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  • BigQuery - Best Practices for Running Queries on Massive Datasets

    BigQuery - Best Practices for Running Queries on Massive Datasets Join Michael Manoochehri and Ryan Boyd from the big data Developer Relations team on Friday, September 21th, at 10am PDT, as they discuss best practices for answering questions about massive datasets with Google BigQuery. They'll explore interesting Big Data use cases with some of our public datasets, using BigQuery's SQL-like language to return query results in seconds. They will also cover some of BigQuery's unique query functions as well. For a general overview of BigQuery, watch our overview video: youtu.be Please use the moderator below (goo.gl to ask your questions, which will be answered live! More info here: developers.google.com From: GoogleDevelopers Views: 0 0 ratings Time: 00:00 More in Science & Technology

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  • How do engines avoid "Phase Lock" (multiple objects in same location) in a Physics Engine?

    - by C0M37
    Let me explain Phase Lock first: When two objects of non zero mass occupy the same space but have zero energy (no velocity). Do they bump forever with zero velocity resolution vectors or do they just stay locked together until an outside force interacts? In my home brewed engine, I realized that if I loaded a character into a tree and moved them, they would signal a collision and hop back to their original spot. I suppose I could fix this by implementing impulses in the event of a collision instead of just jumping back to the last spot I was in (my implementation kind of sucks). But while I make my engine more robust, I'm just curious on how most other physics engines handle this case. Do objects that start in the same spot with no movement speed just shoot out from each other in a random direction? Or do they sit there until something happens? Which option is generally the best approach?

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  • What program should i use for Ludum Dare?

    - by mFontoura
    I want to participate for the first time on Ludum Dare, but i'm not confortable yet with a language to pick one for making a game on a weekend. So i was looking for a program 'gamemaker' style, just to make something for LD. I was going for Construct 2, but i use Linux and they don't have a linux version. So the alternative i use is Stencyl, witch is great and probably is what i'm going to use. However, i wanted to know if there is something similar and better for Linux. Also, if i get a computer with Win8, is it worth the trouble for Construct 2?

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  • 2D SAT How to find collision center or point or area?

    - by Felipe Cypriano
    I've just implemented collision detection using SAT and this article as reference to my implementation. The detection is working as expected but I need to know where both rectangles are colliding. I need to find the center of the intersection, the black point on the image above. I've found some articles about this but they all involve avoiding the overlap or some kind of velocity, I don't need this. I just need to put a image on top of it. Like two cars crashed so I put an image on top of the collision. Any ideas? ## Update The information I've about the rectangles are the four points that represents them, the upper right, upper left, lower right and lower left coordinates. I'm trying to find an algorithm that can give me the intersection of these points.

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  • How can I download Youtube videos?

    - by Abhijit Navale
    First i tried with youtube-dl and all the times ( and all days) for all videos it gives this same error: youtube-dl http://www.youtube.com/watch?v=6zWwTTAc7O8 [youtube] Setting language [youtube] 6zWwTTAc7O8: Downloading video info webpage [youtube] 6zWwTTAc7O8: Extracting video information ERROR: format not available for video Then I tried minitube latest version. but it just cant open the video. it just keeps trying to open video. it is unable to even play or download any video. Also in old days, whenever i play video in youtube.com that was automatically was saved in my /tmp. But that is also not happening these days. What can I use for downloading Youtube videos? I am using Lucid 64 bit.

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  • Evolution in coding standards, how do you deal with them?

    - by WardB
    How do you deal with evolution in the coding standards / style guide in a project for the existing code base? Let's say someone on your team discovered a better way of object instantiation in the programming language. It's not that the old way is bad or buggy, it's just that the new way is less verbose and feels much more elegant. And all team members really like it. Would you change all exisiting code? Let's say your codebase is about 500.000+ lines of code. Would you still want to change all existing code? Or would you only let new code adhere to the new standard? Basically lose consistency? How do you deal with an evolution in the coding standards on your project?

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  • creating the nodes for path finding during run time - more like path making and more

    - by bigbadbabybear
    i'm making my 1st game. i'm using javascript as i currently want to learn to make games without needing to learn another language but this is more of a general game dev question its a 2d turn-based tile/grid game. you can check it here http://www.patinterotest.tk/ it creates a movable area when you hover a player and it implements the A* algo for moving the player. The Problem: i want to make the 'dynamic movable area creation' already implement a limited number of steps for a player. The Questions: what is a good way to do this? is there another algorithm to use for this? the A* algorithm needs a start and destination, with what i want to do i don't have a destination or should i just limit the iteration of the A* algo to the steps variable? hopefully you understand the problem & questions easily

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  • Thought Oracle Usability Advisory Board Was Stuffy? Wrong. Justification for Attending OUAB: ROI

    - by ultan o'broin
    Looking for reasons tell your boss why your organization needs to join the Oracle Usability Advisory Board or why you need approval to attend one of its meetings (see the requirements)? Try phrases such as "Continued Return on Investment (ROI)", "Increased Productivity" or "Happy Workers". With OUAB your participation is about realizing and sustaining ROI across the entire applications life-cycle from input to designs to implementation choices and integration, usage and performance and on measuring and improving the onboarding and support experience. If you think this is a boring meeting of middle-aged people sitting around moaning about customizing desktop forms and why the BlackBerry is here to stay, think again! How about this for a rich agenda, all designed to engage the audience in a thought-provoking and feedback-illiciting day of swirling interactions, contextual usage, global delivery, mobility, consumerizationm, gamification and tailoring your implementation to reflect real users doing real work in real environments.  Foldable, rollable ereader devices provide a newspaper-like UK for electronic news. Or a way to wrap silicon chips, perhaps. Explored at the OUAB Europe Meeting (photograph from Terrace Restaurant in TVP. Nom.) At the 7 December 2012 OUAB Europe meeting in Oracle Thames Valley Park, UK, Oracle partners and customers stepped up to the mic and PPT decks with a range of facts and examples to astound any UX conference C-level sceptic. Over the course of the day we covered much ground, but it was all related in a contextual, flexibile, simplication, engagement way aout delivering results for business: that means solving problems. This means being about the user and their tasks and how to make design and technology transforms work into a productive activity that users and bean counters will be excited by. The sessions really gelled for me: 1. Mobile design patterns and the powerful propositions for customers and partners offered by using the design guidance with Oracle ADF Mobile. Customers' and partners' developers existing ADF developers are now productive, efficient ADF Mobile developers applying proven UX guidance using ADF Mobile components and other Oracle Fusion Middleware in the development toolkit. You can find the Mobile UX Design Patterns and Guidance on Building Mobile Apps on OTN. 2. Oracle Voice and Apps. How this medium offers so much potentual in the enterprise and offers a window in Fusion Apps cloud webservices, Oracle RightNow NLP and Nuance technology. Exciting stuff, demoed live on a mobile phone. Stay tuned for more features and modalities and how you can tailor your own apps experience.  3. Oracle RightNow Natural Language Processing (NLP) Virtual Assistant technology (Ella): how contextual intervention and learning from users sessions delivers a great personalized UX for users interacting with Ella, a fifth generation VA to solve problems and seek knowledge. 4. BYOD Keynote: A balanced keynote address contrasting Fujitsu's explaining of the conceprt, challenges, and trends and setting the expectation that BYOD must be embraced in a flexible way,  with the resolute, crafted high security enterprise requirements that nuancing the BYOD concept and proposals with the realities of their world of water tight information and device sharing policies. Fascinating stuff, as well providing anecdotes to make us thing about out own DYOD Deployments. One size does not fit all. 5. Icon Cultural Surveys Results and Insights Arising: Ever wondered about the cultural appropriateness of icons used in software UIs and how these icons assessed for global use? Or considered that social media "Like" icons might be  unacceptable hand gestures in culture or enterprise? Or do the old world icons like Save floppy disk icons still find acceptable? Well the survey results told you. Challenges must be tested, over time, and context of use is critical now, including external factors such as the internet and social media adoption. Indeed the fears about global rejection of the face and hand icons was not borne out, and some of the more anachronistic icons (checkbooks, microphones, real-to-real tape decks, 3.5" floppies for "save") have become accepted metaphors for current actions. More importantly the findings brought into focus the reason for OUAB - engage with and illicit feedback though working groups before we build anything. 6. EReaders and Oracle iBook: What is the uptake and trends of ereaders? And how about a demo of an iBook with enterprise apps content?  Well received by the audience, the session included a live running poll of ereader usage. 7. Gamification Design Jam: Fun, hands on event for teams of Oracle staff, partners and customers, actually building gamified flows, a practice that can be applied right away by customers and partners.  8. UX Direct: A new offering of usability best practices, coming to an external website for you in 2013. FInd a real user, observe their tasks, design and approve, build and measure. Simple stuff to improve apps implications no end. 9. FUSE (an internal term only, basically Fusion Simplified Experience): demo of the new Face of Fusion Applications: inherently mobile, simple to use, social, personalizable and FAST, three great demos from the HCM, CRM and ICT world on how these UX designs can be used in different ways. So, a powerful breadth and depth of UX solutions and opporunities for customers and partners to engage with and explore how they can make their users happy and benefit their business reaping continued ROI from those apps investments. Find out more about the OUAB and how to get involved here ... 

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  • Recording Available: March 2010 Quarterly Customer Update Webcast

    - by michelle.huff
    Missed the last Quarterly Customer Update Webcast? We discussed several product updates on the March quarterly customer Webcast, including the first phase of the Oracle Content Management 11g release. Some of the highlights include Information Rights Management (IRM) 11g and Imaging and Process Management (I/PM) 11g Overviews. Additionally, we covered I/PM 11g new features, implementation and migration topics that existing customers would like to know. You can find quick links to all the resources I mentioned on the call, as well as links to the presentation and recording details in My Oracle Support from the March 2010 Webcast Resource Links page on OTN.

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  • Unable to install files with apt-get: "unable to locate package"

    - by Ben Casling
    I'm having issues with my ubuntu server version 12.04 installed on a HP550 laptop, when i try sudo apt-get install <programname>, e.g apache2 it will not work, saying E: Unable to locate package apache2. I have tried to look/edit the sources. but they will not work either the gedit command is broken too, i am trying gedit /etc/apt/sources.list for those wondering, is this a case of the computer network not configured properly? it downloaded a language pack easily enough in the installation though. how do i fix this? a prompt reply would be appreciated.

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  • What threading pratice is good 90% of the time?

    - by acidzombie24
    Since my SO thread was closed i guess i can ask it here. What practice or practices are good 90% of the time when working with threading with multiple cores? Personally all i have done was share immutable classes and pass (copy) data to a queue to the destine thread. Note: This is for research and when i say 90% of the time i dont mean it is allowed to fail 10% of the time (thats ridiculous!) i mean 90% it is a good solution while the other 10% it is not so desirable due to implementation or efficiently reasons (or plainly another technique fits the problem domain a lot better).

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  • How to explain OOP concepts to a non technical person?

    - by John
    I often try to avoid telling people I'm a programmer because most of the time I end up explaining to them what that really means. When I tell them I'm programming in Java they often ask general questions about the language and how it differs from x and y. I'm also not good at explaining things because 1) I don't have that much experience in the field and 2) I really hate explaining things to non-technical people. They say that you truly understand things once you explain them to someone else, in this case how would you explain OOP terminology and concepts to a non technical person?

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  • "Yes, but that's niche."

    - by Geertjan
    JavaOne 2012 has come to an end though it feels like it hasn't even started yet! What happened, time is a weird thing. Too many things to report on. James Gosling's appearance at the JavaOne community keynote was seen, by everyone (which is quite a lot) of people I talked to, as the highlight of the conference. It was interesting that the software for the Duke's Choice Award winning Liquid Robotics that James Gosling is now part of and came to talk about is a Swing application that uses the WorldWind libraries. It was also interesting that James Gosling pointed out to the conference: "There are things you can't do using HTML." That brings me to the wonderful counter argument to the above, which I spend my time running into a lot: "Yes, but that's niche." It's a killer argument, i.e., it kills all discussions completely in one fell swoop. Kind of when you're talking about someone and then this sentence drops into the conversation: "Yes, but she's got cancer now." Here's one implementation of "Yes, but that's niche": Person A: All applications are moving to the web, tablet, and mobile phone. That's especially true now with HTML5, which is going to wipe away everything everywhere and all applications are going to be browser based. Person B: What about air traffic control applications? Will they run on mobile phones too? And do you see defence applications running in a browser? Don't you agree that there are multiple scenarios imaginable where the Java desktop is the optimal platform for running applications? Person A: Yes, but that's niche. Here's another implementation, though it contradicts the above [despite often being used by the same people], since JavaFX is a Java desktop technology: Person A: Swing is dead. Everyone is going to be using purely JavaFX and nothing else. Person B: Does JavaFX have a docking framework and a module system? Does it have a plugin system?  These are some of the absolutely basic requirements of Java desktop software once you get to high end systems, e.g., banks, defence force, oil/gas services. Those kinds of applications need a web browser and so they love the JavaFX WebView component and they also love the animated JavaFX charting components. But they need so much more than that, i.e., an application framework. Aren't there requirements that JavaFX isn't meeting since it is a UI toolkit, just like Swing is a UI toolkit, and what they have in common is their lack, i.e., natively, of any kind of application framework? Don't people need more than a single window and a monolithic application structure? Person A: Yes, but that's niche. In other words, anything that doesn't fit within the currently dominant philosophy is "niche", for no other reason than that it doesn't fit within the currently dominant philosophy... regardless of the actual needs of real developers. Saying "Yes, but that's niche", kills the discussion completely, because it relegates one side of the conversation to the arcane and irrelevant corners of the universe. You're kind of like Cobol now, as soon as "Yes, but that's niche" is said. What's worst about "Yes, but that's niche" is that it doesn't enter into any discussion about user requirements, i.e., there's so few that need this particular solution that we don't even need to talk about them anymore. Note, of course, that I'm not referring specifically or generically to anyone or anything in particular. Just picking up from conversations I've picked up on as I was scurrying around the Hilton's corridors while looking for the location of my next presentation over the past few days. It does, however, mean that there were people thinking "Yes, but that's niche" while listening to James Gosling pointing out that HTML is not the be-all and end-all of absolutely everything. And so this all leaves me wondering: How many applications must be part of a niche for the niche to no longer be a niche? And what if there are multiple small niches that have the same requirements? Don't all those small niches together form a larger whole, one that should be taken seriously, i.e., a whole that is not a niche?

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  • Getting started and learning programming?

    - by Blagersdeath
    Hello, I am looking to get started in programming. I am young and know some html as I am taking a Web Design class at my school now. I am planning to apply to Full Sail University when I graduate High School, but I would like to get started now so that I am ahead of the game if I get accepted. I want to learn any and all programing language's. I would appreciate it if anyone can help me out by telling me where I can learn. By in a book, web site, articles, blog, or whatever you can help me in I would appreciate it. Thanks.

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  • Are JSP and Java still relevant?

    - by dyyyy
    I've been working so long in java and jsp, that for me it's a no-brainer to use it. But now as I'm starting to do my own framework for web applications, I'm wondering if jsp is the right choice. Seing how much php is popular (as well as other languages as ruby and python) Is JSP still a relevant language. Does it have any clear advantage over other languages ? I don't want to use it just because i know it better. So please considering I know nothing, is there a reason to use JSP and JAVA? Thank you

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  • What is the difference between Static code analysis and code review?

    - by Xander
    I just wanted to know what is the difference between static code analysis and code review. How these two are done? What are the tools available today for code review/ static analysis of PHP. I also like to know about good tools for any language code review. Thanks in Advance. Xander Cage Note: I am asking this because I was not able to understand the difference. Please, I expect some answers than "I am Mr.Geek and you asked an irrelevant bla bla..... this is closed". I know this sounds mean. But I am sorry.

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  • Web interface with FastCGI or with direct HTTP?

    - by Basile Starynkevitch
    Let's assume I want (for fun at start) to play with some new DSL (domain specific language) idea. And I really want its user[s] (probably only me at first) to interact thru a web interface. I'll probably implement it in C++ (probably using LLVM). Should I use an HTTP server library (like libonion or microhttpd) to talk directly HTTP or should I use FastCGI? In particular, I am noticing that several recent web frameworks (Opa, Ocsigen, ...) do not have any FastCGI interface but only HTTP one.... So my feeling is that FastCGI is really out of fashion.... Any opinions on that? Do you know recently started project using FastCGI ? (and what about SCGI?)

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  • JavaOne 2012 Sunday Strategy Keynote

    - by Janice J. Heiss
    At the Sunday Strategy Keynote, held at the Masonic Auditorium, Hasan Rizvi, EVP, Middleware and Java Development, stated that the theme for this year's JavaOne is: “Make the future Java”-- meaning that Java continues in its role as the most popular, complete, productive, secure, and innovative development platform. But it also means, he qualified, the process by which we make the future Java -- an open, transparent, collaborative, and community-driven evolution. "Many of you have bet your businesses and your careers on Java, and we have bet our business on Java," he said.Rizvi detailed the three factors they consider critical to the success of Java--technology innovation, community participation, and Oracle's leadership/stewardship. He offered a scorecard in these three realms over the past year--with OS X and Linux ARM support on Java SE, open sourcing of JavaFX by the end of the year, the release of Java Embedded Suite 7.0 middleware platform, and multiple releases on the Java EE side. The JCP process continues, with new JSR activity, and JUGs show a 25% increase in participation since last year. Oracle, meanwhile, continues its commitment to both technology and community development/outreach--with four regional JavaOne conferences last year in various part of the world, as well as the release of Java Magazine, with over 120,000 current subscribers. Georges Saab, VP Development, Java SE, next reviewed features of Java SE 7--the first major revision to the platform under Oracle's stewardship, which has included near-monthly update releases offering hundreds of fixes, performance enhancements, and new features. Saab indicated that developers, ISVs, and hosting providers have all been rapid adopters of the platform. He also noted that Oracle's entire Fusion middleware stack is supported on SE 7. The supported platforms for SE 7 has also increased--from Windows, Linux, and Solaris, to OS X, Linux ARM, and the emerging ARM micro-server market. "In the last year, we've added as many new platforms for Java, as were added in the previous decade," said Saab.Saab also explored the upcoming JDK 8 release--including Project Lambda, Project Nashorn (a modern implementation of JavaScript running on the JVM), and others. He noted that Nashorn functionality had already been used internally in NetBeans 7.3, and announced that they were planning to contribute the implementation to OpenJDK. Nandini Ramani, VP Development, Java Client, ME and Card, discussed the latest news pertaining to JavaFX 2.0--releases on Windows, OS X, and Linux, release of the FX Scene Builder tool, the JavaFX WebView component in NetBeans 7.3, and an OpenJFX project in OpenJDK. Nandini announced, as of Sunday, the availability for download of JavaFX on Linux ARM (developer preview), as well as Scene Builder on Linux. She noted that for next year's JDK 8 release, JavaFX will offer 3D, as well as third-party component integration. Avinder Brar, Senior Software Engineer, Navis, and Dierk König, Canoo Fellow, next took the stage and demonstrated all that JavaFX offers, with a feature-rich, animation-rich, real-time cargo management application that employs Canoo's just open-sourced Dolphin technology.Saab also explored Java SE 9 and beyond--Jigsaw modularity, Penrose Project for interoperability with OSGi, improved multi-tenancy for Java in the cloud, and Project Sumatra. Phil Rogers, HSA Foundation President and AMD Corporate Fellow, explored heterogeneous computing platforms that combine the CPU and the parallel processor of the GPU into a single piece of silicon and shared memory—a hardware technology driven by such advanced functionalities as HD video, face recognition, and cloud workloads. Project Sumatra is an OpenJDK project targeted at bringing Java to such heterogeneous platforms--with hardware and software experts working together to modify the JVM for these advanced applications and platforms.Ramani next discussed the latest with Java in the embedded space--"the Internet of things" and M2M--declaring this to be "the next IT revolution," with Java as the ideal technology for the ecosystem. Last week, Oracle released Java ME Embedded 3.2 (for micro-contollers and low-power devices), and Java Embedded Suite 7.0 (a middleware stack based on Java SE 7). Axel Hansmann, VP Strategy and Marketing, Cinterion, explored his company's use of Java in M2M, and their new release of EHS5, the world's smallest 3G-capable M2M module, running Java ME Embedded. Hansmaan explained that Java offers them the ability to create a "simple to use, scalable, coherent, end-to-end layer" for such diverse edge devices.Marc Brule, Chief Financial Office, Royal Canadian Mint, also explored the fascinating use-case of JavaCard in his country's MintChip e-cash technology--deployable on smartphones, USB device, computer, tablet, or cloud. In parting, Ramani encouraged developers to download the latest releases of Java Embedded, and try them out.Cameron Purdy, VP, Fusion Middleware Development and Java EE, summarized the latest developments and announcements in the Enterprise space--greater developer productivity in Java EE6 (with more on the way in EE 7), portability between platforms, vendors, and even cloud-to-cloud portability. The earliest version of the Java EE 7 SDK is now available for download--in GlassFish 4--with WebSocket support, better JSON support, and more. The final release is scheduled for April of 2013. Nicole Otto, Senior Director, Consumer Digital Technology, Nike, explored her company's Java technology driven enterprise ecosystem for all things sports, including the NikeFuel accelerometer wrist band. Looking beyond Java EE 7, Purdy mentioned NoSQL database functionality for EE 8, the concurrency utilities (possibly in EE 7), some of the Avatar projects in EE 7, some in EE 8, multi-tenancy for the cloud, supporting SaaS applications, and more.Rizvi ended by introducing Dr. Robert Ballard, oceanographer and National Geographic Explorer in Residence--part of Oracle's philanthropic relationship with the National Geographic Society to fund K-12 education around ocean science and conservation. Ballard is best known for having discovered the wreckage of the Titanic. He offered a fascinating video and overview of the cutting edge technology used in such deep-sea explorations, noting that in his early days, high-bandwidth exploration meant that you’d go down in a submarine and "stick your face up against the window." Now, it's a remotely operated, technology telepresence--"I think of my Hercules vehicle as my equivalent of a Na'vi. When I go beneath the sea, I actually send my spirit." Using high bandwidth satellite links, such amazing explorations can now occur via smartphone, laptop, or whatever platform. Ballard’s team regularly offers live feeds and programming out to schools and the world, spanning 188 countries--with embedding educators as part of the expeditions. It's technology at its finest, inspiring the next-generation of scientists and explorers!

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  • How does throwing an ArgumentNullException help?

    - by Scott Whitlock
    Let's say I have a method: public void DoSomething(ISomeInterface someObject) { if(someObject == null) throw new ArgumentNullException("someObject"); someObject.DoThisOrThat(); } I've been trained to believe that throwing the ArgumentNullException is "correct" but an "Object reference not set to an instance of an object" error means I have a bug. Why? I know that if I was caching the reference to someObject and using it later, then it's better to check for nullity when passed in, and fail early. However, if I'm dereferencing it on the next line, why are we supposed to do the check? It's going to throw an exception one way or the other. Edit: It just occurred to me... does the fear of the dereferenced null come from a language like C++ that doesn't check for you (i.e. it just tries to execute some method at memory location zero + method offset)?

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  • Are there web frameworks/tools that optimize for speed of development?

    - by Ahmet Yildirim
    I've been a PHP web developer for about 2 and a half years now. I have started using CodeIgniter framework to shorten development process a while ago. I developed 4 websites using CodeIgniter. It has been really tiring and boring due to code-repetition. Code repetition was vast on form handling functions in controllers.So in my last project , i developed a general form input handling function.This lead a realisation that it could get even faster by more automation. What i think i lack in my development is using CRUD & Code Generation tools. But i am wondering if there is any other utilities that shortens development process. Which web development language or framework more inclined towards code generation utilities?

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  • Are There Realistic/Useful Solutions for Source Control for Ladder Logic Programs

    - by Steven A. Lowe
    Version control for ladder logic (LL) programs for programmable logic controllers (PLCs) seems to be virtually non-existent. It may be because LL is a visual language and tends to be stored in binary files, or it may be because source code control hasn't "caught on" in process control engineering circles - or perhaps my Google-Fu is weak tonight. Do you know of any realistic and useful solutions for version control for such systems? Definitions: realistic = changes to the programs are tracked by user and subject to reversion and merges useful = the system integrates with visual LL designers, is not limited to LL from a single PLC manufacturer, and does not cost a ridiculous amount of money? Note: I have heard of people using SVN or Mercurial et al to track the binary files, but I don't think the diff/merge capabilities would display readable differences.

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  • Trying to detect collision between two polygons using Separating Axis Theorem

    - by Holly
    The only collision experience i've had was with simple rectangles, i wanted to find something that would allow me to define polygonal areas for collision and have been trying to make sense of SAT using these two links Though i'm a bit iffy with the math for the most part i feel like i understand the theory! Except my implementation somewhere down the line must be off as: (excuse the hideous font) As mentioned above i have defined a CollisionPolygon class where most of my theory is implemented and then have a helper class called Vect which was meant to be for Vectors but has also been used to contain a vertex given that both just have two float values. I've tried stepping through the function and inspecting the values to solve things but given so many axes and vectors and new math to work out as i go i'm struggling to find the erroneous calculation(s) and would really appreciate any help. Apologies if this is not suitable as a question! CollisionPolygon.java: package biz.hireholly.gameplay; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import biz.hireholly.gameplay.Types.Vect; public class CollisionPolygon { Paint paint; private Vect[] vertices; private Vect[] separationAxes; CollisionPolygon(Vect[] vertices){ this.vertices = vertices; //compute edges and separations axes separationAxes = new Vect[vertices.length]; for (int i = 0; i < vertices.length; i++) { // get the current vertex Vect p1 = vertices[i]; // get the next vertex Vect p2 = vertices[i + 1 == vertices.length ? 0 : i + 1]; // subtract the two to get the edge vector Vect edge = p1.subtract(p2); // get either perpendicular vector Vect normal = edge.perp(); // the perp method is just (x, y) => (-y, x) or (y, -x) separationAxes[i] = normal; } paint = new Paint(); paint.setColor(Color.RED); } public void draw(Canvas c, int xPos, int yPos){ for (int i = 0; i < vertices.length; i++) { Vect v1 = vertices[i]; Vect v2 = vertices[i + 1 == vertices.length ? 0 : i + 1]; c.drawLine( xPos + v1.x, yPos + v1.y, xPos + v2.x, yPos + v2.y, paint); } } /* consider changing to a static function */ public boolean intersects(CollisionPolygon p){ // loop over this polygons separation exes for (Vect axis : separationAxes) { // project both shapes onto the axis Vect p1 = this.minMaxProjection(axis); Vect p2 = p.minMaxProjection(axis); // do the projections overlap? if (!p1.overlap(p2)) { // then we can guarantee that the shapes do not overlap return false; } } // loop over the other polygons separation axes Vect[] sepAxesOther = p.getSeparationAxes(); for (Vect axis : sepAxesOther) { // project both shapes onto the axis Vect p1 = this.minMaxProjection(axis); Vect p2 = p.minMaxProjection(axis); // do the projections overlap? if (!p1.overlap(p2)) { // then we can guarantee that the shapes do not overlap return false; } } // if we get here then we know that every axis had overlap on it // so we can guarantee an intersection return true; } /* Note projections wont actually be acurate if the axes aren't normalised * but that's not necessary since we just need a boolean return from our * intersects not a Minimum Translation Vector. */ private Vect minMaxProjection(Vect axis) { float min = axis.dot(vertices[0]); float max = min; for (int i = 1; i < vertices.length; i++) { float p = axis.dot(vertices[i]); if (p < min) { min = p; } else if (p > max) { max = p; } } Vect minMaxProj = new Vect(min, max); return minMaxProj; } public Vect[] getSeparationAxes() { return separationAxes; } public Vect[] getVertices() { return vertices; } } Vect.java: package biz.hireholly.gameplay.Types; /* NOTE: Can also be used to hold vertices! Projections, coordinates ect */ public class Vect{ public float x; public float y; public Vect(float x, float y){ this.x = x; this.y = y; } public Vect perp() { return new Vect(-y, x); } public Vect subtract(Vect other) { return new Vect(x - other.x, y - other.y); } public boolean overlap(Vect other) { if( other.x <= y || other.y >= x){ return true; } return false; } /* used specifically for my SAT implementation which i'm figuring out as i go, * references for later.. * http://www.gamedev.net/page/resources/_/technical/game-programming/2d-rotated-rectangle-collision-r2604 * http://www.codezealot.org/archives/55 */ public float scalarDotProjection(Vect other) { //multiplier = dot product / length^2 float multiplier = dot(other) / (x*x + y*y); //to get the x/y of the projection vector multiply by x/y of axis float projX = multiplier * x; float projY = multiplier * y; //we want to return the dot product of the projection, it's meaningless but useful in our SAT case return dot(new Vect(projX,projY)); } public float dot(Vect other){ return (other.x*x + other.y*y); } }

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  • Can non-IT people learn and take advantage of regular expressions? [closed]

    - by user1598390
    Often times, not-IT people has to deal with massive text data, clean it, filter it, modify it. Often times normal office tools like Excel lack the tools to make complex search and replace operations on text. Could this people benefit from regexps ? Can regexp be taught to them ? Are regular expressions the exclusive domain of programmers and unix/linux technicians ? Can they be learned by non-IT people, given regexps are not a programming language? Is this a valid or achievable goal to make some users regexp-literate through appopriate training ? Have you have any experiences on this issue? and if so, have it been successful ?

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  • Animation file format

    - by Paul
    I'm trying to make a simple 2D animation file format. It'll be very rudimentary: only an XML file containing some parameters (such as frame duration) and metadata, and some images, each representing a frame. I'd like to have the whole animation (frames and XML document) packed in a single file. How do you suggest I do that? What libraries are there that would allow easy access to the files inside the animation file itself? The language I'm using is C++ and the platform is Windows, but I'd rather not use a platform dependent library, if possible.

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  • Understanding the Java Ecosystem

    - by syrion
    I have traditionally had the "luxury" of being a one-man development team. I've used Python extensively, have a reasonable command of Perl, PHP, and JavaScript. My problem is Java. I can write Java code. I'm not great at it--unlike Python, I rarely make use of anything unique to Java when I'm writing it. Furthermore, my experience is mostly in simple GUI/console programming. Unfortunately, I'm currently pursuing an IT degree where Java is the lingua franca. My database class is requiring that our projects be written in Java using servlets, and I just can't wrap my head around the ecosystem. Is there a good online overview of or tutorial on how the Java web ecosystem works? I have Thinking in Java, but it's mostly just the language itself (which I understand well enough to get by). I have looked at the Sun servlet tutorial, but it seems outdated.

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