Search Results

Search found 7107 results on 285 pages for 'processing efficiency'.

Page 198/285 | < Previous Page | 194 195 196 197 198 199 200 201 202 203 204 205  | Next Page >

  • 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?

    Read the article

  • Python: Unpack arbitary length bits for database storage

    - by sberry2A
    I have a binary data format consisting of 18,000+ packed int64s, ints, shorts, bytes and chars. The data is packed to minimize it's size, so they don't always use byte sized chunks. For example, a number whose min and max value are 31, 32 respectively might be stored with a single bit where the actual value is bitvalue + min, so 0 is 31 and 1 is 32. I am looking for the most efficient way to unpack all of these for subsequent processing and database storage. Right now I am able to read any value by using either struct.unpack, or BitBuffer. I use struct.unpack for any data that starts on a bit where (bit-offset % 8 == 0 and data-length % 8 == 0) and I use BitBuffer for anything else. I know the offset and size of every packed piece of data, so what is going to be the fasted way to completely unpack them? Many thanks.

    Read the article

  • Using exponential smoothing with NaN values

    - by Eric
    I have a sample of some kind that can create somewhat noisy output. The sample is the result of some image processing from a camera, which indicates the heading of a blob of a certain color. It is an angle from around -45° to +45°, or a NaN, which means that the blob is not actually in view. In order to combat the noisy data, I felt that exponential smoothing would do the trick. However, I'm not sure how to handle the NaN values. On the one hand, involving them in the math would result in a NaN average, which would then prevent any meaningful results. On the other hand, ignoring NaN values completely would mean that a "no-detection" scenario would never be reported. And just to complicate things, the data is also noisy in that it can get false NaN value, which ideally would be smoothed somehow to prevent random noise. Any ideas about how I could implement such an exponential smoother?

    Read the article

  • What does MySqlDataAdapter.Fill return when the results are empty?

    - by Brian
    I have a 'worker' function that will be processing any and all sql queries in my program. I will need to execute queries that return result sets and ones that just execute stored procedures without any results. Is this possible with MySqlDataAdapter.Fill or do I need to use the MySqlCommand.ExecuteNonQuery() method? Here is my 'worker' function for reference: private DataSet RunQuery(string SQL) { MySqlConnection connection; MySqlCommand command; MySqlDataAdapter adapter; DataSet dataset = new DataSet(); lock(locker) { connection = new MySqlConnection(MyConString); command = new MySqlCommand(); command = connection.CreateCommand(); command.CommandText = SQL; adapter = new MySqlDataAdapter(); adapter.Fill(dataset); } return dataset; }

    Read the article

  • Windows Platform Installer fails during Orchard Installation

    - by nullnvoid
    I'm attempting to install Orchard 1.0 on a Windows 7 box. It has only just been released. I downloaded and installed the Windows Platform Installer and attempted to install Orchard. The error message is just that the application has stopped working and asks if I want to debug or close the application. The event log contains a single error: "The event logging service encountered an error while processing an incoming event published from Microsoft-Windows-Security-Auditing." I tried installing MVC3 and it worked without issue. Has anyone experienced a similar problem?

    Read the article

  • Perl: Asynchronous file monitoring

    - by Hussain
    I am wondering if it is possible, and if so how, one could create a perl script that constantly monitors a file/db, and then call a subroutine to perform text processing if the file is changed. I'm pretty sure this would be possible using sockets, but this needs to be used for a webchat application on a site running on a shared host, and I'm not so sure sockets would be allowed on it. The basic idea is: -create a listener for a chat file/database -when the file is updated with a new message, call a subroutine -the called subroutine will send the new message back to the browser to be displayed Thanks in advance.

    Read the article

  • How to avoid exceptions catches copy-paste in .NET

    - by Budda
    Working with .NET framework I have a service with a set of methods that can generates several types of exceptions: MyException2, MyExc1, Exception... To provide proper work for all methods, each of them contains following sections: void Method1(...) { try { ... required functionality } catch(MyException2 exc) { ... process exception of MyException2 type } catch(MyExc1 exc) { ... process exception of MyExc1 type } catch(Exception exc) { ... process exception of Exception type } ... process and return result if necessary } It is very boring to have exactly same stuff in EACH service method with exactly same exceptions processing functionality... Is there any possibility to "group" these catch-sections and use only one line (something similar to C++ macros)? Probably something new in .NET 4.0 is related to this topic? Thanks. P.S. Any thoughts are welcome.

    Read the article

  • Passing a WHERE clause for a Linq-to-Sql query as a parameter

    - by Mantorok
    Hi all This is probably pushing the boundaries of Linq-to-Sql a bit but given how versatile it has been so far I thought I'd ask. I have 3 queries that are selecting identical information and only differ in the where clause, now I know I can pass a delegate in but this only allows me to filter the results already returned, but I want to build up the query via parameter to ensure efficiency. Here is the query: from row in DataContext.PublishedEvents join link in DataContext.PublishedEvent_EventDateTimes on row.guid equals link.container join time in DataContext.EventDateTimes on link.item equals time.guid where row.ApprovalStatus == "Approved" && row.EventType == "Event" && time.StartDate <= DateTime.Now.Date.AddDays(1) && (!time.EndDate.HasValue || time.EndDate.Value >= DateTime.Now.Date.AddDays(1)) orderby time.StartDate select new EventDetails { Title = row.EventName, Description = TrimDescription(row.Description) }; The code I want to apply via a parameter would be: time.StartDate <= DateTime.Now.Date.AddDays(1) && (!time.EndDate.HasValue || time.EndDate.Value >= DateTime.Now.Date.AddDays(1)) Is this possible? I don't think it is but thought I'd check out first. Thanks

    Read the article

  • Error on installing xdebug via MacPorts

    - by Nareille
    I wanted to install xdebug via MacPorts, trying the terminal command sudo port install php5-xdebug But after a while the installation breaks, giving me an error ---> Configuring php5 Error: org.macports.configure for port php5 returned: configure failure: command execution failed Error: Failed to install php5 Please see the log file for port php5 for details: /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_lang_php5/php5/main.log Error: The following dependencies were not installed: php5 To report a bug, follow the instructions in the guide: http://guide.macports.org/#project.tickets Error: Processing of port php5-xdebug failed I checked with phpinfo(), that my version of php is 5.3.1 What am I missing? Thanks! (I'm on a Mac OSX Lion, running Apache with XAMPP, I installed PEAR and PHPUnit successfully)

    Read the article

  • How to detect column conflicts with Hibernate?

    - by Slim
    So let's say I have an ArrayList full of Products that need to be committed to the database via Hibernate. There are already a large number of Products in the database. Each product has an ID. Note this is NOT the PK that is autogenerated by Hibernate. My questions is: what is the best way to detect conflicts with this ID? I am looking for a relatively efficient method of obtaining, from the the database, a List of Products that share an ID with any of the Products in my ArrayList. This is all in a single table called Products and the ID attribute is in column ProductID. The way I've done it is grabbing a list of all Products in the database, and compared each one with each entry in my ArrayList - but that is seriously inefficient and I don't think it would work well with a larger database. How should it be done? Thanks. I say "relatively" efficient because efficiency is not the primary concern, but it shouldn't take noticeably long to test against a table of ~1000-5000 rows. Help? EDIT* I'm very new to hibernate and below is the best I've come up with. How does this look? for(long id : idList){ //idList just holds the IDs of each Product in my ArrayList Query query = session.createQuery("select product from Product product where product.id = :id"); query.setLong("id", id); for(int i = 0; i < query.list().size(); i++){ listOfConflictingProducts.add((Product) query.list().get(i)); } }

    Read the article

  • How can I loop over a query for a specific number of times that may be greater than the result?

    - by JS
    I need to loop over a query exactly 12 times to complete rows in a form but rarely will the query return 12 rows. The cfquery endRow attribute doesn't force the loop to keep going if the result is < 12. If it did that would be ideal to use something like cfloop query="myQuery" endRow="12"... The 2 options that I have now are to skip the loop and write out all 12 rows but that results in a lot of duplicate code (there are 20 columns), or do a query of queries for each row which seems like a lot of wasted processing. Thanks for any ideas.

    Read the article

  • Preprocessor "macro function" vs. function pointer - best practice?

    - by Dustin
    I recently started a small personal project (RGB value to BGR value conversion program) in C, and I realised that a function that converts from RGB to BGR can not only perform the conversion but also the inversion. Obviously that means I don't really need two functions rgb2bgr and bgr2rgb. However, does it matter whether I use a function pointer instead of a macro? For example: int rgb2bgr (const int rgb); /* * Should I do this because it allows the compiler to issue * appropriate error messages using the proper function name, * not to mention possible debugging benefits? */ int (*bgr2rgb) (const int bgr) = rgb2bgr; /* * Or should I do this since it is merely a convenience * and they're really the same function anyway? */ #define bgr2rgb(bgr) (rgb2bgr (bgr)) I'm not necessarily looking for a change in execution efficiency as it's more of a subjective question out of curiosity. I am well aware of the fact that type safety is neither lost nor gained using either method. Would the function pointer merely be a convenience or are there more practical benefits to be gained of which I am unaware?

    Read the article

  • How do I control script execution time in PHP

    - by mathew
    for example I do have 5 PHP functions on a page which execute when loading. each functions has its own processing time and some of them take more time sometimes to complete the task. hence the total loading time of the said page is slow. my question is how do I control execution time for each script and set time limit for the same. I am aware that there is an in built function in PHP called set_time_limit(); but it gives fatal error if time is beyond the maximum limit...

    Read the article

  • What is the correct method to load an XML file and re-write it as a CVS? (C# Only)

    - by codesmack
    Hello, I have a XML file that I want to load into an unknown object type. (I say unknown object type because I am not sure what direction to go) Once I have the data loaded I need to do some processing on certain elements that are now loaded into the new object. For sake of example, we can say that the xml file is full of elements named and within the car element I need to process the element. Then once this is all done I need to write the file as a CSV file. I would like to do this is the most direct way possible. (The less code the better) I am using VS 2008 C# Thank you, CodeSmack

    Read the article

  • WCF: Callback is not asynchronous

    - by Aquarius
    Hi, I'm trying to program a client server based on the callback infrastructure provided by WCF but it isn't working asynchronously. My client connects to the server calling a login method, where I save the clients callback channel by doing MyCallback callback = OperationContext.Current.GetCallbackChannel() After that the server does some processing and uses the callback object to communicate with the client. All this works, the problem resides on the fact that even though I've set the method in the OperationContract as IsOneWay=true, the server still hangs when doing the call to the client. I've tested this by launching the server for debug in the visual studio, detaching it, launching the client, calling the above mentioned login method, putting a break point in the implemented callback method of the client, and making the server send a response to the client. The server stops doing what it's supposed to do, waiting for the response of the client. Any help is appreciated.

    Read the article

  • How to return the full file path in a C# / ASP.NET web application?

    - by salvationishere
    This should be really simple, but I have tried many solutions posted on the internet so I thought I'd give this a try here. I have a VS 2008 web application that I need to capture the full file path (directories and file name) from the selected file. So user selects a file and then clicks on one of the buttons which transfers control to my code for processing. So how do I get the file path? I can get the file name, but not the path. Thanks!

    Read the article

  • How to convert submitted form array to this array on php?

    - by drfanai
    Lets suppose i have the following array submitted by a html form: array( 'firstname' => array('Sara','Jim'), 'lastname' => array('Gibson','Jobs') ); What i wanna achieve is the following array: array( array( 'firstname' => 'sara', 'lastname' => 'Gibson' ), array( 'firstname' => 'Jim', 'lastname' => 'Jim' ) ); I need a function to automatically sort the array not manually by entering data but automatically processing array data.

    Read the article

  • Is it possible to generate plain-old XML using Haml?

    - by lsdr
    I've been working on a piece of software where I need to generate a custom XML file to send back to a client application. The current solutions on Ruby/Rails world for generating XML files are slow, at best. Using builder or event Nokogiri, while have a nice syntax and are maintainable solutions, they consume too much time and processing. I definetly could go to ERB, which provides a good speed at the expense of building the whole XML by hand. HAML is a great tool, have a nice and straight-forward syntax and is fairly fast. But I'm struggling to build pure XML files using it. Which makes me wonder, is it possible at all? Does any one have some pointers to some code or docs showing how to do this, build a full, valid XML from HAML?

    Read the article

  • Matlab: How to find the right-most point of a white line within the imrect?

    - by mchlfchr
    i've got a question regarding the imrect() function, which is part of the image processing toolbox in MatLab. I'd like to find a starting point within an image. I use the imrect function for setting a region to limit and specify the lookup area, but I can't get the point where the ROI mask is getting back mapped to the original size of the image. As you can see on the image there is a specified rectangle (cyan-colored), which I want to inspect for the white line, especially the nearest point to the right edge of the rectangle. I experimentated with only looking up on the last column of the rectangle, but as I mentioned before, the re-mapping onto the global image coordinates failed. So in this example, the white point I'd like to get would be around (98,302) The original (x,y) coordinates are relevant, so a cropping of the image to the rectangle is not acceptable. So, do you have any ideas? Thanks for any helping comments. Kind regards,

    Read the article

  • Asp.Net Impersonation Fails On First Try But Succeeds on Second

    - by KevDog
    We are using RDLC's in a Asp.net web application. For reasons beyond our understanding, the first call to the database server fails with the following error: An error has occurred during report processing. Cannot open database "TryParkingIt2" requested by the login. The login failed. Login failed for user 'EXTRANET\OurServerNameHere$'. Run the report again, it works. Huh? Update Click the button the first time, it fails. Click the button again, it works. The account being impersonated is a domain account.

    Read the article

  • HOw to Extract image pixels and perform computation on it

    - by gavishna
    What i want to do is extract the pixels into array A(i,j).Let A(i,j) represent the pixel in the ith row & jth colm of the image. Let B(i,j) be the transformed array containing bits such that B(i,j) = 1 if (A(i,j)/2^t) mod 2 =1, where t=0,1,2,3,4,5,6,7 = 0 otherwise Then the array B(i,j) will be mutliplied by another array say C(i,j) representing another image. Then i want to plot the result of B*C as an image. How do i take in the pixels for the above conditions for both gray and RGB color format.Also how do i solve the above problem.Any helo will be usefull because i am not an expert in image processing.

    Read the article

  • Embedded C++, any tips to avoid a local thats only used to return a value on the stack?

    - by lisarc
    I have a local that's only used for the purposes of checking the result from another function and passing it on if it meets certain criteria. Most of the time, that criteria will never be met. Is there any way I can avoid this "extra" local? I only have about 1MB of storage for my binary, and I have several thousand function calls that follow this pattern. I know it's a minor thing, but if there's a better pattern I'd love to know! SomeDataType myclass::myFunction() { SomeDataType result; // do I really need this local??? // i need to check the result and pass it on if it meets a certain condition result = doSomething(); if ( ! result ) { return result; } // do other things here ... // normal result of processing return SomeDataType(whatever); }

    Read the article

  • BASH SHELL IF ELSE run command in background

    - by bikerben
    I have used the & command before to make a script run another script in the background like so: #!/bin/bash echo "Hello World" script1.sh & script2.sh & echo "Please wait..." But lets say I have another script with an IF ELSE statment and I would like to set an ELIF statement mid flow as a background task witht the & and then carry on with processing the rest of my script knowing that while rest of the ELIF will carry running in the back ground: #!/bin/bash if cond1; then stuff sleep 10 & stuff stuff elif cond2; then something else else echo "foo" fi stuff echo "Hello World" I really hope this makes sense any help would be greatly appreciated.

    Read the article

  • HBase as a multimap

    - by Ibrahim
    Hi guys, I'm doing some large scale text processing work and I'm trying to get started with Hadoop and HBase. One of the things I need to do is build a multimap of some stuff, which I later use to look up things and get all items with a certain key (in a M/R job). Would it be OK to use HBase and insert many rows with the same key and rely on versions/timestamps to achieve a multimap-like setup or is this a bad idea? The multimap is built up in the reduce phase of a Mapreduce task by the way, or at least in the way I've formulated it on paper. Thanks! If more information is needed, I'd be happy to provide it. Not sure whether this question is clear.

    Read the article

  • ContextSwitchDeadlock Was Detected error in C#

    - by assassin
    Hi, I am running a C# application, and during run-time I get the following error: The CLR has been unable to transition from COM context 0x20e480 to COM context 0x20e5f0 for 60 seconds. The thread that owns the destination context/apartment is most likely either doing a non pumping wait or processing a very long running operation without pumping Windows messages. This situation generally has a negative performance impact and may even lead to the application becoming non responsive or memory usage accumulating continually over time. To avoid this problem, all single threaded apartment (STA) threads should use pumping wait primitives (such as CoWaitForMultipleHandles) and routinely pump messages during long running operations. Can anyone please help me out with the problem here? Thanks a lot.

    Read the article

< Previous Page | 194 195 196 197 198 199 200 201 202 203 204 205  | Next Page >