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• Problem with testing In App with sandbox test account

  - by Nava Carmon

  Hi, I created a test user account through the Manage User Accounts in iTunes Connect. When you create such an account you have to select a valid storefront for your account. I chose US Store. Now I signed out from the store in App Store settings on my device. Ran the application and tried to perform a purchase. I successfully login with my test account. After I press Confirm when entering my credentials I get an alert, that comes from SKPaymentTransactionStateFailed from the observer. It says "Your account is only valid for purchases in the US iTunes Store". The error state = 0 unknown. Second time when i try to perform the purchase, StoreKit only asks me for a password like the previous login was successful. After entering a password I can perform a purchase. My question is whether it's only because it's a testing account and the application is not actually on AppStore? What should I do to avoid this message or at least to continue the purchasing process? Thanks a lot, Nava

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• Why do properties require explicit typing during compilation?

  - by ctpenrose

  Compilation using property syntax requires the type of the receiver to be known at compile time. I may not understand something, but this seems like a broken or incomplete compiler implementation considering that Objective-C is a dynamic language. The property "comment" is defined with: @property (nonatomic, retain) NSString *comment; and synthesized with: @synthesize comment; "document" is an instance of one of several classes which conform to: @protocol DocumentComment <NSObject> @property (nonatomic, retain) NSString *comment; @end and is simply declared as: id document; When using the following property syntax: stringObject = document.comment; the following error is generated by gcc: error: request for member 'comment' in something not a structure or union However, the following equivalent receiver-method syntax, compiles without warning or error and works fine, as expected, at run-time: stringObject = [document comment]; I don't understand why properties require the type of the receiver to be known at compile time. Is there something I am missing? I simply use the latter syntax to avoid the error in situations where the receiving object has a dynamic type. Properties seem half-baked.

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• Advice on optimzing speed for a Stored Procedure that uses Views

  - by Belliez

  Based on a previous question and with a lot of help from Damir Sudarevic (thanks) I have the following sql code which works great but is very slow. Can anyone suggest how I can speed this up and optimise for speed. I am now using SQL Server Express 2008 (not 2005 as per my original question). What this code does is retrieves parameters and their associated values from several tables and rotates the table in a form that can be easily compared. Its great for one of two rows of data but now I am testing with 100 rows and to run GetJobParameters takes over 7 minutes to complete? Any advice is gratefully accepted, thank you in advanced. /*********************************************************************************************** ** CREATE A VIEW (VIRTUAL TABLE) TO ALLOW EASIER RETREIVAL OF PARMETERS ************************************************************************************************/ CREATE VIEW dbo.vParameters AS SELECT m.MachineID AS [Machine ID] ,j.JobID AS [Job ID] ,p.ParamID AS [Param ID] ,t.ParamTypeID AS [Param Type ID] ,m.Name AS [Machine Name] ,j.Name AS [Job Name] ,t.Name AS [Param Type Name] ,t.JobDataType AS [Job DataType] ,x.Value AS [Measurement Value] ,x.Unit AS [Unit] ,y.Value AS [JobDataType] FROM dbo.Machines AS m JOIN dbo.JobFiles AS j ON j.MachineID = m.MachineID JOIN dbo.JobParams AS p ON p.JobFileID = j.JobID JOIN dbo.JobParamType AS t ON t.ParamTypeID = p.ParamTypeID LEFT JOIN dbo.JobMeasurement AS x ON x.ParamID = p.ParamID LEFT JOIN dbo.JobTrait AS y ON y.ParamID = p.ParamID GO -- Step 2 CREATE VIEW dbo.vJobValues AS SELECT [Job Name] ,[Param Type Name] ,COALESCE(cast([Measurement Value] AS varchar(50)), [JobDataType]) AS [Val] FROM dbo.vParameters GO /*********************************************************************************************** ** GET JOB PARMETERS FROM THE VIEW JUST CREATED ************************************************************************************************/ CREATE PROCEDURE GetJobParameters AS -- Step 3 DECLARE @Params TABLE ( id int IDENTITY (1,1) ,ParamName varchar(50) ); INSERT INTO @Params (ParamName) SELECT DISTINCT [Name] FROM dbo.JobParamType -- Step 4 DECLARE @qw TABLE( id int IDENTITY (1,1) , txt nchar(300) ) INSERT INTO @qw (txt) SELECT 'SELECT' UNION SELECT '[Job Name]' ; INSERT INTO @qw (txt) SELECT ',MAX(CASE [Param Type Name] WHEN ''' + ParamName + ''' THEN Val ELSE NULL END) AS [' + ParamName + ']' FROM @Params ORDER BY id; INSERT INTO @qw (txt) SELECT 'FROM dbo.vJobValues' UNION SELECT 'GROUP BY [Job Name]' UNION SELECT 'ORDER BY [Job Name]'; -- Step 5 --SELECT txt FROM @qw DECLARE @sql_output VARCHAR (MAX) SET @sql_output = '' -- NULL + '' = NULL, so we need to have a seed SELECT @sql_output = -- string to avoid losing the first line. COALESCE (@sql_output + txt + char (10), '') FROM @qw EXEC (@sql_output) GO

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• IoC - Dynamic Composition of object instances

  - by Joshua Starner

  Is there a way using IoC, MEF [Imports], or another DI solution to compose dependencies on the fly at object creation time instead of during composition time? Here's my current thought. If you have an instance of an object that raises events, but you are not creating the object once and saving it in memory, you have to register the event handlers every time the object is created. As far as I can tell, most IoC containers require you to register all of the classes used in composition and call Compose() to make it hook up all the dependencies. I think this may be horrible design (I'm dealing with a legacy system here) to do this due to the overhead of object creation, dependency injection, etc... but I was wondering if it was possible using one of the emergent IoC technologies. Maybe I have some terminology mixed up, but my goal is to avoid writing a framework to "hook up all the events" on an instance of an object, and use something like MEF to [Export] handlers (dependencies) that adhere to a very specific interface and [ImportMany] them into an object instance so my exports get called if the assemblies are there when the application starts. So maybe all of the objects could still be composed when the application starts, but I want the system to find and call all of them as the object is created and destroyed.

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• Undefined symbols compiling apache module mod_transform on Mac OS X

  - by Laurence Rowe

  I'm trying to compile mod_transform on Mac OS X 10.6, but get an ld error while running make. Thanks to diciu I have added some CFLAGS which resolve most of the linking problems, but I still am unable to get the apreq2 linking to work $ CFLAGS="-lxml2 -lxslt -L/opt/local/lib -lapreq2" ./configure --with-apr=/opt/local/bin/apr-1-config --with-apr-util=/opt/local/bin/apu-1-config --with-apxs=/opt/local/apache2/bin/apxs --with-apreq2=/opt/local/bin/apreq2-config ...snip... $ make $ make Making all in src /opt/local/share/apr-1/build/libtool --tag=CC --mode=link gcc -Wall -I../include -I/usr/local/include -I/usr/local/include/libxml2 -O2 -arch x86_64 -I/opt/local/include -DDARWIN -DSIGPROCMASK_SETS_THREAD_MASK -no-cpp-precomp -I/opt/local/apache2/include -I/opt/local/include/apr-1 -I/opt/local/include/apr-1 -I/opt/local/include -O2 -arch x86_64 -I/opt/local/include -DDARWIN -DSIGPROCMASK_SETS_THREAD_MASK -no-cpp-precomp -I/opt/local/apache2/include -I/opt/local/include/apr-1 -I/opt/local/include -I/opt/local/include/apr-1 -I/opt/local/include/apreq2 -I/opt/local/include/apr-1 -I/opt/local/include -lxml2 -lxslt -L/opt/local/lib -lapreq2 -module -export-dynamic -avoid-version -no-undefined /opt/local/lib/libapreq2.la -L/opt/local/lib -laprutil-1 -L/opt/local/lib/db46 -L/opt/local/lib -lapr-1 -lpthread -ldb-4.6 -lexpat -liconv -o http.la -rpath /opt/local/apache2/modules/mod_transform http_la-http.lo /usr/bin/gcc-4.2 -o .libs/http.so -bundle .libs/http_la-http.o -lxml2 -lxslt -L/opt/local/lib /opt/local/lib/libapreq2.dylib -L/opt/local/lib/db46 /opt/local/lib/libaprutil-1.dylib /opt/local/lib/libapr-1.dylib -lpthread /opt/local/lib/db46/libdb-4.6.dylib /opt/local/lib/libexpat.dylib /opt/local/lib/libiconv.dylib -arch x86_64 -arch x86_64 Undefined symbols: "_apreq_handle_apache2", referenced from: _transform_run_begin in http_la-http.o _filter_init in http_la-http.o ld: symbol(s) not found collect2: ld returned 1 exit status make[1]: *** [http.la] Error 1 make: *** [all-recursive] Error 1 Anyone have any other tweaks to fix this? This is mod_transform from http://svn.outoforder.cc/svn/mod%5Ftransform/trunk/ Laurence

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• Does HDC use alpha channel?

  - by Crend King

  Hello. Is there a way I can determine if an HDC uses alpha channel? I read Question 333559 and Question 685684, but their questions are about BITMAP. Apparently, some HDC has alpha channel (though they may not use it. Call this "Type 1") while others do not ("Type 2"). I know this by doing the following: Given a HDC, Create a compatible DC, and create a DIB section. Select the created HBITMAP into the compatible DC. BitBlt the source HDC to the compatible DC. Now examine the DIB section bits. For type 2 HDC, after every 3 bytes there is a byte always 0 (like 255 255 255 0); for type 1, these bytes are usualy 255 (like 250 240 230 255). To avoid false positive, I memset the bits to all 0x80 prior to the calls. Use GetDIBits directly on the source HDC, specify the HBITMAP as GetCurrentObject(hdc, OBJ_BITMAP). For both types of HDC, the 4th bytes are always 0. Change the DC bitmap by calling ExtTextOut. For type 2, ExtTextOut always set the 4th bytes to 0. For type 1, ExtTextOut always leave them untouched. I also noticed that the source HDC that are created by APIs (CreateCompatibleDC(), BeginPaint() ...) are always type 2. Type 1 HDC are from standard controls (like menu text). Even the HDC I CreateCompatibleDC from a type 1 becomes a type 2. So, on one hand, I'm frustrated that Microsoft does not provide equal information to developers (another example may be that you cannot know the direction of a HBITMAP after it is created), on the other hand, I'm still wondering is there a way to distinguish these HDC. Thanks for help.

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• Button Click Event Getting Lost

  - by AlishahNovin

  I have a Menu and Submenu structure in Silverlight, and I want the submenu to disappear when the parent menu item loses focus - standard Menu behavior. I've noticed that the submenu's click events are lost when a submenu item is clicked, because the parent menu item loses focus and the submenu disappears. It's easier to explain with code: ParentMenuBtn.Click += delegate { SubMenu.Visibility = (SubMenu.Visibility == Visibility.Visible) ? SubMenu.Collapsed : SubMenu.Visible; }; ParentMenuBtn.LostFocus += delegate { SubMenu.Visibility = Visibility.Collapsed; }; SubMenuBtn.Click += delegate { throw new Exception("This will never be thrown."); }; In my example, when SubMenuBtn is clicked, the first event that triggers is ParentMenuBtn.LostFocus(), which hides the container of SubMenuBtn. Once the container's visibility collapses, the Click event is never triggered. I'd rather avoid having to hide the sub-menu each time, but I'm a little surprised that the Click event is never triggered as a result... Anyone have any thoughts about this?

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• Casting generics and the generic type

  - by Kragen

  Consider, I have the following 3 classes / interfaces: class MyClass<T> { } interface IMyInterface { } class Derived : IMyInterface { } And I want to be able to cast a MyClass<Derived> into a MyClass<IMyInterface> or visa-versa: MyClass<Derived> a = new MyClass<Derived>(); MyClass<IMyInterface> b = (MyClass<IMyInterface>)a; But I get compiler errors if I try: Cannot convert type 'MyClass<Derived>' to 'MyClass<IMyInterface>' I'm sure there is a very good reason why I cant do this, but I can't think of one. As for why I want to do this - The scenario I'm imagining is one whereby you ideally want to work with an instance of MyClass<Derived> in order to avoid lots of nasty casts, however you need to pass your instance to an interface that accepts MyClass<IMyInterface>. So my question is twofold: Why can I not cast between these two types? Is there any way of keeping the niceness of working with an instance of MyClass<Derived> while still being able to cast this into a MyClass<IMyInterface>?

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• EAV Database Sheme

  - by GLO

  Hello Stackoverflow comunity! I believe that my question has to do with all db guru here! Do you know the EAV DB Scheme ( http://en.wikipedia.org/wiki/Entity-attribute-value_model ) and what they say about the performing of this model. I wonder, If I break this model into smaller tables what the result is? Let's talk about it. I have a db with more that 100K records. A lot of categories and many items ( with different properties per category ) Everything is stored in a EAV. If I try to break this scheme and create for any category a unique table is something that will I have to avoid? Yes, I know that probably I'll have a lot of tables and I'll need to ALTER them if I want to add an extra field, BUT is this so wrong? I have also read that as many tables I have, the db will be populate with more files and this isn't good for any filesystem. Any suggestion? Thank you!

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• R: dev.copy2pdf, multiple graphic devices to a single file, how to append to file?

  - by Timtico

  Hi everybody, I have a script that makes barplots, and opens a new window when 6 barplots have been written to the screen and keeps opening new graphic devices whenever necessary. Depending on the input, this leaves me with a potential large number of openened windows (graphic devices) which I would like to write to a single PDF file. Considering my Perl background, I decided to iterate over the different graphics devices, printing them out one by one. I would like to keep appending to a single PDF file, but I do not know how to do this, or if this is even possible. I would like to avoid looping in R. :) The code I use: for (i in 1:length(dev.list()) { dev.set(which = dev.list()[i] dev.copy2pdf(device = quartz, file = "/Users/Tim/Desktop/R/Filename.pdf") } However, this is not working as it will overwrite the file each time. Now is there an append function in R, like there is in Perl. Which allows me to keep adding pages to the existing pdf file? Or is there a way to contain the information in a graphic window to a object, and keep adding new graphic devices to this object and finally print the whole thing to a file? Other possible solutions I thought about: writing different pdf files, combining them after creation (perhaps even possible in R, with the right libraries installed?) copying the information in all different windows to one big graphic device and then print this to a pdf file.

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• Displaying Many-To-Many Database relationship in VB.NET 2008 with DataGrid, MS SQL 2008

  - by user337501

  Computer bombed while posting this, couldnt find a duplicate question but if there is one, forgive me. So, I've run into a wall. And rather than use a ladder to avoid it, I'd like go through it. I'm setting up what I can best describe as a many-to-many relationship in a database. To examplify, imagine I have three primary tables: Items, Categories, Sections(nevermind the potential redundancy) Then I have another table, Properties. Items, Categories, and Sections can be associated with many properties. A single property can be associated with one, all, or none of the other tables. The best way I can figure to do this is to have join tables make the relationship. i.e. tblItems----(Foreign Key)----tblItems_To_Properties----(Foreign Key)----tblProperties In this example, tblItems simply has an "ItemID" Primary Key. tblItems_To_Properties has its own Primary Key(tblItems_To_PropertiesID), a Foreign Key to the Item(ItemID) and a Foreign key to the Property(PropertyID). The Properties table simply has its primary key(PropertyID) I hope this example isnt too confusing...if I have to I can find a way to put a diagram up or something. My problem is, I want to display this in a DataGrid using the Master-Detail method(DevExpress GridControl). I use the tblItems as a test, and I can see the Items in the parent view, but in the child view I see(understandably) the join table and that is it. My goal is to make it so the Grid ignores the join table and shows the Properties table as the only child. Any help on this method or insight into another solution would be muuuuuuuch appreciat

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• Is This a Valid Way to Use Blocks in Objective-C?

  - by Carter

  I've been building a HTTP client that uses web services to synchronize information between the client and server. I've been using Blocks and NSURLConnection to achieve this on the client side, but I'm getting frequent EXC_BAD_ACCESS crashes in objc_msgSend(). From what I understand, this usually means that a stored block that has fallen off the stack has been called. I think I've coded things correctly to avoid this, but I'm still stuck. Here is conceptually what my code is doing. It starts by calling "synchronizeWithWebServer". That method invokes "listRootObjectsOnServerWithBlock:" which takes in a block to be called when the method returns. "listRootObjectsOnServersWithBlock:" initiates a NSURLConnection to the web server asynchronously. It to expects a block to be called when it returns. Inside that block I want to be able to execute the original Block (so aptly named 'block'). This is only a simplified version of my code. The real synchronization process is more complex but it's mostly more of the same as what you see below. Sometimes the code works perfectly, but about 80% of the time it crashes very early on in the routine. It seems to be more vulnerable to crashing when my data set gets larger. - (void)synchronizeWithWebServer { [self listRootObjectsOnServerWithBlock:^(NSArray *results, NSError *error) { //Iterate over result objects and perform some other similar routines. }]; } - (void)listRootObjectsOnServerWithBlock:(void (^)(NSArray *results, NSError *error))block { //Create NSURLRequest Here //Create connection asynchronously. block = [block copy]; [NSURLConnection sendAsynchronousRequest:urlRequest queue:[NSOperationQueue currentQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *error){ //Parse response from web server (stored in NSData *data) NSArray *results = ..... //Call 'block' block(results, error); [block release]; }]; }

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• Entity Framework lazy loading doesn't work from other thread

  - by Thomas Levesque

  Hi, I just found out that lazy loading in Entity Framework only works from the thread that created the ObjectContext. To illustrate the problem, I did a simple test, with a simple model containing just 2 entities : Person and Address. Here's the code : private static void TestSingleThread() { using (var context = new TestDBContext()) { foreach (var p in context.Person) { Console.WriteLine("{0} lives in {1}.", p.Name, p.Address.City); } } } private static void TestMultiThread() { using (var context = new TestDBContext()) { foreach (var p in context.Person) { Person p2 = p; // to avoid capturing the loop variable ThreadPool.QueueUserWorkItem( arg => { Console.WriteLine("{0} lives in {1}.", p2.Name, p2.Address.City); }); } } } The TestSingleThread method works fine, the Address property is lazily loaded. But in TestMultiThread, I get a NullReferenceException on p2.Address.City, because p2.Address is null. It that a bug ? Is this the way it's supposed to work ? If so, is there any documentation mentioning it ? I couldn't find anything on the subject on MSDN or Google... And more importantly, is there a workaround ? (other than explicitly calling LoadProperty from the worker thread...) Any help would be very appreciated PS: I'm using VS2010, so it's EF 4.0. I don't know if it was the same in the previous version of EF...

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• Validation in n-tier asp.net mvc applications

  - by sTodorov

  Dear Stack Overflow gurus, I am looking for some practical/theoretical information regarding best practices for validation in asp.net mvc n-tier applications. I am working on a .Net application divided into the following layers: UI - Mvc3 BLL layer - all business rules. Decoupled from data access and UI layers through interfaces DAL layer - Data access with the repository pattern, EF4 and pocos Now, I am looking for a nice, clean and transparent way to specify my validation rules. Here are some thoughts on the matter so far: UI validation should only be responsible for user input and its validity. BLL validation should be handling the validity of the data regarding the application business rules. My main concern is how to bind the BLL and UI validation in the most efficient way. One think I am would like to avoid is having the UI check in a collection of validation and adding manually errors to the ModelState. Furthermore, I do not want to pass the ModelState to the BLL to be populated in there. I will appreciate any thoughts on the matter. P.S. Should this question be marked as a discussion ?

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• Can I trigger PHP garbage collection to happen automatically if I have circular references?

  - by Beau Simensen

  I seem to recall a way to setup the __destruct for a class in such a way that it would ensure that circular references would be cleaned up as soon as the outside object falls out of scope. However, the simple test I built seems to indicate that this is not behaving as I had expected/hoped. Is there a way to setup my classes in such a way that PHP would clean them up correctly when the outermost object falls out of scope? I am not looking for alternate ways to write this code, I am looking for whether or not this can be done, and if so, how? I generally try to avoid these types of circular references where possible. class Bar { private $foo; public function __construct($foo) { $this->foo = $foo; } public function __destruct() { print "[destroying bar]\n"; unset($this->foo); } } class Foo { private $bar; public function __construct() { $this->bar = new Bar($this); } public function __destruct() { print "[destroying foo]\n"; unset($this->bar); } } function testGarbageCollection() { $foo = new Foo(); } for ( $i = 0; $i < 25; $i++ ) { echo memory_get_usage() . "\n"; testGarbageCollection(); } The output looks like this: 60440 61504 62036 62564 63092 63620 [ destroying foo ] [ destroying bar ] [ destroying foo ] [ destroying bar ] [ destroying foo ] [ destroying bar ] [ destroying foo ] [ destroying bar ] [ destroying foo ] [ destroying bar ] What I had hoped for: 60440 [ destorying foo ] [ destorying bar ] 60440 [ destorying foo ] [ destorying bar ] 60440 [ destorying foo ] [ destorying bar ] 60440 [ destorying foo ] [ destorying bar ] 60440 [ destorying foo ] [ destorying bar ] 60440 [ destorying foo ] [ destorying bar ]

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• IRC Server configuration possibilities

  - by Katai

  I need to know a couple of things, concerning IRC servers that I couldnt directly find out over google (or werent clear enough for me to be sure if it actually works) I'm working at a larger community site, and wanted to deliver an in-page chat. Since it would be a nice feature to let people access it from outside too, over their own clients, I tought implementing an IRC Server would be the best solution (probably dedicated, I'll have to teach myself a couple of things for that) I plan to include a Web-based IRC client over an APE Client / Server. The problem is, I want to strip down the user rights, to disallow many functionalities that IRC would offer: Change of nicknames: The user logs in over the Page login, and I'll automatically create an IRC auth for this user with that password. So basically, he would connect to the IRC client over a button. And after connecting, he shouldnt be able to change his nickname at all Creating channels: I want the possibility to create channels, but not from 'normal' users. Basically, I would prefer to set up basic channels that are public, and if a user really creates an own channel, that one should be private and via invitation (is that possible?) Private conversations: private conversations should be filtered out from the allaround IRC client, into separate 'in-browser-windows' that I create over JS. I guess I just have to filter the stuff coming from IRC - or is there a better solution to that? Only 'registered' users have access: Like I said, if someone registers on the page, I would like to create an IRC 'account' for him. Users that arent registered on the page, cant access the IRC server at all (or get thrown out). Mainly to avoid spammers or bots from outside. Is this stuff solvable over IRC? I've read some FAQ's and Instructions for IRC OP's and servers, but I couldnt find a clear answer - it seems that everyone can do pretty much everything - I would like to configure it in a way that user possibilities are more cut down. Basically, giving users the possibility to chat, but not more. So the Question basically is, how possible / solvable this issues are allaround, or if I have to find other solutions for this.

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• How can I improve my real-time behavior in multi-threaded app using pthreads and condition variables

  - by WilliamKF

  I have a multi-threaded application that is using pthreads. I have a mutex() lock and condition variables(). There are two threads, one thread is producing data for the second thread, a worker, which is trying to process the produced data in a real time fashion such that one chuck is processed as close to the elapsing of a fixed time period as possible. This works pretty well, however, occasionally when the producer thread releases the condition upon which the worker is waiting, a delay of up to almost a whole second is seen before the worker thread gets control and executes again. I know this because right before the producer releases the condition upon which the worker is waiting, it does a chuck of processing for the worker if it is time to process another chuck, then immediately upon receiving the condition in the worker thread, it also does a chuck of processing if it is time to process another chuck. In this later case, I am seeing that I am late processing the chuck many times. I'd like to eliminate this lost efficiency and do what I can to keep the chucks ticking away as close to possible to the desired frequency. Is there anything I can do to reduce the delay between the release condition from the producer and the detection that that condition is released such that the worker resumes processing? For example, would it help for the producer to call something to force itself to be context switched out? Bottom line is the worker has to wait each time it asks the producer to create work for itself so that the producer can muck with the worker's data structures before telling the worker it is ready to run in parallel again. This period of exclusive access by the producer is meant to be short, but during this period, I am also checking for real-time work to be done by the producer on behalf of the worker while the producer has exclusive access. Somehow my hand off back to running in parallel again results in significant delay occasionally that I would like to avoid. Please suggest how this might be best accomplished.

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• Boost Mersenne Twister: how to seed with more than one value?

  - by Eamon Nerbonne

  I'm using the boost mt19937 implementation for a simulation. The simulation needs to be reproducible, and that means storing and potentially reusing the RNG seeds later. I'm using the windows crypto api to generate the seed values because I need an external source for the seeds and not because of any particular guarantees of randomness. The output of any simulation run will have a note including the RNG seed - so the seed needs to be reasonably short. On the other hand, as part of the analysis of the simulation, I'll be comparing several runs - but to be sure that these runs are actually different, I'll need to use different seeds - so the seed needs to be long enough to avoid accidental collisions. I've determined that 64-bits of seeding should suffice; the chance of a collision will reach 50% after about 2^32 runs - that probability is low enough that the average error caused by it is negligible to me. Using just 32-bits of seed is tricky; the chance of a collision reaches 50% already after 2^16 runs; and that's a little too likely for my tastes. Unfortunately, the boost implementation either seeds with a full state vector - which is far, far too long - or a single 32-bit unsigned long - which isn't ideal. How can I seed the generator with more than 32-bits but less than a full state vector? I tried just padding the vector or repeating the seeds to fill the state vector, but even a cursory glance at the results shows that that generates poor results.

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• Looped jQuery slideshow with smooth cross-fades

  - by artlung

  I'm trying to do a simple rotating image on the home page. Under the hood I'm reading a directory and then populating urls for the images into an array. What I want to do is cross-fade the images. If it was just a matter of showing the next one, it's easy, but since I need to cross-fade, it's a bit harder. I think what I want to do is do the fades by calling animate() on the opacity value of the <img> tag, and in between swapping out the css background-image property of the enclosing <div>. But the results are not that great. I've used tools for more full featured slideshows, but I don't want the overhead of adding a plugin if I can avoid it, and a simple crossfade seems like it should be easier. Here's my JavaScript (I'm using jQuery 1.3.2): var slideshow_images = ["http:\/\/example.com\/wordpress\/wp-content\/themes\/testtheme\/sidebar-home-bg\/bg1.jpg","http:\/\/example.com\/wordpress\/wp-content\/themes\/testtheme\/sidebar-home-bg\/bg2.jpg","http:\/\/example.com\/wordpress\/wp-content\/themes\/testtheme\/sidebar-home-bg\/bg3.jpg"]; var slideshow_index = 0; var delay = 4000; var swapSlides = function() { var slideshow_count = slideshow_images.length; // initialize the background to be the current image $('#home-slideshow').css({ 'background-image': 'url(' + slideshow_images[slideshow_index] + ')', 'background-repeat:': 'no-repeat', 'width': 200, 'overflow': 'hidden' }); slideshow_index = ((slideshow_index + 1) == slideshow_count) ? 0 : slideshow_index + 1; // fade out the img $('#home-slideshow img').animate({opacity: 0}, delay); // now, the background is visible // next change the url on the img $('#home-slideshow img').attr('src', slideshow_images[slideshow_index]); // and fade it up $('#home-slideshow img').animate({opacity: 1.0}, delay); // do it again setTimeout('swapSlides()', 4000); } jQuery(document).ready(function(){ if (swapSlides) { swapSlides(); } }); And here's the markup I'm using: <div id="home-slideshow"><img src="http://example.com/wordpress/wp-content/themes/testtheme/sidebar-home-bg/bg1.jpg" alt="" /></div>

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• How to temporarily replace one primitive type with another when compiling to different targets in c#

  - by Keith

  How to easily/quickly replace float's for doubles (for example) for compiling to two different targets using these two particular choices of primitive types? Discussion: I have a large amount of c# code under development that I need to compile to alternatively use float, double or decimals depending on the use case of the target assembly. Using something like “class MYNumber : Double” so that it is only necessary to change one line of code does not work as Double is sealed, and obviously there is no #define in C#. Peppering the code with #if #else statements is also not an option, there is just too much supporting Math operators/related code using these particular primitive types. I am at a loss on how to do this apparently simple task, thanks! Edit: Just a quick comment in relation to boxing mentioned in Kyles reply: Unfortunately I need to avoid boxing, mainly since float's are being chosen when maximum speed is required, and decimals when maximum accuracy is the priority (and taking the 20x+ performance hit is acceptable). Boxing would probably rules out decimals as a valid choice and defeat the purpose somewhat. Edit2: For reference, those suggesting generics as a possible answer to this question note that there are many issues which count generics out (at least for our needs). For an overview and further references see Using generics for calculations

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• Reduce number of config files to as few as possible

  - by Scott

  For most of my applications I use iBatis.Net for database access/modeling and log4Net for logging. In doing this, I need a number of *.config files for each project. For example, for a simple application I need to have the following *.config files: app.config ([AssemblyName].[Extention].config) [AssemblyName].SqlMap.config [AssemblyName].log4Net.config [AssemblyName].SqlMapProperties.config providers.config When these applications go from DEV to TEST to PRODUCTION environments, the settings contained in these files change depending on the environment. When the number of files get compounded by having 5-10 (or more) supporting executables per project, the work load on the infrastructure team (the ones doing the roll-outs to the different environments) gets rather high. We also have a high risk of one of the config files being missed, or a mistype in the config file. What is the best way to avoid these risks? Should I combine all of the config files into one file? (is that possible with iBatis?) I know that with VisualStudio 2010 they introduce transforms for these config files that allow the developer to setup all the settings for the different environments and then dynamically (depending on the build kicked off) the config files get updated to the correct versions. (VS 2010 - transforms) Thank you for any help that you can provide.

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• jQuery set selected value in option box once the box has been loaded

  - by Maarten

  I want to preset the value of a selectbox based on a hidden field. I need this after an error has been detected in a form to avoid the user having to set the value themselves again. I do this by setting the value of a hidden field server side. The problem I have seems to be that the select box isn't done yet at the time I try to set the selected value. Anyone know how to solve this (possibly in a very different way?) <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.js"></script> <script type="text/javascript" charset="utf-8"> $(function(){ // this functions loads the state select box with states if a country with states is selected $("select#countries").change(function(){ $.getJSON("/ajax/exhibition/getstates.php?idCountry="+$("select#countries").val(), function(j){ var options = ''; $.each(j, function(key, value){ options += '<option value="' + key + '">' + value + '</option>'; }); $("select#state").html(options); }); }); }); $(document).ready(function(){ // preset the state select box on page ready $('select#countries').change(); // set the selected value of the state select box var foo = $('#statepreset').val(); $("select#state option[value="+foo+"]").attr('selected', 'selected'); }); </script>

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• ASP.NET MVC Image refreshing

  - by user295541

  Hi, I have an Employee object which has an image property. Image class contains image metadata as image caption, and image file name. If I upload a new image for an employee on async way without full post back the new image is not appeared on the page. I use GUID to name the image file to avoid the page caching. I do the image modifying the following way: ctrEmployee employee = Repository.Get(PassedItemID); if (employee.ctrImage != null) { string fullFileName = serverFolder + employee.ctrImage.FileName; FileInfo TheFile = new FileInfo(fullFileName); if (TheFile.Exists) { TheFile.Delete(); } fileName = Guid.NewGuid() + ".jpg"; employee.ctrImage.FileName = fileName; } resizedBmp.Save(string.Format("{0}{1}", serverFolder, fileName), System.Drawing.Imaging.ImageFormat.Jpeg); Repository.Edit<ctrEmployee>(employee); ImageID = employee.Image.Value; return PartialView(UserControlPaths.Thumbnail, new ThumbnailDataModel(employee.Image.Value, 150, 150)); The partial view has an image tag which gets the saved image url string which is a GUID. Anybody has an idea what I do wrong?

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• Identifying and Resolving Oracle ITL Deadlock

  - by Allan

  I have an Oracle DB package that is routinely causing what I believe is an ITL (Interested Transaction List) deadlock. The relevant portion of a trace file is below. Deadlock graph: ---------Blocker(s)-------- ---------Waiter(s)--------- Resource Name process session holds waits process session holds waits TM-0000cb52-00000000 22 131 S 23 143 SS TM-0000ceec-00000000 23 143 SX 32 138 SX SSX TM-0000cb52-00000000 30 138 SX 22 131 S session 131: DID 0001-0016-00000D1C session 143: DID 0001-0017-000055D5 session 143: DID 0001-0017-000055D5 session 138: DID 0001-001E-000067A0 session 138: DID 0001-001E-000067A0 session 131: DID 0001-0016-00000D1C Rows waited on: Session 143: no row Session 138: no row Session 131: no row There are no bit-map indexes on this table, so that's not the cause. As far as I can tell, the lack of "Rows waited on" plus the "S" in the Waiter waits column likely indicates that this is an ITL deadlock. Also, the table is written to quite often (roughly 8 insert or updates concurrently, as often as 240 times a minute), so and ITL deadlock seems like a strong possibility. I've increased the INITRANS parameter of the table and it's indexes to 100 and increased the PCT_FREE on the table from 10 to 20 (then rebuilt the indexes), but the deadlocks are still occurring. The deadlock seems to happen most often during an update, but that could just be a coincidence, as I've only traced it a couple of times. My questions are two-fold: 1) Is this actually an ITL deadlock? 2) If it is an ITL deadlock, what else can be done to avoid it?

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• PHP CURL Google Calendar using Private URL

  - by MooCow

  I'm trying to get an array of events from Google Calendar using the Private URL. I read the Google API document but I want to try doing this without using the ZEND library since I have no idea what the eventual server file structure is and avoid having other people edit the codes. I also did a search before posting and ran into the same condition where PHP CURL_EXEC returns false with the URL but I get a JSON file if the URL is open using a web browser. Since I'm using the Private URL, do I really need to authenticate against the Google server using ZEND? I'm trying to have PHP clean up the array before encoding it for Flash. $URL = <string of the private URL from Google Calendar> $ch = curl_init($URL); curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); $data = curl_exec($ch); curl_close($ch); $result = json_decode($data); print '<pre>'.var_export($data,1).'</pre>'; Screen output >>> false

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