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  • Seeking suggestions on redesigning the interface

    - by ratkok
    As a part of maintaining large piece of legacy code, we need to change part of the design mainly to make it more testable (unit testing). One of the issues we need to resolve is the existing interface between components. The interface between two components is a class that contains static methods only. Simplified example: class ABInterface { static methodA(); static methodB(); ... static methodZ(); }; The interface is used by component A so that different methods can use ABInterface::methodA() in order to prepare some input data and then invoke appropriate functions within component B. Now we are trying to redesign this interface for various reasons: Extending our unit test coverage - we need to resolve this dependency between the components and stubs/mocks are to be introduced The interface between these components diverged from the original design (ie. a lots of newer functions, used for the inter-component i/f are created outside this interface class). The code is old, changed a lot over the time and needs to be refactored. The change should not be disruptive for the rest of the system. We try to limit leaving many test-required artifacts in the production code. Performance is very important and should be no (or very minimal) degradation after the redesign. Code is OO in C++. I am looking for some ideas what approach to take. Any suggestions on how to do this efficiently?

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  • PHP post request to retrieve JSON

    - by Brian
    I'm trying to write some simple php code that will make a post request and then retrieve a JSON result from the server. It seemed simple to me, but the below code simply doesn't open a connection. $port = 2057; $path = "/validate/"; $request = "value1=somevalue&value2=somevalue&value3=somevalue"; $http_request = "POST $path HTTP/1.0\r\n"; $http_request .= "Host: $server\r\n"; $http_request .= "Content-Type: application/x-www-form-urlencoded;\r\n"; $http_request .= "Content-Length: " . strlen($request) . "\r\n"; $http_request .= "\r\n"; $http_request .= $request; $response = ''; if( false == ( $fs = @fsockopen($server, $port) ) ) { die ('Could not open socket'); } fwrite($fs, $http_request); while ( !feof($fs) ) { $response .= fgets($fs, 1160); } fclose($fs); In addition I've tried a more simple approach with: $handle = fopen('http://localhost:2057/validate/?'.$request, "r"); or $response = file_get_contents('http://localhost:2057/validate/' . $request); but both of these approaches just time out. I'm trying to connect to a development server I'm running in Visual Studio, so I'm not sure if that has anything to do with the timeout/connection issues. Open to any suggestions here as long as they are built in PHP.

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  • How do I create rows with alternating colors for a UITableView on iPhone?

    - by Mat
    Hi all, i would to have alternate 2 colors of rows, like the first black, the second white, the third black, etc, etc... my approach is like a basic exercise of programming to calculate if a number is odd number or not: - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CellIdentifier = @"Cell"; cell = ((MainCell*)[tableView dequeueReusableCellWithIdentifier:CellIdentifier]); if (cell==nil) { NSArray *topLevelObjects=[[NSBundle mainBundle] loadNibNamed:@"MainCell" owner:self options:nil]; for (id currentObject in topLevelObjects){ if ([currentObject isKindOfClass:[UITableViewCell class]]){ if ((indexPath.row % 2)==0) { [cell.contentView setBackgroundColor:[UIColor purpleColor]]; }else{ [cell.contentView setBackgroundColor:[UIColor whiteColor]]; } cell = (MainCell *) currentObject; break; } } }else { AsyncImageView* oldImage = (AsyncImageView*) [cell.contentView viewWithTag:999]; [oldImage removeFromSuperview]; }return cell; The problem is that when i do a rapid scroll, the background of cells become like the last 2 cell black, the first 2 cell white or something like this, but if i scroll slow works fine. I think the problem is the cache of reusableCell. Any ideas? TIA

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  • Reasonably faster way to traverse a directory tree in Python?

    - by Sridhar Ratnakumar
    Assuming that the given directory tree is of reasonable size: say an open source project like Twisted or Python, what is the fastest way to traverse and iterate over the absolute path of all files/directories inside that directory? I want to do this from within Python (subprocess is allowed). os.path.walk is slow. So I tried ls -lR and tree -fi. For a project with about 8337 files (including tmp, pyc, test, .svn files): $ time tree -fi > /dev/null real 0m0.170s user 0m0.044s sys 0m0.123s $ time ls -lR > /dev/null real 0m0.292s user 0m0.138s sys 0m0.152s $ time find . > /dev/null real 0m0.074s user 0m0.017s sys 0m0.056s $ tree appears to be faster than ls -lR (though ls -R is faster than tree, but it does not give full paths). find is the fastest. Can anyone think of a faster and/or better approach? On Windows, I may simply ship a 32-bit binary tree.exe or ls.exe if necessary. Update 1: Added find

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  • How do I send floats in window messages.

    - by yngvedh
    Hi, What is the best way to send a float in a windows message using c++ casting operators? The reason I ask is that the approach which first occurred to me did not work. For the record I'm using the standard win32 function to send messages: PostWindowMessage(UINT nMsg, WPARAM wParam, LPARAM lParam) What does not work: Using static_cast<WPARAM>() does not work since WPARAM is typedef'ed to UINT_PTR and will do a numeric conversion from float to int, effectively truncating the value of the float. Using reinterpret_cast<WPARAM>() does not work since it is meant for use with pointers and fails with a compilation error. I can think of two workarounds at the moment: Using reinterpret_cast in conjunction with the address of operator: float f = 42.0f; ::PostWindowMessage(WM_SOME_MESSAGE, *reinterpret_cast<WPARAM*>(&f), 0); Using an union: union { WPARAM wParam, float f }; f = 42.0f; ::PostWindowMessage(WM_SOME_MESSAGE, wParam, 0); Which of these are preffered? Are there any other more elegant way of accomplishing this?

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  • How to return ArrayList results from an IntentService

    - by gcl1
    I have an IntentService that loads up an ArrayList with data from a network source (AWS SDB tables). The ArrayList is in a global space -- accessible to both the calling Activity and the IntentService (like this: appState = ((App)getApplicationContext())). When the IntentService is done, it notifies the Activity through a ResultReceiver, and the Activity calls adapter.notifyDataChanged() to update the ListView. This solution works most of the time, ... but it violates the rule that only the UI thread should make changes to data underlying a ListView. So as it is, I sometimes get an error: "The content of the adapter has changed but ListView did not receive a notification." I think this must be a common situation. Please let me know if you have any suggestions or best practices for this problem. Here are three options I'm aware of: Keep the IntentService, and have it store the results in another "working" ArrayList, also in the global space. When the result is ready, the IntentService calls the ResultReceiver (on the UI thread), which can then: a) copy the result to the ArrayList associated with the ListView, and b) call adapter.notifyDataChanged(). CONS: I don't like the idea of putting temp/working data in a global space, and copying the result list seems inefficient. Keep the IntentService, and have it pass the results back through a bundle loaded with a ParcelableArrayList. CONS: I'm not sure if this approach would scale for very large result sets. It also requires copying the result list. Switch to a Service which builds a local copy of the result list. Have the Activity directly access the address space of the Service in order to read the result list. CON: Still requires copying results to the ArrayList associated with the ListView. Thank you.

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  • Implementing Dispose on a class derived from Stream

    - by AnthonyWJones
    I'm building a class that derives from Stream to wrap a COM IStream. However I've come across an issue where I need to release the COM IStream deteministically. Ok so that's easy just use Marshal.ReleaseComObject in the Dispose method. However I'm not sure its that simple. The Stream base class already has an protected virtual method Dispose(boolean). Here is my first idea:- ~ComStreamWrapper() { if (!_Disposed) { iop.Marshal.FreeCoTaskMem(_Int64Ptr); iop.Marshal.ReleaseComObject(_IStream); } } protected override void Dispose(bool disposing) { base.Dispose(disposing); if (!_Disposed) { if (disposing) { iop.Marshal.FreeCoTaskMem(_Int64Ptr); iop.Marshal.ReleaseComObject(_IStream); } _Disposed = true; } } You'll notice there isn't an implementation of Dispose() itself. I'm currently making the asssumption that the existing implementation on Stream does what I need it to. That is calling Diposing(true) and GC.SuppressFinalize. Is this assumption faulty? Have I missed something? Is there a better approach? You see more of the basic class in this answer to an ealier question.

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  • Help with mysql sum and group query and managing results for jquery graph.

    - by Scarface
    I have a system I am trying to design that will retrieve information from a database, so that it can be plotted in a jquery graph. I need to retrieve the information and somehow put it in the necessary coordinates format (for example two coordinates var d = [[1269417600000, 10],[1269504000000, 15]];). My table that I am selecting from is a table that stores user votes with fields: points_id (1=vote up, 2=vote down), user_id, timestamp, topic_id What I need to do is select all the votes and somehow group them into respective days and then sum the difference between 1 votes and 2 votes for each day. I then need to somehow display the data in the appropriate plotting format shown earlier. For example April 1, 4 votes. The data needs to be separated by commas, except the last plot entry, so I am not sure how to approach that. I showed an example below of the kind of thing I need but it is not correct, echo "var d=["; $query=mysql_query( "SELECT *, SUM(IF(points_id = \"1\", 1,0))-SUM(IF([points_id = \"2\", 1,0)) AS 'total' FROM points LEFT JOIN topic ON topic.topic_id=points.topic_id WHERE topic.creator='$user' GROUP by timestamp HAVING certain time interval" ); while ($row=mysql_fetch_assoc($query)){ $timestamp=$row['timestamp']; $votes=$row['total']; echo "[$timestamp,$vote],"; } echo "];";

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  • Converting contents of a byte array to wchar_t*

    - by Christopher MacKinnon
    I seem to be having an issue converting a byte array (containing the text from a word document) to a LPTSTR (wchar_t *) object. Every time the code executes, I am getting a bunch of unwanted Unicode characters returned. I figure it is because I am not making the proper calls somewhere, or not using the variables properly, but not quite sure how to approach this. Hopefully someone here can guide me in the right direction. The first thing that happens in we call into C# code to open up Microsoft Word and convert the text in the document into a byte array. byte document __gc[]; document = word->ConvertToArray(filename); The contents of document are as follows: {84, 101, 115, 116, 32, 68, 111, 99, 117, 109, 101, 110, 116, 13, 10} Which ends up being the following string: "Test Document". Our next step is to allocate the memory to store the byte array into a LPTSTR variable, byte __pin * value; value = &document[0]; LPTSTR image; image = (LPTSTR)malloc( document->Length + 1 ); Once we execute the line where we start allocating the memory, our image variable gets filled with a bunch of unwanted Unicode characters: ????????????????? And then we do a memcpy to transfer over all of the data memcpy(image,value,document->Length); Which just causes more unwanted Unicode characters to appear: ????????????????? I figure the issue that we are having is either related to how we are storing the values in the byte array, or possibly when we are copying the data from the byte array to the LPTSTR variable. Any help with explaining what I'm doing wrong, or anything to point me in the right direction will be greatly appreciated.

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  • Is there a programmatic way to transform a sequence of image files into a PDF?

    - by Salim Fadhley
    I have a sequence of JPG images. Each of the scans is already cropped to the exact size of one page. They are sequential pages of a valuable and out of print book. The publishing application requires that these pages be submitted as a single PDF file. I could take each of these images and just past them into a word-processor (e.g. OpenOffice) - unfortunately the problem here is that it's a very big book and I've got quite a few of these books to get through. It would obviously be time-consuming. This is volunteer work! My second idea was to use LaTeX - I could make a very simple document that consists of nothing more than a series of in-line image includes. I'm sure that this approach could be made to work, it's just a little on the complex side for something which seems like a very simple job. It occurred to me that there must be a simpler way - so any suggestions? I'm on Ubuntu 9.10, my primary programming language is Python, but if the solution is super-simple I'd happily adopt any technology that works.

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  • iOS layout; I'm not getting it

    - by Tbee
    Well, "not getting it" is too harsh; I've got it working in for what for me is a logical setup, but it does not seem to be what iOS deems logical. So I'm not getting something. Suppose I've got an app that shows two pieces of information; a date and a table. According to the MVC approach I've got three MVC at work here, one for the date, one for the table and one that takes both these MCVs and makes it into a screen, wiring them up. The master MVC knows how/where it wants to layout the two sub MVC's. Each detail MVC only takes care of its own childeren within the bounds that were specified by the master MVC. Something like: - (void)loadView { MVC* mvc1 = [[MVC1 alloc] initwithFrame:...] [self.view addSubview:mvc1.view]; MVC* mvc2 = [[MVC2 alloc] initwithFrame:...] [self.view addSubview:mvc2.view]; } If the above is logical (which is it for me) then I would expect any MVC class to have a constructor "initWithFrame". But an MVC does not, only view have this. Why? How would one correctly layout nested MVCs? (Naturally I do not have just these two, but the detail MVCs have sub MVCs again.)

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  • Partioning with Hibernate

    - by Alex
    Hello, We have a requirement to delete data in the range of 200K from database everyday. Our application is Java/JEE based using Oracle DB and Hibernate ORM tool. We explored various options like Hibernate batch processing Stored procedure Database partitioning Our DBA suggests database partitioning is the best way to go, so we can easily recreate and drop the partitioned table everyday. Now the issue is we have 2 kinds of data, one which we want to delete everyday and the other which we want to keep it. Suppose this data is stored in table "Trade". Now with partitioning, we have 2 tables "Trade". We have already existing Hibernate based DAO layer to fetch/store trades from/to DB. When we decide to partition the database, how can we control the trades to go in which of the two tables through hibernate. Basically I want , the trades need to be deleted by end of the day, to go in partitioned table and the trades I want to keep, in main table. Please suggest how can this be possible with Hibernate. We may add an additional column to identify the trades to be deleted but how can we ensure these trades should go to partitioned trade table using hibernate. I would appreciate if someone can suggest any better approach in case we are on wrong path.

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  • VB.NET Update Access Database with DataTable

    - by sinDizzy
    I've been perusing some hep forums and some help books but cant seem to get my head wrapped around this. My task is to read data from two text files and then load that data into an existing MS Access 2007 database. So here is what i'm trying to do: Read data from first text file and for every line of data add data to a DataTable using CarID as my unique field. Read data from second text file and look for existing CarID in DataTable if exists update that row. If it doesnt exist add a new row. once im done push the contents of the DataTable to the database. What i have so far: Dim sSQL As String = "SELECT * FROM tblCars" Dim da As New OleDb.OleDbDataAdapter(sSQL, conn) Dim ds As New DataSet da.Fill(ds, "CarData") Dim cb As New OleDb.OleDbCommandBuilder(da) 'loop read a line of text and parse it out. gets dd, dc, and carId 'create a new empty row Dim dsNewRow As DataRow = ds.Tables("CarData").NewRow() 'update the new row with fresh data dsNewRow.Item("DriveDate") = dd dsNewRow.Item("DCode") = dc dsNewRow.Item("CarNum") = carID 'about 15 more fields 'add the filled row to the DataSet table ds.Tables("CarData").Rows.Add(dsNewRow) 'end loop 'update the database with the new rows da.Update(ds, "CarData") Questions: In constructing my table i use "SELECT * FROM tblCars" but what if that table has millions of records already. Is that not a waste of resources? Should i be trying something different if i want to update with new records? Once Im done with the first text file i then go to my next text file. Whats the best approach here: To First look for an existing record based on CarNum or to create a second table and then merge the two at the end? Finally when the DataTable is done being populated and im pushing it to the database i want to make sure that if records already exist with three primary fields (DriveDate, DCode, and CarNum) that they get updated with new fields and if it doesn't exist then those records get appended. Is that possible with my process? tia AGP

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  • Determining if an unordered vector<T> has all unique elements

    - by Hooked
    Profiling my cpu-bound code has suggested I that spend a long time checking to see if a container contains completely unique elements. Assuming that I have some large container of unsorted elements (with < and = defined), I have two ideas on how this might be done: The first using a set: template <class T> bool is_unique(vector<T> X) { set<T> Y(X.begin(), X.end()); return X.size() == Y.size(); } The second looping over the elements: template <class T> bool is_unique2(vector<T> X) { typename vector<T>::iterator i,j; for(i=X.begin();i!=X.end();++i) { for(j=i+1;j!=X.end();++j) { if(*i == *j) return 0; } } return 1; } I've tested them the best I can, and from what I can gather from reading the documentation about STL, the answer is (as usual), it depends. I think that in the first case, if all the elements are unique it is very quick, but if there is a large degeneracy the operation seems to take O(N^2) time. For the nested iterator approach the opposite seems to be true, it is lighting fast if X[0]==X[1] but takes (understandably) O(N^2) time if all the elements are unique. Is there a better way to do this, perhaps a STL algorithm built for this very purpose? If not, are there any suggestions eek out a bit more efficiency?

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  • design an extendable database model

    - by wishi_
    Hi! Currently I'm doing a project whose specifications are unclear - well who doesn't. I wonder what's the best development strategy to design a DB, that's going to be extended sooner or later with additional tables and relations. I want to include "changeability". My main concern is that I want to apply design patterns (it's a university project) and I want to separate the constant factors from those, that change by choosing appropriate design patterns - in my case MVC and a set of sub-patterns at model level. When it comes to the DB however, I may have to resdesign my model in my MVC approach, because my domain model at a later stage my require a different set of classes representing the DB tables. I use Hibernate as an abstraction layer between DB and application. Would you start with a very minimal DB, just a few tables and relations? And what if I want an efficient DB, too? I wonder what strategies are applied in the real world. Stakeholder analysis for example isn't a sufficient planing solution when it comes to changing requirements. I think - at a DB level - my design pattern ends. So there's breach whose impact I'd like to minimize with a smart strategy.

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  • Custom Android control with children

    - by Gromix
    Hi, I'm trying to create a custom Android control that contains a LinearLayout. You can think of it as an extended LinearLayout with fancy borders, a background, an image on the left... I could do it all in XML (works great) but since I have dozens of occurences in my app it's getting hard to maintain. I thought it would be nicer to have something like this: /* Main.xml */ <MyFancyLayout> <TextView /> /* what goes inside my control's linear layout */ </MyfancyLayout> How would you approach this? I'd like to avoid re-writing the whole linear layout onMeasure / onLayout methods. This is what I have for the moment: /* MyFancyLayout.xml */ <TableLayout> <ImageView /> <LinearLayout id="container" /> /* where I want the real content to go */ </TableLayout> and /* MyFancyLayout.java */ public class MyFancyLayout extends LinearLayout { public MyFancyLayout(Context context) { super(context); View.inflate(context, R.layout.my_fancy_layout, this); } } How would you go about inserting the user-specified content (the TextView in main.xml) in the right place (id=container)? Cheers! Romain ----- edit ------- Still no luck on this, so I changed my design to use a simpler layout and decided to live with a bit of repeated XML. Still very interested in anyone knows how to do this though!

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  • A good data model for finding a user's favorite stories

    - by wings
    Original Design Here's how I originally had my Models set up: class UserData(db.Model): user = db.UserProperty() favorites = db.ListProperty(db.Key) # list of story keys # ... class Story(db.Model): title = db.StringProperty() # ... On every page that displayed a story I would query UserData for the current user: user_data = UserData.all().filter('user =' users.get_current_user()).get() story_is_favorited = (story in user_data.favorites) New Design After watching this talk: Google I/O 2009 - Scalable, Complex Apps on App Engine, I wondered if I could set things up more efficiently. class FavoriteIndex(db.Model): favorited_by = db.StringListProperty() The Story Model is the same, but I got rid of the UserData Model. Each instance of the new FavoriteIndex Model has a Story instance as a parent. And each FavoriteIndex stores a list of user id's in it's favorited_by property. If I want to find all of the stories that have been favorited by a certain user: index_keys = FavoriteIndex.all(keys_only=True).filter('favorited_by =', users.get_current_user().user_id()) story_keys = [k.parent() for k in index_keys] stories = db.get(story_keys) This approach avoids the serialization/deserialization that's otherwise associated with the ListProperty. Efficiency vs Simplicity I'm not sure how efficient the new design is, especially after a user decides to favorite 300 stories, but here's why I like it: A favorited story is associated with a user, not with her user data On a page where I display a story, it's pretty easy to ask the story if it's been favorited (without calling up a separate entity filled with user data). fav_index = FavoriteIndex.all().ancestor(story).get() fav_of_current_user = users.get_current_user().user_id() in fav_index.favorited_by It's also easy to get a list of all the users who have favorited a story (using the method in #2) Is there an easier way? Please help. How is this kind of thing normally done?

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  • Creating a method for wrapping a loaded image in a UIImageView

    - by eco_bach
    I have the following un my applicationDidFinishLaunching method UIImage *image2 = [UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"image2.jpg" ofType:nil]]; view2 = [[UIImageView alloc] initWithImage:image2]; view2.hidden = YES; [containerView addSubview:view2]; I'm simply adding an image to a view. But because I need to add 30-40 images I need to wrap the above in a function (which returns a UIImageView) and then call it from a loop. This is my first attempt at creating the function -(UIImageView)wrapImageInView:(NSString *)imagePath { UIImage *image = [UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForResource:imagePath ofType:nil]]; UIImageView *view = [[UIImageView alloc] initWithImage:image]; view.hidden = YES; } And then to invoke it I have the following so far, for simplicity I am only wrapping 3 images //Create an array and add elements to it NSMutableArray *anArray = [[NSMutableArray alloc] init]; [anArray addObject:@"image1.jpg"]; [anArray addObject:@"image2.jpg"]; [anArray addObject:@"image3.jpg"]; //Use a for each loop to iterate through the array for (NSString *s in anArray) { UIImageView *wrappedImgInView=[self wrapImage:s]; [containerView addSubview:wrappedImgInView]; NSLog(s); } //Release the array [anArray release]; I have 2 general questions 1-Is my approach correct?, ie following best practices, for what I am trying to do (load a multiple number of images(jpgs, pngs, etc.) and adding them to a container view) 2-For this to work properly with a large number of images, do I need to keep my array creation separate from my method invocation? Any other suggestions welcome!

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  • Multiple grids in one area

    - by anon
    I'm currently creating a WPF application, using C# and XAML in Visual Studios 2010. I have a master grid. In that master grid I have a group bar which you can select different items. Depending on what you select, the middle of the master grid can be totally different. What I was wondering is, what's the best way to program the middle part? Right now, I have it set up in such a way that everything in the middle is dynamically programed in C#, and everything on the outside is programmed in XAML. In C# I programmed: for each group bar item, there is a grid that goes with it (so that different content can be displayed on it). Each grid is a child of the master grid. Each grid is visible or hidden when necessary. Is this the best way to approach this? The best example of this is in Outlook 2007, where you have your group bar on the right hand side. When you select different items on the group bar (mail, calendar, tasks) the right of the group bar completely changes.

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  • Treating differential operator as algebraic entity

    - by chappar
    I know that this question is offtopic and don't belong here. But i didn't know somewhere else to ask. So here is the question. I was reading e:the story of a number by Eli Maor, where he treats differential operator as just like any algebraic entity. For example if we have a differential equation like y’’ + 5y’ - 6y = 0. This can be treaed as (D^2 + 5D – 6)y = 0. So, either y = 0 (trivial solution) or (D^2 + 5D – 6) = 0. Factoring out above equation we get (D-1)(D+6)= 0 with solutions as D = 1 and D = -6. Since D does not have any meaning on its own, multiplying by y on both the sides we get Dy = y and Dy = -6y for which the solutions are Ae^x and Be^-6x. Combining these 2 solutions we get Ae^x + Be^-6x. Now my doubt is this approach break when we have an equation like D^2y = 0. Which means y = 0 (again trivial) or D^2 = 0 which means D = 0. Now Dy = y*0 = 0. That means y = C ( a constant). The actual answer should be Cx. I know that it is stupidity to treat D^2 = 0 as D = 0, it led me to doubt the entire process of treating differential equation as algebraic equation. Can someone throw light on this? Or any other site where i might get answer?

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  • WCF data services (OData), query with inheritance limitation?

    - by Mathieu Hétu
    Project: WCF Data service using internally EF4 CTP5 Code-First approach. I configured entities with inheritance (TPH). See previous question on this topic: Previous question about multiple entities- same table The mapping works well, and unit test over EF4 confirms that queries runs smoothly. My entities looks like this: ContactBase (abstract) Customer (inherits from ContactBase), this entity has also several Navigation properties toward other entities Resource (inherits from ContactBase) I have configured a discriminator, so both Customer and Resource map to the same table. Again, everythings works fine on the Ef4 point of view (unit tests all greens!) However, when exposing this DBContext over WCF Data services, I get: - CustomerBases sets exposed (Customers and Resources sets seems hidden, is it by design?) - When I query over Odata on Customers, I get this error: Navigation Properties are not supported on derived entity types. Entity Set 'ContactBases' has a instance of type 'CodeFirstNamespace.Customer', which is an derived entity type and has navigation properties. Please remove all the navigation properties from type 'CodeFirstNamespace.Customer'. Stacktrace: at System.Data.Services.Serializers.SyndicationSerializer.WriteObjectProperties(IExpandedResult expanded, Object customObject, ResourceType resourceType, Uri absoluteUri, String relativeUri, SyndicationItem item, DictionaryContent content, EpmSourcePathSegment currentSourceRoot) at System.Data.Services.Serializers.SyndicationSerializer.WriteEntryElement(IExpandedResult expanded, Object element, ResourceType expectedType, Uri absoluteUri, String relativeUri, SyndicationItem target) at System.Data.Services.Serializers.SyndicationSerializer.<DeferredFeedItems>d__b.MoveNext() at System.ServiceModel.Syndication.Atom10FeedFormatter.WriteItems(XmlWriter writer, IEnumerable`1 items, Uri feedBaseUri) at System.ServiceModel.Syndication.Atom10FeedFormatter.WriteFeedTo(XmlWriter writer, SyndicationFeed feed, Boolean isSourceFeed) at System.ServiceModel.Syndication.Atom10FeedFormatter.WriteFeed(XmlWriter writer) at System.ServiceModel.Syndication.Atom10FeedFormatter.WriteTo(XmlWriter writer) at System.Data.Services.Serializers.SyndicationSerializer.WriteTopLevelElements(IExpandedResult expanded, IEnumerator elements, Boolean hasMoved) at System.Data.Services.Serializers.Serializer.WriteRequest(IEnumerator queryResults, Boolean hasMoved) at System.Data.Services.ResponseBodyWriter.Write(Stream stream) Seems like a limitation of WCF Data services... is it? Not much documentation can be found on the web about WCF Data services (OData) and inheritance specifications. How can I overpass this exception? I need these navigation properties on derived entities, and inheritance seems the only way to provide mapping of 2 entites on the same table with Ef4 CTP5... Any thoughts?

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  • NSNotification vs. Delegate Protocols?

    - by jr
    I have an iPhone application which basically is getting information from an API (in XML, but maybe JSON eventually). The result objects are typically displayed in view controllers (tables mainly). Here is the architecture right now. I have NSOperation classes which fetch the different objects from the remote server. Each of these NSOperation classes, will take a custom delegate method which will fire back the resulting objects as they are parsed, and then finally a method when no more results are available. So, the protocol for the delegates will be something like: (void) ObjectTypeResult:(ObjectType *)result; (void) ObjectTypeNoMoreResults; I think the solution works well, but I do end up with a bunch of delegate protocols around and then my view controllers have to implement all these delegate methods. I don't think its that bad, but I'm always on the lookout for a better design. So, I'm thinking about using NSNotifications to remove the use of the delegates. I could include the object in the userInfo part of the notification and just post objects as received, and then a final event when no more are available. Then I could just have one method in each view controller to receive all the data, even when using multiple objects in one controller.† So, can someone share with me some pros/cons of each approach. Should I consider refactoring my code to use Events rather then the delegates? Is one better then the other in certain situations? In my scenario I'm really not looking to receive notifications in multiple places, so maybe the protocol based delegates are the way to go. Thanks!

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  • breadth-first traversal of directory tree is not lazy

    - by user855443
    I try to traverse the diretory tree. A naive depth-first traversal seems not to produce the data in a lazy fashion and runs out of memory. I next tried a breadth first approach, which shows the same problem - it uses all the memory available and then crashes. the code i have is: getFilePathBreadtFirst :: FilePath -> IO [FilePath] getFilePathBreadtFirst fp = do fileinfo <- getInfo fp res :: [FilePath] <- if isReadableDirectory fileinfo then do children <- getChildren fp lower <- mapM getFilePathBreadtFirst children return (children ++ concat lower) return (children ++ concat () else return [fp] -- should only return the files? return res getChildren :: FilePath -> IO [FilePath] getChildren path = do names <- getUsefulContents path let namesfull = map (path </>) names return namesfull testBF fn = do -- crashes for /home/frank, does not go to swap fps <- getFilePathBreadtFirst fn putStrLn $ unlines fps I think all the code is either linear or tail recursive, and I would expect that the listing of filenames starts immediately, but in fact it does not. Where is the error in my code and my thinking? where have I lost lazy evaluation?

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  • import csv file/excel into sql database asp.net

    - by kiev
    Hi everyone! I am starting a project with asp.net visual studio 2008 / SQL 2000 (2005 in future) using c#. The tricky part for me is that the existing DB schema changes often and the import files columns will all have to me matched up with the existing db schema since they may not be one to one match on column names. (There is a lookup table that provides the tables schema with column names I will use) I am exploring different ways to approach this, and need some expert advice. Is there any existing controls or frameworks that I can leverage to do any of this? So far I explored FileUpload .NET control, as well as some 3rd party upload controls to accomplish the upload such as SlickUpload but the files uploaded should be < 500mb Next part is reading of my csv /excel and parsing it for display to the user so they can match it with our db schema. I saw CSVReader and others but for excel its more difficult since I will need to support different versions. Essentially The user performing this import will insert and/or update several tables from this import file. There are other more advance requirements like record matching but and preview of the import records, but I wish to get through understanding how to do this first. Update: I ended up using csvReader with LumenWorks.Framework for uploading the csv files.

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  • Idiomatic PHP web page creation

    - by GreenMatt
    My PHP experience is rather limited. I've just inherited some stuff that looks odd to me, and I'd like to know if this is a standard way to do things. The page which shows up in the browser location (e.g. www.example.com/example_page) has something like: <? $title = "Page Title"; $meta = "Some metadata"; require("pageheader.inc"); ?> <!-- Content --> Then pageheader.inc has stuff like: <? @$title = ($title) ? $title : ""; @$meta = ($meta) ? $meta : ""; ?> <html> <head> <title><?=$title?></title </head> <!-- and so forth --> Maybe others find this style useful, but it confuses me. I suppose this could be a step toward a rudimentary content management system, but the way it works here I'd think it adds to the processing the server has to do without reducing the load on the web developer enough to make it worth the effort. So, is this a normal way to create pages with PHP? Or should I pull all this in favor of a better approach? Also, I know that "<?" (vs. "<?php" ) is undesirable; I'm just reproducing what is in the code.

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