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• Genetics algorithms theoretical question

  - by mandelart

  Hi All! I'm currently reading "Artificial Intelligence: A Modern Approach" (Russell+Norvig) and "Machine Learning" (Mitchell) - and trying to learn basics of AINN. In order to understand few basic things I have two 'greenhorn' questions: Q1: In a genetic algorithm given the two parents A and B with the chromosomes 001110 and 101101, respectively, which of the following offspring could have resulted from a one-point crossover? a: 001101 b: 001110 Q2: Which of the above offspring could have resulted from a two-point crossover? and why? Please advise.

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• SwingWorker in Java (beginner question)

  - by Malachi

  I am relatively new to multi-threading and want to execute a background task using a Swingworker thread - the method that is called does not actually return anything but I would like to be notified when it has completed. The code I have so far doesn't appear to be working: private void crawl(ActionEvent evt) { try { SwingWorker<Void, Void> crawler = new SwingWorker<Void, Void>() { @Override protected Void doInBackground() throws Exception { Discoverer discover = new Discoverer(); discover.crawl(); return null; } @Override protected void done() { JOptionPane.showMessageDialog(jfThis, "Finished Crawling", "Success", JOptionPane.INFORMATION_MESSAGE); } }; crawler.execute(); } catch (Exception ex) { JOptionPane.showMessageDialog(this, ex.getMessage(), "Exception", JOptionPane.ERROR_MESSAGE); } } Any feedback/advice would be greatly appreciated as multi-threading is a big area of programming that I am weak in.

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• jQuery UI AutoComplete remote json response question

  - by Greg-J

  I was using geonames.org to autocomplete city and state but found it to be far too slow to be reliable. My code is as follows, and does work (wait about 10 seconds to see the autocomplete results) Old (working) code here: http://jsbin.com/umewo3/2/edit Now I am using YQL as they provide a much quicker response. The issue is that I don't seem to understand how to properly map the response. You can see I am sending a well formed request, and getting the response back - but I am somehow not dealing with the response properly. New (broken) code here: http://jsbin.com/aqoke3/2/edit Any and all help appreciated.

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• MySQL Stored Procedures not working with SELECT (basic question)

  - by TMG

  Hello, I am using a platform (perfectforms) that requires me to use stored procedures for most of my queries, and having never used stored procedures, I can't figure out what I'm doing wrong. The following statement executes without error: DELIMITER // DROP PROCEDURE IF EXISTS test_db.test_proc// CREATE PROCEDURE test_db.test_proc() SELECT 'foo'; // DELIMITER ; But when I try to call it using: CALL test_proc(); I get the following error: #1312 - PROCEDURE test_db.test_proc can't return a result set in the given context I am executing these statements from within phpmyadmin 3.2.4, PHP Version 5.2.12 and the mysql server version is 5.0.89-community. When I write a stored procedure that returns a parameter, and then select it, things work fine (e.g.): DELIMITER // DROP PROCEDURE IF EXISTS test_db.get_sum// CREATE PROCEDURE test_db.get_sum(out total int) BEGIN SELECT SUM(field1) INTO total FROM test_db.test_table; END // DELIMITER ; works fine, and when I call it: CALL get_sum(@t); SELECT @t; I get the sum no problem. Ultimately, what I need to do is have a fancy SELECT statement wrapped up in a stored procedure, so I can call it, and return multiple rows of multiple fields. For now I'm just trying to get any select working. Any help is greatly appreciated.

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• Rails: simple bundler question

  - by Joern Akkermann

  Hi! I just installed the ruby-openid gem and then bundled it by entering gem 'ruby-openid', :require => 'openid' in the gemfile. Then I started bundle install and bundle lock. Everything worked fine so far. But how can I now access the classes of ruby-openid. OpenID::method won't work for me. It raises a not found error. What have I forgot or done wrong? I'm thankful for any help!

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• basic boost date_time input format question

  - by Chris H

  I've got a pointer to a string, (char *) as input. The date/time looks like this: Sat, 10 Apr 2010 19:30:00 I'm only interested in the date, not the time. I created an "input_facet" with the format I want: boost::date_time::date_input_facet inFmt("%a %d %b %Y"); but I'm not sure what to do with it. Ultimately I'd like to create a date object from the string. I'm pretty sure I'm on the right track with that input facet and format, but I have no idea how to use it. Thanks.

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• JSON Select option question?

  - by user303832

  Hello,I wrote somethinh like this, `$sql = "SELECT * FROM dbase"; $strOptions = ""; if (!$q=mysql_query($sql)) { $strOptions = "<option>There was an error connecting to database</option>"; } if (mysql_num_rows($q)==0) { $strOptions = "<option>There are no news in database</option>"; }else { $a=0; while ($redak=mysql_fetch_assoc($q)) { $a=$a+1; $vvvv[$a]["id"]=$redak["id"]; $vvvv[$a]["ssss"]=$redak["ssss"]; } } for ($i=1; $i<=$a; $i++) { $strOptions = $strOptions. '<option value="'. $vvvv[$i]["id"] .'">'.$i.'.) - '.strip_tags($vvvv[$i]["ssss"]).'</option>'; } echo '[{ "message": "3" },{ "message": "' . count($wpdb->get_results("SELECT * FROM dbase")) . '" },{ "message": "'.$strOptions .'"}]';` I just cannot later parse json file,later I parse it on this way to fill select-option $jq("#select-my").children().remove(); $jq("#select-my").append(data[2].message); I use jquery form pluing,everything work fine,except this,I cant parse data for select-option element.I try and with json_encode in php.Can someone help please?

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• Grouping with operands question

  - by Filip

  I have a table: mysql> desc kursy_bid; +-----------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-----------+-------------+------+-----+---------+-------+ | datetime | datetime | NO | PRI | NULL | | | currency | varchar(6) | NO | PRI | NULL | | | value | varchar(10) | YES | | NULL | | +-----------+-------------+------+-----+---------+-------+ 3 rows in set (0.01 sec) I would like to select some rows from a table, grouped by some time interval (can be one day) where I will have the first row and the last row of the group, the max(value) and min(value). I tried: select datetime, (select value order by datetime asc limit 1) open, (select value order by datetime desc limit 1) close, max(value), min(value) from kursy_bid_test where datetime > '2009-09-14 00:00:00' and currency = 'eurpln' group by month(datetime), day(datetime), hour(datetime); but the output is: | open | close | datetime | max(value) | min(value) | +--------+--------+---------------------+------------+------------+ | 1.4581 | 1.4581 | 2009-09-14 00:00:05 | 4.1712 | 1.4581 | | 1.4581 | 1.4581 | 2009-09-14 01:00:01 | 1.4581 | 1.4581 | As you see open and close is the same (but they shouldn't be). What should be the query to do what I want?

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• ASP.NET connection pool question

  - by James Evans

  Does the same connection string used on two different physical servers hosting different web applications that talk to the same database draw connections from the same connection pool? Or are pooled connections confined to at the application level? I ask because I inherited a 7 year old .NET 1.1 web application which is riddled with in-line SQL, unclosed and undisposed sql connection and datareader objects. Recently, I was tasked to write a small web app that is hosted on another server and talks to the same database and therefore used the same database connection string. I created a LINQ object to read and write the one table required by the app. Now the original .NET 1.1 app is throwing exceptions like "Timeout expired. The timeout period elapsed prior to obtaining a connection from the pool. This may have occurred because all pooled connections were in use and max pool size was reached." Maybe these are unreleated, but wanted to get your opinions to make sure I cover all my bases. Thanks!

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• Java Framework Choice Question.

  - by Sarang

  We do have many frameworks available in Java. Struts, Swing, JSF 2.0, Spring etc are used as per their priority. Actually, I don't know how many they are as well! But, as I am fresher to Java, even learning after their architecture, I cannot decide which framework can be used with what type of Projects ! Also, I am confused with mixed use of framework like Spring + JSF. What is the benefit to it ? Another thing making me confusing is about the UI components available in market. Like, we do have Primefaces, Ice-faces, MyFaces, Rich-faces. They may or may not have been supporting AJAX in-built. They may contains some bugs as well. What is best choice for Framework + UI component that can directly provide a best feet solution for any project ?

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• iPhone SDK/General Xcode question.

  - by user354779

  In the iPhone SDK, in my .n, I can say: -(IBOutlet) UITextField *MyNameIs; -(IBOutlet) UILabel *DisplayMyNameIsHere; } -(IBAction)PressButtonToDisplayYourName; Then in my .m, I'll do: -(IBAction)PressButtonToDisplayYourName { DisplayMyNameIsHere = MyNameIs.text; } But now how would I translate that to making a Mac application. If I wanted to display someones name from a textfield in a label? I have been trying to figure this out, but the ".text" extension only works in the iPhone SDK, not the Mac SDK. Someone please help! Thanks!

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• Xcode & 64 bit & 32 bit Question

  - by I00I

  Hello All, I have a 32bit iMac that I am writing an iPhone app in Xcode with, and I was wondering if I saved my project to a flash drive and dropped it on my MacBookPro which is 64 bit and continued to code the iPhone project on my laptop in Xcode would this cause a problem? I don't see how it would since the target is not for either of those computers, but I thought I would ask since I would like to work on the project when I am not always around my iMac. Are there any gottcha's with doing this that I should look out for? Thanks, I00I

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• A Question About Embedding HTML In PHP

  - by Brian

  Hello all Some time ago I read a posting on a board where the person was talking poorly about people that have HTML embedded/within their PHP. I do quite a bit of PHP development but I still interleave HTML and PHP in the same document. Is there a better way to do this, am I doing it wrong? I know that in JSP/JSF they use an XML document with namespaces to insert their HTML code so I was wondering if there was a similar function that PHP uses that I should be taking advantage of. Thanks for taking the time to read. :-)

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• .NET threading question

  - by MusiGenesis

  Is there any essential difference between this code: ThreadStart starter = new ThreadStart(SomeMethod); starter.Invoke(); and this? ThreadStart starter = new ThreadStart(SomeMethod); Thread th = new Thread(starter); th.Start(); Or does the first invoke the method on the current thread while the second invokes it on a new thread?

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• question about recursive even sum program

  - by davit-datuashvili

  hello i need program which returns sum of all even number <= to given n number for example if n=even (let say 10) sum will be 2+4+6+8+10 or if n is odd (let say 13) 2+4+6+8+10+12 please help it should be recursive algorithm

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• Question related to date format

  - by user217572

  I have 1 string NSString *string = @"2010-04-16 15:42:58"; now i want to convert it to 16 april So,my string will be converted to NSString *stringOutPut =@"16 April";

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• Commercial Website architecture question

  - by Maxime ARNSTAMM

  Hello everyone, I have to write an architecture case study but there are some things that i don't know, so i'd like some pointers on the following : The website must handle 5k simultaneous users. The backend is composed by a commercial software, some webservices, some message queues, and a database. I want to recommend to use Spring for the backend, to deal with the different elements, and to expose some Rest services. I also want to recommend wicket for the front (not the point here). What i don't know is : must i install the front and the back on the same tomcat server or two different ? and i am tempted to put two servers for the front, with a load balancer (no need for session replication in this case). But if i have two front servers, must i have two back servers ? i don't want to create some kind of bottleneck. Based on what i read on this blog a really huge charge is handle by one tomcat only for the first website mentionned. But i cannot find any info on this, so i can't tell if it seems plausible. If you can enlight me, so i can go on in my case study, that would be really helpful. Thanks :)

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• Newb Question: passing objects in java?

  - by Adam Outler

  Hello, I am new at java. I am doing the following: Read from file, then put data into a variable. checkToken = lineToken.nextToken(); processlinetoken() } But then when I try to process it... public static void readFile(String fromFile) throws IOException { BufferedReader reader = new BufferedReader(new FileReader(fromFile)); String line = null; while ((line=reader.readLine()) != null ) { if (line.length() >= 2) { StringTokenizer lineToken = new StringTokenizer (line); checkToken = lineToken.nextToken(); processlinetoken() ...... But here's where I come into a problem. public static void processlinetoken() checkToken=lineToken.nextToken(); } it fails out. Exception in thread "main" java.lang.Error: Unresolved compilation problem: The method nextToken() is undefined for the type String at testread.getEngineLoad(testread.java:243) at testread.readFile(testread.java:149) at testread.main(testread.java:119) so how do I get this to work? It seems to pass the variable, but nothing after the . works.

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• Emacs & PHP indenting question

  - by Danny

  Hi all, I'm a bit new to using emacs for webdevelopment. I am using php-mode and i am happy with it. There is only one issue i have which causes me a lot of problems because of our company's coding style. When i have a function, e.g.: $instance = new Model('foo', 'bar'); And I want to indent it like this: $instance = new Model( 'foo', 'bar' ); Emacs does the following when i insert a newline before the first argument and indents it like this: $instance = new Model( 'foo', 'bar' ); Can anyone point me in a direction on how i can configure/change this? Thanks in advance

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• Scala match question

  - by javier

  Hello to everyone. I came across with an error on my Scala code that I cannot solve by myself (I am new at Scala). I have the following code: def myFunction(list: List[Any]): String = { var strItems : String = ""; list.foreach(item => { strItems += item match { case x:JsonSerializable => x.toJson() case y:String => ("\"" + y + "\"") case _ => item.toString } if(item != list.last) strItems += ","; }) strItems; } The error I am getting is: error: pattern type is incompatible with expected type; found : String required: Unit case y:String = ("\"" + y + "\"") Any idea why? PS: is there a more performant way to code myFunction

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• MySQL database design question

  - by Greelmo

  I'm trying to weigh the pros and cons of a database design, and would like to get some feedback as to the best approach. Here is the situation: I have users of my system that have only a few required items (username, password). They can then supply a lot of optional information. This optional information continues to grow as the system grows, so I want to do it in such a way that adding new optional information is easy. Currently, I have a separate table for each piece of information. For example, there's a table called 'names' that holds 'user_id', 'first_name', and 'last_name'. There's 'address', 'occupation', etc. You get the drift. In most cases, when I talk to my database, I'm looking only for users with one particular qualifier (name, address, etc.). However, there are instances when I want to see what information a user has set. The 'edit account' page, for example, must run queries for each piece of information it wants. Is this wasteful? Is there a way I can structure my queries or my database to make it so I never have to do one query for each piece of information like that without getting my tables to huge? If i want to add 'marital status', how hard will that be if I don't have a one-table-per-attribute system? Thanks in advance.

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• Question regarding XST bitstream generation

  - by Richi

  Hi all, I have a very simple VHDL module, consisting of a few lines of code. The thing is, when I generate the bitstream, I end up with a huge bitstream. The reason for this is, I guess, that XST adds lots of extra information so that the bitstream can run standalone on a FPGA. However, for my purpose it would be interesting to see the size of the bitstream of the module alone without any extra bits and pieces, just the vaniall module alone. Is there an option in Xilinx ISE 12.1 that allows me to do that? Many thanks, Richi

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• Newbie question - MySQL index size

  - by Tommy

  I've just started to investigating how I should optimize my database. Indexing seems to be a good idea, so I want to index a VARCHAR column, the engine is MyISAM. From what I've read, I understand that an index is limited to a size of 1000 bytes. A VARCHAR character is 3 bytes in size. Does this mean that if I want to index a VARCHAR column with 50 rows, I need an index prefix of 6 characters? I came to that number by dividing 1000 with the row number 50, then the bytesize per character that is 3. 1000/50/3=6,66. It seems a little complicated, so I'm just wondering if I'm thinking right? It seems weird to me that you'd only be able to index 333 rows in a VARCHAR column, using a prefix of 1 character.

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• Javascript ajax asynchronous question...

  - by Polaris878

  Hello, I'm wondering if anyone can help me understand some asynchronous javascript concepts... Say I make an asynch ajax call like so: xmlhttp=new XMLHttpRequest(); xmlhttp.onreadystatechange= myFoo; xmlhttp.open("GET",url,true); Here is my callback function: function myFoo() { if (xmlhttp.readyState==4) { if (xmlhttp.status==200) { // Success message } else { // some error message } } } Now, where and when does the execution path start again? Once I make the call to open(), does execution continue directly below the open() and another "thread" enters the asynch function once the ajax request has been completed? Or, does the browser wait for the request to complete, make the Asynch call, and then execution continues right after the open? Thanks!

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• JSP Servlets simple question.

  - by loddn

  What is the simplest way to use a variable in the URL in servlets. Eg. http://somesite.com/MyServlet/[ID]

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