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  • Building an extension framework for a Rails app

    - by obvio171
    I'm starting research on what I'd need in order to build a user-level plugin system (like Wordpress plugins) for a Rails app, so I'd appreciate some general pointers/advice. By user-level plugin I mean a package a user can extract into a folder and have it show up on an admin interface, allowing them to add some extra configuration and then activate it. What is the best way to go about doing this? Is there any other opensource project that does this already? What does Rails itself already offer for programmer-level plugins that could be leveraged? Any Rails plugins that could help me with this? A plugin would have to be able to: run its own migrations (with this? it's undocumented) have access to my models (plugins already do) have entry points for adding content to views (can be done with content_for and yield) replace entire views or partials (how?) provide its own admin and user-facing views (how?) create its own routes (or maybe just announce its presence and let me create the routes for it, to avoid plugins stepping on each other's toes) Anything else I'm missing? Also, is there a way to limit which tables/actions the plugin has access to concerning migrations and models, and also limit their access to routes (maybe letting them include, but not remove routes)? P.S.: I'll try to keep this updated, compiling stuff I figure out and relevant answers so as to have a sort of guide for others.

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  • Fast sign in C++ float...are there any platform dependencies in this code?

    - by Patrick Niedzielski
    Searching online, I have found the following routine for calculating the sign of a float in IEEE format. This could easily be extended to a double, too. // returns 1.0f for positive floats, -1.0f for negative floats, 0.0f for zero inline float fast_sign(float f) { if (((int&)f & 0x7FFFFFFF)==0) return 0.f; // test exponent & mantissa bits: is input zero? else { float r = 1.0f; (int&)r |= ((int&)f & 0x80000000); // mask sign bit in f, set it in r if necessary return r; } } (Source: ``Fast sign for 32 bit floats'', Peter Schoffhauzer) I am weary to use this routine, though, because of the bit binary operations. I need my code to work on machines with different byte orders, but I am not sure how much of this the IEEE standard specifies, as I couldn't find the most recent version, published this year. Can someone tell me if this will work, regardless of the byte order of the machine? Thanks, Patrick

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  • kick off a map reduce job from my java/mysql webapp

    - by Brian
    Hi guys, I need a bit of archecture advice. I have a java based webapp, with a JPA based ORM backed onto a mysql relational database. Now, as part of the application I have a batch job that compares thousands of database records with each other. This job has become too time consuming and needs to be parallelized. I'm looking at using mapreduce and hadoop in order to do this. However, I'm not too sure about how to integrate this into my current architecture. I think the easiest initial solution is to find a way to push data from mysql into hadoop jobs. I have done some initial research on this and found the following relevant information and possibilities: 1) https://issues.apache.org/jira/browse/HADOOP-2536 this gives an interesting overview of some inbuilt JDBC support 2) This article http://architects.dzone.com/articles/tools-moving-sql-database describes some third party tools to move data from mysql to hadoop. To be honest I'm just starting out with learning about hbase and hadoop but I really don't know how to integrate this into my webapp. Any advice is greatly appreciated. cheers, Brian

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  • Bash and regex problem : check for tokens entered into a Coke vending machine

    - by Michael Mao
    Hi all: Here is a "challenge question" I've got from Linux system programming lecture. Any of the following strings will give you a Coke if you kick: L = { aaaa, aab, aba, baa, bb, aaaa"a", aaaa"b", aab"a", … ab"b"a, ba"b"a, ab"bbbbbb"a, ... } The letters shown in wrapped double quotes indicate coins that would have fallen through (but those strings are still part of the language in this example). Exercise (a bit hard) show this is the language of a regular expression And this is what I've got so far : #!/usr/bin/bash echo "A bottle of Coke costs you 40 cents" echo -e "Please enter tokens (a = 10 cents, b = 20 cents) in a sequence like 'abba' :\c" read tokens #if [ $tokens = aaaa ]||[ $tokens = aab ]||[ $tokens = bb ] #then # echo "Good! now a coke is yours!" #else echo "Thanks for your money, byebye!" if [[ $token =~ 'aaaa|aab|bb' ]] then echo "Good! now a coke is yours!" else echo "Thanks for your money, byebye!" fi Sadly it doesn't work... always outputs "Thanks for your money, byebye!" I believe something is wrong with syntax... We didn't provided with any good reference book and the only instruction from the professor was to consult "anything you find useful online" and "research the problem yourself" :( I know how could I do it in any programming language such as Java, but get it done with bash script + regex seems not "a bit hard" but in fact "too hard" for anyone with little knowledge on something advanced as "lookahead"(is this the terminology ?) I don't know if there is a way to express the following concept in the language of regex: Valid entry would consist of exactly one of the three components : aaaa, aab and bb, regardless of order, followed by an arbitrary sequence of a or b's So this is what is should be like : (a{4}Ua{2}bUb{2})(aUb)* where the content in first braces is order irrelevant. Thanks a lot in advance for any hints and/or tips :)

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  • How would I go about sharing variables in a class with Lua?

    - by Nicholas Flynt
    I'm fairly new to Lua, I've been working on trying to implement Lua scripting for logic in a Game Engine I'm putting together. I've had no trouble so far getting Lua up and running through the engine, and I'm able to call Lua functions from C and C functions from Lua. The way the engine works now, each Object class contains a set of variables that the engine can quickly iterate over to draw or process for physics. While game objects all need to access and manipulate these variables in order for the Game Engine itself to see any changes, they are free to create their own variables, a Lua is exceedingly flexible about this so I don't forsee any issues. Anyway, currently the Game Engine side of things are sitting in C land, and I really want them to stay there for performance reasons. So in an ideal world, when spawning a new game object, I'd need to be able to give Lua read/write access to this standard set of variables as part of the Lua object's base class, which its game logic could then proceed to run wild with. So far, I'm keeping two separate tables of objects in place-- Lua spawns a new game object which adds itself to a numerically indexed global table of objects, and then proceeds to call a C++ function, which creates a new GameObject class and registers the Lua index (an int) with the class. So far so good, C++ functions can now see the Lua object and easily perform operations or call functions in Lua land using dostring. What I need to do now is take the C++ variables, part of the GameObject class, and expose them to Lua, and this is where google is failing me. I've encountered a very nice method here which details the process using tags, but I've read that this method is deprecated in favor of metatables. What is the ideal way to accomplish this? Is it worth the hassle of learning how to pass class definitions around using libBind or some equivalent method, or is there a simple way I can just register each variable (once, at spawn time) with the global lua object? What's the "current" best way to do this, as of Lua 5.1.4?

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  • A way for a file to have its own MD5 inside? Or a string that is it's own MD5?

    - by Eli
    Hi all, In considering several possible solutions to a recent task, I found myself considering how to get a php file that includes it's own MD5 hash. I ended up doing something else, but the question stayed with me. Something along the lines of: <?php echo("Hello, my MD5 is [MD5 OF THIS FILE HERE]"); ?> Whatever placeholder you have in the file, the second you take its MD5 and insert it, you've changed it, which changes it's MD5, etc. Edit: Perhaps I should rephrase my question: Does anyone know if it has been proven impossible, or if there has been any research on an algorithm that would result in a file containing it's own MD5 (or other hash)? I suppose if the MD5 was the only content in the file, then the problem can be restated as how to find a string that is it's own MD5. It may well be impossible for us to create a process that will result in such a thing, but I can't think of any reason the solution itself can't exist. The question is basically whether it really is impossible, simply improbable (on the order of monkeys randomly typing Shakespeare), or actually solvable by somebody smarter than myself.

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  • DQL delete from multiple tables (doctrine)

    - by singer
    Need to perform DQL delete from multple related tables. In SQL it is something like this: DELETE r1,r2 FROM ComRealty_objects r1, com_realty_objects_phones r2 WHERE r1.id IN (10,20) AND r2.id_object IN (10,20) I need to perform this statement using DQL, but I'm stuck on this :( <?php $dql = Doctrine_Query::create() ->delete('phones, comrealtyobjects') ->from('ComRealtyObjects comrealtyobjects') ->from('ComRealtyObjectsPhones phones') ->whereIn("comrealtyobjects.id", $ids) ->whereIn("phones.id_object", $ids); echo($dql->getSqlQuery()); ?> But DQL parser gives me this result: DELETE FROM `com_realty_objects_phones`, `ComRealty_objects` WHERE (`id` IN (?) AND `id_object` IN (?)) Searching google and stack overflow I found this(useful) topic: http://stackoverflow.com/questions/2247905/what-is-the-syntax-for-a-multi-table-delete-on-a-mysql-database-using-doctrine But this is not exactly my case - there was delete from single table. If there is a way to override dql parser behaviour? Or maybe some other way to delete records from multiple tables using doctrine. Note: If you are using doctrine behaviours(Doctrine_Record_Generator) you need first to initialize those tables using Doctrine_Core::initializeModels() to perform DQL operations on them.

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  • OO Design / Patterns - Fat Model Vs Transaction Script?

    - by ben
    Ok, 'Fat' Model and Transaction Script both solve design problems associated with where to keep business logic. I've done some research and popular thought says having all business logic encapsulated within the model is the way to go (mainly since Transaction Script can become really complex and often results in code duplication). However, how does this work if I want to use the TDG of a second Model in my business logic? Surely Transaction Script presents a neater, less coupled solution than using one Model inside the business logic of another? A practical example... I have two classes: User & Alert. When pushing User instances to the database (eg, creating new user accounts), there is a business rule that requires inserting some default Alerts records too (eg, a default 'welcome to the system' message etc). I see two options here: 1) Add this rule as a User method, and in the process create a dependency between User and Alert (or, at least, Alert's Table Data Gateway). 2) Use a Transaction Script, which avoids the dependency between models. (Also, means the business logic is kept in a 'neutral' class & easily accessible by Alert. That probably isn't too important here, though). User takes responsibility for it's own validation etc, however, but because we're talking about a business rule involving two Models, Transaction Script seems like a better choice to me. Anyone spot flaws with this approach?

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  • Neural Network with softmax activation

    - by Cambium
    This is more or less a research project for a course, and my understanding of NN is very/fairly limited, so please be patient :) ============== I am currently in the process of building a neural network that attempts to examine an input dataset and output the probability/likelihood of each classification (there are 5 different classifications). Naturally, the sum of all output nodes should add up to 1. Currently, I have two layers, and I set the hidden layer to contain 10 nodes. I came up with two different types of implementations 1) Logistic sigmoid for hidden layer activation, softmax for output activation 2) Softmax for both hidden layer and output activation I am using gradient descent to find local maximums in order to adjust the hidden nodes' weights and the output nodes' weights. I am certain in that I have this correct for sigmoid. I am less certain with softmax (or whether I can use gradient descent at all), after a bit of researching, I couldn't find the answer and decided to compute the derivative myself and obtained softmax'(x) = softmax(x) - softmax(x)^2 (this returns an column vector of size n). I have also looked into the MATLAB NN toolkit, the derivative of softmax provided by the toolkit returned a square matrix of size nxn, where the diagonal coincides with the softmax'(x) that I calculated by hand; and I am not sure how to interpret the output matrix. I ran each implementation with a learning rate of 0.001 and 1000 iterations of back propagation. However, my NN returns 0.2 (an even distribution) for all five output nodes, for any subset of the input dataset. My conclusions: o I am fairly certain that my gradient of descent is incorrectly done, but I have no idea how to fix this. o Perhaps I am not using enough hidden nodes o Perhaps I should increase the number of layers Any help would be greatly appreciated! The dataset I am working with can be found here (processed Cleveland): http://archive.ics.uci.edu/ml/datasets/Heart+Disease

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  • Application log aggregation, management and notifications...

    - by Matthew Savage
    I'm wondering what everyone is using for logging, log management and log aggregation on their systems. I am working in a company which uses .NET for all it's applications and all systems are Windows based. Currently each application looks after its own logging and notifications of failures (e.g. if app A fails it will send out its own 'call for help' to an admin). While this current practice works its a bit hacky and hard to manage. I've been trying to find some options for making this work better and I've come up with the following: log4net & Chainsaw (ah, if it works). Logging via log4net or another framework into a central database & rolling our own management tool. Logging to the Windows event log and using MOM or System Center Operations Manager to aggregate and manage each of these servers & their apps. A hand-rolled solution to suck all the log files into one point and work some magic across them. Essentially what we are after is something which can pull log entries all together and allow for some analytics to be run across them, plus use a kind of event based system to, for example, send out a warning email when there have been 30+ warning level logs for an application in the last x minutes. So is there anything I've missed, or something someone else can suggest?

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  • Writing fortran robust and "modern" code

    - by Blklight
    In some scientific environments, you often cannot go without FORTRAN as most of the developers only know that idiom, and there is lot of legacy code and related experience. And frankly, there are not many other cross-platform options for high performance programming ( C++ would do the task, but the syntax, zero-starting arrays, and pointers are too much for most engineers ;-) ). I'm a C++ guy but I'm stuck with some F90 projects. So, let's assume a new project must use FORTRAN (F90), but I want to build the most modern software architecture out of it. while being compatible with most "recent" compilers (intel ifort, but also including sun/HP/IBM own compilers) So I'm thinking of imposing: global variable forbidden, no gotos, no jump labels, "implicit none", etc. "object-oriented programming" (modules with datatypes + related subroutines) modular/reusable functions, well documented, reusable libraries assertions/preconditions/invariants (implemented using preprocessor statements) unit tests for all (most) subroutines and "objects" an intense "debug mode" (#ifdef DEBUG) with more checks and all possible Intel compiler checks possible (array bounds, subroutine interfaces, etc.) uniform and enforced legible coding style, using code processing tools C stubs/wrappers for libpthread, libDL (and eventually GPU kernels, etc.) C/C++ implementation of utility functions (strings, file operations, sockets, memory alloc/dealloc reference counting for debug mode, etc.) ( This may all seem "evident" modern programming assumptions, but in a legacy fortran world, most of these are big changes in the typical programmer workflow ) The goal with all that is to have trustworthy, maintainable and modular code. Whereas, in typical fortran, modularity is often not a primary goal, and code is trustworthy only if the original developer was very clever, and the code was not changed since then ! (i'm a bit joking here, but not much) I searched around for references about object-oriented fortran, programming-by-contract (assertions/preconditions/etc.), and found only ugly and outdated documents, syntaxes and papers done by people with no large-scale project involvement, and dead projects. Any good URL, advice, reference paper/books on the subject?

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  • Using MSBuild 4 command line to publish ASP.NET web application

    - by meandmycode
    In previous msbuild we used the target '_CopyWebApplication' in order to build and convert the source of a project into a published site, this worked OK, but wasn't ideal. In .NET 4, the publishing process is somewhat more sophisticated and additionally seems a bit of a black box to understand. Whilst packages look great, I cannot fully understand how they can be harnessed by a build server, the build server would not get any manifest information, and equally, something (msbuild?) is CREATING this manifest information FROM the project file. In our build server, I ideally want to say, here is my csproj file, deploy it by the package configuration 'x'. I'm trying to understand the workflow I need to make this happen. Right now when I use _CopyWebApplication, the result is different to doing a publish from visual studio 2010, primarily that web.config transforms aren't processed, and obviously msdeploy isn't involved at all. Can somebody point me in the right direction, I believe I need to get msbuild to do the equiv of 'Build Deployment Package', and then use msdeploy to deploy this from our build server to our CI testing environments. I know this is a very vague post, but I hope somebody can give me some hints, I'll be continuing research also, so if I make any progress, I'll post my findings here. Thanks in advance, Stephen.

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  • Is a red-black tree my ideal data structure?

    - by Hugo van der Sanden
    I have a collection of items (big rationals) that I'll be processing. In each case, processing will consist of removing the smallest item in the collection, doing some work, and then adding 0-2 new items (which will always be larger than the removed item). The collection will be initialised with one item, and work will continue until it is empty. I'm not sure what size the collection is likely to reach, but I'd expect in the range 1M-100M items. I will not need to locate any item other than the smallest. I'm currently planning to use a red-black tree, possibly tweaked to keep a pointer to the smallest item. However I've never used one before, and I'm unsure whether my pattern of use fits its characteristics well. 1) Is there a danger the pattern of deletion from the left + random insertion will affect performance, eg by requiring a significantly higher number of rotations than random deletion would? Or will delete and insert operations still be O(log n) with this pattern of use? 2) Would some other data structure give me better performance, either because of the deletion pattern or taking advantage of the fact I only ever need to find the smallest item? Update: glad I asked, the binary heap is clearly a better solution for this case, and as promised turned out to be very easy to implement. Hugo

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  • What is the 'page lifecycle' of an ASP.NET MVC page, compared to ASP.NET WebForms?

    - by Simon
    What is the 'page lifecycle' of an ASP.NET MVC page, compared to ASP.NET WebForms? I'm tryin to better understand this 'simple' question in order to determine whether or not existing pages I have in a (very) simple site can be easily converted from ASP.NET WebForms. Either a 'conversion' of the process below, or an alternative lifecycle would be what I'm looking for. What I'm currently doing: (yes i know that anyone capable of answering my question already knows all this -- i'm just tryin to get a comparison of the 'lifecycle' so i thought i'd start by filling in what we already all know) Rendering the page: I have a master page which contains my basic template I have content pages that give me named regions from the master page into which I put content. In an event handler for each content page I load data from the database (mostly read-only). I bind this data to ASP.NET controls representing grids, dropdowns or repeaters. This data all 'lives' inside the HTML generated. Some of it gets into ViewState (but I wont go into that too much!) I set properties or bind data to certain items like Image or TextBox controls on the page. The page gets sent to the client rendered as non-reusable HTML. I try to avoid using ViewState other than what the page needs as a minimum. Client side (not using ASP.NET AJAX): I may use JQuery and some nasty tricks to find controls on the page and perform operations on them. If the user selects from a dropdown -- a postback is generated which triggers a C# event in my codebehind. This event may go to the database, but whatever it does a completely newly generated HTML page ends up getting sent back to the client. I may use Page.Session to store key value pairs I need to reuse later So with MVC how does this 'lifecycle' change?

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  • How to highlight the button untill the next view is changed in iphone?

    - by Pugal Devan
    Hi, I am new to iphone development. I have created five buttons in the view controller. If i clicked the button it goes to the corresponding view. Now i want to display the button in highlighted state when it is clicked. It should go back to the normal state only when i click the other button.(See the image below). I have set the another image for highigthting buttons when i clicked it, but it shows that highlighted state only one sec. Now i want to display the buttons highlighted till another button is clicked. Same like a Tabbar operations.(I have used buttons instead of tabbar for my requirements). Now i have used the following code, void didLoad { [btn1 setImage:[UIImage imageNamed:@"ContentColor.png"] forState:UIControlStateHighlighted]; [btn2 setImage:[UIImage imageNamed:@"bColor.png"] forState:UIControlStateHighlighted]; [btn3 setImage:[UIImage imageNamed:@"ShColor.png"] forState:UIControlStateHighlighted]; [btn4 setImage:[UIImage imageNamed:@"PicturesColor.png"] forState:UIControlStateHighlighted]; [btn5 setImage:[UIImage imageNamed:@"infoColor.png"] forState:UIControlStateHighlighted]; } Please help me out. Thanks.

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  • Parsing basic math equations for children's educational software?

    - by Simucal
    Inspired by a recent TED talk, I want to write a small piece of educational software. The researcher created little miniature computers in the shape of blocks called "Siftables". [David Merril, inventor - with Siftables in the background.] There were many applications he used the blocks in but my favorite was when each block was a number or basic operation symbol. You could then re-arrange the blocks of numbers or operation symbols in a line, and it would display an answer on another siftable block. So, I've decided I wanted to implemented a software version of "Math Siftables" on a limited scale as my final project for a CS course I'm taking. What is the generally accepted way for parsing and interpreting a string of math expressions, and if they are valid, perform the operation? Is this a case where I should implement a full parser/lexer? I would imagine interpreting basic math expressions would be a semi-common problem in computer science so I'm looking for the right way to approach this. For example, if my Math Siftable blocks where arranged like: [1] [+] [2] This would be a valid sequence and I would perform the necessary operation to arrive at "3". However, if the child were to drag several operation blocks together such as: [2] [\] [\] [5] It would obviously be invalid. Ultimately, I want to be able to parse and interpret any number of chains of operations with the blocks that the user can drag together. Can anyone explain to me or point me to resources for parsing basic math expressions? I'd prefer as much of a language agnostic answer as possible.

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  • SQL Server 2008: CASE vs IF-ELSE-IF vs GOTO

    - by Saharsh Shah
    I have some rules in my application and I have written the business logic of that rules in my procedure. At the time of creation of procedure I came to know that CASE statement won't work in my scenario. So I have tried two ways to perform same operations (using IF-ELSE-IF or GOTO) shown as below. Method 1 Using IF-ELSE-IF conditions: DECLARE @V_RuleId SMALLINT; IF (@V_RuleId = 1) BEGIN /*My business logic*/ END ELSE IF (@V_RuleId = 2) BEGIN /*My business logic*/ END ELSE IF (@V_RuleId = 3) BEGIN /*My business logic*/ END /* ... ... ... ...*/ ELSE IF (@V_RuleId = 19) BEGIN /*My business logic*/ END ELSE IF (@V_RuleId = 20) BEGIN /*My business logic*/ END Method 2 Using GOTO statement: DECLARE @V_RuleId SMALLINT, @V_Temp VARCHAR(100); SET @V_Temp = 'GOTO RULE' + CONVERT(VARCHAR, @V_RuleId); EXECUTE sp_executesql @V_Temp; RULE1: BEGIN /*My business logic*/ END RULE2: BEGIN /*My business logic*/ END RULE3: BEGIN /*My business logic*/ END /* ... ... ... ...*/ RULE19: BEGIN /*My business logic*/ END RULE20: BEGIN /*My business logic*/ END Today I have 20 rules. It can be increase to any number in future. If I can able to use CASE statement then I have not any problem with performance, but I can't do that so I am worried about the performance of my procedure. Also one thing to be noticed that this procedure will execute very frequently by application. My questions are: Is there any way to use CASE statement in my procedure? If not, which method is best to use in my procedure to improve the performance of my code? Thanks in advance...

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  • IE performance issues with offsetHeight and offsetWidth

    - by Paul
    I have a site that grabs the response text from an AJAX call and does 'innerHTML' on a div that is going to contain it. After I do the 'innerHTML' I process the DIV by traversing the whole hierarchy of nodes and grabbing their [offsetWidth/offsetHeight] to do some operations with it. Why not css style width/height? because sometimes those values are not available since I don't control what is coming from the AJAX response, plus I want the real box dimensions including borders/scrolls/padding. On large injections (let's say 7,000 new DOM elements) IE takes way longer time than FF/Safari just to get this [offsetWidth/offsetHeight], actually if I wasn't doing injection but just render the contents of the HTML in the browser and processing it, it would be much faster. But that is not an option since I have to inject it on a div that will contain it. Anybody has deal with this kind of issue before? is there an alternative to innerHTML, I have try using documentFragment to inject and process and the move it to the div and still I don't see much gain. How can I get the values that are available with [offsetWidth/offsetHeight]? Thanks a bunch for any suggestions. Paul

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  • Game of life in F# with accelerator

    - by jpalmer
    I'm trying to write life in F# using accelerator v2, but for some odd reason my output isn't square despite all my arrays being square - It appears that everything but a rectangular area in the top left of the matrix is being set to false. I've got no idea how this could be happening as all my operations should treat the entire array equally. Any ideas? open Microsoft.ParallelArrays open System.Windows.Forms open System.Drawing type IPA = IntParallelArray type BPA = BoolParallelArray type PAops = ParallelArrays let RNG = new System.Random() let size = 1024 let arrinit i = Array2D.init size size (fun x y -> i) let target = new DX9Target() let threearr = new IPA(arrinit 3) let twoarr = new IPA(arrinit 2) let onearr = new IPA(arrinit 1) let zeroarr = new IPA(arrinit 0) let shifts = [|-1;-1|]::[|-1;0|]::[|-1;1|]::[|0;-1|]::[|0;1|]::[|1;-1|]::[|1;0|]::[|1;1|]::[] let progress (arr:BPA) = let sums = shifts //adds up whether a neighbor is on or not |> List.fold (fun (state:IPA) t ->PAops.Add(PAops.Cond(PAops.Rotate(arr,t),onearr,zeroarr),state)) zeroarr PAops.Or(PAops.CompareEqual(sums,threearr),PAops.And(PAops.CompareEqual(sums,twoarr),arr)) //rule for life let initrandom () = Array2D.init size size (fun x y -> if RNG.NextDouble() > 0.5 then true else false) type meform () as self= inherit Form() let mutable array = new BoolParallelArray(initrandom()) let timer = new System.Timers.Timer(1.0) //redrawing timer do base.DoubleBuffered <- true do base.Size <- Size(size,size) do timer.Elapsed.Add(fun _ -> self.Invalidate()) do timer.Start() let draw (t:Graphics) = array <- array |> progress let bmap = new System.Drawing.Bitmap(size,size) target.ToArray2D array |> Array2D.iteri (fun x y t -> if not t then bmap.SetPixel(x,y,Color.Black)) t.DrawImageUnscaled(bmap,0,0) do self.Paint.Add(fun t -> draw t.Graphics) do Application.Run(new meform())

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  • CouchDB, HDFS, HBase or which is right for my situation?

    - by Lucas
    Hello all, This question is regarding data storage systems such as CouchDB, HDFS and HBase, specifically, which is right. I am looking at making a simple and customized Document Management System for my organization. Basically, we need the ability to store some Word Documents, PDFs and other similar files. I also want to store metadata about these files (e.g., Author, Dates, etc). Usage permissions would also be handy, but that can probably be built using meta-data. I would also need the ability to full-text index. The ability to version, while not required would be extremely useful. I would like the ability to simply add hardware to expand the resources of the system and the system must support Network Attached Storage over the CIFS or NFS protocol(s). I have read about CouchDB, HDFS and HBase. My preferred programming language is C# as all of my end-users will be running Windows machines and I will want to make both web and winforms client implementations. My question is which solution best fits my needs? Based on my research it appears that CouchDB (utilizing the CouchDB-Lounge and CouchDB-Lucene) perfectly fits my needs. However, I am worried that since I have worked with CouchDB that I might be overlooking something useful for my needs in HDFS or HBase or something similar due to a bias. Any and all opinions are welcome as I am looking for the community input as I really do not want to make the wrong choice at the start of my project. Please ask if you need more information. I thank you all for your time, input and assistance.

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  • Adding a UIPickerView over a UITabBarController

    - by Kai
    I'm trying to have a UIPickerView slide from the bottom of the screen (over the top of a tab bar) but can't seem to get it to show up. The actual code for the animation is coming from one of Apple's example code projects (DateCell). I'm calling this code from the first view controller (FirstViewController.m) under the tab bar controller. - (IBAction)showModePicker:(id)sender { if (self.modePicker.superview == nil) { [self.view.window addSubview:self.modePicker]; // size up the picker view to our screen and compute the start/end frame origin for our slide up animation // // compute the start frame CGRect screenRect = [[UIScreen mainScreen] applicationFrame]; CGSize pickerSize = [self.modePicker sizeThatFits:CGSizeZero]; CGRect startRect = CGRectMake(0.0, screenRect.origin.y + screenRect.size.height, pickerSize.width, pickerSize.height); self.modePicker.frame = startRect; // compute the end frame CGRect pickerRect = CGRectMake(0.0, screenRect.origin.y + screenRect.size.height - pickerSize.height, pickerSize.width, pickerSize.height); // start the slide up animation [UIView beginAnimations:nil context:NULL]; [UIView setAnimationDuration:0.3]; // we need to perform some post operations after the animation is complete [UIView setAnimationDelegate:self]; self.modePicker.frame = pickerRect; // shrink the vertical size to make room for the picker CGRect newFrame = self.view.frame; newFrame.size.height -= self.modePicker.frame.size.height; self.view.frame = newFrame; [UIView commitAnimations]; // add the "Done" button to the nav bar self.navigationItem.rightBarButtonItem = self.doneButton; }} Whenever this action fires via a UIBarButtonItem that lives in a UINavigationBar (which is all under the FirstViewController) nothing happens. Can anyone please offer some advice?

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  • Complex derived attributes in Django models

    - by rabidpebble
    What I want to do is implement submission scoring for a site with users voting on the content, much like in e.g. reddit (see the 'hot' function in http://code.reddit.com/browser/sql/functions.sql). My submission model currently keeps track of up and down vote totals. Currently, when a user votes I create and save a related Vote object and then use F() expressions to update the Submission object's voting totals. The problem is that I want to update the score for the submission at the same time, but F() expressions are limited to only simple operations (it's missing support for log(), date_part(), sign() etc.) From my limited experience with Django I can see 4 options here: extend F() somehow (haven't looked at the code yet) to support the missing SQL functions; this is my preferred option and seems to fit within the Django framework the best define a scoring function (much like reddit's 'hot' function) in my database, and have Django use the value of that function for the value of the score field; as far as I can tell, #2 is not possible wrap my two step voting process in a suitably isolated transaction so that I can calculate the voting totals in Python and then update the Submission's voting totals without fear that another vote against the submission could be added/changed in the meantime; I'm hesitant to take this route because it seems overly complex - what is a "suitably isolated transaction" in this case anyway? use raw SQL; I would prefer to avoid this entirely -- what's the point of an ORM if I have to revert to SQL for such a common use case as this! (Note that this coming from somebody who loves sprocs, but is using Django for ease of development.) Before I embark on this mission to extend F() (which I'm not sure is even possible), am I about to reinvent the wheel? Is there a more standard way to do this? It seems like such a common use case and yet in an hour of searching I have yet to find a common solution...

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  • Why use INCLUDE in a SQL index

    - by StarLite
    I recently encountered an index in a database I maintain that was of the form: CREATE INDEX [IX_Foo] ON [Foo] ( Id ASC ) INCLUDE ( SubId ) In this particular case, the performance problem that I was encountering (a slow SELECT filtering on both Id and SubId) could be fixed by simply moving the SubId column into the index proper rather than as an included column. This got me thinking however that I don't understand the reasoning behind included columns at all, when generally, they could simply be a part of the index itself. Even if I don't particularly care about the items being in the index itself is there any downside to having column in the index rather than simply being included. After some research, I am aware that there are a number of restrictions on what can go into an indexed column (maximum width of the index, and some column types that can't be indexed like 'image'). In these cases I can see that you would be forced to include the column in the index page data. The only thing I can think of is that if there are updates on SubId, the row will not need to be relocated if the column is included (though the value in the index would need to be changed). Is there something else that I'm missing? I'm considering going through the other indexes in the database and shifting included columns in the index proper where possible. Would this be a mistake? I'm primarily interested in MS SQL Server, but information on other DB engines is welcome also.

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  • JMX - MBean automated registration on application deployment

    - by Gadi
    Hi All, I need some direction with JMX and J2EE. I am aware (after few weeks of research) that the JMX specification is missing as far as deployment is concerned. There are few vendor specific implementations for what I am looking for but none are cross vendor. I would like to automate the deployment of MBeans and registration with the Server. I need the server to load and register my MBeand when the application is deployed and remove when the application is un-deployed. I develop with: NetBean 6.7.1, GlassFish 2.1, J2EE5, EJB3 More specific, I need a way to manage timer service runs. My application need to run different archiving agents and batch reporting. I was hoping the JMX will give me remote access to create and manage the timer services and enable the user to create his own schedule. If the JMX is auto registered on application deployment the user can immediately connect and manage the schedule. On the other hand, how can an EJB connect/access an MBean? Many thanks in advance. Gadi.

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  • Changing CSS Rules using JavaScript or jQuery

    - by Praveen Kumar
    Initial Research I am aware of using .css() to get and set the CSS rules of a particular element. I have seen a website with this CSS: body, table td, select { font-family: Arial Unicode MS, Arial, sans-serif; font-size: small; } I never liked Arial Unicode as a font. Well, that was my personal feel. So, I would use Chrome's Style Inspector to edit the Arial Unicode MS to Segoe UI or something which I like. Is there anyway, other than using the following to achieve the same? Case I $("body, table td, select").css("font-family", "Segoe UI"); Recursive, performance intensive. Doesn't work when things are loaded on the fly. Case II $('<style>body, table td, select {font-famnily: "Segoe UI";}</style>') .appendTo("head"); Any other better method than this? Creates a lot of <style> tags!

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