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  • VS2010 Code: 2104 Could not download the Silverlight application

    - by rotary_engine
    I've just started getting this Javascript error running VS2010 with SL4 Error: Unhandled Error in Silverlight Application Code: 2104 Category: InitializeError Message: Could not download the Silverlight application. Check web server settings Everything was working fine, changed 1 line of code to use a RegularExpression in the web project (using the Silverlight Business Application template) then when rebuilding I get this error. Google says this is IIS and mimetype related. I'm using Cassini not IIS with VS2010. Rebooted, cleared xap from IE cache. Error on both IE and FF. What could be wrong?

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  • Application Architecture using WCF and System.AddIn

    - by Silverhalide
    A little background -- we're designing an application that uses a client/server architecture consisting of: A server which loads server-side modules, potentially developed by other teams. A client which loads corresponding client-side modules (also potentially developed by those other teams; each client module corresponds with a server module). The client side communicates with the server side for general coordination, and as well as module specific tasks. (At this point, I think that means client talks to server, client modules talk to server modules.) Environment is .NET 3.5, and client side is WPF. The deployment scenario introduces the potential to upgrade the server, any server-side module, the client, and any client-side module independently. However, being able to "work" using mismatched versions is required. I'm therefore concerned about versioning issues. My thinking so far: A Windows Service for the server. Using System.AddIn for the server to load and communicate with the server modules will give us the greatest flexibility in terms of version compatability between server and server modules. The server and each server module vend WCF services for communication to the client side; communication between the server and a server module, or between two server modules use the AddIn contracts. (One advantage of this is that a module can expose a different interface within the server and outside it.) Similarly, the client uses System.AddIn to find, load, and communicate with the client modules. Client communications with client modules is via the AddIn interface; communications from the client and from client modules to the server side are via WCF. For maximum resilience, each module will run in a separate app-domain. In general, the system has modest performance requirements, so marshalling and crossing process boundaries is not expected to be a performance concern. (Performance requirement is basically summed up by: don't get in the way of the other parts of the system not described here.) My questions are around the idea of having two different communication and versioning models to work with which will be an added burden on our developers. System.AddIn seems quite powerful, but also a little unwieldly. (I'm also unsure of Microsoft's commitment to it in the future.) On the other hand, I'm not thrilled with WCF's versioning capabilities. I have a feeling that it would be possible to implement the System.AddIn view/adapter/contract system within WCF, but being fairly new to both technologies, I would have no idea of where to start. So... Am I on the right track here? Am I doing this the hard way? Are there gotchas I need to be aware of on this road? Thanks.

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  • MSSQL EXPRESS 2008 Stored Procedure execution time spikes periodically

    - by user156241
    I have a big stored procedure on a MSSQL 2008 Express SP2 database that gets run about every 200 ms. Normal execution time is about 50ms. What I am seeing is large inconsistencies in this run time. It will execute for while, say 50-100 times at 40-60ms which is expected, then seemingly at random the same stored procedure will take way longer, say 900ms or 1.5 seconds to run. Sometimes more than one call of the same procedure in a row will take longer too. It appears that something is causing sql server to slow down dramatically every minute or so, but I can't figure out what. There is no timing pattern between the occurences. I have the same setup on two different computers, one of which is a clean XP Pro load with no virus checking and nothing installed except SQL server. Also, The recovery options for all the databases are set to "Simple".

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  • Java: micro-optimizing array manipulation

    - by Martin Wiboe
    Hello all, I am trying to make a Java port of a simple feed-forward neural network. This obviously involves lots of numeric calculations, so I am trying to optimize my central loop as much as possible. The results should be correct within the limits of the float data type. My current code looks as follows (error handling & initialization removed): /** * Simple implementation of a feedforward neural network. The network supports * including a bias neuron with a constant output of 1.0 and weighted synapses * to hidden and output layers. * * @author Martin Wiboe */ public class FeedForwardNetwork { private final int outputNeurons; // No of neurons in output layer private final int inputNeurons; // No of neurons in input layer private int largestLayerNeurons; // No of neurons in largest layer private final int numberLayers; // No of layers private final int[] neuronCounts; // Neuron count in each layer, 0 is input // layer. private final float[][][] fWeights; // Weights between neurons. // fWeight[fromLayer][fromNeuron][toNeuron] // is the weight from fromNeuron in // fromLayer to toNeuron in layer // fromLayer+1. private float[][] neuronOutput; // Temporary storage of output from previous layer public float[] compute(float[] input) { // Copy input values to input layer output for (int i = 0; i < inputNeurons; i++) { neuronOutput[0][i] = input[i]; } // Loop through layers for (int layer = 1; layer < numberLayers; layer++) { // Loop over neurons in the layer and determine weighted input sum for (int neuron = 0; neuron < neuronCounts[layer]; neuron++) { // Bias neuron is the last neuron in the previous layer int biasNeuron = neuronCounts[layer - 1]; // Get weighted input from bias neuron - output is always 1.0 float activation = 1.0F * fWeights[layer - 1][biasNeuron][neuron]; // Get weighted inputs from rest of neurons in previous layer for (int inputNeuron = 0; inputNeuron < biasNeuron; inputNeuron++) { activation += neuronOutput[layer-1][inputNeuron] * fWeights[layer - 1][inputNeuron][neuron]; } // Store neuron output for next round of computation neuronOutput[layer][neuron] = sigmoid(activation); } } // Return output from network = output from last layer float[] result = new float[outputNeurons]; for (int i = 0; i < outputNeurons; i++) result[i] = neuronOutput[numberLayers - 1][i]; return result; } private final static float sigmoid(final float input) { return (float) (1.0F / (1.0F + Math.exp(-1.0F * input))); } } I am running the JVM with the -server option, and as of now my code is between 25% and 50% slower than similar C code. What can I do to improve this situation? Thank you, Martin Wiboe

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  • Optimizations employed by ORM's

    - by Kartoch
    I'm teaching JEE, especially JPA, Spring and Spring MVC. As I have not so much experience in large projects, it is difficult to know what to present to students about optimisation of ORM. At the present time, I present some classic optimisation tricks: prepared statements (most of ORM implicitely uses it by default) first and second-level caches "write first, optimize later" it is possible to switch off ORM and send SQL commands directly to the database for very frequent, specialized and costly requests Is there any other point the community see about other way to optimize ORM ? I'm especially interested by DAO patterns...

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  • Why aren't we programming on the GPU???

    - by Chris
    So I finally took the time to learn CUDA and get it installed and configured on my computer and I have to say, I'm quite impressed! Here's how it does rendering the Mandelbrot set at 1280 x 678 pixels on my home PC with a Q6600 and a GeForce 8800GTS (max of 1000 iterations): Maxing out all 4 CPU cores with OpenMP: 2.23 fps Running the same algorithm on my GPU: 104.7 fps And here's how fast I got it to render the whole set at 8192 x 8192 with a max of 1000 iterations: Serial implemetation on my home PC: 81.2 seconds All 4 CPU cores on my home PC (OpenMP): 24.5 seconds 32 processors on my school's super computer (MPI with master-worker): 1.92 seconds My home GPU (CUDA): 0.310 seconds 4 GPUs on my school's super computer (CUDA with static domain decomposition): 0.0547 seconds So here's my question - if we can get such huge speedups by programming the GPU instead of the CPU, why is nobody doing it??? I can think of so many things we could speed up like this, and yet I don't know of many commercial apps that are actually doing it. Also, what kinds of other speedups have you seen by offloading your computations to the GPU?

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  • Slow query with unexpected index scan

    - by zerkms
    Hello I have this query: SELECT * FROM sample INNER JOIN test ON sample.sample_number = test.sample_number INNER JOIN result ON test.test_number = result.test_number WHERE sampled_date BETWEEN '2010-03-17 09:00' AND '2010-03-17 12:00' the biggest table here is RESULT, contains 11.1M records. The left 2 tables about 1M. this query works slowly (more than 10 minutes) and returns about 800 records. executing plan shows clustered index scan (over it's PRIMARY KEY (result.result_number, which actually doesn't take part in query)) over all 11M records. RESULT.TEST_NUMBER is a clustered primary key. if I change 2010-03-17 09:00 to 2010-03-17 10:00 - i get about 40 records. it executes for 300ms. and plan shows index seek (over result.test_number index) if i replace * in SELECT clause to result.test_number (covered with index) - then all become fast in first case too. this points to hdd IO issues, but doesn't clarifies changing plan. so, any ideas? UPDATE: sampled_date is in table sample and covered by index. other fields from this query: test.sample_number is covered by index and result.test_number too. UPDATE 2: obviously than sql server in any reasons don't want to use index. i did a small experiment: i remove INNER JOIN with result, select all test.test_number and after that do SELECT * FROM RESULT WHERE TEST_NUMBER IN (...) this, of course, works fast. but i cannot get what is the difference and why query optimizer choose such inappropriate way to select data in 1st case.

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  • Was Joel right about XML being slow?

    - by Will
    A long time ago Joel explained how various every-day coding things were slow, and this led to XML as a data store being slow: http://www.joelonsoftware.com/articles/fog0000000319.html Are those every-day coding things - strcat and malloc - still slow in a std::string and dlmalloc world? What else has changed in modern processors and mainstream frameworks? And is XML still slow? You can't find an RDBMS that doesn't claim some kind of native XML support these days; haven't they got it faster - a single pass to index it for example - yet?

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  • How to speed up WPF programs?

    - by Sam
    I love programming with and for Windows Presentation Framework. Mostly I write browser-like apps using WPF and XAML. But what really annoys me is the slowness of WPF. A simple page with only a few controls loads fast enough, but as soon as a page is a teeny weeny bit more complex, like containing a lot of data entry fields, one or two tab controls, and stuff, it gets painful. Loading of such a page can take more than one second. Seconds, indeed, especially on not so fast computers (read: the customers computers) it can take ages. Same with changing values on the page. Everything about the WPF UI is somehow sluggy. This is so mean! They give me this beautiful framework, but make it so excruciatingly slow so I'll have to apologize to our customers all the time! My Question: How do you speed up WPF? How do you profile bottlenecks? How do you deal with the slowness? Since this seems to be an universal problem with WPF, I'm looking for general advice, useful for many situations and problems. Some other related questions: What tools do you use for WPF development Tools to develop WPF or Silverlight applications

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  • Problem with room/screen/menu controller in python game: old rooms are not removed from memory

    - by Jordan Magnuson
    I'm literally banging my head against a wall here (as in, yes, physically, at my current location, I am damaging my cranium). Basically, I've got a Python/Pygame game with some typical game "rooms", or "screens." EG title screen, high scores screen, and the actual game room. Something bad is happening when I switch between rooms: the old room (and its various items) are not removed from memory, or from my event listener. Not only that, but every time I go back to a certain room, my number of event listeners increases, as well as the RAM being consumed! (So if I go back and forth between the title screen and the "game room", for instance, the number of event listeners and the memory usage just keep going up and up. The main issue is that all the event listeners start to add up and really drain the CPU. I'm new to Python, and don't know if I'm doing something obviously wrong here, or what. I will love you so much if you can help me with this! Below is the relevant source code. Complete source code at http://www.necessarygames.com/my_games/betraveled/betraveled_src0328.zip MAIN.PY class RoomController(object): """Controls which room is currently active (eg Title Screen)""" def __init__(self, screen, ev_manager): self.room = None self.screen = screen self.ev_manager = ev_manager self.ev_manager.register_listener(self) self.room = self.set_room(config.room) def set_room(self, room_const): #Unregister old room from ev_manager if self.room: self.room.ev_manager.unregister_listener(self.room) self.room = None #Set new room based on const if room_const == config.TITLE_SCREEN: return rooms.TitleScreen(self.screen, self.ev_manager) elif room_const == config.GAME_MODE_ROOM: return rooms.GameModeRoom(self.screen, self.ev_manager) elif room_const == config.GAME_ROOM: return rooms.GameRoom(self.screen, self.ev_manager) elif room_const == config.HIGH_SCORES_ROOM: return rooms.HighScoresRoom(self.screen, self.ev_manager) def notify(self, event): if isinstance(event, ChangeRoomRequest): if event.game_mode: config.game_mode = event.game_mode self.room = self.set_room(event.new_room) #Run game def main(): pygame.init() screen = pygame.display.set_mode(config.screen_size) ev_manager = EventManager() spinner = CPUSpinnerController(ev_manager) room_controller = RoomController(screen, ev_manager) pygame_event_controller = PyGameEventController(ev_manager) spinner.run() EVENT_MANAGER.PY class EventManager: #This object is responsible for coordinating most communication #between the Model, View, and Controller. def __init__(self): from weakref import WeakKeyDictionary self.last_listeners = {} self.listeners = WeakKeyDictionary() self.eventQueue= [] self.gui_app = None #---------------------------------------------------------------------- def register_listener(self, listener): self.listeners[listener] = 1 #---------------------------------------------------------------------- def unregister_listener(self, listener): if listener in self.listeners: del self.listeners[listener] #---------------------------------------------------------------------- def clear(self): del self.listeners[:] #---------------------------------------------------------------------- def post(self, event): # if isinstance(event, MouseButtonLeftEvent): # debug(event.name) #NOTE: copying the list like this before iterating over it, EVERY tick, is highly inefficient, #but currently has to be done because of how new listeners are added to the queue while it is running #(eg when popping cards from a deck). Should be changed. See: http://dr0id.homepage.bluewin.ch/pygame_tutorial08.html #and search for "Watch the iteration" print 'Number of listeners: ' + str(len(self.listeners)) for listener in list(self.listeners): #NOTE: If the weakref has died, it will be #automatically removed, so we don't have #to worry about it. listener.notify(event) def notify(self, event): pass #------------------------------------------------------------------------------ class PyGameEventController: """...""" def __init__(self, ev_manager): self.ev_manager = ev_manager self.ev_manager.register_listener(self) self.input_freeze = False #---------------------------------------------------------------------- def notify(self, incoming_event): if isinstance(incoming_event, UserInputFreeze): self.input_freeze = True elif isinstance(incoming_event, UserInputUnFreeze): self.input_freeze = False elif isinstance(incoming_event, TickEvent) or isinstance(incoming_event, BoardCreationTick): #Share some time with other processes, so we don't hog the cpu pygame.time.wait(5) #Handle Pygame Events for event in pygame.event.get(): #If this event manager has an associated PGU GUI app, notify it of the event if self.ev_manager.gui_app: self.ev_manager.gui_app.event(event) #Standard event handling for everything else ev = None if event.type == QUIT: ev = QuitEvent() elif event.type == pygame.MOUSEBUTTONDOWN and not self.input_freeze: if event.button == 1: #Button 1 pos = pygame.mouse.get_pos() ev = MouseButtonLeftEvent(pos) elif event.type == pygame.MOUSEBUTTONDOWN and not self.input_freeze: if event.button == 2: #Button 2 pos = pygame.mouse.get_pos() ev = MouseButtonRightEvent(pos) elif event.type == pygame.MOUSEBUTTONUP and not self.input_freeze: if event.button == 2: #Button 2 Release pos = pygame.mouse.get_pos() ev = MouseButtonRightReleaseEvent(pos) elif event.type == pygame.MOUSEMOTION: pos = pygame.mouse.get_pos() ev = MouseMoveEvent(pos) #Post event to event manager if ev: self.ev_manager.post(ev) # elif isinstance(event, BoardCreationTick): # #Share some time with other processes, so we don't hog the cpu # pygame.time.wait(5) # # #If this event manager has an associated PGU GUI app, notify it of the event # if self.ev_manager.gui_app: # self.ev_manager.gui_app.event(event) #------------------------------------------------------------------------------ class CPUSpinnerController: def __init__(self, ev_manager): self.ev_manager = ev_manager self.ev_manager.register_listener(self) self.clock = pygame.time.Clock() self.cumu_time = 0 self.keep_going = True #---------------------------------------------------------------------- def run(self): if not self.keep_going: raise Exception('dead spinner') while self.keep_going: time_passed = self.clock.tick() fps = self.clock.get_fps() self.cumu_time += time_passed self.ev_manager.post(TickEvent(time_passed, fps)) if self.cumu_time >= 1000: self.cumu_time = 0 self.ev_manager.post(SecondEvent(fps=fps)) pygame.quit() #---------------------------------------------------------------------- def notify(self, event): if isinstance(event, QuitEvent): #this will stop the while loop from running self.keep_going = False EXAMPLE CLASS USING EVENT MANAGER class Timer(object): def __init__(self, ev_manager, time_left): self.ev_manager = ev_manager self.ev_manager.register_listener(self) self.time_left = time_left self.paused = False def __repr__(self): return str(self.time_left) def pause(self): self.paused = True def unpause(self): self.paused = False def notify(self, event): #Pause Event if isinstance(event, Pause): self.pause() #Unpause Event elif isinstance(event, Unpause): self.unpause() #Second Event elif isinstance(event, SecondEvent): if not self.paused: self.time_left -= 1

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  • Code Trivia: optimize the code for multiple nested loops

    - by CodeToGlory
    I came across this code today and wondering what are some of the ways we can optimize it. Obviously the model is hard to change as it is legacy, but interested in getting opinions. Changed some names around and blurred out some core logic to protect. private static Payment FindPayment(Order order, Customer customer, int paymentId) { Payment payment = Order.Payments.FindById(paymentId); if (payment != null) { if (payment.RefundPayment == null) { return payment; } if (String.Compare(payment.RefundPayment, "refund", true) != 0 ) { return payment; } } Payment finalPayment = null; foreach (Payment testpayment in Order.payments) { if (testPayment.Customer.Name != customer.Name){continue;} if (testPayment.Cancelled) { continue; } if (testPayment.RefundPayment != null) { if (String.Compare(testPayment.RefundPayment, "refund", true) == 0 ) { continue; } } if (finalPayment == null) { finalPayment = testPayment; } else { if (testPayment.Value > finalPayment.Value) { finalPayment = testPayment; } } } if (finalPayment == null) { return payment; } return finalPayment; } Making this a wiki so code enthusiasts can answer without worrying about points.

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  • Load balancing a console application or service

    - by David
    So it's easy to load balance an ASP.NET web application. You set up a load balancer between two servers, and if the web server isn't responding on Port 80, it won't receive requests. Are there any proven techniques for doing this for a C# console application or Windows service that takes actions of its own volition? Are there any frameworks for knowing if peer processes are alive or dead, doing heartbeats, etc? I've been experimenting a bit with NServiceBus and it seems like, for certain kinds of applications, it would help to have most of the work done as a response to an event, which makes it more like a web application, actually, and therefore easier to scale and load balance with multiple processes, but I feel like that's a half-baked solution since in most cases there usually needs to be some concept of a "master" process that's responsible for getting work started.

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  • Rails, Capistrano, Nginx, Unicorn - Application has been already initialized (RuntimeError)

    - by Andy Copley
    Can anyone shed some light on what exactly this error refers to? I'm having trouble deploying new versions of the site. I, INFO -- : reloading config_file=[snip]/current/config/unicorn.rb I, INFO -- : Refreshing Gem list E, ERROR -- : error reloading config_file=[snip]/current/config/unicorn.rb: Application has been already initialized. (RuntimeError) E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/railties-3.2.3/lib/rails/application.rb:135:in `initialize!' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/railties-3.2.3/lib/rails/railtie/configurable.rb:30:in `method_missing' E, ERROR -- : [snip]/releases/20120907085937/config/environment.rb:5:in `<top (required)>' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/activesupport-3.2.3/lib/active_support/dependencies.rb:251:in `require' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/activesupport-3.2.3/lib/active_support/dependencies.rb:251:in `block in require' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/activesupport-3.2.3/lib/active_support/dependencies.rb:236:in `load_dependency' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/activesupport-3.2.3/lib/active_support/dependencies.rb:251:in `require' E, ERROR -- : config.ru:4:in `block in <main>' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/rack-1.4.1/lib/rack/builder.rb:51:in `instance_eval' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/rack-1.4.1/lib/rack/builder.rb:51:in `initialize' E, ERROR -- : config.ru:1:in `new' E, ERROR -- : config.ru:1:in `<main>' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/unicorn-4.3.1/lib/unicorn.rb:44:in `eval' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/unicorn-4.3.1/lib/unicorn.rb:44:in `block in builder' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/unicorn-4.3.1/lib/unicorn/http_server.rb:696:in `call' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/unicorn-4.3.1/lib/unicorn/http_server.rb:696:in `build_app!' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/unicorn-4.3.1/lib/unicorn/http_server.rb:677:in `load_config!' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/unicorn-4.3.1/lib/unicorn/http_server.rb:303:in `join' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/unicorn-4.3.1/bin/unicorn:121:in `<top (required)>' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/bin/unicorn:23:in `load' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/bin/unicorn:23:in `<main>' I, INFO -- : reaped #<Process::Status: pid 3182 exit 0> worker=0 I, INFO -- : reaped #<Process::Status: pid 3185 exit 0> worker=1 I, INFO -- : reaped #<Process::Status: pid 3188 exit 0> worker=2 I, INFO -- : reaped #<Process::Status: pid 3191 exit 0> worker=3 I, INFO -- : worker=0 ready I, INFO -- : worker=3 ready I, INFO -- : worker=1 ready I, INFO -- : worker=2 ready Unicorn.rb root = "/home/[user]/apps/[site]/current" working_directory root pid "#{root}/tmp/pids/unicorn.pid" stderr_path "#{root}/log/unicorn.log" stdout_path "#{root}/log/unicorn.log" listen "/tmp/unicorn.[site].sock", :backlog => 2048 worker_processes 4 preload_app true timeout 30 before_fork do |server, worker| defined?(ActiveRecord::Base) and ActiveRecord::Base.connection.disconnect! end after_fork do |server, worker| defined?(ActiveRecord::Base) and ActiveRecord::Base.establish_connection end Any help appreciated - I can pull more config files if required.

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  • How to create a Word document from a Silverlight 4 application

    - by George Durzi
    I'm looking for some options to programmatically create a Word document from within a Silverlight 4 application. I found two approaches which seemed promising at first but don't look like they will work. OpenXML SDK The OpenXML SDK isn't available for Silverlight at this time. Word Automation via COM Interop dynamic wordApplication = AutomationFactory.CreateObject("Word.Application"); Apparently this requires that the Silverlight 4 application be granted permission to run with elevated privileges, which is only available for out-of-browser applications (which ours isn't) My other thought is to hand off the request to a back-end service which doesn't have these limitations. Wanted to check for any ideas before going down that path. Thank you!

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  • Set username credential for a new channel without creating a new factory

    - by Ramon
    I have a backend service and front-end services. They communicate via the trusted subsystem pattern. I want to transfer a username from the frontend to the backend and do this via username credentials as found here: http://msdn.microsoft.com/en-us/library/ms730288.aspx This does not work in our scenerio where the front-end builds a backend service channel factory via: channelFactory = new ChannelFactory<IBackEndService>(.....); Creating a new channel is done via die channel factory. I can only set the credentials one time after that I get an exception that the username object is read-only. channelFactory.Credentials.Username.Username = "myCoolFrontendUser"; var channel = channelFactory.CreateChannel(); Is there a way to create the channel factory only one time as this is expensive to create and then specify username credential when creating a channel?

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  • Fastest gap sequence for shell sort ?

    - by Tony
    According to Marcin Ciura's Optimal (best known) sequence of increments for shell sort algorithm. The best sequence for shellsort is 1, 4, 10, 23, 57, 132, 301, 701... But how can I generate such a sequence ? In Marcin Ciura's paper he said : Both Knuth’s and Hibbard’s sequences are relatively bad, because they are defined by simple linear recurrences but most algorithm books I searched , they all tend to use Knuth’s sequence : k = 3k + 1 ; because it's easy to generate , what's your way of generating shellsort sequence ?

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  • Building a directory tree from a list of file paths

    - by Abignale
    I am looking for a time efficient method to parse a list of files into a tree. There can be hundreds of millions of file paths. The brute force solution would be to split each path on occurrence of a directory separator, and traverse the tree adding in directory and file entries by doing string comparisons but this would be exceptionally slow. The input data is usually sorted alphabetically, so the list would be something like: C:\Users\Aaron\AppData\Amarok\Afile C:\Users\Aaron\AppData\Amarok\Afile2 C:\Users\Aaron\AppData\Amarok\Afile3 C:\Users\Aaron\AppData\Blender\alibrary.dll C:\Users\Aaron\AppData\Blender\and_so_on.txt From this ordering my natural reaction is to partition the directory listings into groups... somehow... before doing the slow string comparisons. I'm really not sure. I would appreciate any ideas. Edit: It would be better if this tree were lazy loaded from the top down if possible.

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  • Things you can draw with HTML tables

    - by Coronatus
    So I was watching a talk by Google's Marissa Mayer about speeding up Google's pages. They found that a shopping cart icon increased load time by 2%, and users then searched 2% less. They managed to replace the icon with an HTML table. Here is my attempt at drawing a shopping cart: (live example page) <html> <head> <style> table {border-collapse: collapse;} th, td {width: 8px; height: 8px;} th {background-color: blue;} td {background-color: white;} </style> </head> <body> <table> <!-- this row is just to see alignment --> <tr> <td></td><td></td><td></td><td></td><td></td> <td></td><td></td><td></td><td></td><td></td> <td></td><td></td><td></td><td></td><td></td> <td></td><td></td><td></td><td></td><td></td> </tr> <!-- handle --> <tr> <td colspan="14"></td> <th colspan="3"></th> <td colspan="3"></td> </tr> <tr> <td colspan="13"></td> <th colspan="2"></th> <td colspan="1"></td> <th colspan="2"></th> <td colspan="2"></td> </tr> <tr> <td colspan="13"></td> <th colspan="2"></th> <td colspan="1"></td> <th colspan="2"></th> <td colspan="2"></td> </tr> <tr> <td colspan="14"></td> <th colspan="3"></th> <td colspan="3"></td> </tr> <!-- main body --> <tr> <td colspan="5"></td> <th colspan="13"></th> <td colspan="2"></td> </tr> <tr> <td colspan="5"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="2"></td> </tr> <tr> <td colspan="5"></td> <th colspan="1"></th> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <th colspan="1"></th> <td colspan="3"></td> </tr> <tr> <td colspan="5"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="2"></td> </tr> <tr> <td colspan="5"></td> <th colspan="1"></th> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <th colspan="1"></th> <td colspan="3"></td> </tr> <tr> <td colspan="5"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="2"></td> </tr> <tr> <td colspan="5"></td> <th colspan="1"></th> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <th colspan="1"></th> <td colspan="3"></td> </tr> <tr> <td colspan="5"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="2"></td> </tr> <tr> <td colspan="5"></td> <th colspan="1"></th> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <td colspan="1"></td> <th colspan="1"></th> <th colspan="1"></th> <td colspan="3"></td> </tr> <tr> <td colspan="5"></td> <th colspan="13"></th> <td colspan="2"></td> </tr> <!-- wheels --> <tr> <td colspan="7"></td> <th colspan="2"></th> <td colspan="4"></td> <th colspan="2"></th> <td colspan="5"></td> </tr> <tr> <td colspan="6"></td> <th colspan="4"></th> <td colspan="2"></td> <th colspan="4"></th> <td colspan="4"></td> </tr> <tr> <td colspan="7"></td> <th colspan="2"></th> <td colspan="4"></td> <th colspan="2"></th> <td colspan="5"></td> </tr> </table> </body> </html> What can you draw in tables?! Impress us.

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  • Problem with WPF perfomance.

    - by Polaris
    I have form which has many tabs. Every tab has many controls textboxes, comboboxes, datagrids and e .t.c. I bind form to one data source in such way this.DataContext=MyClassInstance But with this way my form opening very slow. about one minute. When I comment above code, form opens very quickly. All My controls I bound to the class properties in XAML. Please tell me the way to bind every tab when it's activated, or bind controls in background thread or any other idea which can help me to speed up my form. Thanks in advance.

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  • CUDA: Memory copy to GPU 1 is slower in multi-GPU

    - by zenna
    My company has a setup of two GTX 295, so a total of 4 GPUs in a server, and we have several servers. We GPU 1 specifically was slow, in comparison to GPU 0, 2 and 3 so I wrote a little speed test to help find the cause of the problem. //#include <stdio.h> //#include <stdlib.h> //#include <cuda_runtime.h> #include <iostream> #include <fstream> #include <sstream> #include <string> #include <cutil.h> __global__ void test_kernel(float *d_data) { int tid = blockDim.x*blockIdx.x + threadIdx.x; for (int i=0;i<10000;++i) { d_data[tid] = float(i*2.2); d_data[tid] += 3.3; } } int main(int argc, char* argv[]) { int deviceCount; cudaGetDeviceCount(&deviceCount); int device = 0; //SELECT GPU HERE cudaSetDevice(device); cudaEvent_t start, stop; unsigned int num_vals = 200000000; float *h_data = new float[num_vals]; for (int i=0;i<num_vals;++i) { h_data[i] = float(i); } float *d_data = NULL; float malloc_timer; cudaEventCreate(&start); cudaEventCreate(&stop); cudaEventRecord( start, 0 ); cudaMemcpy(d_data, h_data, sizeof(float)*num_vals,cudaMemcpyHostToDevice); cudaMalloc((void**)&d_data, sizeof(float)*num_vals); cudaEventRecord( stop, 0 ); cudaEventSynchronize( stop ); cudaEventElapsedTime( &malloc_timer, start, stop ); cudaEventDestroy( start ); cudaEventDestroy( stop ); float mem_timer; cudaEventCreate(&start); cudaEventCreate(&stop); cudaEventRecord( start, 0 ); cudaMemcpy(d_data, h_data, sizeof(float)*num_vals,cudaMemcpyHostToDevice); cudaEventRecord( stop, 0 ); cudaEventSynchronize( stop ); cudaEventElapsedTime( &mem_timer, start, stop ); cudaEventDestroy( start ); cudaEventDestroy( stop ); float kernel_timer; cudaEventCreate(&start); cudaEventCreate(&stop); cudaEventRecord( start, 0 ); test_kernel<<<1000,256>>>(d_data); cudaEventRecord( stop, 0 ); cudaEventSynchronize( stop ); cudaEventElapsedTime( &kernel_timer, start, stop ); cudaEventDestroy( start ); cudaEventDestroy( stop ); printf("cudaMalloc took %f ms\n",malloc_timer); printf("Copy to the GPU took %f ms\n",mem_timer); printf("Test Kernel took %f ms\n",kernel_timer); cudaMemcpy(h_data,d_data, sizeof(float)*num_vals,cudaMemcpyDeviceToHost); delete[] h_data; return 0; } The results are GPU0 cudaMalloc took 0.908640 ms Copy to the GPU took 296.058777 ms Test Kernel took 326.721283 ms GPU1 cudaMalloc took 0.913568 ms Copy to the GPU took[b] 663.182251 ms[/b] Test Kernel took 326.710785 ms GPU2 cudaMalloc took 0.925600 ms Copy to the GPU took 296.915039 ms Test Kernel took 327.127930 ms GPU3 cudaMalloc took 0.920416 ms Copy to the GPU took 296.968384 ms Test Kernel took 327.038696 ms As you can see, the cudaMemcpy to the GPU is well double the amount of time for GPU1. This is consistent between all our servers, it is always GPU1 that is slow. Any ideas why this may be? All servers are running windows XP.

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  • How to optimize simple linked server select query?

    - by tomaszs
    Hello, I have a table called Table with columns: ID (int, primary key, clustered, unique index) TEXT (varchar 15) on a MSSQL linked server called LS. Linked server is on the same server computer. And: When I call: SELECT ID, TEXT FROM OPENQUERY(LS, 'SELECT ID, TEXT FROM Table') It takes 400 ms. When I call: SELECT ID, TEXT FROM LS.dbo.Table It takes 200 ms And when I call the query directly while being at LS server: SELECT ID, TEXT FROM dbo.Table It takes 100 ms. In many places i've read that OPENQUERY is faster, but in this simple case it does not seem to work. What can I do to make this query faster when I call it from another server, not LS directly?

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