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• Visual Studio 2008 awful performance

  - by Nima

  Hi, I have ported a piece of C++ code, that works out of core, from Linux(Ubuntu) to Windows(Vista) and I realized that it works about 50times slower on VS2008! I removed all the out of core parts and now I just have a piece of code that has nothing to do with the hard disk. I set compiler parameters to O2 in Project Properties but still get about 10times slower than g++ in linux! Does anybody have an idea why it is this much slower under VS? I really appreciate any kind of hint! Thanks,

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• What technologies are appropriate for a human workflow system?

  - by CCw

  I'm researching various workflow architectures and it is overwhelming. The workflow system I am creating will be almost completely human-driven. Very little, if any, asynchronous activity will be taking place. One possibility is to simply use a RDBMS and have a task table, from which stored procedures would be used to enforce synchronous access to each task. This seems very simple, but I'm having a hard time coming up with reasons why I might need to involve a heavier solution. If my system has ~500 concurrent users, and there is very little in the way of automated or asynchronous tasks, should I even consider the various workflow patterns/packages out there like Mule, BPEL/SOA, Spring Work Flow, etc?

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• How are a session identifiers generated?

  - by Asaf R

  Most web applications depend on some kind of session with the user (for instance, to retain login status). The session id is kept as a cookie in the user's browser and sent with every request. To make it hard to guess the next user's session these session-ids need to be sparse and somewhat random. The also have to be unique. The question is - how to efficiently generate session ids that are sparse and unique? This question has a good answer for unique random numbers, but it seems not scalable for a large range of numbers, simply because the array will end up taking a lot of memory.

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• Java data structure to use with Hibernate to store unknown number of parameters?

  - by Lunikon

  Following problem: I want to render a news stream of short messages based on localized texts. In various places of these messages I have to insert parameters to "customize" them. I guess you know what I mean ;) My question probably falls into the "Which is the best style to do it?" category: How would you store these parameters (they may be Strings and Numbers that need to be formatted according to Locale) in the database? I'm using Hibernate to do the ORM and I can think of the following solutions: build a combined String and save it as such (ugly and hard to maintain I think) do some kind of fancy normalization and and make every parameter a single row on the database (clean I guess, but a performance nightmare) Put the params into an Array, Map or other Java data structure and save it in binary format (probably causes a lot of overhead size-wise) I tend towards option #3 but I'm afraid that it might be to costly in terms of size in the database. What do you think?

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• Storing Instances of Classes in Flex Shared Objects

  - by babyangel86

  Is it possible to store instances of a class in a cookie or in shared objects. Basically in my application I have an object "Diagram" that the user can create. If they hit save, I want to store the current instance as a cookie and allows them to reload it later. Alternatively, I could see about getting them to store the saved version on the hard disk. But even then, all I want to save and retreive is my actionscript object. Is this possible? I've tried storing the object to SharedObject.data.diag, but when I try to retrieve the object from the cookie doing SharedObject.data.diag as Diag returns null.

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• Why are there so many floats in the Android API?

  - by Brian

  The default floating point type in Java is the double. If you hard code a constant like 2.5 into your program, Java makes it a double automatically. When you do an operation on floats or ints that could potentially benefit from more precision, the type is 'promoted' to a double. But in the Android API, everything seems to be a float from sound volumes to rectangle coordinates. There's a structure called RectF used in most drawing; the F is for float. It's really a pain for programmers who are casting promoted doubles back to (float) pretty often. Don't we all agree that Java code is messy and verbose enough as it is? Usually math coprocessors and accelerators prefer double in Java because it corresponds to one of the internal types. Is there something about Android's Dalvik VM that prefers floats for some reason? Or are all the floats just a result of perversion in API design?

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• How to make a daemon which will accept arbitrary commands

  - by Jono

  Right now the program can be launched in a linux terminal. Once running you can type various commands and the program will do stuff on the machine until the user quits. I would like to make the program into a service that the user runs and it goes to the background. Then the user should be able to make commands to it. Like start and stop, and write something to a log and whatever else my program does. Note that I need to send it arbitrary commands that my program will handle, not just start and stop. Maybe this means it is no longer a daemon - I dont know. How do I do this? Also, if this is not too hard, I would like to be able to run multiple instances of this service. But it is not essential.

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• MongoDB or CouchDB - fit for production?

  - by Alan

  I was wondering if anyone can tell me if MongoDB or CouchDB are ready for a production environment. I'm now looking at these storage solutions (I'm favouring MongoDB at the moment), however these projects are quite young and so I foresee that I'm going to have to work quite hard to convince my manager that we should adopt this new technology. What I'd like to know is: 1) Who is using MongoDB or CouchDB today in a production environment? 2) How are you using MongoDB/CouchDB? 3) What problems (if any) did you come across when you adopted this new storage mechanism (and how did you overcome them)? 4) How did you deal with any migration issues that you had to deal with? 5) Do you have any good/bad experiences with either of these solutions that you'd like to share? Thanks.

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• What is Ruby's double-colon (::) all about?

  - by Meltemi

  I'd probably be able to answer this for myself if "::" wasn't so hard to Google. Didn't see anything on SO so thought I'd try my luck. What is this double-colon :: all about? I see it everywhere in Rails: class User < ActiveRecord::Base or… ActionController::Routing::Routes.draw do |map| I found a definition from this guy: The :: is a unary operator that allows: constants, instance methods and class methods defined within a class or module, to be accessed from anywhere outside the class or module. but that just leads to more questions. What good is scope (private, protected) if you can just use :: to expose anything?

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• django url tag performance

  - by zxygentoo

  I was trying to integrate django-voting into my project following the RedditStyleVoting instruction. In my urls.py, i did something like this: url(r'^sections/(?P<object_id>\d+)/(?P<direction>up|down|clear)vote/?$', vote_on_object, dict( model=Section, template_object_name='section', template_name='script/section_confirm_vote.html', allow_xmlhttprequest=True ), name="section_vote", then, in my template: {% vote_by_user user on section as vote %} {% score_for_object section as score %} {% vote_by_user user on section as vote %} {% score_for_object section as score %} {{ score.score|default:0 }} It takes over 1.3s to load the page, but by hard coding it like this: {% vote_by_user user on section as vote %} {% score_for_object section as score %} {{ score.score|default:0 }} I got 50ms. Just avoid the url tag resolving stuff I got a 20+ times performance improvement. Is there something I did wrong? If not, then what's the best practice here, should we do things the right way or the fast way?

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• MPI Large Data all to all transfer

  - by csslayer

  My application of MPI has some process that generate some large data. Say we have N+1 process (one for master control, others are workers), each of worker processes generate large data, which is now simply write to normal file, named file1, file2, ..., fileN. The size of each file may be quite different. Now I need to send all fileM to rank M process to do the next job, So it's just like all to all data transfer. My problem is how should I use MPI API to send these files efficiently? I used to use windows share folder to transfer these before, but I think it's not a good idea. I have think about MPI_file and MPI_All_to_all, but these functions seems not to be so suitable for my case. Simple MPI_Send and MPI_Recv seems hard to be used because every process need to transfer large data, and I don't want to use distributed file system for now.

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• How MVC (ASP.NET MVC) band 3-tier architecture can work together?

  - by Martin

  I am writing a design document and people on my team are willing to do the move from ASP.NET WebForm to ASP.NET MVC. This is great, but I have a hard time to understand how MVC workswith in a 3-tier (Data Layer, Business Layer and Presentation Layer) architecture. Can we say that the Model, View and Controller are part of the Presentation Layer? Is the Model part of the Business Layer? In brief, how MVC and 3-tier architecture can work together? Thanks for the help!

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• How to pass PHP array parameter to Javascript Function???

  - by Son of Man

  index.php <script type="text/javascript" src="javascript.js"> </script> <?php $movies = array("Bloodsport", "Kickboxer", "Cyborg", "Timecop", "Universal Soldier", "In Hell", "The Quest"); ?> <input type="submit" value="Test Javascript" onclick="showMovies(<?php echo $movies; ?>);" /> javascript.js function showMovies(movies) { alert(movies.length); return false; } I am new to programming so Im having hard time fixing this one which is obviously simple for you guys. When I hit the submit button it says the that the array size is 1 which I think should be 7. How could this be??? Pls tell me what to do... Thanks in Advance...

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• How to access Session values from layers beneath the web application layer.

  - by Matthew Vines

  We have many instances in our application where we would like to be able to access things like the currently logged in user id in our business domain and data access layer. On log we push this information to the session, so all of our front end code has access to it fairly easily of course. However, we are having huge issues getting at the data in lower layers of our application. We just can't seem to find a way to store a value in the business domain that has global scope just for the user (static classes and properties are of course shared by the application domain, which means all users in the session share just one copy of the object). We have considered passing in the session to our business classes, but then our domain is very tightly coupled to our web application. We want to keep the prospect of a winforms version of the application possible going forward. I find it hard to believe we are the first people to have this sort of issue. How are you handling this problem in your applications?

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• Doctrine SQL Server uniqueidentifier isn't cast as char or nvarchar when retrieved from the database

  - by Tres

  When I retrieve a record from the database which has a column of type "uniqueidentifier", Doctrine fills it with "null" rather than the unique id from the database. Some research and testing has brought this down to a PDO/dblib driver issue. When directly querying via PDO, null is returned in place of the unique id. For reference, http://trac.doctrine-project.org/ticket/1096, has a bit on this, however, it was updated 11 months ago with no comment for resolution. A way around this, as mentioned at http://bugs.php.net/bug.php?id=24752&edit=1, is to cast the column as a char. However, it doesn't seem Doctrine exposes the native field type outside of generating models which makes it a bit hard to detect uniqueidentifier types and cast them internally when building the sql query. Has anyone found a workaround for this?

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• What's wrong with Xsendfile in Yii

  - by petwho

  I have been trying Xsendfile() method in Yii over 20 times and none of them gave me a result. Here is my code: $file_path = "D:/xampp/htdocs/mywebapp/protected/modules/file_upload".DS. 'views'.DS.'upload'.DS.testfile.".pdf"; Yii::app()->request->xSendFile($file_path ,array( 'saveName'=>$result['gen_name'] .".pdf", 'mimeType'=>'application/pdf', 'terminate'=>true, )); And despite changing the location of testfile.pdf everywhere on my hard drive, none of them works. I am nearly exhausted with this method. Anyone could help me from being headache? I am using windows and xampp 1.7.4. Thanks so much!

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• Are there some good and modern alternatives to Javadoc?

  - by ivan_ivanovich_ivanoff

  Let's face it: You don't need to be a designer to see that default Javadoc looks ugly. There are some resources on the web which offer re-styled Javadoc. But the default behaviour represents the product and should be as reasonably good-looking. Another problem is the fact that the usability of Javadoc is not up-to-date compared to other similar resources. Especially huge projects are hard to navigate using Firefox's quick search. Practical question: Are there any standalone (desktop) applications which are able to browse existing Javadoc in a more usable way than a browser would? I'm thinking about something like Mono's documentation browser. Theoretical question: Does anyone know, if there some plans to evolve Javadoc, in a somehow-standardized way? EDIT: A useful link to Sun' wiki on this topic.

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• Collectable<T> serialization, Root Namespaces on T in .xml files.

  - by Stacey

  I have a Repository Class with the following method... public T Single<T>(Predicate<T> expression) { using (var list = (Models.Collectable<T>)System.Xml.Serializer.Deserialize(typeof(Models.Collectable<T>), FileName)) { return list.Find(expression); } } Where Collectable is defined.. [Serializable] public class Collectable<T> : List<T>, IDisposable { public Collectable() { } public void Dispose() { } } And an Item that uses it is defined.. [Serializable] [System.Xml.Serialization.XmlRoot("Titles")] public partial class Titles : Collectable<Title> { } The problem is when I call the method, it expects "Collectable" to be the XmlRoot, but the XmlRoot is "Titles" (all of object Title). I have several classes that are collected in .xml files like this, but it seems pointless to rewrite the basic methods for loading each up when the generic accessors do it - but how can I enforce the proper root name for each file without hard coding methods for each one? The [System.Xml.Serialization.XmlRoot] seems to be ignored.

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• what does < < mean in the shell

  - by stib

  when looping recursively through folders with files containing spaces the shell script I use is of this form, copied from the internet: while IFS= read -r -d $'\0' file; do dosomethingwith "$file" # do something with each file done < <(find /bar -name *foo* -print0) I think I understand he IFS bit, but I don't understand what the < < characters mean. Obviously there's some sort of piping going on here.. It's very hard to google "< <", you see. TIA -stib

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• Django - Check users messages every request

  - by Hanpan

  Hi, I want to check if a user has any new messages each time they load the page. Up until now, I have been doing this inside of my views but it's getting fairly hard to maintain since I have a fair number of views now. I assume this is the kind of thing middleware is good for, a check that will happen every single page load. What I need it to do is so: Check if the user is logged in If they are, check if they have any messages Store the result so I can reference the information in my templates Has anyone ever had to write any middleware like this? I've never used middleware before so any help would be greatly appreciated.

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• Why does it not allowed to use try-catch statement without {} ?

  - by alex

  Why can't I use code like this ? 1 int i = 0; try i = int.Parse("qwerty"); catch throw; 2 try i = int.Parse("qwerty"); catch; finally Log.Write("error"); And should write like this 1 int i = 0; try { i = int.Parse("qwerty"); } catch { throw; } 2 try { i = int.Parse("qwerty");} catch {} finally {Log.Write("error");} PS: I can use if-else statement without {}. Why should I use them with try-catch(-finally) statement ? Is there any meaningful reason ? Is it only because that some people think that code is hard to read ? Several months ago I asked that question on russian programming forum but I got no satisfactory answer ...

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• Rolling back or re-creating the master branch in git?

  - by Matthew Savage

  I have a git repo which has a few branches - there's the master branch, which is our stable working version, and then there is a development/staging branch which we're doing new work in. Unfortunately it would appear that without thinking I was a bit overzealous with rebasing and have pulled all of the staging code into Master over a period of time (about 80 commits... yes, I know, stupid, clumsy, poor code-man-ship etc....). Due to this it makes it very hard for me to do minor fixes on the current version of our app (a rails application) and push out the changes without also pushing out the 'staged' new features which we don't yet want to release. I am wondering if it is possible to do the following: Determine the last 'trunk' commit Take all commits from that point onward and move them into a separate branch, more or less rolling back the changes Start using the branches like they were made for. Unfortunately, though, I'm still continually learning about git, so I'm a bit confused about what to really do here. Thanks!

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• SQL Server 2008 - Get Geography From Record

  - by user336786

  Hello, I am new to using the geography types in SQL Server 2008. I have a table in my database called "Location". "Location" has the following columns and types: Location -------- City nvarchar(256) State nvarchar(256) PostalCode nvarchar(25) Latitude decimal(9, 6) Longitude decimal(9, 6) Each Location is related to a Store record in my database. I am trying to find the stores within a 10 mile radius or postal code or city/state that a user enters. To accomplish this, I know that I need to rely on geographies. At this time I have: DECLARE @startingPoint geography; SET @startingPoint=geography::STGeomFromText('POINT(-122.34900 47.65100)', 4326); That gives me the starting point from a hard-coded textual value. However, I do not know how to convert a lat/long from my Location table into a geography instance. How do I convert a lat/long in my database to a geography instance so I can continue to work on my query? Thank you!

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• Mapping enum to a table with hibernate annotation

  - by Thierry-Dimitri Roy

  I have a table DEAL and a table DEAL_TYPE. I would like to map this code: public class Deal { DealType type; } public enum DealType { BASE("Base"), EXTRA("Extra"); } The problem is that the data already exist in the database. And I'm having a hard time mapping the classes to the database. The database looks something like that: TABLE DEAL { Long id; Long typeId; } TABLE DEAL_TYPE { Long id; String text; } I know I could use a simple @OneToMany relationship from deal to deal type, but I would prefer to use an enum. Is this possible? I almost got it working by using a EnumType.ORDINAL type. But unfortunately, my IDs in my deal type table are not sequential, and do not start at 1. Any suggestions?

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• PHP reads 1.10 value as 1.1 (0 at end of variable not honored)

  - by adbox

  Hello, This is hard for me to word, but easier for me to demonstrate: I have a select option: <option <?php if($frequency[$key]=='1.10'){echo "selected";}?> value='1.10'>1 every 10 days</option> Really, $frequency[$key]=1.1; , but the above still shows up selected. I've never seen this before, and didnt know it could happen. Any ideas on how to prevent this? Working with php5. Thank you, Hudson

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