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  • php - sort and delete duplicates?

    - by c41122ino
    I've got an array that looks like this: Array ( [0] => Array ( num => 09989, dis => 20 ) [1] => Array ( num => 09989, dis => 10 ) [2] => Array ( num => 56676, dis => 15 ) [3] => Array ( num => 44533, dis => 20 ) [4] => Array ( num => 44533, dis => 50 ) ) First, I'm trying to sort them by num, and can't seem to get the usort example from php.net working here. It simply doesn't appear to be sorting... I'm also trying to delete the array element if it's a duplicate and whose dis value is higher than the other one. So, based on the example above, I'm trying to create: Array ( [0] => Array ( num => 09989, dis => 10 ) [1] => Array ( num => 44533, dis => 20 ) [2] => Array ( num => 56676, dis => 15 ) ) This is the code from php.net: function cmp($a, $b) { if ($a == $b) { return 0; } return ($a < $b) ? -1 : 1; }

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  • Runtime Exception when using Custom Healthmonitoring event in medium trust

    - by Elementenfresser
    Hi, I'm using custom healthmonitoring events in ASP.NET We recently moved to a new server with default High Trust Permissions. Literature says that healthmonitoring and custom events should work under Medium or higher trust (http://msdn.microsoft.com/en-us/library/bb398933.aspx). Problem is it doesn't. In less than high trust I get a SecurityException saying The application attempted to perform an operation not allowed by the security policy It works in Full trust or when I remove the inheritance of System.Web.Management.WebErrorEvent. Any suggestions anyone? Here is the super simple code behind with a custom event defined: public partial class Default : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { try { CallCustomEvent(); } catch (Exception ex) { Response.Write(ex.Message); throw ex; } } /// <summary> /// this metho is never called due to lacking permissions... /// </summary> private void CallCustomEvent() { try { //do something useful here } catch (Exception) { //code to instantiate the forbidden inheritance... WebBaseEvent.Raise(new CustomEvent()); } } } /// <summary> /// custom error inheriting WebErrorEvent which is not allowed in high trust? can't believe that... /// </summary> public class CustomEvent : WebErrorEvent { public CustomEvent() : base("test", HttpContext.Current.Request, 100001, new ApplicationException("dummy")) { } } and the Web Config excerpt for high trust: <system.web> <trust level="High" originUrl="" />

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  • Value objects in DDD - Why immutable?

    - by Hobbes
    I don't get why value objects in DDD should be immutable, nor do I see how this is easily done. (I'm focusing on C# and Entity Framework, if that matters.) For example, let's consider the classic Address value object. If you needed to change "123 Main St" to "123 Main Street", why should I need to construct a whole new object instead of saying myCustomer.Address.AddressLine1 = "123 Main Street"? (Even if Entity Framework supported structs, this would still be a problem, wouldn't it?) I understand (I think) the idea that value objects don't have an identity and are part of a domain object, but can someone explain why immutability is a Good Thing? EDIT: My final question here really should be "Can someone explain why immutability is a Good Thing as applied to Value Objects?" Sorry for the confusion! EDIT: To clairfy, I am not asking about CLR value types (vs reference types). I'm asking about the higher level DDD concept of Value Objects. For example, here is a hack-ish way to implement immutable value types for Entity Framework: http://rogeralsing.com/2009/05/21/entity-framework-4-immutable-value-objects. Basically, he just makes all setters private. Why go through the trouble of doing this?

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  • Creating a smart text generator

    - by royrules22
    I'm doing this for fun (or as 4chan says "for teh lolz") and if I learn something on the way all the better. I took an AI course almost 2 years ago now and I really enjoyed it but I managed to forget everything so this is a way to refresh that. Anyway I want to be able to generate text given a set of inputs. Basically this will read forum inputs (or maybe Twitter tweets) and then generate a comment based on the learning. Now the simplest way would be to use a Markov Chain Text Generator but I want something a little bit more complex than that as the MKC basically only learns by word order (which word is more likely to appear after word x given the input text). I'm trying to see if there's something I can do to make it a little bit more smarter. For example I want it to do something like this: Learn from a large selection of posts in a message board but don't weight it too much For each post: Learn from the other comments in that post and weigh these inputs higher Generate comment and post See what other users' reaction to your post was. If good weigh it positively so you make more posts that are similar to the one made, and vice versa if negative. It's the weighing and learning from mistakes part that I'm not sure how to implement. I thought about Artificial Neural Networks (mainly because I remember enjoying that chapter) but as far as I can tell that's mainly used to classify things (i.e. given a finite set of choices [x1...xn] which x is this given input) not really generate anything. I'm not even sure if this is possible or if it is what should I go about learning/figuring out. What algorithm is best suited for this? To those worried that I will use this as a bot to spam or provide bad answers to SO, I promise that I will not use this to provide (bad) advice or to spam for profit. I definitely will not post it's nonsensical thoughts on SO. I plan to use it for my own amusement. Thanks!

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  • Presenting an image cropping interface

    - by wkw
    I'm trying to engineer a UI for cropping images in iphone OS and suspect I'm going about things the hard way. My goal is pretty much what the Tapbots duo have done with Pastebot. In that app, they dim the source image but provide a movable and resizable cropping view and the image you're cropping is in a zoomable scrollview; when you resize or move the underlying image, the cropping view adjusts appropriately. I mocked up a composite image which will give a sense of the design I'm after, along with how I presently have my view hierarchy setup, viewable here The approach I've started with is the following: UIImageView with the image to crop is in a scrollview, a plain UIView with black fill and suitable transparency/alpha setting is added in front of the imageview. I then use a custom UIView which is a sibling to the scrollview at a higher level, which implements the drawRect: method and for the most part calls CGImageCreateWithImageInRect to get the portion of the image's bitmap that matches the position of the cropping view and draws that to the CGContext. in the viewcontroller I'm using the UIScrollViewDelegate methods to track scrolling and passing those changes to the custom cropping UIView so it stays in sync with the scroll contentOffset. That much is finally working. But trying to keep in sync as the scrollview zoomScale changes is when I figured I should ask for help. Looking for suggestions or guidance. My initial approach just seems like more work than is required. Could this be done with a masking layer in the ImageView? And if so, how would I setup the tracking for moving and resizing the cropping rect? My experience working with layers is non-nil, but very limited thus far.

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  • What's next for all of these Microsoft "overlapping" and "enhanced" products ?

    - by pointlesspolitics
    Recently I attended a road show, organised by MS Gold Partner company in the UK. The products discussed were: SharePoint server (2010 and 2007), Exchange server, Office Communication Server 2007, Exchange hosted services Office Live meeting, Office Communicator, System Center Configuration Manager and Operation Manager, VMware, Windows 7 etc. As Microsoft claims the enhancement in the each product against higher version, I felt that clients are not much interested in all these details. For example Office Communicator, surely they have improved a lot the product and first site all said 'WOW' great product, but nobody wish to pay money for all these extra features. Some argued, they are bogged down by all these increased number of menus. They don't need soft call feature included with mobile call. It apply for all other products as well such as MS office (next what 2 ribbons ?), windows OS and many more. Indeed there must be good features in all these products, but is it worth to spend money and time to update the older system ? Also sometimes these feature will decrease the productivity instead increase it. *So do you think what ever enhancement MS is doing in the products is only for selling purpose, not a real use ?? and I think also keep the developer busy learning the new tools and features. * I am sure some some people here will argue that some people need this sort of features. But I am not talking about NASA or MI5 guys. I am talking of usual businesses and joe public. Any ideas welcome.

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  • Modeling a Generic Relationship (expressed in C#) in a Database

    - by StevenH
    This is most likely one for all you sexy DBAs out there: How would I effieciently model a relational database whereby I have a field in an "Event" table which defines a "SportType"? This "SportsType" field can hold a link to different sports tables E.g. "FootballEvent", "RubgyEvent", "CricketEvent" and "F1 Event". Each of these Sports tables have different fields specific to that sport. My goal is to be able to genericly add sports types in the future as required, yet hold sport specific event data (fields) as part of my Event Entity. Is it possible to use an ORM such as NHibernate / Entity framework / DataObjects.NET which would reflect such a relationship? I have thrown together a quick C# example to express my intent at a higher level: public class Event<T> where T : new() { public T Fields { get; set; } public Event() { EventType = new T(); } } public class FootballEvent { public Team CompetitorA { get; set; } public Team CompetitorB { get; set; } } public class TennisEvent { public Player CompetitorA { get; set; } public Player CompetitorB { get; set; } } public class F1RacingEvent { public List<Player> Drivers { get; set; } public List<Team> Teams { get; set; } } public class Team { public IEnumerable<Player> Squad { get; set; } } public class Player { public string Name { get; set; } public DateTime DOB { get; set;} }

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  • Reducing moire when downsampling halftone comic images.

    - by drawnonward
    How can I reduce moire effects when downsampling halftone comic book images during live zoom on an iPhone or iPad? I am writing a comic book viewer. It would be nice to provide higher resolution images and allow the user to zoom in while reading the comic book. However, my client is averse to moire effects and will not allow this feature if there are noticeable moire artifacts while zooming, which of course there are. Modifying the images to be less susceptible to moire would only work if the modifications were not perceptible. Blur was specifically prohibited, as is anything that removes the beloved halftone dots. The images are black and white halftone and line art. The originals are 600 dpi but what we ship with the application will be half that at best, so probably 2500 pixels or less tall. So what are my options? If I write a custom downsampling algorithm would it be fast enough for real time on these devices? Are there other tricks I can do? Would it work to just avoid the size ratios that have the most visual moire effects? As you zoom in an out, there are definitely peaks where the moire effects are worst. Is there a way to calculate what those points are and just zoom to a nearby scale that is not as bad? Any suggestions are welcome. I have very little experience with image and signal processing, but am enjoying the opportunity to learn. I know nothing of wavelets and acutance and other jargon, so please be verbose.

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  • Making text align equally in both IE and Chrome

    - by bobo
    <style type="text/css"> h2{ font-size:13px; line-height:16px; color:#000000; margin:0; padding:6px 22px; font-family: 'Times New Roman'; } div{ border:1px solid black; } </style> <div> <h2> ????????</h2> </div> Pasting the above codes here: http://htmledit.squarefree.com/ You will see that the text stays a little bit higher in the div in IE than in Chrome, I would like to make them consistent. By adding a &nbsp; after the text within the <h2>in IE, the text will automatically move up, which is consistent with Chrome. But I don't quite like this hack, so I would like to know if anybody knows what problem this is and recommends a better way to fix it if possible. Many thanks to you all. Note: this problem does not appear if the text is english only.

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  • (x86) Assembler Optimization

    - by Pindatjuh
    I'm building a compiler/assembler/linker in Java for the x86-32 (IA32) processor targeting Windows. High-level concepts of a "language" (in essential a Java API for creating executables) are translated into opcodes, which then are wrapped and outputted to a file. The translation process has several phases, one is the translation between languages: the highest-level code is translated into the medium-level code which is then translated into the lowest-level code (probably more than 3 levels). My problem is the following; if I have higher-level code (X and Y) translated to lower-level code (x, y, U and V), then an example of such a translation is, in pseudo-code: x + U(f) // generated by X + V(f) + y // generated by Y (An easy example) where V is the opposite of U (compare with a stack push as U and a pop as V). This needs to be 'optimized' into: x + y (essentially removing the "useless" code) My idea was to use regular expressions. For the above case, it'll be a regular expression looking like this: x:(U(x)+V(x)):null, meaning for all x find U(x) followed by V(x) and replace by null. Imagine more complex regular expressions, for more complex optimizations. This should work on all levels. What do you suggest? What would be a good approach to optimize in these situations?

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  • Should a new language compiler target the JVM?

    - by Pindatjuh
    I'm developing a new language. My initial target was to compile to native x86 for the Windows platform, but now I am in doubt. I've seen some new languages target the JVM (most notable Scala and Clojure). Ofcourse it's not possible to port every language easily to the JVM; to do so, it may lead to small changes to the language and it's design. So that's the reason behind this doubt, and thus this question: Is targetting the JVM a good idea, when creating a compiler for a new language? Or should I stick with x86? I have experience in generating JVM bytecode. Are there any workarounds to JVM's GC? The language has deterministic implicit memory management. How to produce JIT-compatible bytecode, such that it will get the highest speedup? Is it similar to compiling for IA-32, such as the 4-1-1 muops pattern on Pentium? I can imagine some advantages (please correct me if I'm wrong): JVM bytecode is easier than x86. Like x86 communicates with Windows, JVM communicates with the Java Foundation Classes. To provide I/O, Threading, GUI, etc. Implementing "lightweight"-threads.I've seen a very clever implementation of this at http://www.malhar.net/sriram/kilim/. Most advantages of the Java Runtime (portability, etc.) The disadvantages, as I imagined, are: Less freedom? On x86 it'll be more easy to create low-level constructs, while JVM has a higher level (more abstract) processor. Most disadvantages of the Java Runtime (no native dynamic typing, etc.)

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  • Hadoop reduce task gets hung

    - by user806098
    I set up a hadoop cluster with 4 nodes, When running a map-reduce task, the map task finishes quickly, while the reduce task hangs at 27% percent. I checked the log, it's that the reduce task fails to fetch map output from map nodes. The job tracker log of master shows messages like this: 2011-06-27 19:55:14,748 INFO org.apache.hadoop.mapred.JobTracker: Adding task (REDUCE) 'attempt_201106271953_0001_r_000000_0' to tip task_201106271953_0001_r_000000, for tracker 'tracker_web30.bbn.com.cn:localhost/127.0.0.1:56476' And the name node log of master shows messages like this: 2011-06-27 14:00:52,898 INFO org.apache.hadoop.ipc.Server: IPC Server handler 4 on 54310, call register(DatanodeRegistration(202.106.199.39:50010, storageID=DS-1989397900-202.106.199.39-50010-1308723051262, infoPort=50075, ipcPort=50020)) from 192.168.225.19:16129: error: java.io.IOException: verifyNodeRegistration: unknown datanode 202.106.199.3 9:50010 However, neither the "web30.bbn.com.cn" or 202.106.199.39, 202.106.199.3 is the slave node. I think such ip/domains appear because hadoop fails to resolve a node(first in the Intranet DNS server), then it goes to a higher-level DNS server, later to the top, still fails, then the "junk" ip/domains are returned. But I checked my config, it goes like this: /etc/hosts: 127.0.0.1 localhost.localdomain localhost ::1 localhost6.localdomain6 localhost6 192.168.225.16 master 192.168.225.66 slave1 192.168.225.20 slave5 192.168.225.17 slave17 conf/core-site.xml: hadoop.tmp.dir /root/hadoop_tmp/hadoop_${user.name} fs.default.name hdfs://master:54310 io.sort.mb 1024 hdfs-site.xml: dfs.replication 3 masters: master slaves: master slave1 slave5 slave17 Also, all firewalls(iptables) are turned off, and ssh between each 2 nodes is ok. so I don't know where exact the error comes from. Please help. Thanks a lot.

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  • Appropriate SQL Server Permissions for Developers

    - by BJ Safdie
    After a couple of Google searches and a quick look at questions here, I cannot seem to find what I thought would be a cookbook answer for SQL Server permissions. As I often see in small shops, most developers here were using an admin account for SQL Server while developing. I want to set up roles and permissions that I can assign to developers so that we can get our jobs done, but also do so with the minimum permissions required. Can anyone offer advice on what SQL Server permissions to assign? Components: SQL Server 2008 SQL Server Reporting Services (SSRS) 2008 SQL Server Integration Services (SSIS) 2008 Platforms: Production Staging/QA Development/Integration We are running "Mixed Mode" security because of some legacy apps and networks, but are moving to Windows Auth. I am not sure if that really affects the role set up. I plan to set up access for Developers to Prod and Staging/QA DBs as Read-Only. However, I still want developers to retain the ability to run Profiling. We need Deployment accounts with higher privilege levels. We are currently trying to figure out exactly what privileges we need for SSIS package deployments. Within the Development Server, Developers need broad privileges. However, I am not sure that just making them all admins is really the best choice. It's hard to believe that no one has published a decent example script that sets up these kinds of roles with a good set of appropriate permissions for developers and deployers. We can probably figure this all out by locking things down and then adding permissions as we discover the need, but that will be way too big a PITA for everyone. Can anyone point me to, or provide, a good exemplar for permissions for these kinds of roles on these kinds of platforms?

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  • Web-app currency input/manipulation/calculation with javascript .. there has got to be a better (fra

    - by dreftymac
    BACKGROUND: I am of the "user-input-lockdown" school of thought. Whenever possible, I try to mistrust and sanitize user input, both client side and server side; and I try to take multiple opportunities to restrict possible inputs to a known subset of possibilities, usually this means providing a lot of checkboxes and select lists. (This is from the usability side of things, I know security-wise that malicious users can easily bypass fixed user input GUI controls). PROBLEM: Anyway, the problem always arises with non-fixed input of currency. Whenever I have to accept a freely-specified dollar amount as user input, I always have to confront these problems/annoyances and it is always painful: 1) Make sure to give the user two input boxes for each currency_datapoint, one for the whole_dollar_part and another for the fractional_pennies_part 2) Whenever the user changes a currency_datapoint, provide keystroke-by-keystroke GUI feedback to let them know whether the currency_datapoint is well-formed, with context-appropriate validation rules (e.g., no negatives?, nonzero only?, numeric only!, no non-numeric punctuation! no symbols!) 3) For display purposes, every user-provided currency_datapoint should be translated to human-readable currency formatting (dollar sign, period, commas provided by the app, where appropriate) 4) For calculation purposes, every user-provided currency_datapoint has to be converted to integer (all pennies, to avoid floating point errors) and summed into a grand total with zero or more subtotals. 5) Every user-provided currency_datapoint should be displayed or displayable in a nice "tabular" format, which auto-updates as the user enters each currency_datapoint, including a baloon that warns when one or more currency_datapoints is not well-formed. I seem to be re-inventing this wheel every time I have to work with currency in Javascript on the client side (server side is a bit more flexible since most programming languages have higher-level currency formatting logic). QUESTION: Has anyone out there solved the problem of dealing with the above issues, client side, in a way that is server-side-technology-stack agnostic, (preferrably plain javascript or jquery)? This is getting old, there has to be a better way.

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  • AJAX Autosave

    - by antony.trupe
    What's the best javascript library, or plugin or extension to a library, that has implemented autosaving functionality? The specific need is to be able to 'save' a data grid. Think gmail and Google Documents' autosave. I don't want to reinvent the wheel if its already been invented. I'm looking for an existing implementation of the magical autoSave() function. Auto-Saving:pushing to server code that saves to persistent storage, usually a DB. The server code framework is outside the scope of this question. Note that I'm not looking for an Ajax library, but a library/framework a level higher: interacts with the form itself. daemach introduced an implementation on top of jQuery @ http://ideamill.synaptrixgroup.com/?p=3. I'm not convinced it meets the lightweight and well engineered criteria though. Criteria stable, lightweight, well engineered saves onChange and/or onBlur saves no more frequently then a given number of milliseconds handles multiple updates happening at the same time doesn't save if no change has occurred since last save saves to different urls per input class Updates I've stabilized a solution. See my answer below for links.

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  • F# Seq.initInfinite giving StackOverflowException

    - by TrueWill
    I'm learning F#, and I am having trouble understanding why this crashes. It's an attempt to solve Project Euler problem 2. let rec fibonacci n = if n = 1 then 1 elif n = 2 then 2 else fibonacci (n - 1) + fibonacci (n - 2) let debugfibonacci n = printfn "CALC: %d" n fibonacci n let isEven n = n % 2 = 0 let isUnderLimit n = n < 55 let getSequence = //[1..30] Seq.initInfinite (fun n -> n) |> Seq.map debugfibonacci |> Seq.filter isEven |> Seq.takeWhile isUnderLimit Seq.iter (fun x -> printfn "%d" x) getSequence The final version would call a sum function (and would have a higher limit than 55), but this is learning code. As is, this gives a StackOverflowException. However, if I comment in the [1..30] and comment out the Seq.initInfinite, I get: CALC: 1 CALC: 2 2 CALC: 3 CALC: 4 CALC: 5 8 CALC: 6 CALC: 7 CALC: 8 34 CALC: 9 CALC: 10 CALC: 11 It appears to be generating items on demand, as I would expect in LINQ. So why does it blow up when used with initInfinite?

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  • Does Perl auto-vivify variables used as references in subroutine calls?

    - by FM
    I've declared 2010 to be the year of higher-order programming, so I'm learning Haskell. The introduction has a slick quick-sort demo, and I thought, "Hey, that's easy to do in Perl". It turned to be easier than I expected. Note that I don't have to worry about whether my partitions ($less and $more) are defined. Normally you can't use an undefined value as an array reference. use strict; use warnings; use List::MoreUtils qw(part); my @data = (5,6,7,4,2,9,10,9,5,1); my @sorted = qsort(@data); print "@sorted\n"; sub qsort { return unless @_; my $pivot = shift @_; my ($less, $more) = part { $_ < $pivot ? 0 : 1 } @_; # Works, even though $less and $more are sometimes undefined. return qsort(@$less), $pivot, qsort(@$more); } As best I can tell, Perl will auto-vivify a variable that you try to use as a reference -- but only if you are passing it to a subroutine. For example, my call to foo() works, but not the attempted print. use Data::Dumper qw(Dumper); sub foo { print "Running foo(@_)\n" } my ($x); print Dumper($x); # Fatal: Can't use an undefined value as an ARRAY reference. # print @$x, "\n"; # But this works. foo(@$x); # Auto-vivification: $x is now []. print Dumper($x); My questions: Am I understanding this behavior correctly? What is the explanation or reasoning behind why Perl does this? Is this behavior explained anywhere in the docs?

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  • Rails running multiple delayed_job - lock tables

    - by pepernik
    Hey. I use delayed_job for background processing. I have 8 CPU server, MySQL and I start 7 delayed_job processes RAILS_ENV=production script/delayed_job -n 7 start Q1: I'm wondering is it possible that 2 or more delayed_job processes start processing the same process (the same record-row in the database delayed_jobs). I checked the code of the delayed_job plugin but can not find the lock directive in a way it should be. I think each process should lock the database table before executing an UPDATE on lock_by column. They lock the record simply by updating the locked_by field (UPDATE delayed_jobs SET locked_by...). Is that really enough? No locking needed? Why? I know that UPDATE has higher priority than SELECT but I think this does not have the effect in this case. My understanding of the multy-threaded situation is: Process1: Get waiting job X. [OK] Process2: Get waiting jobs X. [OK] Process1: Update locked_by field. [OK] Process2: Update locked_by field. [OK] Process1: Get waiting job X. [Already processed] Process2: Get waiting jobs X. [Already processed] I think in some cases more jobs can get the same information and can start processing the same process. Q2: Is 7 delayed_jobs a good number for 8CPU server? Why yes/not. Thx 10x!

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  • ExecutorService memory leak on exception

    - by TofuBeer
    I am having a hard time tracking this down since the profiler keeps crashing (hotspot error). Before I go too deep into figuring it out I'd like to know if I really have a problem or not :-) I have a few thread pools created via: Executors.newFixedThreadPool(10); The threads connect to different web sites and, on occasion, I get connection refused and wind up throwing an exception. When I later on call Future.get() to get the result it will then catch the ExecutionException that wraps the exception that was thrown when the connection could not be made. The program uses a fairly constant amount of memory up until the point in time that the exceptions get thrown (they tend to happen in batches when a particular site is overloaded). After that point the memory again remains constant but at a higher level. So my question is along the lines of is the memory behaviour (reported by "top" on Unix) expected because the exceptions just triggered something or do I probably have an actual leak that I'll need to track down? Additionally when Future.get() throws an exception is there anything else I need to do besides catch the exception (such as call Future.cancel() on it)?

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  • When to choose which machine learning classifier?

    - by LM
    Suppose I'm working on some classification problem. (Fraud detection and comment spam are two problems I'm working on right now, but I'm curious about any classification task in general.) How do I know which classifier I should use? (Decision tree, SVM, Bayesian, logistic regression, etc.) In which cases is one of them the "natural" first choice, and what are the principles for choosing that one? Examples of the type of answers I'm looking for (from Manning et al.'s "Introduction to Information Retrieval book": http://nlp.stanford.edu/IR-book/html/htmledition/choosing-what-kind-of-classifier-to-use-1.html): a. If your data is labeled, but you only have a limited amount, you should use a classifier with high bias (for example, Naive Bayes). [I'm guessing this is because a higher-bias classifier will have lower variance, which is good because of the small amount of data.] b. If you have a ton of data, then the classifier doesn't really matter so much, so you should probably just choose a classifier with good scalability. What are other guidelines? Even answers like "if you'll have to explain your model to some upper management person, then maybe you should use a decision tree, since the decision rules are fairly transparent" are good. I care less about implementation/library issues, though. Also, for a somewhat separate question, besides standard Bayesian classifiers, are there 'standard state-of-the-art' methods for comment spam detection (as opposed to email spam)? [Not sure if stackoverflow is the best place to ask this question, since it's more machine learning than actual programming -- if not, any suggestions for where else?]

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  • Opening port 80 with Java application on Ubuntu

    - by Featheast
    What I need to do is running a Java application which is a RESTful service server side writtern by Restlet. And this service will be called by another app running on Google App Engine. Because of the restriction of GAE, every http call is limited to port 80 and 443 (http and https) with HttpUrlConnection class. As a result, I have to deploy my server side application on port 80 or 443. However, because the app is running on Ubuntu, and those ports under 1024 cannot be accessed by non-root user, then a Access Denied exception will be thrown when I run my app. The solutions that have come into my mind includs: Changing the security policy of JRE, which is the files resides in /lib/security/java.policy, to grantjava.net.SocketPermission "*.80" "listen, connect, accept, resolve" permission?However, neither using command line to include this file or overrides the content in JRE's java.policy file, the same exception keeps coming out. try to login as a root user, however because my unfamiliarity with Unix, I don't know how to do it. another solution I haven't try is to map all calls to 80 to a higher port like 1234, then I can deploy my app on 1234 without problem, and GAE call send request to port 80. But how to connect the missing gap is still a problem. Currently I am using a "hacking" method, which is to package the application into a jar file, and sudo running the jar file with root privilege. It works now, but definitely not appropriate in the real deployment environment. So if anyone have any idea about the solution, thanks very much!

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  • Collision detections and how efficient they are

    - by Shadow
    How exactly do you implement collision detection? What are the costs involved? Do different platforms(c/c++, java, cocoa/iphone, flash, directX) have different optimizations for calculating collisions. And lastly are there libraries available to do this for me, or some that I can just interpret for my platform of choice? As I understand it you would need to loop through the collision map and find the area in question and then compair the input thing(e.g. a sprite) to the type of pixel that is in the questioned area. I understand the very basic idea, but I don't understand the underlying implementation or even a higher level one for that matter. It would seem that this type of detection, or any for that matter, is very costly. Tile map? Bit array? How are these created from an image(I would guess looping and doing stuff)? The reason I ask this question is to get a better understanding of the efficiency behind the scenes and to understand exactly what is going on. Links, references, or examples would be very helpful. I know this question is a bit longwinded so any help or references would be very welcome. Thanks SO!

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  • Submit button not focused even though tabindex is properly set

    - by Nicsoft
    Hello, I have defined tabindex for the input fields in a form. When tabbing through the input fields the submit button is never getting the focus, some other input fields in a different form on the page gets the focus. Those are all having tabindexes higher than 3. How come? <form action="subscription.php" name="subscribe" method="post" onsubmit="return isValidEmailAndEqual()"> <p id="formlabel">E-mail</p> <input type="text" name="email1" tabindex=1> <br/> <p id="formlabel">Repeat e-mail</p> <input type="text" name="email2" tabindex=2> <br/> <input id="inputsubmit" type="submit" value="Subscribe" tabindex=3> </form> .css: input { background-color : #333; border: 1px solid #EEE; color: #EEE; margin-bottom: 6px; margin-top: 4px; padding: 1px; width : 200px; } #inputsubmit { background-color : #d7e6f1; border: 1px solid #EEE; color: #0000ff; margin-bottom: 6px; margin-top: 4px; padding: 1px; width : 200px; } #inputsubmit:hover { cursor: pointer; cursor: hand; background-color : #d7e6f1; border: 1px solid #0000ff; color: #0000ff; margin-bottom: 6px; margin-top: 4px; padding: 1px; width : 200px; } p#formlabel{ width: 100; } Thanks in advance!

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  • C++ operator new, object versions, and the allocation sizes

    - by mizubasho
    Hi. I have a question about different versions of an object, their sizes, and allocation. The platform is Solaris 8 (and higher). Let's say we have programs A, B, and C that all link to a shared library D. Some class is defined in the library D, let's call it 'classD', and assume the size is 100 bytes. Now, we want to add a few members to classD for the next version of program A, without affecting existing binaries B or C. The new size will be, say, 120 bytes. We want program A to use the new definition of classD (120 bytes), while programs B and C continue to use the old definition of classD (100 bytes). A, B, and C all use the operator "new" to create instances of D. The question is, when does the operator "new" know the amount of memory to allocate? Compile time or run time? One thing I am afraid of is, programs B and C expect classD to be and alloate 100 bytes whereas the new shared library D requires 120 bytes for classD, and this inconsistency may cause memory corruption in programs B and C if I link them with the new library D. In other words, the area for extra 20 bytes that the new classD require may be allocated to some other variables by program B and C. Is this assumption correct? Thanks for your help.

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  • why does entity framework+mysql provider enumeration returns partial results with no exceptions

    - by Freddy Rios
    I'm trying to make sense of a situation I have using entity framework on .net 3.5 sp1 + MySQL 6.1.2.0 as the provider. It involves the following code: Response.Write("Products: " + plist.Count() + "<br />"); var total = 0; foreach (var p in plist) { //... some actions total++; //... other actions } Response.Write("Total Products Checked: " + total + "<br />"); Basically the total products is varying on each run, and it isn't matching the full total in plist. Its varies widely, from ~ 1/5th to half. There isn't any control flow code inside the foreach i.e. no break, continue, try/catch, conditions around total++, anything that could affect the count. As confirmation, there are other totals captured inside the loop related to the actions, and those match the lower and higher total runs. I don't find any reason to the above, other than something in entity framework or the mysql provider that causes it to end the foreach when retrieving an item. The body of the foreach can have some good variation in time, as the actions involve file & network access, my best shot at the time is that when the .net code takes beyond certain threshold there is some type of timeout in the underlying framework/provider and instead of causing an exception it is silently reporting no more items for enumeration. Can anyone give some light in the above scenario and/or confirm if the entity framework/mysql provider has the above behavior? Update: I can't reproduce the behavior by using Thread.Sleep in a simple foreach in a test project, not sure where else to look for this weird behavior :(.

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