing psych (for YAML output). > To eliminate this warning, please install libyaml and reinstall your ruby. > .... I've not been able to cleanly uninstall ruby (wtf?!), and installing libyaml at this point didn't help either. So it seems I've ended up with a fk-ed up server since I can't rollback nor fix the issue. Of course, I do have backups, but this situation is ridiculous nonetheless. Surely there must be a real fix?

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• Life and Career guidance

  - by Andrei TheGiant Haxtor

  Hello programmers. I have a current dilemma I'm pondering over. I will be graduating from high school with ~60 credits worth of community college work (pre-engineering courses), and I am wondering what would experienced programmers suggest I do with my time since I have all of the bull courses out of the way. Should I start taking computer science/engineering courses or should I take some other courses that interest me?(psych, math) The reason I am asking this is, well , I like doing a lot of self studying, especially relating to software and tech. I don't like to have the pressure of hard classes on me, so I could make up for the time lost doing the CC courses and dive deep in programming and books. I've started getting into programming recently unfortunately, since I didn't have much time b/c of my course load. Right now I am doing Java and messing around with android. I would like to get involved in web&mobile development, operating systems, and finance software. If any of you experienced people could please give me some guidance and words of wisdom, I would greatly appreciated. Sorry that this isn't necessarily related to programming. All the best.

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• Installing Ruby On Rails - Issues with gem (and no RVM)

  - by JXPheonix

  I'm having this issue whenever i run "gem install rails": usr/local/lib/ruby/1.9.1/yaml.rb:56:in `<top (required)>': It seems your ruby installation is missing psych (for YAML output). To eliminate this warning, please install libyaml and reinstall your ruby. ERROR: Loading command: install (LoadError) cannot load such file -- zlib ERROR: While executing gem ... (NameError) uninitialized constant Gem::Commands::InstallCommand Ruby and Rubygems were both installed from source. I've installed libyaml from source and from apt-get. I'm running ubuntu 12.04. I am NOT running RVM as far as I know (trying "rvm" returns "bla bla bla not installed apt-get". I'm pretty sure this speaks of 2 separate issues but I need solutions to both. Thanks.

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• rvm `require': no such file to load -- rubygems (LoadError)

  - by xxd

  run a ruby code got error "rvm `require': no such file to load -- rubygems (LoadError)" bash-3.2$ rvm --default ruby-2.0.0-p451 -bash-3.2$ rvm list rvm rubies =* ruby-2.0.0-p451 [ x86_64 ] -bash-3.2$ gem list --local *** LOCAL GEMS *** bigdecimal (1.2.0) bundler (1.5.3) bundler-unload (1.0.2) executable-hooks (1.3.1) gem-wrappers (1.2.4) io-console (0.4.2) json (1.7.7) minitest (4.3.2) net-ssh (2.9.1) psych (2.0.0) rake (0.9.6) rdoc (4.0.0) rubygems-bundler (1.4.2) rvm (1.11.3.9) test-unit (2.0.0.0) -bash-3.2$ gem list --local rubygems *** LOCAL GEMS *** rubygems-bundler (1.4.2) to run the script: ruby test.rb `require': no such file to load -- rubygems (LoadError) $ cat test.rb require 'rubygems' require 'net/ssh' Net::SSH.start(............. what's going on? please advice. thanks

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• How to include multiple tables programmaticaly into a Sweave document using R

  - by PaulHurleyuk

  Hello, I want to have a sweave document that will include a variable number of tables in. I thought the example below would work, but it doesn't. I want to loop over the list foo and print each element as it's own table. % \documentclass[a4paper]{article} \usepackage[OT1]{fontenc} \usepackage{longtable} \usepackage{geometry} \usepackage{Sweave} \geometry{left=1.25in, right=1.25in, top=1in, bottom=1in} \listfiles \begin{document} <<label=start, echo=FALSE, include=FALSE>>= startt<-proc.time()[3] library(RODBC) library(psych) library(xtable) library(plyr) library(ggplot2) options(width=80) #Produce some example data, here I'm creating some dummy dataframes and putting them in a list foo<-list() foo[[1]]<-data.frame(GRP=c(rep("AA",10), rep("Aa",10), rep("aa",10)), X1=rnorm(30), X2=rnorm(30,5,2)) foo[[2]]<-data.frame(GRP=c(rep("BB",10), rep("bB",10), rep("BB",10)), X1=rnorm(30), X2=rnorm(30,5,2)) foo[[3]]<-data.frame(GRP=c(rep("CC",12), rep("cc",18)), X1=rnorm(30), X2=rnorm(30,5,2)) foo[[4]]<-data.frame(GRP=c(rep("DD",10), rep("Dd",10), rep("dd",10)), X1=rnorm(30), X2=rnorm(30,5,2)) @ \title{Docuemnt to test putting a variable number of tables into a sweave Document} \author{"Paul Hurley"} \maketitle \section{Text} This document was created on \today, with \Sexpr{print(version$version.string)} running on a \Sexpr{print(version$platform)} platform. It took approx \input{time} sec to process. <<label=test, echo=FALSE, results=tex>>= cat("Foo") @ that was a test, so is this <<label=table1test, echo=FALSE, results=tex>>= print(xtable(foo[[1]])) @ \newpage \subsection{Tables} <<label=Tables, echo=FALSE, results=tex>>= for(i in seq(foo)){ cat("\n") cat(paste("Table_",i,sep="")) cat("\n") print(xtable(foo[[i]])) cat("\n") } #cat("<<label=endofTables>>= ") @ <<label=bye, include=FALSE, echo=FALSE>>= endt<-proc.time()[3] elapsedtime<-as.numeric(endt-startt) @ <<label=elapsed, include=FALSE, echo=FALSE>>= fileConn<-file("time.tex", "wt") writeLines(as.character(elapsedtime), fileConn) close(fileConn) @ \end{document} Here, the table1test chunk works as expected, and produced a table based on the dataframe in foo[[1]], however the loop only produces Table(underscore)1.... Any ideas what I'm doing wrong ?

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• Help with Neuroph neural network

  - by user359708

  For my graduate research I am creating a neural network that trains to recognize images. I am going much more complex than just taking a grid of RGB values, downsampling, and and sending them to the input of the network, like many examples do. I actually use over 100 independently trained neural networks that detect features, such as lines, shading patterns, etc. Much more like the human eye, and it works really well so far! The problem is I have quite a bit of training data. I show it over 100 examples of what a car looks like. Then 100 examples of what a person looks like. Then over 100 of what a dog looks like, etc. This is quite a bit of training data! Currently I am running at about one week to train the network. This is kind of killing my progress, as I need to adjust and retrain. I am using Neuroph, as the low-level neural network API. I am running a dual-quadcore machine(16 cores with hyperthreading), so this should be fast. My processor percent is at only 5%. Are there any tricks on Neuroph performance? Or Java peroformance in general? Suggestions? I am a cognitive psych doctoral student, and I am decent as a programmer, but do not know a great deal about performance programming.

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• gems, bundle command, and ruby not found in new terminal window

  - by user3579987

  So I installed ruby with rvm, ran a bundle install and installed a bunch of gems, etc. It all works just fine in the original terminal window I did all of this in but I opened up a new terminal window and now I'm getting errors like bundle: command not found and gem command not found. I tried doing a symbolic link for the gem command but then when I do gem list it displays a much shorter list of my local gems and not at all the ones I need for bundle install. Is there something I need to do to configure bash or rvm so that it recognizes that I did indeed install all the gems I have installed? name@crunchbang:~/ug_research_portal$ which gem /home/name/.rvm/rubies/ruby-2.1.1/bin/gem name@crunchbang:~/ug_research_portal$ which ruby /home/name/.rvm/rubies/ruby-2.1.1/bin/ruby And in ~/.bashrc: GEM_HOME="/home/name/.rvm/gems/ruby-2.1.1" GEMGLOBAL_HOME="/home/ name/.rvm/gems/ruby-2.1.1@global" export PATH=$PATH:$GEM_HOME/bin:$GEMGLOBAL_HOME/bin:$HOME/.rvm/bin Edit: Looks like my $PATH is somehow wrong? bash: /home/name/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games:/home/name/.rvm/gems/ruby-2.1.1/bin:/home/name/.rvm/gems/ruby-2.1.1@global/bin:/home/name/.rvm/bin/: No such file or directory which is odd since ls for /home/name/.rvm/bin and /home/name/.rvm/gems/ruby-2.1.1@global/bin and /home/name/.rvm/gems/ruby-2.1.1/bin work just fine Psych, I was just doing $PATH instead of echo "$PATH" which was giving me the No such file or directory error. The original problem still stands though.

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• A Guided Tour of Complexity

  - by JoshReuben

  I just re-read Complexity – A Guided Tour by Melanie Mitchell , protégé of Douglas Hofstadter ( author of “Gödel, Escher, Bach”) http://www.amazon.com/Complexity-Guided-Tour-Melanie-Mitchell/dp/0199798109/ref=sr_1_1?ie=UTF8&qid=1339744329&sr=8-1 here are some notes and links:   Evolved from Cybernetics, General Systems Theory, Synergetics some interesting transdisciplinary fields to investigate: Chaos Theory - http://en.wikipedia.org/wiki/Chaos_theory – small differences in initial conditions (such as those due to rounding errors in numerical computation) yield widely diverging outcomes for chaotic systems, rendering long-term prediction impossible. System Dynamics / Cybernetics - http://en.wikipedia.org/wiki/System_Dynamics – study of how feedback changes system behavior Network Theory - http://en.wikipedia.org/wiki/Network_theory – leverage Graph Theory to analyze symmetric  / asymmetric relations between discrete objects Algebraic Topology - http://en.wikipedia.org/wiki/Algebraic_topology – leverage abstract algebra to analyze topological spaces There are limits to deterministic systems & to computation. Chaos Theory definitely applies to training an ANN (artificial neural network) – different weights will emerge depending upon the random selection of the training set. In recursive Non-Linear systems http://en.wikipedia.org/wiki/Nonlinear_system – output is not directly inferable from input. E.g. a Logistic map: Xt+1 = R Xt(1-Xt) Different types of bifurcations, attractor states and oscillations may occur – e.g. a Lorenz Attractor http://en.wikipedia.org/wiki/Lorenz_system Feigenbaum Constants http://en.wikipedia.org/wiki/Feigenbaum_constants express ratios in a bifurcation diagram for a non-linear map – the convergent limit of R (the rate of period-doubling bifurcations) is 4.6692016 Maxwell’s Demon - http://en.wikipedia.org/wiki/Maxwell%27s_demon - the Second Law of Thermodynamics has only a statistical certainty – the universe (and thus information) tends towards entropy. While any computation can theoretically be done without expending energy, with finite memory, the act of erasing memory is permanent and increases entropy. Life & thought is a counter-example to the universe’s tendency towards entropy. Leo Szilard and later Claude Shannon came up with the Information Theory of Entropy - http://en.wikipedia.org/wiki/Entropy_(information_theory) whereby Shannon entropy quantifies the expected value of a message’s information in bits in order to determine channel capacity and leverage Coding Theory (compression analysis). Ludwig Boltzmann came up with Statistical Mechanics - http://en.wikipedia.org/wiki/Statistical_mechanics – whereby our Newtonian perception of continuous reality is a probabilistic and statistical aggregate of many discrete quantum microstates. This is relevant for Quantum Information Theory http://en.wikipedia.org/wiki/Quantum_information and the Physics of Information - http://en.wikipedia.org/wiki/Physical_information. Hilbert’s Problems http://en.wikipedia.org/wiki/Hilbert's_problems pondered whether mathematics is complete, consistent, and decidable (the Decision Problem – http://en.wikipedia.org/wiki/Entscheidungsproblem – is there always an algorithm that can determine whether a statement is true).  Godel’s Incompleteness Theorems http://en.wikipedia.org/wiki/G%C3%B6del's_incompleteness_theorems  proved that mathematics cannot be both complete and consistent (e.g. “This statement is not provable”). Turing through the use of Turing Machines (http://en.wikipedia.org/wiki/Turing_machine symbol processors that can prove mathematical statements) and Universal Turing Machines (http://en.wikipedia.org/wiki/Universal_Turing_machine Turing Machines that can emulate other any Turing Machine via accepting programs as well as data as input symbols) that computation is limited by demonstrating the Halting Problem http://en.wikipedia.org/wiki/Halting_problem (is is not possible to know when a program will complete – you cannot build an infinite loop detector). You may be used to thinking of 1 / 2 / 3 dimensional systems, but Fractal http://en.wikipedia.org/wiki/Fractal systems are defined by self-similarity & have non-integer Hausdorff Dimensions !!!  http://en.wikipedia.org/wiki/List_of_fractals_by_Hausdorff_dimension – the fractal dimension quantifies the number of copies of a self similar object at each level of detail – eg Koch Snowflake - http://en.wikipedia.org/wiki/Koch_snowflake Definitions of complexity: size, Shannon entropy, Algorithmic Information Content (http://en.wikipedia.org/wiki/Algorithmic_information_theory - size of shortest program that can generate a description of an object) Logical depth (amount of info processed), thermodynamic depth (resources required). Complexity is statistical and fractal. John Von Neumann’s other machine was the Self-Reproducing Automaton http://en.wikipedia.org/wiki/Self-replicating_machine  . Cellular Automata http://en.wikipedia.org/wiki/Cellular_automaton are alternative form of Universal Turing machine to traditional Von Neumann machines where grid cells are locally synchronized with their neighbors according to a rule. Conway’s Game of Life http://en.wikipedia.org/wiki/Conway's_Game_of_Life demonstrates various emergent constructs such as “Glider Guns” and “Spaceships”. Cellular Automatons are not practical because logical ops require a large number of cells – wasteful & inefficient. There are no compilers or general program languages available for Cellular Automatons (as far as I am aware). Random Boolean Networks http://en.wikipedia.org/wiki/Boolean_network are extensions of cellular automata where nodes are connected at random (not to spatial neighbors) and each node has its own rule –> they demonstrate the emergence of complex  & self organized behavior. Stephen Wolfram’s (creator of Mathematica, so give him the benefit of the doubt) New Kind of Science http://en.wikipedia.org/wiki/A_New_Kind_of_Science proposes the universe may be a discrete Finite State Automata http://en.wikipedia.org/wiki/Finite-state_machine whereby reality emerges from simple rules. I am 2/3 through this book. It is feasible that the universe is quantum discrete at the plank scale and that it computes itself – Digital Physics: http://en.wikipedia.org/wiki/Digital_physics – a simulated reality? Anyway, all behavior is supposedly derived from simple algorithmic rules & falls into 4 patterns: uniform , nested / cyclical, random (Rule 30 http://en.wikipedia.org/wiki/Rule_30) & mixed (Rule 110 - http://en.wikipedia.org/wiki/Rule_110 localized structures – it is this that is interesting). interaction between colliding propagating signal inputs is then information processing. Wolfram proposes the Principle of Computational Equivalence - http://mathworld.wolfram.com/PrincipleofComputationalEquivalence.html - all processes that are not obviously simple can be viewed as computations of equivalent sophistication. Meaning in information may emerge from analogy & conceptual slippages – see the CopyCat program: http://cognitrn.psych.indiana.edu/rgoldsto/courses/concepts/copycat.pdf Scale Free Networks http://en.wikipedia.org/wiki/Scale-free_network have a distribution governed by a Power Law (http://en.wikipedia.org/wiki/Power_law - much more common than Normal Distribution). They are characterized by hubs (resilience to random deletion of nodes), heterogeneity of degree values, self similarity, & small world structure. They grow via preferential attachment http://en.wikipedia.org/wiki/Preferential_attachment – tipping points triggered by positive feedback loops. 2 theories of cascading system failures in complex systems are Self-Organized Criticality http://en.wikipedia.org/wiki/Self-organized_criticality and Highly Optimized Tolerance http://en.wikipedia.org/wiki/Highly_optimized_tolerance. Computational Mechanics http://en.wikipedia.org/wiki/Computational_mechanics – use of computational methods to study phenomena governed by the principles of mechanics. This book is a great intuition pump, but does not cover the more mathematical subject of Computational Complexity Theory – http://en.wikipedia.org/wiki/Computational_complexity_theory I am currently reading this book on this subject: http://www.amazon.com/Computational-Complexity-Christos-H-Papadimitriou/dp/0201530821/ref=pd_sim_b_1   stay tuned for that review!

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