Search Results

Search found 11015 results on 441 pages for 'explain plan'.

Page 290/441 | < Previous Page | 286 287 288 289 290 291 292 293 294 295 296 297  | Next Page >

• Neural Network Basics

  - by Stat Onetwothree

  I'm a computer science student and for this years project, I need to create and apply a Genetic Algorithm to something. I think Neural Networks would be a good thing to apply it to, but I'm having trouble understanding them. I fully understand the concepts but none of the websites out there really explain the following which is blocking my understanding: How the decision is made for how many nodes there are. What the nodes actually represent and do. What part the weights and bias actually play in classification. Could someone please shed some light on this for me? Also, I'd really appreciate it if you have any similar ideas for what I could apply a GA to. Thanks very much! :)

  Read the article

• Why isn't my Ruby object deleted when the last reference goes out of scope?

  - by Andrew Clegg

  Hi gurus, I've found a weird effect when trying to track down a memory leak in a Rails app. Can anyone explain what's going on here? Save this script as a plain Ruby script (Rails not necessary): class Fnord def to_s 'fnord' end end def test f = Fnord.new end test GC.start sleep 2 ObjectSpace.each_object do |o| puts o if o.is_a? Fnord end When I run this via ruby 1.8.7 (2009-06-12 patchlevel 174) [i486-linux] I get the following: bash $ ruby var_test fnord Although the variable f is out of scope, there are no other references to the single Fnord object, and I've garbage collected, the object still seems to exist. Is this a nefarious memory leak of some sort, or am I completely missing something about Ruby? Further, if I change the test method to this: def test f = Fnord.new f = nil end I get no output. But surely this should not change the semantics here? Many thanks!

  Read the article

• Jsp declaration element

  - by Stardust

  <%! class father { static int s = 0; } %> <% father f1 = new father(); father f2 = new father(); f1.s++; out.println(f2.s); // It must print "1" %> When I run the file, I got this error. Can anybody explain? "The field s cannot be declared static; static fields can only be declared in static or top level types"

  Read the article

• Confused by this PHP Exception try..catch nesting

  - by Domenic

  Hello. I'm confused by the following code: class MyException extends Exception {} class AnotherException extends MyException {} class Foo { public function something() { print "throwing AnotherException\n"; throw new AnotherException(); } public function somethingElse() { print "throwing MyException\n"; throw new MyException(); } } $a = new Foo(); try { try { $a->something(); } catch(AnotherException $e) { print "caught AnotherException\n"; $a->somethingElse(); } catch(MyException $e) { print "caught MyException\n"; } } catch(Exception $e) { print "caught Exception\n"; } I would expect this to output: throwing AnotherException caught AnotherException throwing MyException caught MyException But instead it outputs: throwing AnotherException caught AnotherException throwing MyException caught Exception Could anyone explain why it "skips over" catch(MyException $e) ? Thanks.

  Read the article

• How to find scrollable elements in DOM using XPath?

  - by ak.

  Basically I need to find all elements on the page that have a scrollbar (vertical or horizontal) How to tell if an element has a scrollbar and can actually be scrolled? I found this code snippet on jsperf. Is it possible to capture the logic behind the code into and XPath expression? Or are there any other ways to check for scrollbars? Added: Just to explain what I'm trying to do: I'm developing extension for Firefox. Basically it introduces Vim-style mouseless shortcuts (I know there is Vimperator and Pentadactyl...). One of the features I'd like to implement is to allow the use to select the container that's scrolled with j/k keys. That's why I need to discover all scrollable elements on any given random page.

  Read the article

• How to get the "#" symbol in the :id into the redirect_to method in Rails

  - by Matthias Günther

  Hello, this is a silly questions but I don't understand, why rails isn't evaluating my string as expected. Here is my problem: I want to redirect to an url in the form ~/:controller/index/#_76 redirect_to :action => "index", :id => '#_76' But I'm getting the url in the form: ~/:controller/index/%25_76 and so my anchor for linking to a certain place in the website isn't working. Can someone please explain me, why rails makes this rendering? I think this hase something to do with url encoding. Again thanks for your help, I'm learning every day a little bit more about rails :).

  Read the article

• Javascript array length incorrect on array of objects

  - by Serenti

  Could someone explain this (strange) behavior? Why is the length in the first example 3 and not 2, and most importantly, why is the length in the second example 0? As long as the keys are numerical, length works. When they are not, length is 0. How can I get the correct length from the second example? Thank you. a = []; a["1"] = {"string1":"string","string2":"string"}; a["2"] = {"string1":"string","string2":"string"}; alert(a.length); // returns 3 b = []; b["key1"] = {"string1":"string","string2":"string"}; b["key2"] = {"string1":"string","string2":"string"}; alert(b.length); // returns 0

  Read the article

• Delays in .net app when connecting to oracle db using Oracle.DataAccess

  - by chris

  I have a .net desktop app that connects to an oracle database. At times, there are very noticable delays. I ran a trace on the code, and it was always in the DataReader.Read(). I turned on sql tracing, and found the following, which corresponds to the delays I'm seeing: (2128) [23-MAR-2010 13:00:07:310] nsprecv: reading from transport... (2128) [23-MAR-2010 13:00:07:310] nttrd: entry (2128) [23-MAR-2010 13:00:24:655] nttrd: socket 676 had bytes read=2047 (2128) [23-MAR-2010 13:00:24:655] nttrd: exit (2128) [23-MAR-2010 13:00:24:655] nsprecv: 2047 bytes from transport There's about a 14 second pause in there. I'm pretty sure that there's not a problem in the code, but not sure where to look at next. Is there anyone out there with experience with oracle trace that can explain what's going on?

  Read the article

• Kernel thread exit in linux

  - by Raffo

  Hi guys, I'm here to ask you the difference between a process and a thread in linux. I know that a thread for linux is just a "task", which shares with the father process things that they need to have in common (the address space and other important informations). I also know that the two are creating calling the same function ('clone()'), but there's still something that I'm missing: what really happens when a thread exit? What function is called inside the linux kernel? I know that when a process exits calls the do_exit function, but here or somewhere else there should be a way to understand if it is just a thread exiting or a whole process. Can you explain me this thing or redirect to some textbook?? I tried 'Understanding the linux kernel' but I was not satisfied with it. I'm asking this thing because a need to add things to the task_struct struct, but I need to discriminate how to manage those informations for a process and its children. Thank you.

  Read the article

• I have a problem with the following Java code

  - by Sanjeev

  public class b { public static void main(String[] args) { byte b = 1; long l = 127; // b = b + l; // 1 if I try this then it does not compile b += l; // 2 if I try this then it does compile System.out.println(b); } } I am using this code but I have problem: I don't understand why b=b+l; is not compiling but if I write b+=l; then it compiles and runs. Please explain why this happens.

  Read the article

• urllib alternative for iPhone

  - by Pr301

  hi, I am trying to create an iPhone application which in some point connects to the internet, fills an on-line form, fetches the resulting website, parses it and returns a string to the user. I want all this process to happen in the background. I know how to do this kind of things with python and urllib but in objc I can't find an alternative, from on-line search I found either sites that explain how to use webkit to retrieve webpages (I suppose this is for displaying them to the user) or how to parse an existing HTML file or string. Since I want the file to be retrieved from the internet and the whole process should be running in the background, neither of these solutions covers my needs.

  Read the article

• Question About Abstract Classes?

  - by IbrarMumtaz

  URL: Link (1) According to this wesbite .. you cannot implement Abstract classes but derive from them. This makes sense and I have read this many times. Like an interface, you cannot implement an instance of an abstract class, however you can implement methods, fields, and properties in the abstract class that can be used by the child class. But on MSDN URL: TextWriter CLass on MSDN TextWriter is an abstract class but it has two constructors defined ... and according to the MS 70-536 book, the following statement is valid: TextWriter tw = new File.CreateText("myFile.Txt") The static file class and it's CreateText method is fine by me as I have studied it on MSDN but can somebody explain this little contradiction I have found? Surely I am not the first? Why is instantaion of base abstract classes possible????

  Read the article

• Create DataGridView columns from Table values

  - by fireBand

  Hi, I am using data grid view to display items as excel spread sheet in VB.NET. I got a table named CostTypes with column names [CostTypeID, CostType] and values [1,External] and [2,Internal] (These are constant but more values can be added to table). I want to create columns with names of the values[External , Internal] in DataGridView. If I use databiding directly I get columns [CostTypeID,CostType] which is not what I am looking for. If some one could explain how to create columns at runtime in datagridview or how to retrieve data from data base using LINQ so that [External , Internal] turn out to be columns that would be great. Thanks in advance.

  Read the article

• What benefits can Java developer have moving to a *NIX platform?

  - by dave-keiture

  Hi everyone, A friend of mine is a Java developer, who's using *NIX for ages. He claims that *NIX is for real Java geeks, whereas WIN is for dummies (and I'm one of them, according to him) and girls. When I ask him to argue his position, and explain, what's so good for Java developer on *NIX, he starts talking about console, wget, curl and grep. But sorry, wget and curl analogues exist for the WIN platform as well. As for the console - I'm using FAR Commander, and have access to the command line when I need. Moreover, even if I decide moving to *NIX, I will certainly use Netbeans or Eclipse there, so there will be no big difference. Guys, who use Java on *NIX, could you please give me a real killer examples, when *NIX (any util or technique) dramatically increases Java development productivity (in the way the hints are given in "The Pragmatic Programmer"), or, which is also important, gives more fun from the process. Thanks in advance!

  Read the article

• Right rotate of tree in Haskell: how is it work?

  - by Roman

  I don't know haskell syntax, but I know some FP concepts (like algebraic data types, pattern matching, higher-order functions ect). Can someone explain please, what does this code mean: data Tree ? = Leaf ? | Fork ? (Tree ?) (Tree ?) rotateR tree = case tree of Fork q (Fork p a b) c -> Fork p a (Fork q b c) As I understand, first line is something like Tree-type declaration (but I don't understand it exactly). Second line includes pattern matching (I don't understand as well why do we need to use pattern matching here). And third line does something absolutely unreadable for non-haskell developer. I've found definition of Fork as fork (f,g) x = (f x, g x) but I can't move further anymore.

  Read the article

• Multi-tab application (C#)

  - by Zach

  Hi, I'm creating a multi-tabbed .NET application that allows the user to dynamically add and remove tabs at runtime. When a new tab is added, a control is added to it (as a child), in which the contents can be edited (eg. a text box). The user can perform tasks on the currently visible text box using a toolbar/menu bar. To better explain this, look at the picture below to see an example of what I want to accomplish. It's just a mock-up, so it doesn't actually work that way, but it shows what I want to get done. Essentially, like a multi-tabbed Notepad. View the image here: http://picasion.com/pic15/324b466729e42a74b9632c1473355d3b.gif Is this possible in .NET? I'm pretty sure it is, I'm just looking for a way that it can be implemented.

  Read the article

• How to implement python to find value between xml tags?

  - by Harshit Sharma

  I am using google site to retrieve weather information , I want to find values between XML tags. Following code give me weather condition of a city , but I am unable to obtain other parameters such as temperature and if possible explain working of split function implied in the code: import urllib def getWeather(city): #create google weather api url url = "http://www.google.com/ig/api?weather=" + urllib.quote(city) try: # open google weather api url f = urllib.urlopen(url) except: # if there was an error opening the url, return return "Error opening url" # read contents to a string s = f.read() # extract weather condition data from xml string weather = s.split("<current_conditions><condition data=\"")[-1].split("\"")[0] # if there was an error getting the condition, the city is invalid if weather == "<?xml version=": return "Invalid city" #return the weather condition return weather def main(): while True: city = raw_input("Give me a city: ") weather = getWeather(city) print(weather) if __name__ == "__main__": main() Thank You

  Read the article

• what is the meaning of this code

  - by spific

  i have this code : use strict; use LWP::UserAgent; use warnings; my $ua = new LWP::UserAgent(agent => 'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.0.5) Gecko/20060719 Firefox/1.5.0.5'); $ua->proxy([qw(http https)] => 'http://59.39.92.148:1080'); my $response = $ua->get("http://www.google.com"); print $response->code,' ', $response->message,"\n"; is the mean of code " open www.google.com with sock proxy"? pls explain for me .

  Read the article

• functions in F# .. why is it not compiling

  - by Tanmoy

  Hi, I have written two versions of code. The first one works as expected and print "Hi". the second one gives me error that "block following this let is unfinished" 1st version #light let samplefn() = let z = 2 let z = z * 2 printfn "hi" samplefn() 2nd version #light let samplefn() = let z = 2 let z = z * 2 samplefn() Only difference is the printfn is absent in the second version. I am using Visual Studio 2010 as my IDE. I am very new to F# but this error seems very strange to me. I guess I am missing some very important concept. Please explain. Edit: Also if I do it outside the function I get error even with the first version of code. #light let z = 2 let z = z * 2 printfn "Error: Duplicate definition of value z"

  Read the article

• How do I add a VSTO project as a reference to a unit testing project?

  - by Mathias

  In order not to pollute my projects with unit tests, I like to create a separate project for my unit tests; I add a reference to the project under test in the unit tests project. However, this isn't working that well with my VSTO excel add-in projects: when I create a separate unit test project and go to Add Reference Projects, there is no project to pick. What I have done so far is Add Reference Browse, and pick the add-in dll from the debug folder. I have also run into issues from time to time with this, with the reference suddenly not working, requiring to remove/re-add the dll reference. Can anybody explain why a VSTO project doesn't show up as a regular project? And is there a better way to go about it than what I am doing presently?

  Read the article

• Simplest way of creating java next/previous buttons

  - by Holly

  I know that when creating buttons, like next and previous, that the code can be somewhat long to get those buttons to function. My professor gave us this example to create the next button: private void jbtnNext_Click() { JOptionPane.showMessageDialog(null, "Next" ,"Button Pressed", JOptionPane.INFORMATION_MESSAGE); try { if (rset.next()) { fillTextFields(false); }else{ //Display result in a dialog box JOptionPane.showMessageDialog(null, "Not found"); } } catch (SQLException ex) { ex.printStackTrace(); } } Though, I do not really understand how that short and simple if statement is what makes the next button function. I see that the fillTextFields(false) uses a boolean value and that you need to initialize that boolean value in the beginning of the code I believe. I had put private fillTextFields boolean = false; but this does not seem to be right... I'm just hoping someone could explain it better. Thanks :)

  Read the article

• Analyzing Python Code: Modulus Operator

  - by Bhubhu Hbuhdbus

  I was looking at some code in Python (I know nothing about Python) and I came across this portion: def do_req(body): global host, req data = "" s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect((host, 80)) s.sendall(req % (len(body), body)) tmpdata = s.recv(8192) while len(tmpdata) > 0: data += tmpdata tmpdata = s.recv(8192) s.close() return data This is then called later on with body of huge size, as in over 500,000 bytes. This is sent to an Apache server that has the max request size on the default 8190 bytes. My question is what is happening at the "s.sendall()" part? Obviously the entire body cannot be sent at once and I'm guessing it is reduced by way of the modulus operator. I don't know how it works in Python, though. Can anyone explain? Thanks.

  Read the article

• How do Java mocking frameworks work?

  - by Amir Rachum

  This is NOT a question about which is the best framework, etc. I have never used a mocking framework and I'm a bit puzzled by the idea. How does it know how to create the mock object? Is it done in runtime or generates a file? How do you know its behavior? And most importantly - what is the work flow of using such a framework (what is the step-by-step for creating a test). Can anyone explain? You can choose whichever framework you like for example, just say what it is.

  Read the article

• deny direct access to a php file by typing the link in the url

  - by aeonsleo

  hi, I am using php session for a basic login without encryption for my site. I want to prevent a user from directly accessing a php page by typing the url when he/she is not signed in. But this is not happening. I am using session_start(), initializing session variables and aslo unsetting and destroying sesssion during logout. Also if I type the link in a different browser the page is getting displayed. I am not very well versed with php , only a beginner. I googled for such problem and found few alternatives as keeping all files in a seperate folder from the web root, using .htaccess etc. Can someone explain in simple terms what could be a good solution.thanks in advance.

  Read the article

• c# Generic overloaded method dispatching ambiguous

  - by sebgod

  Hello, I just hit a situation where a method dispatch was ambiguous and wondered if anyone could explain on what basis the compiler (.NET 4.0.30319) chooses what overload to call interface IfaceA { } interface IfaceB<T> { void Add(IfaceA a); T Add(T t); } class ConcreteA : IfaceA { } class abstract BaseClassB<T> : IfaceB<T> { public virtual T Add(T t) { ... } public virtual void Add(IfaceA a) { ... } } class ConcreteB : BaseClassB<IfaceA> { // does not override one of the relevant methods } void code() { var concreteB = new ConcreteB(); // it will call void Add(IfaceA a) concreteB.Add(new ConcreteA()); } In any case, why does the compiler not warn me or even why does it compile? Thank you very much for any answers.

  Read the article

< Previous Page | 286 287 288 289 290 291 292 293 294 295 296 297  | Next Page >