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  • Loading a Win32 control in C# (specifically WPF)

    - by Mmarquee
    I have written a set of Win32 dlls that encapsulate a Delphi Frame (see Snippet 1 below), and can load them into another Delphi program by loading the dll and assigning the right variables (Snippet 2). I now want to be able to do the same thing in C# (I can load the DLL in pinvoke, but am unsure how to connect up the control to the basic WPF 'form'. Snippet 1 var frame : TFrame1; function CreateFrame(hParent:TWinControl):Integer; stdcall; export; begin try frame := TFrame1.Create(hParent); frame.Parent := hParent; frame.Align := alClient; finally result := 1; end; end; exports CreateFrame name 'CreateFrame'; Snippet 2 DLLHandle := LoadLibrary('Library/Demo.Frame.dll'); If DLLHandle > 32 then begin ReturnValue := GetProcAddress(DLLHandle, 'CreateFrame'); end; ts1 := TTabSheet.Create(PageControl1); with ts1 do begin PageControl := PageControl1; Name := 'tsExternal'; Caption := 'External'; Align := alClient; ReturnValue (ts1); end; Any help would be greatly appreciated.

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  • How to format dates in Jahia 6 CMS?

    - by dpb
    I am helping a friend of mine put up a site for his business. I’ve read different posts and sites trying to find the ideal CMS tool, but people have different views of what is the best, so I finally just picked one of them at random. So I went for an evaluation of Jahia 6.0-CE. As you’ve probably guessed by now, I don’t have so much experience with CMS tools. I just want to setup the CMS, write the templates for the site and let my friend manage the content from there on. So I extracted the sources from SVN and went for a test drive. I managed to create some simple templates to get a hang of things but now I have an issue with a date format. In my definitions.cnd I declared the field like so: date myDateField (datetimepicker[format='dd.MM.yyyy']) This is formatted in the page and the selector also presents this in the dd.MM.yyyy format when inserting the content. But how about sites in other countries, countries that represent the date as MM.dd.yyyy for example? If I specify the format in the CND, hard coded, how can I change this later on so that it adapts based on the browser’s language? Do I extract the content from the repository and format it by hand in the JSP template based on a Locale, or is there a better way? Thank you.

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  • How do software events work internally?

    - by Duddle
    Hello! I am a student of Computer Science and have learned many of the basic concepts of what is going on "under the hood" while a computer program is running. But recently I realized that I do not understand how software events work efficiently. In hardware, this is easy: instead of the processor "busy waiting" to see if something happened, the component sends an interrupt request. But how does this work in, for example, a mouse-over event? My guess is as follows: if the mouse sends a signal ("moved"), the operating system calculates its new position p, then checks what program is being drawn on the screen, tells that program position p, then the program itself checks what object is at p, checks if any event handlers are associated with said object and finally fires them. That sounds terribly inefficient to me, since a tiny mouse movement equates to a lot of cpu context switches (which I learned are relatively expensive). And then there are dozens of background applications that may want to do stuff of their own as well. Where is my intuition failing me? I realize that even "slow" 500MHz processors do 500 million operations per second, but still it seems too much work for such a simple event. Thanks in advance!

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  • What should a hobbyist do to develop good programming skills after basics?

    - by thyrgle
    So I'll say right here that I'm no professional coder. I'm a hobbyist. And pretty much like other people I feel like I'm doing it wrong. Like this question A feeling that I'm not a good programmer if have began to feel like that. Now I know basically that they say you shouldn't worry and that your good even if you continuously doubt yourself. But, they are talking to him. I'm not like him (in the sense I'm more of a newbie)... I've been coding as a hobbyist for 3 years (3 hobbyist years mind you!) unlike his 10-11 years that he states. Also, the only thing I've probably read in-depth is Teach Yourself C++ in 21 Days. And before I continue, just so your not confused about the various questions I've posted on (mostly) iPhone and OpenGL, I have poked and prodded at those two things for a few months each and finally sort of got a hang of both of them. But, from what I've noticed, is that I suck at making good code. For me its not even a debate of whether I'm doing it wrong or not: I can tell (from the various spaghetti code I create and other various discrepancies I, and others, can see and have noted in my code). What is a good way to get rid of these awful habits of mine and do it in a more correct, or if there is no "correct way" then I mean "typical", way?

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  • MemoryStream instance timing help

    - by rod
    Hi All, Is it ok to instance a MemoryStream at the top of my method, do a bunch of stuff to it, and then use it? For instance: public static byte[] TestCode() { MemoryStream m = new MemoryStream(); ... ... whole bunch of stuff in between ... ... //finally using(m) { return m.ToArray(); } } Updated code public static byte[] GetSamplePDF() { using (MemoryStream m = new MemoryStream()) { Document document = new Document(); PdfWriter.GetInstance(document, m); document.Open(); PopulateTheDocument(document); document.Close(); return m.ToArray(); } } private static void PopulateTheDocument(Document document) { Table aTable = new Table(2, 2); aTable.AddCell("0.0"); aTable.AddCell("0.1"); aTable.AddCell("1.0"); aTable.AddCell("1.1"); document.Add(aTable); for (int i = 0; i < 20; i++) { document.Add(new Phrase("Hello World, Hello Sun, Hello Moon, Hello Stars, Hello Sea, Hello Land, Hello People. ")); } } My point was to try to reuse building the byte code. In other words, build up any kind of document and then send it to TestCode() method.

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  • How to make this JavaScript much faster?

    - by Ralph
    Still trying to answer this question, and I think I finally found a solution, but it runs too slow. var $div = $('<div>') .css({ 'border': '1px solid red', 'position': 'absolute', 'z-index': '65535' }) .appendTo('body'); $('body *').live('mousemove', function(e) { var topElement = null; $('body *').each(function() { if(this == $div[0]) return true; var $elem = $(this); var pos = $elem.offset(); var width = $elem.width(); var height = $elem.height(); if(e.pageX > pos.left && e.pageY > pos.top && e.pageX < (pos.left + width) && e.pageY < (pos.top + height)) { var zIndex = document.defaultView.getComputedStyle(this, null).getPropertyValue('z-index'); if(zIndex == 'auto') zIndex = $elem.parents().length; if(topElement == null || zIndex > topElement.zIndex) { topElement = { 'node': $elem, 'zIndex': zIndex }; } } }); if(topElement != null ) { var $elem = topElement.node; $div.offset($elem.offset()).width($elem.width()).height($elem.height()); } }); It basically loops through all the elements on the page and finds the top-most element beneath the cursor. Is there maybe some way I could use a quad-tree or something and segment the page so the loop runs faster?

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  • Android while getting HTTP response to file how to know it wasn't fully loaded?

    - by Stan
    I'm using this approach to store a big-sized response from server to parse it later: final HttpClient client = new DefaultHttpClient(new BasicHttpParams()); final HttpGet mHttpGetRequest = new HttpGet(strUrl); mHttpGetRequest.setHeader("Content-Type", "application/x-www-form-urlencoded"); FileOutputStream fos = null; try { final HttpResponse response = client.execute(mHttpGetRequest); final StatusLine statusLine = response.getStatusLine(); lastHttpErrorCode = statusLine.getStatusCode(); lastHttpErrorMsg = statusLine.getReasonPhrase(); if (lastHttpErrorCode == 200) { HttpEntity entity = response.getEntity(); fos = new FileOutputStream(reponseFile); entity.writeTo(fos); entity.consumeContent(); fos.flush(); } } catch (ClientProtocolException e) { e.printStackTrace(); lastHttpErrorMsg = e.toString(); return null; } catch (final ParseException e) { e.printStackTrace(); lastHttpErrorMsg = e.toString(); return null; } catch (final UnknownHostException e) { e.printStackTrace(); lastHttpErrorMsg = e.toString(); return null; } catch (IOException e) { e.printStackTrace(); lastHttpErrorMsg = e.toString(); } finally{ if (fos!=null) try{ fos.close(); } catch (IOException e){} } now how could I ensure the response was completely received and thus saved to file? Assume client's device lost Internet connection while this code was running. So the app received only some part of real response. And I'm pretty sure it happens cuz I got parsing exceptions like "tag not closed", "unexpected end of file" etc. So I need to detect somehow this situation to prevent code from parsing partial response but can't see how. Is it possible at all and how to do it? Or has it has to raise IOException in such cases?

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  • Is this a safe PHP mail function?

    - by Eystein
    I've finally got this PHP email script working (didn't work on localhost…), but my concern is that it's not safe. So - is this safe for spamming and any other security pitfalls I'm not aware of? <?php $email = '[email protected]'; $subject = 'Notify about stuff'; $notify = $_REQUEST['email']; if (!preg_match("/\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*/", $notify)) { echo "<h4>Your email address doesn't validate, please check that you typed it correct.</h4>"; echo "<a href='javascript:history.back(1);'>Back</a>"; } elseif(mail($email, $subject, $notify)) { echo "<h4>Thank you, you will be notified.</h4>"; } else { echo "<h4>Sorry, your email didn't get registered.</h4>"; } ?> Unrelated: is there a PHP function I can use instead of javascript:history.back(1) ?

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  • Where to add an overloaded operator for the tr1::array?

    - by phlipsy
    Since I need to add an operator& for the std::tr1::array<bool, N> I wrote the following lines template<std::size_t N> std::tr1::array<bool, N> operator& (const std::tr1::array<bool, N>& a, const std::tr1::array<bool, N>& b) { std::tr1::array<bool, N> result; std::transform(a.begin(), a.end(), b.begin(), result.begin(), std::logical_and<bool>()); return result; } Now I don't know in which namespace I've to put this function. I considered the std namespace as a restricted area. Only total specialization and overloaded function templates are allowed to be added by the user. Putting it into the global namespace isn't "allowed" either in order to prevent pollution of the global namespace and clashes with other declarations. And finally putting this function into the namespace of the project doesn't work since the compiler won't find it there. What had I best do? I don't want to write a new array class putted into the project namespace. Because in this case the compiler would find the right namespace via argument dependent name lookup. Or is this the only possible way because writing a new operator for existing classes means extending their interfaces and this isn't allowed either for standard classes?

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  • How to connect SQLite with Java?

    - by Rajapandian
    Hi, I am using one simple code to access the SQLite database from Java application . My code is import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.Statement; public class ConnectSQLite { public static void main(String[] args) { Connection connection = null; ResultSet resultSet = null; Statement statement = null; try { Class.forName("org.sqlite.JDBC"); connection = DriverManager.getConnection("jdbc:sqlite:D:\\testdb.db"); statement = connection.createStatement(); resultSet = statement .executeQuery("SELECT EMPNAME FROM EMPLOYEEDETAILS"); while (resultSet.next()) { System.out.println("EMPLOYEE NAME:" + resultSet.getString("EMPNAME")); } } catch (Exception e) { e.printStackTrace(); } finally { try { resultSet.close(); statement.close(); connection.close(); } catch (Exception e) { e.printStackTrace(); } } } } But this code gives one exception like java.lang.ClassNotFoundException: org.sqlite.JDBC Any body knows how to slove it,please help me.

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  • Outlook VSTO AddIn for Meetings

    - by BigDubb
    We have created a VSTO addin for Outlook Meetings. As part of this we trap on the SendEvent of the message on the FormRegionShowing event: _apptEvents.Send += new Microsoft.Office.Interop.Outlook.ItemEvents_SendEventHandler(_apptEvents_Send); The method _apptEvents_Send then tests on a couple of properties and exits where appropriate. private void _apptEvents_Send(ref bool Cancel) { if (!_Qualified) { MessageBox.Show("Meeting has not been qualified", "Not Qualified Meeting", MessageBoxButtons.OK, MessageBoxIcon.Information); chkQualified.Focus(); Cancel = true; } } The problem that we're having is that some users' messages get sent twice. Once when the meeting is sent and a second time when the user re-opens outlook. I've looked for memory leaks, thinking that something might not be getting disposed of properly, and have added explicit object disposal on all finally calls to try and make sure resources are managed, but still getting the functionality incosistently across the organization. i.e. I never encountered the problem during development, nor other developers during testing. All users are up to date on framework (3.5 SP1) and Hotfixes for Outlook. Does anyone have any ideas on what might be causing this? Any ideas anyone might have would be greatly appreciated.

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  • ASP.NET DynamicData: Whats happening during an update?

    - by Jens A.
    I am using ASP.NET DynamicData (based on LINQ to SQL) on my site for basic scaffolding. On one table I have added additional properties, that are not stored in the table, but are retrieved from somewhere else. (Profile information for a user account, in this case). They are displayed just fine, but when editing these values and pressing "Update", they are not changed. Here's what the properties look like, the table is the standard aspnet_Users table: public String Address { get { UserProfile profile = UserProfile.GetUserProfile(UserName); return profile.Address; } set { UserProfile profile = UserProfile.GetUserProfile(UserName); profile.Address = value; profile.Save(); } } When I fired up the debugger, I've noticed that for each update the set accessor is called three times. Once with the new value, but on a newly created instance of user, then once with the old value, again on an new instance, and finally with the old value on the existing instance. Wondering a bit, I checked with the properties created by the designer, and they, too, are called three times in (almost) the same fashion. The only difference is, that the last call contains the new value for the property. I am a bit stumped here. Why three times, and why are my new properties behaving differently? I'd be grateful for any help on that matter! =)

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  • Java Generics error when implementing Hibernate message interpolator

    - by Jayaprakash
    Framework: Spring, Hibernate. O/S: Windows I am trying to implement hibernate's Custom message interpolator following the direction of this Link. When implementing the below class, it gives an error "Cannot make a static reference to the non-static type Locale". public class ClientLocaleThreadLocal<Locale> { private static ThreadLocal tLocal = new ThreadLocal(); public static void set(Locale locale) { tLocal.set(locale); } public static Locale get() { return tLocal.get(); } public static void remove() { tLocal.remove(); } } As I do not know generics enough, not sure how is being used by TimeFilter class below and the purpose of definition in the above class. public class TimerFilter implements Filter { public void destroy() { } public void doFilter(ServletRequest req, ServletResponse res, FilterChain filterChain) throws IOException, ServletException { try { ClientLocaleThreadLocal.set(req.getLocale()); filterChain.doFilter(req, res); }finally { ClientLocaleThreadLocal.remove(); } } public void init(FilterConfig arg0) throws ServletException { } } Will doing the following be okay? Change static method/field in ClientLocaleThreadLocal to non-static method/fields In TimeFilter, set locale by instantiating new object as below. new ClientLocaleThreadLocal().set(req.getLocale()) Thanks for your help in advance

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  • how do I remove rows/columns from this matrix using python

    - by banditKing
    My matrix looks like this. ['Hotel', ' "excellent"', ' "very good"', ' "average"', ' "poor"', ' "terrible"', ' "cheapest"', ' "rank"', ' "total reviews"'] ['westin', ' 390', ' 291', ' 70', ' 43', ' 19', ' 215', ' 27', ' 813'] ['ramada', ' 136', ' 67', ' 53', ' 30', ' 24', ' 149', ' 49', ' 310 '] ['sutton place', '489', ' 293', ' 106', ' 39', ' 20', ' 299', ' 24', ' 947'] ['loden', ' 681', ' 134', ' 17', ' 5', ' 0', ' 199', ' 4', ' 837'] ['hampton inn downtown', ' 241', ' 166', ' 26', ' 5', ' 1', ' 159', ' 21', ' 439'] ['shangri la', ' 332', ' 45', ' 20', ' 8', ' 2', ' 325', ' 8', ' 407'] ['residence inn marriott', ' 22', ' 15', ' 5', ' 0', ' 0', ' 179', ' 35', ' 42'] ['pan pacific', ' 475', ' 262', ' 86', ' 29', ' 16', ' 249', ' 15', ' 868'] ['sheraton wall center', ' 277', ' 346', ' 150', ' 80', ' 26', ' 249', ' 45', ' 879'] ['westin bayshore', ' 390', ' 291', ' 70', ' 43', ' 19', ' 199', ' 813'] I want to remove the top row and the 0th column from this and create a new matrix. How do I do this? Normally in java or so Id use the following code: for (int y; y< matrix[x].length; y++) for(int x; x < matrix[Y].length; x++) { if(x == 0 || y == 0) { continue } else { new_matrix[x][y] = matrix[x][y]; } } Is there a way such as this in python to iterate and selectively copy elements? Thanks EDIT Im also trying to convert each matrix element from a string to a float as I iterate over the matrix. This my updated modified code based on the answer below. A = [] f = open("csv_test.csv",'rt') try: reader = csv.reader(f) for row in reader: A.append(row) finally: f.close() new_list = [row[1:] for row in A[1:]] l = np.array(new_list) l.astype(np.float32) print l However Im getting an error --> l.astype(np.float32) print l ValueError: setting an array element with a sequence.

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  • Downloading Large JSON File to local file using Java

    - by user1279675
    I'm attempting to download a JSON from the following URL - http://api.crunchbase.com/v/1/companies.js - to a local file. I'm using Java 1.7 and the following JSON Libraries - http://www.json.org/java/ - to attempt to make it work. Here's my code: public static void download(String address, String localFileName) { OutputStream out = null; URLConnection conn = null; InputStream in = null; try { URL url = new URL(address); out = new BufferedOutputStream( new FileOutputStream(localFileName)); conn = url.openConnection(); in = conn.getInputStream(); byte[] buffer = new byte[1024]; int numRead; long numWritten = 0; while ((numRead = in.read(buffer)) != -1) { out.write(buffer, 0, numRead); numWritten += numRead; System.out.println(buffer.length); System.out.println(" " + buffer.hashCode()); } System.out.println(localFileName + "\t" + numWritten); } catch (Exception exception) { exception.printStackTrace(); } finally { try { if (in != null) { in.close(); } if (out != null) { out.close(); } } catch (IOException ioe) { } } } When I run the code everything seems to work until midway through the loop the program seems to stop and not continue reading the JSON Object. Does anyone know why this would stop reading? How could I fix the issue?

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  • How do I manage multiple development branches in GIT?

    - by Ian
    I have 5 branches of one system - lets call them master, London, Birmingham, Manchester and demo. These differ in only a configuration file and each has its own set of graphics files. When I do some development, I create a temp branch from master, called after the feature, and work on that. When ready to merge I checkout master, and git merge feature to bring in my work. That appears to work just fine. Now I need to get my changes into the other Branches, without losing the differences between then that are there already. How can I do that? I have been having no end of problems with Birmingham geting London's graphics, and with conflicts within the configuration file. When the branch is finally correct, I push it up to a depot, and pull each Branch down to a linux box for final testing, From there the release into production is using rsync (set to ignore the .git repository itself). This phase works just fine also. I am the only developer at the moment, but I need to get the process solid before inviting assistance :)

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  • PNG Textures not loading on HTC desire

    - by Matthew Tatum
    Hi I'm developing a game for android using OpenGL es and have hit a problem: My game loads fine in the emulator (windows xp and vista from eclipse), it also loads fine on a T-Mobile G2 (HTC Hero) however when I load it on my new HTC Desire none of the textures appear to load correctly (or at all). I'm suspecting the BitmapFactory.decode method although I have no evidence that that is the problem. All of my textures are power of 2 and JPG textures seem to load (although they don't look great quality) but anything that is GIF or PNG just doesn't load at all except for a 2x2 red square which loads fine and one texture that maps to a 3d object but seems to fill each triangle of the mesh with the nearest colour). This is my code for loading images: AssetManager am = androidContext.getAssets(); BufferedInputStream is = null; try { is = new BufferedInputStream(am.open(fileName)); Bitmap bitmap; bitmap = BitmapFactory.decodeStream(is); GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0); bitmap.recycle(); } catch(IOException e) { Logger.global.log(Level.SEVERE, e.getLocalizedMessage()); } finally { try { is.close(); } catch(Exception e) { // Ignore. } } thanks

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  • Cannot implicitly convert type ...

    - by Newbie
    I have the following function public Dictionary<DateTime, object> GetAttributeList( EnumFactorType attributeType ,Thomson.Financial.Vestek.Util.DateRange dateRange) { DateTime startDate = dateRange.StartDate; DateTime endDate = dateRange.EndDate; return (( //Step 1: Iterate over the attribute list and filter the records by // the supplied attribute type from assetAttribute in AttributeCollection where assetAttribute.AttributeType.Equals(attributeType) //Step2:Assign the TimeSeriesData collection into a temporary variable let timeSeriesList = assetAttribute.TimeSeriesData //Step 3: Iterate over the TimeSeriesData list and filter the records by // the supplied date from timeSeries in timeSeriesList.ToList() where timeSeries.Key >= startDate && timeSeries.Key <= endDate //Finally build the needed collection select new AssetAttribute() { TimeSeriesData = PopulateTimeSeriesData(timeSeries.Key, timeSeries.Value) }).ToList<AssetAttribute>().Select(i => i.TimeSeriesData)); } private Dictionary<DateTime, object> PopulateTimeSeriesData(DateTime dateTime, object value) { Dictionary<DateTime, object> timeSeriesData = new Dictionary<DateTime, object>(); timeSeriesData.Add(dateTime, value); return timeSeriesData; } Error:Cannot implicitly convert type 'System.Collections.Generic.IEnumerable' to 'System.Collections.Generic.Dictionary'. An explicit conversion exists (are you missing a cast?) Using C#3.0 Please help

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  • Problem with using Jquery.ajax over .load on Zend

    - by Matthew
    Right now, what i'm trying to do is to replace a label on the front page with a block of html. Right now, the page basically has: <label id="replace"></label> the js currently has: $(document).ready(function(){ $("#replace").load('/test'); }); the Zend class function has: public function indexAction(){ $this->_helper->layout()->disableLayout(); $this->_view->message = "This is from TestController index"; } and finally the index.phtml template simply has: <?php echo $this->message;?> Right now, I want to change the code around so that instead of just replacing that label with the same message, it would do a POST where the function will pull out a parameter, do something (like for instance, go to the database and pull something out with the POST parameter) and then return the message. I've tried editing the js so that it would look like: $.post('/test', {param : "test_param"}, function(data) {$("#replace").html(data);}); or $.ajax({ type: 'POST', url: '/test', data: "{param:test_param}", contentType: "application/json; charset=utf-8", dataType: "json", success: function(data) {$("#replace").html(data);} }); and neither worked. I took a step back and tried to replicate the .load functionality and do: $.ajax({ url: '/test', success: function(data) { $('#replace').html(data); alert('Load was performed.'); } }); and it doesn't work either. Anyone have any tips on how to go about doing this?

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  • Moving Computer Player in Xcode

    - by user1631497
    I am working on a 2d game using xcode and objective-c. I am trying to make my enemy player move left if I am left of him, until he is touching my character. The same will go when I am right of him. Basically just trying to get him to move towards me. But my code to do so is not working. So I have my code that says the following -(void)moveTowardsCharacter { enemyLeftTimer = [NSTimer scheduledTimerWithTimeInterval:0.05 target:self selector:@selector(goEnemyLeft) userInfo:nil repeats:YES]; if (enemyLeftTimer == nil){ enemyLeftTimer = [NSTimer scheduledTimerWithTimeInterval:0.05 target:self selector:@selector(goEnemyLeft) userInfo:nil repeats:YES]; } } -(IBAction)enemyStopLeft { if (CGRectIntersectsRect(bluebox.frame, redbox.frame)) { [enemyLeftTimer invalidate]; enemyLeftTimer = nil; } } -(void)goEnemyLeft { if (redbox.center.x + [self getRedboxWidthLeft] > bluebox.center.x + [self getBlueboxWidthRight]) { redbox.center = CGPointMake(redbox.center.x -5, redbox.center.y); } } So the first bit is saying for it to set up a timer to continue moving left. The next will stop the timer if my player(bluebox) and the Computer player(redbox) collide. Finally, the thing that actually tells it to go left, but only if the bluebox is left of the redbox. The getRedBoxWidth Left and getBlueBoxWidthRight are just voids that get, well, the left and right edges. If you could, please help try and solve this code. Thank You.

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  • Best (functional?) programming language to learn coming from Mathematica

    - by Will Robertson
    As a mechanical engineering PhD student, I haven't had a great pedigree in programming as part of my “day job”. I started out in Matlab (having written some Hypercard and Applescript back in the day, and being introduced to Ada, of all things, in my 1st undergrad year), learned to program—if you can call it that—in (La)TeX; and finally discovered and fell for Mathematica. Now I'm interested in learning a "real" programming language that I can enjoy in the same sort of style as Mathematica, which tries to stress functional programming since it seems to map more nicely to how certain kinds of mathematics can be written algorithmically. So which functional language should I learn? I guess the obvious answer is “as many as possible”, but let's start out humble and give a single, well-considered option a good crack. I've heard good things about, say, Haskell and Scala, but I wonder if (given my non–computer science background) I'd be better off starting in more “grounded” territory and going with Ruby or Python (the latter having the big advantage of being used for Sage, which I'd also like to investigate…after my PhD). Well, I guess this is pretty subjective, so perhaps I could rephrase: would it be better to start looking at Haskell (say) straight after an ad-hoc education to functional programming in Mathematica, or will I get more out of learning Python (say) first? In reference to the question "what do I want to do with it?", I guess my answer is "fun, and learning more". I've got this list of languages that I'd like to look at, and I don't know how to trim them down. And I'd rather start with something a little higher-level than C simply so that I can be somewhat productive without having to re-invent many wheels for any code I'd like to write.

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  • Effective simulation of compound poisson process in Matlab

    - by Henrik
    I need to simulate a huge bunch of compound poisson processes in Matlab on a very fine grid so I am looking to do it most effectively. I need to do a lot of simulations on the same random numbers but with parameters changing so it is practical to draw the uniforms and normals beforehand even though it means i have to draw a lot more than i will probably need and won't matter much because it will only need to be done once compared to in the order 500*n repl times the actual compound process generation. My method is the following: Let T be for how long i need to simulate and N the grid points, then my grid is: t=linspace(1,T,N); Let nrepl be the number of processes i need then I simulate P=poissrnd(lambda,nrepl,1); % Number of jumps for each replication U=(T-1)*rand(10000,nrepl)+1; % Set of uniforms on (1,T) for jump times N=randn(10000,nrepl); % Set of normals for jump size Then for replication j: Poiss=P(j); % Jumps for replication Uni=U(1:Poiss,j);% Jump times Norm=mu+sigma*N(1:Poiss,j);% Jump sizes Then this I guess is where I need your advice, I use this one-liner but it seems very slow: CPP_norm=sum(bsxfun(@times,bsxfun(@gt,t,Uni),Norm),1); In the inner for each jump it creates a series of same length as t with 0 until jump and then 1 after, multiplying this will create a grid with zeroes until jump has arrived and then the jump size and finally adding all these will produce the entire jump process on the grid. How can this be done more effectively? Thank you very much.

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  • Sorting by some field and fetching whole tree from DB

    - by Niaxon
    Hello everyone, I am trying to do file browser in a tree form and have a problem to sort it somehow. I use PHP and MySQL for that. I've created mixed (nested set + adjacency) table 'element' with the following fields: element_id, left_key, right_key, level, parent_id, element_name, element_type (enum: 'folder','file'), element_size. Let's not discuss right now that it is better to move information about element (name, type, size) into other table. Function to scan specified directory and fill table work correctly. Noteworthy, i am adding elements to tree in specific order: folders first and only files. After that i can easily fetch and display whole table on the page using simple query: SELECT * FROM element WHERE 1=1 ORDER BY left_key With the result of that query and another function i can generate correct html code (<ul><li>... and so on). Now back to the question (finally, huh?). I am struggling to add sorting functionality. For example i want to order my result by size. Here i need to keep in my mind whole hierarchy of tree and rule: folders first, files later. I believe i can do that by generating in PHP recursive query: SELECT * FROM element WHERE parent_id = {$parentId} ORDER BY element_type (so folders would be first), size (or name for example) After that for each result which is folder i will send another query to get it's content. Also it's possible to fetch whole tree by left_key and after that sort it in PHP as array but i guess that would be worse :) I wonder if there is better and more efficient way to do such thing?

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  • What new Unicode functions are there in C++0x?

    - by luiscubal
    It has been mentioned in several sources that C++0x will include better language-level support for Unicode(including types and literals). If the language is going to add these new features, it's only natural to assume that the standard library will as well. However, I am currently unable to find any references to the new standard library. I expected to find out the answer for these answers: Does the new library provide standard methods to convert UTF-8 to UTF-16, etc.? Does the new library allowing writing UTF-8 to files, to the console (or from files, from the console). If so, can we use cout or will we need something else? Does the new library include "basic" functionality such as: discovering the byte count and length of a UTF-8 string, converting to upper-case/lower-case(does this consider the influence of locales?) Finally, are any of these functions are available in any popular compilers such as GCC or Visual Studio? I have tried to look for information, but I can't seem to find anything? I am actually starting to think that maybe these things aren't even decided yet(I am aware that C++0x is a work in progress).

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  • How do I make a lock that allows only ONE thread to read from the resource ?

    - by mare
    I have a file that holds an integer ID value. Currently reading the file is protected with ReaderWriterLockSlim as such: public int GetId() { _fileLock.EnterUpgradeableReadLock(); int id = 0; try { if(!File.Exists(_filePath)) CreateIdentityFile(); FileStream readStream = new FileStream(_filePath, FileMode.Open, FileAccess.Read); StreamReader sr = new StreamReader(readStream); string line = sr.ReadLine(); sr.Close(); readStream.Close(); id = int.Parse(line); return int.Parse(line); } finally { SaveNextId(id); // increment the id _fileLock.ExitUpgradeableReadLock(); } } The problem is that subsequent actions after GetId() might fail. As you can see the GetId() method increments the ID every single time, disregarding what happens after it has issued an ID. The issued ID might be left hanging (as said, exceptions might occur). As the ID is incremented, some IDs might be left unused. So I was thinking of moving the SaveNextId(id) out, remove it (the SaveNextId() actually uses the lock too, except that it's EnterWriteLock). And call it manually from outside after all the required methods have executed. That brings out another problem - multiple threads might enter the GetId() method before the SaveNextId() gets executed and they might all receive the same ID. I don't want any solutions where I have to alter the IDs after the operation, correcting them in any way because that's not nice and might lead to more problems. I need a solution where I can somehow callback into the FileIdentityManager (that's the class that handles these IDs) and let the manager know that it can perform the saving of the next ID and then release the read lock on the file containing the ID. Essentialy I want to replicate the relational databases autoincrement behaviour - if anything goes wrong during row insertion, the ID is not used, it is still available for use but it also never happens that the same ID is issued. Hopefully the question is understandable enough for you to provide some solutions..

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