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  • What is the right approach to checksumming UDP packets

    - by mr.b
    I'm building UDP server application in C#. I've come across a packet checksum problem. As you probably know, each packet should carry some simple way of telling receiver if packet data is intact. Now, UDP already has 2-byte checksum as part of header, which is optional, at least in IPv4 world. Alternative method is to have custom checksum as part of data section in each packet, and to verify it on receiver. My question boils down to: is it better to rely on (optional) checksum in UDP packet header, or to make a custom checksum implementation as part of packet data section? Perhaps the right answer depends on circumstances (as usual), so one circumstance here is that, even though code is written and developed in .NET on Windows, it might have to run under platform-independent Mono.NET, so eventual solution should be compatible with other platforms. I believe that custom checksum algorithm would be easily portable, but I'm not so sure about the first one. Any thoughts? Also, shouts about packet checksumming in general are welcome.

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  • R: disentangling scopes

    - by rescdsk
    Hi, Right now, in my R project, I have functions1.R with doFoo() and doBar(), functions2.R with other functions, and main.R with the main program in it, which first does source('functions1.R'); source('functions2.R'), and then calls the other functions. I've been starting the program from the R GUI in Mac OS X, with source('main.R'). This is fine the first time, but after that, the variables that were defined the first time through the program are defined for the second time functions*.R are sourced, and so the functions get a whole bunch of extra variables defined. I don't want that! I want an "undefined variable" error when my function uses a variable it shouldn't! Twice this has given me very late nights of debugging! So how do other people deal with this sort of problem? Is there something like source(), but that makes an independent namespace that doesn't fall through to the main one? Making a package seems like one solution, but it seems like a big pain in the butt compared to e.g. Python, where a source file is automatically a separate namespace. Any tips? Thank you!

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  • Webbased data modelling and management tool

    - by pixeldude
    Is there a web-based tool available, where I am able to... ...define data models (like in a database admin tool) ...fill in data (in custom web forms, not too generic) with basic features like completion ...import data from CSV oder Excel Sheets ...export data to CSV or SQL ...create snapshots of my data models (versions, diff, etc.) ...share my data models ...discuss/collaborate with other people about my data models Well, I can develop something like this in PHP or with Ruby or whatever. But this is such a common task, where the application support could be a lot better. And it would be language and database independent. This would help to maintain data models in different versions and you can maybe share your data models with others, extend it with your team members, etc. There is a website called FreeBase, which allows you to define a data entity model and fill in data, which also has export features, but I need to define my own data model with my own granularity and structure. And it should not be shared in public if I don't want to. How do you solve problems like this yourself?

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  • How to give the menus associated with dojo's dijit.ComboBox different css from those of dijit.Menu

    - by sprugman
    When you use a dijit.ComboBox, the type ahead suggestions get implemented as a dijit.Menu. I've got a design which calls for the matched portion of the suggestion rows to be normal, and the unmatched portion to be bold. The structure that dojo creates is like this: <ul class="dijitReset dijitMenu"> <li role="option" class="dijitReset dijitMenuItem"> <span class="dijitComboBoxHighlightMatch">Ch</span>oice One </li> <li role="option" class="dijitReset dijitMenuItem"> <span class="dijitComboBoxHighlightMatch">Ch</span>oice Two </li> </ul> So I can target the matched part, but not the unmatched part. So my css needs to be something like: .dijitMenuItem { font-weight: bold; } .dijitMenuItem .dijitComboBoxHighlightMatch { font-weight: normal; } The problem is, if I do that, all menus will be bolded, and I don't want that. Just doing something like this: <select dojoType="dijit.form.ComboBox" class="foobar">[options]</select> puts the foobar class in the ComboBox, but the menu is an independent node not under that hierarchy. What's the easiest way to add a css class around the popup menu that the ComboBox generates?

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  • wopen calls when porting to Linux

    - by laura
    I have an application which was developed under Windows, but for gcc. The code is mostly OS-independent, with very few classes which are Windows specific because a Linux port was always regarded as necessary. The API, especially that which gets called as a direct result of user interaction, is using wide char arrays instead of char arrays (as a side note, I cannot change the API itself - at this point, std::wstring cannot be used). These are considered as encoded in UTF-16. In some places, the code opens files, mostly using the windows-specific _wopen function call. The problem with this is there is no wopen-like substitute for Linux because Linux "only deals with bytes". The question is: how do I port this code ? What if I wanted to open a file with the name "something™.log", how would I go about doing so in Linux ? Is a cast to char* sufficient, would the wide chars be picked up automatically based on the locale (probably not) ? Do I need to convert manually ? I'm a bit confused regarding this, perhaps someone could point me to some documentation regarding the matter.

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  • WordPerfect programmers refusing to use anything but assembler

    - by Totophil
    There is a version (popularised by Joel Spolsky) attributing the demise of WordPerfect to a refusal of its programmers to use anything but assembler that led to delay of the first WPwin release and as result eventually to losing the all important battle with Microsoft. There are a few references to programming work being done using assembler in the autobiographical book "Almost Perfect" by W. E. Pete Peterson who used to have a major influence at running the corporation. But these references go back to early 80's when WordPerfect was trying to gain a significant market share by defeating WordStar and not early nineties when the battle with MS took place. I am looking for a second independent source to confirm the assumption. Maybe someone who worked for WordPerfect Corporation at a time, who was close to the company, or had a chance to see the source could clarify the issue. Your help is much appreciated, thanks! Please note that this question is not about any other theories or reasons behind WordPerfect demise. I really just need to clarify whether they used assembler as a primary language for WPwin and (as a bonus really) whether there were discussions held within the corporation about assembler being the right choice. Concisely: Did WPCorp use assembler as a primary language for WPwin? Were discussions held at a time amongst WP Corp staff about assembler being the right choice (was it management or programmers decision)?

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  • ADO/SQL Server: What is the error code for "timeout expired"?

    - by Ian Boyd
    i'm trying to trap a "timeout expired" error from ADO. When a timeout happens, ADO returns: Number: 0x80040E31 (DB_E_ABORTLIMITREACHED in oledberr.h) SQLState: HYT00 NativeError: 0 The NativeError of zero makes sense, since the timeout is not a function of the database engine (i.e. SQL Server), but of ADO's internal timeout mechanism. The Number (i.e. the COM hresult) looks useful, but the definition of DB_E_ABORTLIMITREACHED in oledberr.h says: Execution stopped because a resource limit was reached. No results were returned. This error could apply to things besides "timeout expired" (some potentially server-side), such as a governor that limits: CPU usage I/O reads/writes network bandwidth and stops a query. The final useful piece is SQLState, which is a database-independent error code system. Unfortunately the only reference for SQLState error codes i can find have no mention of HYT00. What to do? What do do? Note: i can't trust 0x80040E31 (DB_E_ABORTLIMITREACHED) to mean "timeout expired", anymore than i could trust 0x80004005 (E_UNSPECIFIED_ERROR) to mean "Transaction was deadlocked on lock resources with another process and has been chosen as the deadlock victim". My pseudo-question becomes: does anyone have documentation on what the SQLState "HYT000" means? And my real question still remains: How can i specifically trap an ADO timeout expired exception thrown by ADO? Gotta love the questions where the developer is trying to "do the right thing", but nobody knows how to do the right thing. Also gotta love how googling for DB_E_ABORTLIMITREACHED and this question is #9, with MSDN nowhere to be found. Update 3 From the OLEdb ICommand.Execute reference: DB_E_ABORTLIMITREACHED Execution has been aborted because a resource limit has been reached. For example, a query timed out. No results have been returned. "For example", meaning not an exhaustive list.

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  • The algorithm used to generate recommendations in Google News?

    - by Siddhant
    Hi everyone. I'm study recommendation engines, and I went through the paper that defines how Google News generates recommendations to users for news items which might be of their interest, based on collaborative filtering. One interesting technique that they mention is Minhashing. I went through what it does, but I'm pretty sure that what I have is a fuzzy idea and there is a strong chance that I'm wrong. The following is what I could make out of it :- Collect a set of all news items. Define a hash function for a user. This hash function returns the index of the first item from the news items which this user viewed, in the list of all news items. Collect, say "n" number of such values, and represent a user with this list of values. Based on the similarity count between these lists, we can calculate the similarity between users as the number of common items. This reduces the number of comparisons a lot. Based on these similarity measures, group users into different clusters. This is just what I think it might be. In Step 2, instead of defining a constant hash function, it might be possible that we vary the hash function in a way that it returns the index of a different element. So one hash function could return the index of the first element from the user's list, another hash function could return the index of the second element from the user's list, and so on. So the nature of the hash function satisfying the minwise independent permutations condition, this does sound like a possible approach. Could anyone please confirm if what I think is correct? Or the minhashing portion of Google News Recommendations, functions in some other way? I'm new to internal implementations of recommendations. Any help is appreciated a lot. Thanks!

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  • How to verify the SSL connection when calling a URI?

    - by robertokl
    Hello, I am developing a web application that is authenticated using CAS (A single-sign-on solution: http://www.ja-sig.org/wiki/display/CAS/Home). For security reasons, I need two things to work: The communication between CAS and my application needs to be secure My application needs to accept the certification coming from CAS, so that I can guarantee that the CAS responding is the real CAS server This is what I got so far: uri = URI.parse("https://www.google.com/accounts") https = Net::HTTP.new(uri.host, uri.port) https.use_ssl = (uri.scheme == 'https') https.verify_mode = (OpenSSL::SSL::VERIFY_PEER) raw_res = https.start do |conn| conn.get("#{uri.path}?#{uri.query}") end This works just great in Mac OS X. When I try to reach an insecure URI, it raises an exception, and when I try to reach a secure URI, it allows me normally, just like expected. The problem starts when I deploy my application on my Linux server. I tried in both Ubuntu and Red Hat. Independent of what URI I try to reach, it always raises this exception: OpenSSL::SSL::SSLError: SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed from /usr/local/lib/ruby/1.8/net/http.rb:586:in `connect' from /usr/local/lib/ruby/1.8/net/http.rb:586:in `connect' from /usr/local/lib/ruby/1.8/net/http.rb:553:in `do_start' from /usr/local/lib/ruby/1.8/net/http.rb:542:in `start' from (irb):7 I think this have something to do with my installed OpenSSL package, but I can't be sure. This are my installed OpenSSL packages: openssl.x86_64 0.9.8e-12.el5 installed openssl-devel.x86_64 0.9.8e-12.el5 installed I tried using HTTParty as well, but it just ignores the SSL certificate. I hope someone can help me, or tell me about a gem that works the way I need. Thanks.

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  • Maven Mojo & SCM Plugin: Check for a valid working directory

    - by Patrick Bergner
    Hi there. I'm using maven-scm-plugin from within a Mojo and am trying to figure out how to determine if a directory D is a valid working directory of an SCM URL U (i.e. a checkout of U to D already happened). The context is that I want to do a checkout of U if D is a working set or do an update if it isn't. The plan is to check out U to D if D does not exist, update D if D is a valid working directory of U, display an error if D exists and is not a valid working directory of U. What I tried is to call ScmManager.status(), ScmManager.list() and ScmManager.changelog() and try to guess something from their results. But that didn't work. The results from status and changelog always return something positive (isSuccess() = true, getChangedFiles() = valid List, no exceptions to catch), whereas list throws an exception in any case. ScmRepository and ScmFileSet don't seem to provide suitable methods as well. An option would be to always do an update if D exists but then I cannot tell if it is a working directory of U or any SCM working directory at all. The ideal solution would be independent of the actual SCM system and a specific ScmVersion. Thanks for your help! Patrick

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  • Understanding F# Asynchronous Programming

    - by Yin Zhu
    I kind of know the syntax of asynchronous programming in F#. E.g. let downloadUrl(url:string) = async { let req = HttpWebRequest.Create(url) // Run operation asynchronously let! resp = req.AsyncGetResponse() let stream = resp.GetResponseStream() // Dispose 'StreamReader' when completed use reader = new StreamReader(stream) // Run asynchronously and then return the result return! reader.AsyncReadToEnd() } In F# expert book (and many other sources), they say like let! var = expr simply means "perform the asynchronous operation expr and bind the result to var when the operation completes. Then continue by executing the rest of the computation body" I also know that a new thread is created when performing async operation. My original understanding was that there are two parallel threads after the async operation, one doing I/O and one continuing to execute the async body at the same time. But in this example, I am confused at let! resp = req.AsyncGetResponse() let stream = resp.GetResponseStream() What happens if resp has not started yet and the thread in the async body wants to GetResponseStream? Is this a possible error? So maybe my original understanding was wrong. The quoted sentences in the F# expert book actually means that "creating a new thread, hang the current thread up, when the new thread finishes, wake up the body thread and continue", but in this case I don't see we could save any time. In the original understanding, the time is saved when there are several independent IO operations in one async block so that they could be done at the same time without intervention with each other. But here, if I don't get the response, I cannot create the stream; only I have stream, I can start reading the stream. Where's the time gained?

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  • git workflow incorporating many, but not all commits from many forks

    - by becomingGuru
    I have a git repo. It has been forked several times and many independent commits are made on top of it. Everything normal, like what happens in many github hosted projects. Now, what exact workflow should I follow, if I want to see all that commits individually and apply the ones I like. The workflow I followed, which is not the optimal is to create a branch of the name github-username and merge the changes into my master and undo any changes in the commit I dont need manually (there are not many, so it worked). What I want is the ability to see all commits from different forks individually and cherry pick and apply them on top of my master. What is the workflow to follow for that? And what gui (gitk?) enables me to see all different individual commits. I realize that merge should be a primary part of the workflow and not cherry-pick as it creates a different commit (from git's point of view). Even rebasing other's changes on top of mine might not preserve the history on the graph to indicate that it is his commits I have rebased. So then, How do I ignore just a few commits from a lot of them? I think github should have a "apply this commit on top of my master" thing in their graph after each commit node; so I can just pull it, after doing all that.

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  • Configuring IHS server to direct traffic to the Netty component bound to a port

    - by rbot
    I have a Server Component ( based on Jboss-Netty, which could maintain & handle persistent connections ) deployed in WAS. This component when deployed & initiated within the WAS environment, binds to a port & listens for incoming HTTP connection. [ Why i had to deploy a Netty HTTP Server within WAS is another story - management requirement !! Netty is deployed in WAS as a spring bean which when initiated runs on a port in the machine, independent of WAS ] Clients (mobile app) were able to establish persistent HTTP connections (to the above URL::Port) with this netty component & send/receive requests. Now, I have to replicate this feature in our Production Environment where a IHS Server (Web Server) which sits before the WAS. What i expected is to get a IHS URL which could redirect the incoming packets to the specific PORT on WAS, so that the Client apps can establish a similar persistent http connection. Our Server Admin tried a few combinations and we are not able to identify how to proceed further on this. Your expert ideas would be highly appreciated.

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  • What's the relationship between the Intel Atom Developer Program and the MeeGo operating system?

    - by Arne Evertsson
    I'm trying to understand the relationship between the Intel Atom Developer Program (IADP) and the new OS called MeeGo. IADP let's me create applications that run on both MeeGo as well as Windows devices, as long as the device is based on the Atom processor. The IADP apps are published in an app store called AppUp, which is very much like the Apple App Store. The MeeGo operating system merges Intel's Moblin and Nokia's Maemo into one OS. The purpose seems to be to make it possible to develop software that will run on Intel powered devices, Nokia-made devices, as well devices from other companies. Nokia has its Ovi Store that will support MeeGo apps. With its OS independent runtime, the question is what an IADP app really is? Is an IADP app a beast of its own, or is it just a MeeGo app that has been restricted to run only on Atom powered devices? Will it be possible to recompile my IADP app to run on all MeeGo devices? Sold in Ovi Store? Intel and Nokia have me really confused. Where should I go as a developer?

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  • How to get current datetime on windows command line, in a suitable format for using in a filename?

    - by Rory
    What's a windows command line statement(s) I can use to get the current datetime in a format that I can put into a filename? I want to have a .bat file that zips up a directory into an archive with the current date & time as part of the name, eg "Code_2008-10-14_2257.zip". Is there any easy way I can do this, independent of the regional settings of the machine? I don't really mind about the date format, ideally it'd be yyyy-mm-dd but anything simple is fine. So far I've got this, which on my machine gives me "Tue_10_14_2008_230050_91" rem Get the datetime in a format that can go in a filename. set _my_datetime=%date%_%time% set _my_datetime=%_my_datetime: =_% set _my_datetime=%_my_datetime::=% set _my_datetime=%_my_datetime:/=_% set _my_datetime=%_my_datetime:.=_% rem now use the timestamp by in a new zip file name "d:\Program Files\7-Zip\7z.exe" a -r Code_%_my_datetime%.zip Code I can live with this but it seems a bit clunky. Ideally it'd be briefer and have the format mentioned earlier. I'm using Windows Server 2003 and Win XP Pro. I don't want to install additional utilities to achieve this (although I realise there are some that will do nice date formatting).

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  • Which language should I use to program a GUI application?

    - by Roman
    I would like to write a GUI application for management of information (text documents). In more details, it should be similar to the TiddlyWiki. I would like to have there some good visual effects (like nice representation for three structures, which you can rotate, some sound). I also would like to include some communication via Internet (for sharing and collaboration). In should include some features of such applications as a web browser, word processor, Skype. Which programming language should I use? I like the idea of usage of JavaScripts (like TddlyWiki). The good thing about that, is that user should not install anything. They open a file in a browser and it works! The bad thing is that JavaScript cannot communicate via internet with other applications. I think the choice of the programming language, in my case, id conditioned by 2 things: What can be done with this programming language (which restrictions are there). How easy to program. I would like to have "block" which can do a lot of things (rather than to program then and, in this way, to "rediscover a bicycle") ADDED: I would like to make it platform independent.

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  • WriteableBitmap failing badly, pixel array very inaccurate

    - by dawmail333
    I have tried, literally for hours, and I have not been able to budge this problem. I have a UserControl, that is 800x369, and it contains, simply, a path that forms a worldmap. I put this on a landscape page, then I render it into a WriteableBitmap. I then run a conversion to turn the 1d Pixels array into a 2d array of integers. Then, to check the conversion, I wire up the custom control's click command to use the Point.X and Point.Y relative to the custom control in the newly created array. My logic is thus: wb = new WriteableBitmap(worldMap, new TranslateTransform()); wb.Invalidate(); intTest = wb.Pixels.To2DArray(wb.PixelWidth); My conversion logic is as such: public static int[,] To2DArray(this int[] arr,int rowLength) { int[,] output = new int[rowLength, arr.Length / rowLength]; if (arr.Length % rowLength != 0) throw new IndexOutOfRangeException(); for (int i = 0; i < arr.Length; i++) { output[i % rowLength, i / rowLength] = arr[i]; } return output; } Now, when I do the checking, I get completely and utterly strange results: apparently all pixels are either at values of -1 or 0, and these values are completely independent of the original colours. Just for posterity: here's my checking code: private void Check(object sender, MouseButtonEventArgs e) { Point click = e.GetPosition(worldMap); ChangeNotification(intTest[(int)click.X,(int)click.Y].ToString()); } The result show absolutely no correlation to the path that the WriteableBitmap has rendered into it. The path has a fill of solid white. What the heck is going on? I've tried for hours with no luck. Please, this is the major problem stopping me from submitting my first WP7 app. Any guidance?

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  • tipfy for Google App Engine: Is it stable? Can auth/session components of tipfy be used with webapp?

    - by cv12
    I am building a web application on Google App Engine that requires users to register with the application and subsequently authenticate with it and maintain sessions. I don't want to force users to have Google accounts. Also, the target audience for the application is the average non-geek, so I'm not very keen on using OpenID or OAuth. I need something simple like: User registers with an e-mail and password, and then can log back in with those credentials. I understand that this approach does not provide the security benefits of Google or OpenID authentication, but I am prepared to trade foolproof security for end-user convenience and hassle-free experience. I explored Django, but decided that consecutive deprecations from appengine-helper to app-engine-patch to django-nonrel may signal that path may be a bit risky in the long-term. I'd like to use a code base that is likely to be maintained consistently. I also explored standalone session/auth packages like gaeutilities and suas. GAEUtilities looked a bit immature (e.g., the code wasn't pythonic in places, in my opinion) and SUAS did not give me a lot of comfort with the cookie-only sessions. I could be wrong with my assessment of these two, so I would appreciate input on those (or others that may serve my objective). Finally, I recently came across tipfy. It appears to be based on Werkzeug and Alex Martelli spoke highly of it here on stackoverflow. I have two primary questions related to tipfy: As a framework, is it as mature as webapp? Is it stable and likely to be maintained for some time? Since my primary interest is the auth/session components, can those components of the tipfy framework be used with webapp, independent of the broader tipfy framework? If yes, I would appreciate a few pointers to how I could go about doing that.

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  • Why is creating a ring buffer shared by different processes so hard (in C++), what I am doing wrong?

    - by recipriversexclusion
    I am being especially dense about this but it seems I'm missing an important, basic point or something, since what I want to do should be common: I need to create a fixed-size ring buffer object from a manager process (Process M). This object has write() and read() methods to write/read from the buffer. The read/write methods will be called by independent processes (Process R and W) I have implemented the buffer, SharedBuffer<T&>, it allocates buffer slots in SHM using boost::interprocess and works perfectly within a single process. I have read the answers to this question and that one on SO, as well as asked my own, but I'm still in the dark about how to have different processes access methods from a common object. The Boost doc has an example of creating a vector in SHM, which is very similar to what I want, but I want to instantiate my own class. My current options are: Use placement new, as suggested by Charles B. to my question; however, he cautions that it's not a good idea to put non-POD objects in SHM. But my class needs the read/write methods, how can I handle those? Add an allocator to my class definition, e.g. have SharedBuffer<T&, Alloc> and proceed similarly to the vector example given in boost. This sounds really complicated. Change SharedBuffer to a POD class, i.e. get rid of all the methods. But then how to synchronize reading and writing between processes? What am I missing? Fixed-length ring buffers are very common, so either this problem has a solution or else I'm doing something wrong.

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  • Stata Nearest neighbor of percentile

    - by Kyle Billings
    This has probably already been answered, but I must just be searching for the wrong terms. Suppose I am using the built in Stata data set auto: sysuse auto, clear and say for example I am working with 1 independent and 1 dependent variable and I want to essentially compress down to the IQR elements, min, p(25), median, p(75), max... so I use command, keep weight mpg sum weight, detail return list local min=r(min) local lqr=r(p25) local med = r(p50) local uqr = r(p75) local max = r(max) keep if weight==`min' | weight==`max' | weight==`med' | weight==`lqr' | weight==`uqr' Hence, I want to compress the data set down to only those 5 observations, and for example in this situation the median is not actually an element of the weight vector. there is an observation above and an observation below (due to the definition of median this is no surprise). is there a way that I can tell stata to look for the nearest neighbor above the percentile. ie. if r(p50) is not an element of weight then search above that value for the next observation? The end result is I am trying to get the data down to 2 vectors, say weight and mpg such that for each of the 5 elements of weight in the IQR have their matching response in mpg. Any thoughts?

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  • What is the best anti-crack scheme for your trial or subscription software?

    - by gmatt
    Writing code takes time and effort and just like any other human being we need to live by making an income (save for the few that are actually self sustainable.) Here are 3 general schemes to make a living: Independent developers can offer a trial then purchase scheme. An alternative is an open source base application with pay extensions. A last (probably least popular with customers) scheme is to enforce some kind of subscription. Then the price of the software pales in comparison to the long term subscription fees. So, my question would be a hypothetical one. Suppose that you invest thousands of hours into developing an application. Now suppose you can choose any one of the three options to make a living off this application--or any other option you want--and suppose you have a very real fear of loosing 80% of your revenue to a cracked version if one can be made. To be clear this application does not require the internet to perform all its useful functions, that is, your application is a prime candidate to be a cracked release on some website. Which option would you feel most comfortable with defending yourself against this possible situation and briefly describe why this option would be the best.

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  • Legitimate uses of the Function constructor

    - by Marcel Korpel
    As repeatedly said, it is considered bad practice to use the Function constructor (also see the ECMAScript Language Specification, 5th edition, § 15.3.2.1): new Function ([arg1[, arg2[, … argN]],] functionBody) (where all arguments are strings containing argument names and the last (or only) string contains the function body). To recapitulate, it is said to be slow, as explained by the Opera team: Each time […] the Function constructor is called on a string representing source code, the script engine must start the machinery that converts the source code to executable code. This is usually expensive for performance – easily a hundred times more expensive than a simple function call, for example. (Mark ‘Tarquin’ Wilton-Jones) Though it's not that bad, according to this post on MDC (I didn't test this myself using the current version of Firefox, though). Crockford adds that [t]he quoting conventions of the language make it very difficult to correctly express a function body as a string. In the string form, early error checking cannot be done. […] And it is wasteful of memory because each function requires its own independent implementation. Another difference is that a function defined by a Function constructor does not inherit any scope other than the global scope (which all functions inherit). (MDC) Apart from this, you have to be attentive to avoid injection of malicious code, when you create a new Function using dynamic contents. Lots of disadvantages and it is intelligible that ECMAScript 5 discourages the use of the Function constructor by throwing an exception when using it in strict mode (§ 13.1). That said, T.J. Crowder says in an answer that [t]here's almost never any need for the similar […] new Function(...), either, again except for some advanced edge cases. So, now I am wondering: what are these “advanced edge cases”? Are there legitimate uses of the Function constructor?

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  • Why are Managed Beans not loaded in Tomcat?

    - by c0d3x
    Hi, I created a JSF 2 web application with facelets. The libs for JSF where stored at tomcat/lib, to share it between several applications. I thought maybe it would be better to store the libs inside the WEB-INF/lib folder of the application, to get the application more independent from server configurations. Now when I start tomcat via eclipse, the managed beans are loaded and working. But when I start tomcat directly / standalone the managed beans are not loaded automatically. I used @ManagedBean @SessionScoped / @RequestScoped annotations to declare classes as managed beans. Why is this? What can I do to fix it? I don't use any faces-config.xml file yet. Thanks in advance. edited: Maybe this helps to see whats going on: javax.el.PropertyNotFoundException: /Artikel.xhtml @12,108 value="#{artikelBackingBean.nameFilterPattern}": Target Unreachable, identifier 'artikelBackingBean' resolved to null at com.sun.faces.facelets.el.TagValueExpression.getType(TagValueExpression.java:93) at com.sun.faces.renderkit.html_basic.HtmlBasicInputRenderer.getConvertedValue(HtmlBasicInputRenderer.java:95) at javax.faces.component.UIInput.getConvertedValue(UIInput.java:1008) at javax.faces.component.UIInput.validate(UIInput.java:934) at javax.faces.component.UIInput.executeValidate(UIInput.java:1189) at javax.faces.component.UIInput.processValidators(UIInput.java:691) at javax.faces.component.UIForm.processValidators(UIForm.java:243) at javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:1080) at javax.faces.component.UIViewRoot.processValidators(UIViewRoot.java:1180) at com.sun.faces.lifecycle.ProcessValidationsPhase.execute(ProcessValidationsPhase.java:76) at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101) at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118) at javax.faces.webapp.FacesServlet.service(FacesServlet.java:312) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:433) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:849) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454) at java.lang.Thread.run(Thread.java:619)

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  • 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?

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  • CSS column height different on Opera/IE to FF

    - by Infiniti Fizz
    Hi all, Thanks to everyone who helped with my last question but I've got a new browser-independent problem: For some reason, the image navigator (not yet functioning) on a website I'm working on is currently not displaying in the correct place on Firefox. It appears in the right place in IE8 and Opera but Firefox seems to have a problem with it. As can be seen in the below image, the imageContainer div (the image and the left/right arrows) appears on top of the footer, this is how it should look i.e. how it looks in IE8 and Opera. But in the image below, the imageContainer div is cutting into the footer div for some reason, and I don't know why. imageContainer has a margin-top: 110px; to get it in the right place at the bottom of its column. There are 2 columns, the left housing the paragraphs and imageContainer and the right housing the Calendar and contact details. The footer div also has clear: both; Also, it's not just the image that is falling into the footer, it's the arrows as well only they are the same colour as the footer so this isn't immediately apparent. Any ideas why it isn't displaying correctly? Is there a better way of aligning the imageContainer to the bottom of it's column (to keep the box shape of the website) other than using the margin-top to position it? Thanks in advance, infinitifizz

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