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  • Code bacteria: evolving mathematical behavior

    - by Stefano Borini
    It would not be my intention to put a link on my blog, but I don't have any other method to clarify what I really mean. The article is quite long, and it's in three parts (1,2,3), but if you are curious, it's worth the reading. A long time ago (5 years, at least) I programmed a python program which generated "mathematical bacteria". These bacteria are python objects with a simple opcode-based genetic code. You can feed them with a number and they return a number, according to the execution of their code. I generate their genetic codes at random, and apply an environmental selection to those objects producing a result similar to a predefined expected value. Then I let them duplicate, introduce mutations, and evolve them. The result is quite interesting, as their genetic code basically learns how to solve simple equations, even for values different for the training dataset. Now, this thing is just a toy. I had time to waste and I wanted to satisfy my curiosity. however, I assume that something, in terms of research, has been made... I am reinventing the wheel here, I hope. Are you aware of more serious attempts at creating in-silico bacteria like the one I programmed? Please note that this is not really "genetic algorithms". Genetic algorithms is when you use evolution/selection to improve a vector of parameters against a given scoring function. This is kind of different. I optimize the code, not the parameters, against a given scoring function.

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  • Using Unix Process Controll Methods in Ruby

    - by John F. Miller
    Ryan Tomayko touched off quite a fire storm with this post about using Unix process control commands. We should be doing more of this. A lot more of this. I'm talking about fork(2), execve(2), pipe(2), socketpair(2), select(2), kill(2), sigaction(2), and so on and so forth. These are our friends. They want so badly just to help us. I have a bit of code (a delayed_job clone for DataMapper that I think would fit right in with this, but I'm not clear on how to take advantage of the listed commands. Any Ideas on how to improve this code? def start say "*** Starting job worker #{@name}" t = Thread.new do loop do delay = Update.work_off(self) break if $exit sleep delay break if $exit end clear_locks end trap('TERM') { terminate_with t } trap('INT') { terminate_with t } trap('USR1') do say "Wakeup Signal Caught" t.run end end

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  • How do I program hardware?

    - by Arlen Beiler
    What would I need to program a piece of hardware to do something for me? Let's say I have something with 15 relays (or equivalent) and I want to tell it to turn off relay 10. Or better yet, when sensor 10 is activated, toggle relay 10.

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  • Difference between 'scope' and 'namespace'?

    - by katriel
    What is the difference, in general, between the concepts of namespaces and scope? To my understanding, both describe the parts of a program in which a variable/object/method/function will be accessible. I understand that 'scope' tends to be a property of the variable (e.g., "This variable has global scope"), while a 'namespace' is a property of the program (e.g., "A Python function creates a local namespace"). Are there other differences? Global scope vs global namespace addresses a slightly narrower question: global namespaces in C++. http://www.alan-g.me.uk/tutor/tutname.htm states, There are a few very subtle differences between the terms but only a Computer Scientist pedant would argue with you, and for our purposes namespace and scope are identical. What are those subtle differences? Under what circumstances or with which kinds of languages do people use each concept?

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  • Consuming Web Services in Netbeans

    - by Seven
    Hi. I've setup a project in Netbeans 6.5 with some web services that I've created myself and some web services that I've imported from WSDL files. I've setup a couple of desktop application through Netbeans in order to consume these web services. I'm not too sure where to go from here. I have the GUI setup but not sure how to reference the web services so they can be consumed. I was wondering would anybody be able to guide me through this process or point me in the direction of a relevant tutorial. I'd also like to learn how to consume a web service through a JSP (also created in Netbeans) if possible. Thanks.

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  • Unix Piping using Fork and Dup

    - by Jacob
    Lets say within my program I want to execute two child processes, one to to execute a "ls -al" command and then pipe that into "wc" command and display the output on the terminal. How can I do this using pipe file descriptors so far the code I have written: An example would be greatly helpful int main(int argc, char *argv[]) { int pipefd[2] pipe(pipefd2); if ((fork()) == 0) { dup2(pipefd2[1],STDOUT_FILENO); close(pipefd2[0]); close(pipefd2[1]); execl("ls", "ls","-al", NULL); exit(EXIT_FAILURE); } if ((fork()) == 0){ dup2(pipefd2[0],STDIN_FILENO); close(pipefd2[0]); close(pipefd2[1]); execl("/usr/bin/wc","wc",NULL); exit(EXIT_FAILURE); } close(pipefd[0]); close(pipefd[1]); close(pipefd2[0]); close(pipefd2[1]); }

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  • how to access class and its functions from another class

    - by vbNewbie
    This is my first major application using multiple classes. It is written in vb and I know about creating objects of the class and using that instance to call functions of the class. But how do I create an object with constructors to allow another program written in C# to access my classes and functions and accept things from the program. Hope this makes sense.

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  • What software development process do you use and how do you implement it?

    - by clyfe
    Post only what you do use not what you would like to use, so we can see what is the most popular in real life. I am interested only in theese issues: Project Model (waterfall, agile...) How are requirements gathered (and stored)? Revision control - what software, what workflow Build automation, what software, where does it fit ? How is the testing done ? How is the documentation done ? How is the quality assurance done ? Please provide short objective answers, don't speak from the books. EXAMPLE: In my company we are a small team of 5 people and we develop webapps using ruby. agile PM cucumber requirements git SCM - Integration Manager Workflow integrity CI rspec automated tests the project lead creats the documentation skeleton then it is filled by the developers ensure quality by peer reviewing code and manual peer-testing

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  • How to sort a list in Scala by two fields?

    - by Twistleton
    how to sort a list in Scala by two fields, in this example I will sort by lastName and firstName? case class Row(var firstName: String, var lastName: String, var city: String) var rows = List(new Row("Oscar", "Wilde", "London"), new Row("Otto", "Swift", "Berlin"), new Row("Carl", "Swift", "Paris"), new Row("Hans", "Swift", "Dublin"), new Row("Hugo", "Swift", "Sligo")) rows.sortBy(_.lastName) I try things like this rows.sortBy(_.lastName + _.firstName) but it doesn't work. So I be curious for a good and easy solution. Thanks in advance! Pongo

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  • Evaluating a function at a particular value in parallel

    - by Gaurav Kalra
    Hi. The question may seem vague, but let me explain it. Suppose we have a function f(x,y,z ....) and we need to find its value at the point (x1,y1,z1 .....). The most trivial approach is to just replace (x,y,z ...) with (x1,y1,z1 .....). Now suppose that the function is taking a lot of time in evaluation and I want to parallelize the algorithm to evaluate it. Obviously it will depend on the nature of function, too. So my question is: what are the constraints that I have to look for while "thinking" to parallelize f(x,y,z...)? If possible, please share links to study.

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  • Running Network Application on port Server side give me error how can i solve it?

    - by Phsika
    if i run Server App. Exception occurs: on Dinle.Start() System.Net.SocketException - Only one usage of each socket address (protocol/network address/port) is normally permitted How can i solve this error? Server.cs using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.IO; using System.Net; using System.Net.Sockets; using System.Threading; namespace Server { public partial class Server : Form { Thread kanal; public Server() { InitializeComponent(); try { kanal = new Thread(new ThreadStart(Dinle)); kanal.Start(); kanal.Priority = ThreadPriority.Normal; this.Text = "Kanla Çalisti"; } catch (Exception ex) { this.Text = "kanal çalismadi"; MessageBox.Show("hata:" + ex.ToString()); kanal.Abort(); throw; } } private void Server_Load(object sender, EventArgs e) { Dinle(); } private void btn_Listen_Click(object sender, EventArgs e) { Dinle(); } void Dinle() { // IPAddress localAddr = IPAddress.Parse("localhost"); // TcpListener server = new TcpListener(port); // server = new TcpListener(localAddr, port); //TcpListener Dinle = new TcpListener(localAddr,51124); TcpListener Dinle = new TcpListener(51124); try { while (true) { Dinle.Start(); Exception is occured. Socket Baglanti = Dinle.AcceptSocket(); if (!Baglanti.Connected) { MessageBox.Show("Baglanti Yok"); } else { TcpClient tcpClient = Dinle.AcceptTcpClient(); if (tcpClient.ReceiveBufferSize 0) { byte[] Dizi = new byte[250000]; Baglanti.Receive(Dizi, Dizi.Length, 0); string Yol; saveFileDialog1.Title = "Dosyayi kaydet"; saveFileDialog1.ShowDialog(); Yol = saveFileDialog1.FileName; FileStream Dosya = new FileStream(Yol, FileMode.Create); Dosya.Write(Dizi, 0, Dizi.Length - 20); Dosya.Close(); listBox1.Items.Add("dosya indirildi"); listBox1.Items.Add("Dosya Boyutu=" + Dizi.Length.ToString()); listBox1.Items.Add("Indirilme Tarihi=" + DateTime.Now); listBox1.Items.Add("--------------------------------"); } } } } catch (Exception ex) { MessageBox.Show("hata:" + ex.ToString()); } } } }

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  • What is your favourite cleverly written functional code?

    - by sdcvvc
    What are your favourite short, mind-blowing snippets in functional languages? My two favourite ones are (Haskell): powerset = filterM (const [True, False]) foldl f v xs = foldr (\x g a -> g (f a x)) id xs v -- from Hutton's tutorial (I tagged the question as Haskell, but examples in all languages - including non-FP ones - are welcome as long as they are in functional spirit.)

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  • Errors when connecting to HTTPS using HTTP::Net routines (Ruby on Rails)

    - by jaycode
    Hi all, the code below explains the problem in detail #this returns error Net::HTTPBadResponse url = URI.parse('https://sitename.com') response = Net::HTTP.start(url.host, url.port) {|http| http.get('/remote/register_device') } #this works url = URI.parse('http://sitename.com') response = Net::HTTP.start(url.host, url.port) {|http| http.get('/remote/register_device') } #this returns error Net::HTTPBadResponse response = Net::HTTP.post_form(URI.parse('https://sitename.com/remote/register_device'), {:text => 'hello world'}) #this returns error Errno::ECONNRESET (Connection reset by peer) response = Net::HTTP.post_form(URI.parse('https://sandbox.itunes.apple.com/verifyReceipt'), {:text => 'hello world'}) #this works response = Net::HTTP.post_form(URI.parse('http://sitename.com/remote/register_device'), {:text => 'hello world'}) So... how do I send POST parameters to https://sitename.com or https://sandbox.itunes.apple.com/verifyReceipt in this example? Further information, I am trying to get this working in Rails: http://developer.apple.com/iphone/library/documentation/NetworkingInternet/Conceptual/StoreKitGuide/VerifyingStoreReceipts/VerifyingStoreReceipts.html#//apple_ref/doc/uid/TP40008267-CH104-SW1

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  • shell script passing arguments

    - by arav
    From the wrapper shell scripts i am calling the Java program. I want the Unix shell script to pass all the arguments to java program except the EMAIL argument. HOW Can i remove the EMAIL argument and pass the rest of the arguments to the java program. EMAIL argument can come at any position. valArgs() { until [ $# -eq 0 ]; do case $1 in -EMAIL) MAILFLAG=Y shift break ;; esac done } main() { valArgs "$@" $JAVA_HOME/bin/java -d64 -jar WEB-INF/lib/test.jar "$@"

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  • Need Descriptive architecture to develop file server in dot net.

    - by Vivek
    Hello All, I have to develop a file server service that transfer file form a specified location to its client.Client when starts, requests file to server for current date. Server transfer those file to client. Now constrains are as 1.Application run in intranet. 2.Need to transfer multiple file at a single transaction. 3.File size may be in GB. 4.System runs in real time environment.So proper transaction and acknowledgment needed. 5.Application develop in .net. 5.More than one client can present. Now please help to decide architecture and .net technology (WCF (Http binding) WCF (net tcp binding) ,Socket Programing ( i want to use WCF )) that i choose to develop file server. and Please refer some sample application.

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  • Ruby: writing a network redirector

    - by Shyam
    Hi, I would like to research protocols such as HTTP. As I am learning Ruby, I would like to write a program that works as a "gateway". I would be connecting to it's port on for example 8080 and the program should forward my request to the real host and send back the answers. The idea of my design is something like this: class EchoProxy def run # run a listening socket on port 8080 myinfiniteloop end def myinfiniteloop # continually run this loop unless the app is terminated puts traffic end end Some pointers in the right direction would be great! Thank you for your comments, answers and feedback!

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  • how to maintain multiple components for multiple client for multiple features?

    - by Dhana
    Basically my project is product based. Once we developed a project and catch the multiple client and deploy the application based on their needs. But We decided to put the new features and project dependent modules are as component. Now my application got many number of customer. Every customer needs a different features based on the component. But we have centralized component for all client . we move the components additional feature to client specific folder and deploy. My problem is , I am unable maintain the components features for multiple client. My component feature code is increased and I am unable to track the client features. Is there any solution for maintaining the multiple component features for multiple client ?

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  • How to handle activity life cycle involving sockets in Android?

    - by Henrik
    Hello all, I have an Android activity which in turn starts a thread. In the thread I open a persistent TCP socket connection. When the socket connects to the server dynamic data is downloaded. The thread sends messages using Handler-class to the activity when data has been received. Now if the user happens to switch from portrait to landscape mode the activity gets an onDestroy call. At this moment I close the socket and stop the thread. When Android has switched landscape mode it calls onCreate yet again and I have to do a socket re-connect. Also, all of the data the activity received needs to be downloaded once more because the server does not have the ability to know what has been sent before, i.e. there is no "resume" feature. Thus the problem is that there is alot of data which is resent all the time when landscape mode is changed. What are my options here? Should I create a service which handles the socket traffic towards the server thus I always got all the data which the server has sent in the service. Or should I disable landscape mode all together perhaps? Or would my best bet be to rewrite my server which is a VERY BIG job :-) All input is welcome :-) / Henrik

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  • What challenges are there in making an iPhone IDE for Windows/Linux?

    - by Moshe
    First of all, is this possible? If so: What challenges would I encounter in making an XCode imitation for iPhone/iPod development for Windows or Linux? I was thinking about using gcc as the actual compiler for the objecitve-c. Will that work? It doesn't need to compile to iPhone OS until it is to be tested on the device or submitted to the app store. Perhaps it will be easier to compile to the local OS format (Windows or Linux) until "prime-time".

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  • MPAPI vs MPI.NET vs ?

    - by Olexandr
    I'm working on college project. I have to develop distributed computing system. And i decided to do some research to make this task fun :) I've found MPAPI and MPI.NET libraries. Yes, they are .NET libraries(Mono, in my case). Why .NET ? I'm choosing between Ada, C++ and C# so to i've choosed C# because of lower development time. I have two goals: Simplicity; Performance; Cluster computing. So, what to choose - MPAPI or MPI.NET or something else ?

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