Search Results

Search found 3533 results on 142 pages for 'jms topic'.

Page 118/142 | < Previous Page | 114 115 116 117 118 119 120 121 122 123 124 125  | Next Page >

• Predefined column names in SQL Server pivot table

  - by Marcos Buarque

  Hi, the other day I opened a topic here in StackOverflow (stackoverflow.com/questions/4663698/how-can-i-display-a-consolidated-version-of-my-sql-server-table). At that time I needed help on how to show data on a pivot table. From the help I got here in the forum, my research led me to this page about dynamic SQL: www.sommarskog.se/dynamic_sql.html. And then it led me to this awesome SQL script by Itzik Ben-Gan that will create a stored procedure that outputs a pivot table exactly the way I want: sommarskog.se/pivot_sp.sp. Well, almost. I need one change in this stored procedure. Instead of having dynamic column names pulled from the @on_cols variable in the SPROC, I need the output table to hold generic column names in simple ASC order. Could be, for example, col1, col2, col3, col4 ... The dynamic column names are a problem for me. So I need them named by their index in the order they appear. I have tried all sorts of things changing this great SQL script, but it won't work. I did not paste the code from the author because it is too long, but the link above will get us there. Any help appreciated. Thank you very much

  Read the article

• how to implement a really efficient bitvector sorting in python

  - by xiao

  Hello guys! Actually this is an interesting topic from programming pearls, sorting 10 digits telephone numbers in a limited memory with an efficient algorithm. You can find the whole story here What I am interested in is just how fast the implementation could be in python. I have done a naive implementation with the module bitvector. The code is as following: from BitVector import BitVector import timeit import random import time import sys def sort(input_li): return sorted(input_li) def vec_sort(input_li): bv = BitVector( size = len(input_li) ) for i in input_li: bv[i] = 1 res_li = [] for i in range(len(bv)): if bv[i]: res_li.append(i) return res_li if __name__ == "__main__": test_data = range(int(sys.argv[1])) print 'test_data size is:', sys.argv[1] random.shuffle(test_data) start = time.time() sort(test_data) elapsed = (time.time() - start) print "sort function takes " + str(elapsed) start = time.time() vec_sort(test_data) elapsed = (time.time() - start) print "sort function takes " + str(elapsed) start = time.time() vec_sort(test_data) elapsed = (time.time() - start) print "vec_sort function takes " + str(elapsed) I have tested from array size 100 to 10,000,000 in my macbook(2GHz Intel Core 2 Duo 2GB SDRAM), the result is as following: test_data size is: 1000 sort function takes 0.000274896621704 vec_sort function takes 0.00383687019348 test_data size is: 10000 sort function takes 0.00380706787109 vec_sort function takes 0.0371489524841 test_data size is: 100000 sort function takes 0.0520560741425 vec_sort function takes 0.374383926392 test_data size is: 1000000 sort function takes 0.867373943329 vec_sort function takes 3.80475401878 test_data size is: 10000000 sort function takes 12.9204008579 vec_sort function takes 38.8053860664 What disappoints me is that even when the test_data size is 100,000,000, the sort function is still faster than vec_sort. Is there any way to accelerate the vec_sort function?

  Read the article

• Properties vs. Fields: Need help grasping the uses of Properties over Fields.

  - by pghtech

  First off, I have read through a list of postings on this topic and I don't feel I have grasped properties because of what I had come to understand about encapsulation and field modifiers (private, public..ect). One of the main aspects of C# that I have come to learn is the importance of data protection within your code by the use of encapsulation. I 'thought' I understood that to be because of the ability of the use of the modifiers (private, public, internal, protected). However, after learning about properties I am sort of torn in understanding not only properties uses, but the overall importance/ability of data protection (what I understood as encapsulation) within C#. To be more specific, everything I have read when I got to properties in C# is that you should try to use them in place of fields when you can because of: 1) they allow you to change the data type when you can't when directly accessing the field directly. 2) they add a level of protection to data access However, from what I 'thought' I had come to know about the use of field modifiers did #2, it seemed to me that properties just generated additional code unless you had some reason to change the type (#1) - because you are (more or less) creating hidden methods to access fields as opposed to directly. Then there is the whole modifiers being able to be added to Properties which further complicates my understanding for the need of properties to access data. I have read a number of chapters from different writers on "properties" and none have really explained a good understanding of properties vs. fields vs. encapsulation (and good programming methods). Can someone explain: 1) why I would want to use properties instead of fields (especially when it appears I am just adding additional code 2) any tips on recognizing the use of properties and not seeing them as simply methods (with the exception of the get;set being apparent) when tracing other peoples code? 3) Any general rules of thumb when it comes to good programming methods in relation to when to use what? Thanks and sorry for the long post - I didn't want to just ask a question that has been asked 100x without explaining why I am asking it again.

  Read the article

• Foosball result prediction

  - by Wolf

  In our office, we regularly enjoy some rounds of foosball / table football after work. I have put together a small java program that generates random 2vs2 lineups from the available players and stores the match results in a database afterwards. The current prediction of the outcome uses a simple average of all previous match results from the 4 involved players. This gives a very rough estimation, but I'd like to replace it with something more sophisticated, taking into account things like: players may be good playing as attacker but bad as defender (or vice versa) players do well against a specific opponent / bad against others some teams work well together, others don't skills change over time What would be the best algorithm to predict the game outcome as accurately as possible? Someone suggested using a neural network for this, which sounds quite interesting... but I do not have enough knowledge on the topic to say if that could work, and I also suspect it might take too many games to be reasonably trained. EDIT: Had to take a longer break from this due to some project deadlines. To make the question more specific: Given the following mysql table containing all matches played so far: table match_result match_id int pk match_start datetime duration int (match length in seconds) blue_defense int fk to table player blue_attack int fk to table player red_defense int fk to table player red_attack int fk to table player score_blue int score_red int How would you write a function predictResult(blueDef, blueAtk, redDef, redAtk) {...} to estimate the outcome as closely as possible, executing any sql, doing calculations or using external libraries?

  Read the article

• segfault during __cxa_allocate_exception in SWIG wrapped library

  - by lefticus

  While developing a SWIG wrapped C++ library for Ruby, we came across an unexplained crash during exception handling inside the C++ code. I'm not sure of the specific circumstances to recreate the issue, but it happened first during a call to std::uncaught_exception, then after a some code changes, moved to __cxa_allocate_exception during exception construction. Neither GDB nor valgrind provided any insight into the cause of the crash. I've found several references to similar problems, including: http://wiki.fifengine.de/Segfault_in_cxa_allocate_exception http://forums.fifengine.de/index.php?topic=30.0 http://code.google.com/p/osgswig/issues/detail?id=17 https://bugs.launchpad.net/ubuntu/+source/libavg/+bug/241808 The overriding theme seems to be a combination of circumstances: A C application is linked to more than one C++ library More than one version of libstdc++ was used during compilation Generally the second version of C++ used comes from a binary-only implementation of libGL The problem does not occur when linking your library with a C++ application, only with a C application The "solution" is to explicitly link your library with libstdc++ and possibly also with libGL, forcing the order of linking. After trying many combinations with my code, the only solution that I found that works is the LD_PRELOAD="libGL.so libstdc++.so.6" ruby scriptname option. That is, none of the compile-time linking solutions made any difference. My understanding of the issue is that the C++ runtime is not being properly initialized. By forcing the order of linking you bootstrap the initialization process and it works. The problem occurs only with C applications calling C++ libraries because the C application is not itself linking to libstdc++ and is not initializing the C++ runtime. Because using SWIG (or boost::python) is a common way of calling a C++ library from a C application, that is why SWIG often comes up when researching the problem. Is anyone out there able to give more insight into this problem? Is there an actual solution or do only workarounds exist? Thanks.

  Read the article

• How do I DYNAMICALLY cast in C# and return for a property

  - by ken-forslund

  I've already read threads on the topic, but can't find a solution that fits. I'm working on a drop-down list that takes an enum and uses that to populate itself. i found a VB.NET one. During the porting process, I discovered that it uses DirectCast() to set the type as it returns the SelectedValue. See the original VB here: http://jeffhandley.com/archive/2008/01/27/enum-list-dropdown-control.aspx the gist is, the control has Type _enumType; //gets set when the datasource is set and is the type of the specific enum The SelectedValue property kind of looks like (remember, it doesn't work): public Enum SelectedValue //Shadows Property { get { // Get the value from the request to allow for disabled viewstate string RequestValue = this.Page.Request.Params[this.UniqueID]; return Enum.Parse(_enumType, RequestValue, true) as _enumType; } set { base.SelectedValue = value.ToString(); } } Now this touches on a core point that I think was missed in the other discussions. In darn near every example, folks argued that DirectCast wasn't needed, because in every example, they statically defined the type. That's not the case here. As the programmer of the control, I don't know the type. Therefore, I can't cast it. Additionally, the following examples of lines won't compile because c# casting doesn't accept a variable. Whereas VB's CType and DirectCast can accept Type T as a function parameter: return Enum.Parse(_enumType, RequestValue, true); or return Enum.Parse(_enumType, RequestValue, true) as _enumType; or return (_enumType)Enum.Parse(_enumType, RequestValue, true) ; or return Convert.ChangeType(Enum.Parse(_enumType, RequestValue, true), _enumType); or return CastTo<_enumType>(Enum.Parse(_enumType, RequestValue, true)); So, any ideas on a solution? What's the .NET 3.5 best way to resolve this?

  Read the article

• Using Sub-Types And Return Types in Scala to Process a Generic Object Into a Specific One

  - by pr1001

  I think this is about covariance but I'm weak on the topic... I have a generic Event class used for things like database persistance, let's say like this: class Event( subject: Long, verb: String, directobject: Option[Long], indirectobject: Option[Long], timestamp: Long) { def getSubject = subject def getVerb = verb def getDirectObject = directobject def getIndirectObject = indirectobject def getTimestamp = timestamp } However, I have lots of different event verbs and I want to use pattern matching and such with these different event types, so I will create some corresponding case classes: trait EventCC case class Login(user: Long, timestamp: Long) extends EventCC case class Follow( follower: Long, followee: Long, timestamp: Long ) extends EventCC Now, the question is, how can I easily convert generic Events to the specific case classes. This is my first stab at it: def event2CC[T <: EventCC](event: Event): T = event.getVerb match { case "login" => Login(event.getSubject, event.getTimestamp) case "follow" => Follow( event.getSubject, event.getDirectObject.getOrElse(0), event.getTimestamp ) // ... } Unfortunately, this is wrong. <console>:11: error: type mismatch; found : Login required: T case "login" => Login(event.getSubject, event.getTimestamp) ^ <console>:12: error: type mismatch; found : Follow required: T case "follow" => Follow(event.getSubject, event.getDirectObject.getOrElse(0), event.getTimestamp) Could someone with greater type-fu than me explain if, 1) if what I want to do is possible (or reasonable, for that matter), and 2) if so, how to fix event2CC. Thanks!

  Read the article

• Weird .net 4.0 exception when running unit tests

  - by vdh_ant

  Hi guys I am receiving the following exception when trying to run my unit tests using .net 4.0 under VS2010 with moq 3.1. Attempt by security transparent method 'SPPD.Backend.DataAccess.Test.Specs_for_Core.When_using_base.Can_create_mapper()' to access security critical method 'Microsoft.VisualStudio.TestTools.UnitTesting.Assert.IsNotNull(System.Object)' failed. Assembly 'SPPD.Backend.DataAccess.Test, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' is marked with the AllowPartiallyTrustedCallersAttribute, and uses the level 2 security transparency model. Level 2 transparency causes all methods in AllowPartiallyTrustedCallers assemblies to become security transparent by default, which may be the cause of this exception. The test I am running is really straight forward and looks something like the following: [TestMethod] public void Can_create_mapper() { this.SetupTest(); var mockMapper = new Moq.Mock<IMapper>().Object; this._Resolver.Setup(x => x.Resolve<IMapper>()).Returns(mockMapper).Verifiable(); var testBaseDa = new TestBaseDa(); var result = testBaseDa.TestCreateMapper<IMapper>(); Assert.IsNotNull(result); //<<< THROWS EXCEPTION HERE Assert.AreSame(mockMapper, result); this._Resolver.Verify(); } I have no idea what this means and I have been looking around and have found very little on the topic. The closest reference I have found is this http://dotnetzip.codeplex.com/Thread/View.aspx?ThreadId=80274 but its not very clear on what they did to fix it... Anyone got any ideas?

  Read the article

• UITextField to show UIPickerView in xcode 4.3.2 using textField.inputView

  - by ChromeBlue

  I'm looking to have a UITextField display a UIPickerView when touched. I found quite a few questions on the same topic that say to use UITextField.inputView. However, when I try, nothing changes. I have a very simple code: setupViewController.h #import <UIKit/UIKit.h> extern NSString *setupRightChannel; @interface setupViewController : UIViewController { UITextField* rightChannelField; UIPickerView *channelPicker; } @property (retain, nonatomic) IBOutlet UITextField* rightChannelField; @property (retain, readwrite) IBOutlet UIPickerView *channelPicker; setupViewController.m #import "setupViewController.h" @Interface setupViewController() @end @implementation setupViewController @synthesize rightChannelField; - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil { self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]; if (self) { // Custom initialization } return self; } - (void)viewDidLoad { [super viewDidLoad]; self.navigationItem.title = @"Setup"; // Do any additional setup after loading the view from its nib. rightChannelField.inputView = channelPicker; } -(IBAction)okClicked:(id)sender { setupRightChannel = rightChannelField.text; } I feel like I might be missing something fundamental here, but I honestly cannot think of what it is.

  Read the article

• Best way to do interprocess communication on Mac OS X

  - by jbrennan

  I'm looking at building a Cocoa application on the Mac with a back-end daemon process (really just a mostly-headless Cocoa app, probably), along with 0 or more "client" applications running locally (although if possible I'd like to support remote clients as well; the remote clients would only ever be other Macs or iPhone OS devices). The data being communicated will be fairly trivial, mostly just text and commands (which I guess can be represented as text anyway), and maybe the occasional small file (an image possibly). I've looked at a few methods for doing this but I'm not sure which is "best" for the task at hand. Things I've considered: Reading and writing to a file (…yes), very basic but not very scalable. Pure sockets (I have no experience with sockets but I seem to think I can use them to send data locally and over a network. Though it seems cumbersome if doing everything in Cocoa Distributed Objects: seems rather inelegant for a task like this NSConnection: I can't really figure out what this class even does, but I've read of it in some IPC search results I'm sure there are things I'm missing, but I was surprised to find a lack of resources on this topic.

  Read the article

• Side by side madness - running binaries on different computer (with a twist)

  - by sbk

  Here's my configuration: Computer A - Windows 7, MS Visual Studio 2005 patched for Win7 compatibility (8.0.50727.867) Computer B - Windows XP SP2, MS Visual Studio 2005 installed (8.0.50727.42) My project has some external dependencies (prebuilt DLLs - either build on A or downloaded from the Internet), a couple of DLLs built from sources and one executable. I am mostly developing on A and all is fine there. At some point I try to build my project on computer B, copying the prebuilt DLLs to the output folder. Everything builds fine, but trying to start my application I get The application failed to initialize properly (0xc0150002).... The event log contains two of those: Dependent Assembly Microsoft.VC80.CRT could not be found and Last Error was The referenced assembly is not installed on your system. plus the slightly more amusing Generate Activation Context failed for some.dll. Reference error message: The operation completed successfully. At this point I'm trying my Google-Fu, but in vain - virtually all hits are about running binaries on machines without Visual Studio installed. In my case, however, the executables fail to run on the computer they are built. Next step was to try dependency walker and it baffled me even more - my DLLs built from sources on the same box cannot find MSVCR80.DLL and MSVCP80.DLL, however the executable seems to be alright in respect to those two DLLs i.e. when I open the executable with dependency walker it shows that the MSVC?80.DLLs can be found, but when I open one of my DLLs it says they cannot. That's where I am completely out of ideas what to do so I'm asking you, dear stackoverflow :) I admit I'm a bit blurry on the whole side-by-side thing, so general reading on the topic will also be appreciated.

  Read the article

• How to identify ideas and concepts in a given text

  - by Nick

  I'm working on a project at the moment where it would be really useful to be able to detect when a certain topic/idea is mentioned in a body of text. For instance, if the text contained: Maybe if you tell me a little more about who Mr Balzac is, that would help. It would also be useful if I could have a description of his appearance, or even better a photograph? It'd be great to be able to detect that the person has asked for a photograph of Mr Balzac. I could take a really naïve approach and just look for the word "photo" or "photograph", but this would obviously be no good if they wrote something like: Please, never send me a photo of Mr Balzac. Does anyone know where to start with this? Is it even possible? I've looked into things like nltk, but I've yet to find an example of someone doing something similar and am still not entirely sure what this kind of analysis is called. Any help that can get me off the ground would be great. Thanks!

  Read the article

• How 'terse' is too terse? -- Practical guidelines for expressing as much intent in as few characters

  - by Christopher Altman

  First, I love writing as little code as possible. I think, and please correct me, one of the golden rules of programming is to express your code in as few of character as possible while maintaining human readability. But I can get a little carried away. I can pack three or four lines into one statement, something like $startDate = $dateTime > time() ? mktime(0,0,0,date('m',time()-86400),date('d',time()*2),2011) : time(); (Note: this is a notional example) I can comprehend the above code when reading it. I prefer 'mushing' it all together because having less lines per page is a good thing to me. So my question: When writing code and thinking about how compact or terse you can express yourself, what are some guidelines you use? Do you write multiple lines because you think it helps other people? Do you write as little as possible, but use comments? Or do you always look for the way to write as little code as possible and enjoy the rewards of compact statements? (Just one slightly off topic comment: I love the Perl one-liners, but that is not what I am talking about here)

  Read the article

• Simple description of worker and I/O threads in .NET

  - by Konstantin

  It's very hard to find detailed but simple description of worker and I/O threads in .NET What's clear to me regarding this topic (but may not be technically precise): Worker threads are threads that should employ CPU for their work; I/O threads (also called "completion port threads") should employ device drivers for their work and essentially "do nothing", only monitor the completion of non-CPU operations. What is not clear: Although method ThreadPool.GetAvailableThreads returns number of available threads of both types, it seems there is no public API to schedule work for I/O thread. You can only manually create worker thread in .NET? It seems that single I/O thread can monitor multiple I/O operations. Is it true? If so, why ThreadPool has so many available I/O threads by default? In some texts I read that callback, triggered after I/O operation completion is performed by I/O thread. Is it true? Isn’t this a job for worker thread, considering that this callback is CPU operation? To be more specific – do ASP.NET asynchronous pages user I/O threads? What exactly is performance benefit in switching I/O work to separate thread instead of increasing maximum number of worker threads? Is it because single I/O thread does monitor multiple operations? Or Windows does more efficient context switching when using I/O threads?

  Read the article

• problem in fetching data from several tables in one query

  - by Mac Taylor

  hey guys in an attempt to union my querries into one query to database , now im in need of geting username of first poster and last poster of a topic in my forums here is my code to do as i told :: $result = $db->sql_query("SELECT t.*,p.*,u.* SUM(t.topic_approved='1') AS Amount_Of_Topics, SUM(p.post_approved ='1') AS Amount_Of_Posts FROM bb3topics t, bb3posts p, bb3users u GROUP BY t.topic_last_post_id ORDER BY t.topic_last_post_id DESC LIMIT 10 " ); while( $row = $db->sql_fetchrow($result) ) { $Amount_Of_Topics = $row['Amount_Of_Topics']; $Amount_Of_Posts = $row['Amount_Of_Posts']; $Amount_Of_Topic_Replies = $Amount_Of_Topic_Replies + $row['topic_replies']; $Amount_Of_Topic_Views = $Amount_Of_Topic_Views + $row['topic_views']; $topic_id = $row['topic_id']; $forum_id = $row['forum_id']; $topic_last_post_id = $row['topic_last_post_id']; $topic_title = $row['topic_title']; $topic_poster = $row['topic_poster']; $topic_views = $row['topic_views']; $topic_replies = $row['topic_replies']; $topic_moved_id = $row['topic_moved_id']; $topic_time = $row['topic_time']; $result2 = $db->sql_query( "SELECT topic_id, poster_id, post_time FROM bb3posts where post_id = '$topic_last_post_id'" ); list( $topic_id, $poster_id, $post_time ) = $db->sql_fetchrow( $result2 ); $result3 = $db->sql_query( "SELECT username, user_id FROM bb3users where user_id='$poster_id'" ); list( $uname, $uid ) = $db->sql_fetchrow( $result3 ); $LastPoster = "$uname"; $result4 = $db->sql_query( "SELECT username, user_id FROM bb3users where user_id='$topic_poster'" ); list( $uname, $uid ) = $db->sql_fetchrow( $result4 ); $OrigPoster = "$uname"; now i need to query all this together not in separated ones i tried using left join but didn't worked what mysql conjunction should i use ?!

  Read the article

• Programming Concepts: What should be done when an exception is thrown?

  - by Dooms101

  This does not really apply to any language specifically, but if it matters I am using VB.NET in Visual Studio 2008. I can't seem to find anything really that useful using Google about this topic, but I was wondering what is common practice when an exception is thrown and caught but since it has been thrown the application cannot continue operating. For example I have exceptions that are thrown by my FileLoader class when a file cannot be found or when a file is deemed corrupt. The exception is only thrown within the class and is not handled really. If the error is detected, then the exception is thrown and whatever function is was thrown is basically quits. So in the code trying to create that object or call one of its members I use a Try...Catch statement. However, I was wondering, what should even do when this exception is caught? My application needs these files to be intact, and if they are not, the application is almost useless. So far I just pop up a message box telling the user their is an error and to reinstall. What else can I do, or better, what's common practice in these situations?

  Read the article

• function objects versus function pointers

  - by kumar_m_kiran

  Hi All, I have two questions related to function objects and function pointers, Question : 1 When I read the different uses sort algorithm of STL, I see that the third parameter can be a function objects, below is an example class State { public: //... int population() const; float aveTempF() const; //... }; struct PopLess : public std::binary_function<State,State,bool> { bool operator ()( const State &a, const State &b ) const { return popLess( a, b ); } }; sort( union, union+50, PopLess() ); Question : Now, How does the statement, sort(union, union+50,PopLess()) work? PopLess() must be resolved into something like PopLess tempObject.operator() which would be same as executing the operator () function on a temporary object. I see this as, passing the return value of overloaded operation i.e bool (as in my example) to sort algorithm. So then, How does sort function resolve the third parameter in this case? Question : 2 Question Do we derive any particular advantage of using function objects versus function pointer? If we use below function pointer will it derive any disavantage? inline bool popLess( const State &a, const State &b ) { return a.population() < b.population(); } std::sort( union, union+50, popLess ); // sort by population PS : Both the above references(including example) are from book "C++ Common Knowledge: Essential Intermediate Programming" by "Stephen C. Dewhurst". I was unable to decode the topic content, thus have posted for help. Thanks in advance for your help.

  Read the article

• Could you please provide me with comments on a Java game of mine?

  - by Peter Perhác

  Hello there. I have marked this question as community wiki, so no rep points are thrown around. I made this game, Forest Defender, a proof-of-feasibility little project, which I would like to share with you and collect your constructive comments, first impressions, etc. It is a the first playable (and enjoyable) game I have released to the public, so I am, naturally, very eager to get some recognition by you, as my peers. I read in a StackOverflow blog, that One of the major reasons we created Stack Overflow to give every programmer a chance to be recognized by their peers. Recognized for their knowledge, their passion, [...] It comes in the form of a Java applet, I used an animation framework called PulpCore and I must say that it's been extremely enjoyable to work with it. I do recommend to people interested in Java game development. Since the product is free, fun, entirely commercial-free and I am willing to share the code to it (on request), I thought it would be OK to post this as a topic here. Moderators, please feel free to move this to another place if you deem the other place more appropriate. EDIT: I am ever so stupid to forget to include a link :-) http://www.perhac.com/shared/forest-defender/index.html

  Read the article

• Delphi Performance: Case Versus If

  - by Andreas Rejbrand

  I guess there might be some overlapping with previous SO questions, but I could not find a Delphi-specific question on this topic. Suppose that you want to check if an unsigned 32-bit integer variable "MyAction" is equal to any of the constants ACTION1, ACTION2, ... ACTIONn, where n is - say 1000. I guess that, besides being more elegant, case MyAction of ACTION1: {code}; ACTION2: {code}; ... ACTIONn: {code}; end; if much faster than if MyAction = ACTION1 then // code else if MyAction = ACTION2 then // code ... else if MyAction = ACTIONn then // code; I guess that the if variant takes time O(n) to complete (i.e. to find the right action) if the right action ACTIONi has a high value of i, whereas the case variant takes a lot less time (O(1)?). Am I correct that switch is much faster? Am I correct that the time required to find the right action in the switch case actually is independent of n? I.e. is it true that it does not really take any longer to check a million cases than to check 10 cases? How, exactly, does this work?

  Read the article

• Practical rules for premature optimization

  - by DougW

  It seems that the phrase "Premature Optimization" is the buzz-word of the day. For some reason, iphone programmers in particular seem to think of avoiding premature optimization as a pro-active goal, rather than the natural result of simply avoiding distraction. The problem is, the term is beginning to be applied more and more to cases that are completely inappropriate. For example, I've seen a growing number of people say not to worry about the complexity of an algorithm, because that's premature optimization (eg http://stackoverflow.com/questions/2190275/help-sorting-an-nsarray-across-two-properties-with-nssortdescriptor/2191720#2191720). Frankly, I think this is just laziness, and appalling to disciplined computer science. But it has occurred to me that maybe considering the complexity and performance of algorithms is going the way of assembly loop unrolling, and other optimization techniques that are now considered unnecessary. What do you think? Are we at the point now where deciding between an O(n^n) and O(n!) complexity algorithm is irrelevant? What about O(n) vs O(n*n)? What do you consider "premature optimization"? What practical rules do you use to consciously or unconsciously avoid it? This is a bit vague, but I'm curious to hear other peoples' opinions on the topic.

  Read the article

• Python: circular imports needed for type checking

  - by phild

  First of all: I do know that there are already many questions and answers to the topic of the circular imports. The answer is more or less: "Design your Module/Class structure properly and you will not need circular imports". That is true. I tried very hard to make a proper design for my current project, I in my opinion I was successful with this. But my specific problem is the following: I need a type check in a module that is already imported by the module containing the class to check against. But this throws an import error. Like so: foo.py: from bar import Bar class Foo(object): def __init__(self): self.__bar = Bar(self) bar.py: from foo import Foo class Bar(object): def __init__(self, arg_instance_of_foo): if not isinstance(arg_instance_of_foo, Foo): raise TypeError() Solution 1: If I modified it to check the type by a string comparison, it will work. But I dont really like this solution (string comparsion is rather expensive for a simple type check, and could get a problem when it comes to refactoring). bar_modified.py: from foo import Foo class Bar(object): def __init__(self, arg_instance_of_foo): if not arg_instance_of_foo.__class__.__name__ == "Foo": raise TypeError() Solution 2: I could also pack the two classes into one module. But my project has lots of different classes like the "Bar" example, and I want to seperate them into different module files. After my own 2 solutions are no option for me: Has anyone a nicer solution for this problem?

  Read the article

• is there evidence that offshoring is causing developer salaries to go down? [closed]

  - by jcollum

  I realize this is a controversial and political topic. I'm trying to decide if offshoring is something that is effecting our industry in any substantial way or if it's just some bugaboo. I've read various posts on SO about it, but none addressed the idea of evidence for offshoring. Studies, papers, opinions of people who know about such things etc. I hear a lot about offshoring and its effect on our job market. However it all seems to be hearsay and conjecture. It does seem like some people are genuinely worried about it. This offshoring thing has been going on for quite some time, should be enough time for some real data to come out. If I had to pick a number I'd say it started during the dotcom boom -- a time when the need for developers far outweighed the local talent pool. We're now in a time when the talent pool is expensive and corporate wallets are tight, seems like an ideal time to find a good cheap developer in some other country. But is that actually happening? From reading some posts here on SO, I've concluded that offshoring is a really tough thing to do right. There are a lot of companies who think (or say) they can do it right, but some small percentage of them are actually able to pull it off. Is offshoring affecting the job market in any measurable way? Is offshoring measurable at all? Do we need to stop worrying about this?

  Read the article

• Best ways to copyright protect your work for example Myows

  - by Saif Bechan

  Recently I have read about Myows, they say its: "The universal copyright management and protection app for smart creatives" It is used to protect your application from copyrights and more. Do you think this will be a good idea for large application, or are there better ways to achieve such a thing. url: Myows Update Referencing: http://stackoverflow.com/questions/2618015/has-anyone-tried-myows-to-copyright-protect-your-work/2618628#2618628 Wow there is no better person to have answered this question like the creator himself. Currently I am working on a large web application which is in late testing phase. Because of the complexity of the app there are not many versions of it online so copyright will be a huge issue for me as much of the code is in JavaScript and is easy copyable. I was glad to see that there is some company out there that provide such services, and naturally I wanted to know if there were people using it. I did not know that this type of concept was so 'new'. There were some nice points made in the answer, and I think it will be a good service for people like me. In the next couple of weeks I will be looking further into the subject and start uploading my code and see how it will works out. I will leave this question up because I do want some more suggestions on this topic.

  Read the article

• general learning methodology

  - by momo

  just wanted to hear on the different general learning paths people embark on when learning a new language/framework. the one i currently use, which is how i learned bash and am currently learning python, is: instant hacking tutorial (very short tutorial introducing the basic syntax, variable declaration, loops, data types, etc. and how they are generally used) in depth tutorial with good programming style and slightly topic-specific (e.g. Mark Pilgrim's Dive into Python), important topics for me personally are regex methods, file IO, and ways the different data types are utilized best (i wrote a very primitive bayesian spam filter using python's dictionaries to keep track of word occurrences) spaced-repition of syntax or short recipes (i use anki, with questions like 'create dictionary with filename and filesize metadata, human-readable' or simpler ones like 'match 0 - 3 occurences of the letter M in a string', or 'return/create an iterator from two sequences') the use of spaced-repitition has been invaluable, and i credit it with the ease that i can recall/create python algorithms. however, i've recently started looking into django, and i've found that spaced-repitition, at least in my case, doesn't work very well for learning a framework, it works best with short code recipes (either that or i should start looking into more basic django framework tutorials). the problem i'm encountering is that since framework programming is not only algorithms, but actually learning the API, which can be quite complex since you have to learn all the methods, modules, the places where they are stored, and the sequence of which things have to be done. for ex. in django to start a project that deals with polls (from the django tutorial), one has to create the project, edit the settings.py file, create the polls app, edit the models.py file (which requires knowing the classes that are present in the module models), edit the urls.py file, etc. i found that my spaced-repition method didn't work very well for this type of learning, so i wanted to ask you guys what method(s) you use for learning the different frameworks/APIs.

  Read the article

• Inserting bits into byte

  - by JB_SO

  I was looking at an example of reading bits from a byte and the implementation looked simple and easy to understand. I was wondering if anyone has a similar example of how to insert bits into a byte or byte array, that is easier to understand and also implement like the example below. Here is the example I found of reading bits from a byte (http://bytes.com/topic/c-sharp/answers/505085-reading-bits-byte-file): static int GetBits3(byte b, int offset, int count) { return (b >> offset) & ((1 << count) - 1); } Here is what i'm trying to do....and this is my current implementation.....just a little confused with the bit-masking/shifting, etc, that's why I'm trying to find out if there is an easier way to do what i'm doing BYTE Msg[2]; Msg_Id = 3; Msg_Event = 1; Msg_Ready = 2; Msg[0] = ( ( Msg_Event << 4 ) & 0xF0 ) | ( Msg_Id & 0x0F ) ; Msg[1] = Msg_Ready & 0x0F; //MsgReady & Unused Thanks for your help!

  Read the article

< Previous Page | 114 115 116 117 118 119 120 121 122 123 124 125  | Next Page >