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• Tools for assembling textures into DDS files

  - by Nicol Bolas

  There are plenty of tools for making images. I'm not looking for one of those; I have many tools for creating an image. I've got tools for compressing images, generating mipmaps, and even for poking at their basic data format. My issue is with texture assembly. DDS files support cubemaps, array textures, and even cubemap arrays. But I don't know of a tool that can pack a series of images into a cubemap or the like. What tools are available for doing this kind of thing?

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• Default Parameters vs Method Overloading

  - by João Angelo

  With default parameters introduced in C# 4.0 one might be tempted to abandon the old approach of providing method overloads to simulate default parameters. However, you must take in consideration that both techniques are not interchangeable since they show different behaviors in certain scenarios. For me the most relevant difference is that default parameters are a compile time feature while method overloading is a runtime feature. To illustrate these concepts let’s take a look at a complete, although a bit long, example. What you need to retain from the example is that static method Foo uses method overloading while static method Bar uses C# 4.0 default parameters. static void CreateCallerAssembly(string name) { // Caller class - Invokes Example.Foo() and Example.Bar() string callerCode = String.Concat( "using System;", "public class Caller", "{", " public void Print()", " {", " Console.WriteLine(Example.Foo());", " Console.WriteLine(Example.Bar());", " }", "}"); var parameters = new CompilerParameters(new[] { "system.dll", "Common.dll" }, name); new CSharpCodeProvider().CompileAssemblyFromSource(parameters, callerCode); } static void Main() { // Example class - Foo uses overloading while Bar uses C# 4.0 default parameters string exampleCode = String.Concat( "using System;", "public class Example", "{{", " public static string Foo() {{ return Foo(\"{0}\"); }}", " public static string Foo(string key) {{ return \"FOO-\" + key; }}", " public static string Bar(string key = \"{0}\") {{ return \"BAR-\" + key; }}", "}}"); var compiler = new CSharpCodeProvider(); var parameters = new CompilerParameters(new[] { "system.dll" }, "Common.dll"); // Build Common.dll with default value of "V1" compiler.CompileAssemblyFromSource(parameters, String.Format(exampleCode, "V1")); // Caller1 built against Common.dll that uses a default of "V1" CreateCallerAssembly("Caller1.dll"); // Rebuild Common.dll with default value of "V2" compiler.CompileAssemblyFromSource(parameters, String.Format(exampleCode, "V2")); // Caller2 built against Common.dll that uses a default of "V2" CreateCallerAssembly("Caller2.dll"); dynamic caller1 = Assembly.LoadFrom("Caller1.dll").CreateInstance("Caller"); dynamic caller2 = Assembly.LoadFrom("Caller2.dll").CreateInstance("Caller"); Console.WriteLine("Caller1.dll:"); caller1.Print(); Console.WriteLine("Caller2.dll:"); caller2.Print(); } And if you run this code you will get the following output: // Caller1.dll: // FOO-V2 // BAR-V1 // Caller2.dll: // FOO-V2 // BAR-V2 You see that even though Caller1.dll runs against the current Common.dll assembly where method Bar defines a default value of “V2″ the output show us the default value defined at the time Caller1.dll compiled against the first version of Common.dll. This happens because the compiler will copy the current default value to each method call, much in the same way a constant value (const keyword) is copied to a calling assembly and changes to it’s value will only be reflected if you rebuild the calling assembly again. The use of default parameters is also discouraged by Microsoft in public API’s as stated in (CA1026: Default parameters should not be used) code analysis rule.

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• How to store character moves (sprite animations)?

  - by Saad

  So I'm thinking about making a small rpg, mainly to test out different design patterns I've been learning about. But the one question that I'm not too sure on how to approach is how to store an array of character moves in the best way possible. So let's say I have arrays of different sprites. This is how I'm thinking about implementing it: array attack = new array (10); array attack2 = new array(5); (loop) //blit some image attack.push(imageInstance); (end loop) Now every time I want the animation I call on attack or attack2; is there a better structure? The problem with this is let's say there are 100 different attacks, and a player can have up to 10 attacks equipped. So how do I tell which attack the user has; should I use a hash map?

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• Critical Threads Optimization

  - by Rafael Vanoni

  Background One of the more common issues we've been seeing in the field is the growing difficulty in optimizing performance of multi-threaded applications. A good portion of this difficulty is due to the increasing complexity of modern processors that present various degrees of sharing relationships between hardware components. Take any current CMT processor and you'll find any number of CPUs sharing execution pipelines, floating point units, caches, etc. Consequently, applying the traditional recipe of one software thread for each CPU will have varying degrees of success, according to the layout of the underlying hardware. On top of this increasing complexity we've also seen processors with features that aim at dynamically resourcing software threads according to their utilization. Intel's Turbo Boost allows processors to increase their operating frequency if there is enough thermal headroom available and the processor isn't fully utilized. More recently, the SPARC T4 processor introduced dynamic threading, allowing each core to dynamically allocate more resources to its active CPUs. Both cases are in essence recognizing that current processors will be running a wide mix of workloads, some will be designed for throughput, others for low latency. The hardware is providing mechanisms to dynamically resource threads according to their runtime behavior. We're very aware of these challenges in Solaris, and have been working to provide the best out of box performance while providing mechanisms to further optimize applications when necessary. The Critical Threads Optimzation was introduced in Solaris 10 8/11 and Solaris 11 as one such mechanism that allows customers to both address issues caused by contention over shared hardware resources and explicitly take advantage of features such as T4's dynamic threading. What it is The basic idea is to allow performance critical threads to execute with more exclusive access to hardware resources. For example, when deploying an application that implements a producer/consumer model, it'll likely be advantageous to give the producer more exclusive access to the hardware instead of having it competing for resources with all the consumers. In the case of a T4 based system, we may want to have a producer running by itself on a single core and create one consumer for each of the remaining CPUs. With the Critical Threads Optimization we're extending the semantics of scheduling priorities (which thread should run first) to include priority over shared resources (which thread should have more "space"). Now the scheduler will not only run higher priority threads first: it will also provide them with more exclusive access to hardware resources if they are available. How does it work ? Using the previous example in Solaris 11, all you'd have to do would be to place the producer in the Fixed Priority (FX) scheduling class at priority 60, or in the Real Time (RT) class at any priority and Solaris will try to give it more "hardware space". On both Solaris 10 8/11 and Solaris 11 this can be achieved through the existing priocntl(1,2) and priocntlset(2) interfaces. If your application already assigns these priorities to performance critical threads, there's no additional step you need to take. One important aspect of this optimization is that it requires some level of idleness in the system, either as a result of sizing the application before hand or through periods of transient idleness during runtime. If the system is fully committed, the scheduler will put all the available CPUs to work.Best practices If you're an application developer, we encourage you to look into assigning the right priorities for the different threads in your application. Solaris provides different scheduling classes (Time Share, Interactive, Fair Share, Fixed Priority and Real Time) that offer different policies and behaviors. It is not always simple to figure out which set of threads are critical to the performance of a workload, and it may not always be feasible to take advantage of this optimization, but we believe that this can be correctly (and safely) done during development. Overall, the out of box performance in Solaris should meet your workload's requirements. If you are looking into that extra bit of performance, then the Critical Threads Optimization may be what you're looking for.

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• How do I resolve this exercise on C++? [closed]

  - by user40630

  (Card Shuffling and Dealing) Create a program to shuffle and deal a deck of cards. The program should consist of class Card, class DeckOfCards and a driver program. Class Card should provide: a) Data members face and suit of type int. b) A constructor that receives two ints representing the face and suit and uses them to initialize the data members. c) Two static arrays of strings representing the faces and suits. d) A toString function that returns the Card as a string in the form “face of suit.” You can use the + operator to concatenate strings. Class DeckOfCards should contain: a) A vector of Cards named deck to store the Cards. b) An integer currentCard representing the next card to deal. c) A default constructor that initializes the Cards in the deck. The constructor should use vector function push_back to add each Card to the end of the vector after the Card is created and initialized. This should be done for each of the 52 Cards in the deck. d) A shuffle function that shuffles the Cards in the deck. The shuffle algorithm should iterate through the vector of Cards. For each Card, randomly select another Card in the deck and swap the two Cards. e) A dealCard function that returns the next Card object from the deck. f) A moreCards function that returns a bool value indicating whether there are more Cards to deal. The driver program should create a DeckOfCards object, shuffle the cards, then deal the 52 cards. This above is the exercise I'm trying to solve. I'd be very much appreciated if someone could solve it and explain it to me. The main idea of the program is quite simple. What I don't get is how to build the constructor for the class DeckOfCards and how to generate the 52 cards of the deck with different suits and faces. Untill now I've managed to do this: #include <iostream> #include <vector> using namespace std; /* * */ /* a) Data members face and suit of type int. b) A constructor that receives two ints representing the face and suit and uses them to initialize the data members. c) Two static arrays of strings representing the faces and suits. d) A toString function that returns the Card as a string in the form “face of suit.” You can use the + operator to concatenate strings. */ class Card { public: Card(int, int); string toString(); private: int suit, face; static string faceNames[13]; static string suitNames[4]; }; string Card::faceNames[13] = {"Ace","Two","Three","Four","Five","Six","Seven","Eight","Nine","Ten","Queen","Jack","King"}; string Card::suitNames[4] = {"Diamonds","Clubs","Hearts","Spades"}; string Card::toString() { return faceNames[face]+" of "+suitNames[suit]; } Card::Card(int f, int s) :face(f), suit(s) { } /* Class DeckOfCards should contain: a) A vector of Cards named deck to store the Cards. b) An integer currentCard representing the next card to deal. c) A default constructor that initializes the Cards in the deck. The constructor should use vector function push_back to add each Card to the end of the vector after the Card is created and initialized. This should be done for each of the 52 Cards in the deck. d) A shuffle function that shuffles the Cards in the deck. The shuffle algorithm should iterate through the vector of Cards. For each Card, randomly select another Card in the deck and swap the two Cards. e) A dealCard function that returns the next Card object from the deck. f) A moreCards function that returns a bool value indicating whether there are more Cards to deal. */ class DeckOfCards { public: DeckOfCards(); void shuffleCards(); Card dealCard(); bool moreCards(); private: vector<Card> deck(52); int currentCard; }; int main(int argc, char** argv) { return 0; } DeckOfCards::DeckOfCards() { //I'm stuck here I have no idea of what to take out of here. //I still don't fully get the idea of class inside class and that's turning out as a problem. I try to find a way to set the suits and faces members of the class Card but I can't figure out how. for(int i=0; i<deck.size(); i++) { deck[i]//....There is no function to set them. They must be set when initialized. But how?? } } For easier reading: http://pastebin.com/pJeXMH0f

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• Introducing the First Global Web Experience Management Content Management System

  - by kellsey.ruppel

  By Calvin Scharffs, VP of Marketing and Product Development, Lingotek Globalizing online content is more important than ever. The total spending power of online consumers around the world is nearly $50 trillion, a recent Common Sense Advisory report found. Three years ago, enterprises would have to translate content into 37 language to reach 98 percent of Internet users. This year, it takes 48 languages to reach the same amount of users.  For companies seeking to increase global market share, “translate frequently and fast” is the name of the game. Today’s content is dynamic and ever-changing, covering the gamut from social media sites to company forums to press releases. With high-quality translation and localization, enterprises can tailor content to consumers around the world.  Speed and Efficiency in Translation When it comes to the “frequently and fast” part of the equation, enterprises run into problems. Professional service providers provide translated content in files, which company workers then have to manually insert into their CMS. When companies update or edit source documents, they have to hunt down all the translated content and change each document individually.  Lingotek and Oracle have solved the problem by making the Lingotek Collaborative Translation Platform fully integrated and interoperable with Oracle WebCenter Sites Web Experience Management. Lingotek combines best-in-class machine translation solutions, real-time community/crowd translation and professional translation to enable companies to publish globalized content in an efficient and cost-effective manner. WebCenter Sites Web Experience Management simplifies the creation and management of different types of content across multiple channels, including social media.  Globalization Without Interrupting the Workflow The combination of the Lingotek platform with WebCenter Sites ensures that process of authoring, publishing, targeting, optimizing and personalizing global Web content is automated, saving companies the time and effort of manually entering content. Users can seamlessly integrate translation into their WebCenter Sites workflows, optimizing their translation and localization across web, social and mobile channels in multiple languages. The original structure and formatting of all translated content is maintained, saving workers the time and effort involved with inserting the text translation and reformatting.  In addition, Lingotek’s continuous publication model addresses the dynamic nature of content, automatically updating the status of translated documents within the WebCenter Sites Workflow whenever users edit or update source documents. This enables users to sync translations in real time. The translation, localization, updating and publishing of Web Experience Management content happens in a single, uninterrupted workflow.  The net result of Lingotek Inside for Oracle WebCenter Sites Web Experience Management is a system that more than meets the need for frequent and fast global translation. Workflows are accelerated. The globalization of content becomes faster and more streamlined. Enterprises save time, cost and effort in translation project management, and can address the needs of each of their global markets in a timely and cost-effective manner.  About Lingotek Lingotek is an Oracle Gold Partner and is going to be one of the first Oracle Validated Integrator (OVI) partners with WebCenter Sites. Lingotek is also an OVI partner with Oracle WebCenter Content.  Watch a video about how Lingotek Inside for Oracle WebCenter Sites works! Oracle WebCenter will be hosting a webinar, “Hitachi Data Systems Improves Global Web Experiences with Oracle WebCenter," tomorrow, September 13th. To attend the webinar, please register now! For more information about Lingotek for Oracle WebCenter, please visit http://www.lingotek.com/oracle.

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• Sprinkle Some Magik on that Java Virtual Machine

  - by Jim Connors

  GE Energy, through its Smallworld subsidiary, has been providing geospatial software solutions to the utility and telco markets for over 20 years.  One of the fundamental building blocks of their technology is a dynamically-typed object oriented programming language called Magik.  Like Java, Magik source code is compiled down to bytecodes that run on a virtual machine -- in this case the Magik Virtual Machine. Throughout the years, GE has invested considerable engineering talent in the support and maintenance of this virtual machine.  At the same time vast energy and resources have been invested in the Java Virtual Machine. The question for GE has been whether to continue to make that investment on its own or to leverage massive effort provided by the Java community? Utilizing the Java Virtual Machine instead of maintaining its own virtual machine would give GE more opportunity to focus on application solutions.   At last count, there are dozens, perhaps hundreds of examples of programming languages that have been hosted atop the Java Virtual Machine.  Prior to the release of Java 7, that effort, although certainly possible, was generally less than optimal for languages like Magik because of its dynamic nature.  Java, as a statically typed language had little use for this capability.  In the quest to be a more universal virtual machine, Java 7, via JSR-292, introduced a new bytecode called invokedynamic.  In short, invokedynamic affords a more flexible method call mechanism needed by dynamic languages like Magik. With this new capability GE Energy has succeeded in hosting their Magik environment on top of the Java Virtual Machine.  So you may ask, why would GE wish to do such a thing?  The benefits are many: Competitors to GE Energy claimed that the Magik environment was proprietary.  By utilizing the Java Virtual Machine, that argument gets put to bed.  JVM development is done in open source, where contributions are made world-wide by all types of organizations and individuals. The unprecedented wealth of class libraries and applications written for the Java platform are now opened up to Magik/JVM platform as first class citizens. In addition, the Magik/JVM solution vastly increases the developer pool to include the 9 million Java developers -- the largest developer community on the planet. Applications running on the JVM showed substantial performance gains, in some cases as much as a 5x speed up over the original Magik platform. Legacy Magik applications can still run on the original platform.  They can be seamlessly migrated to run on the JVM by simply recompiling the source code. GE can now leverage the huge Java community.  Undeniably the best virtual machine ever created, hundreds if not thousands of world class developers continually improve, poke, prod and scrutinize all aspects of the Java platform.  As enhancements are made, GE automatically gains access to these. As Magik has little in the way of support for multi-threading, GE will benefit from current and future Java offerings (e.g. lambda expressions) that aim to further facilitate multi-core/multi-threaded application development. As the JVM is available for many more platforms, it broadens the reach of Magik, including the potential to run on a class devices never envisioned just a few short years ago.  For example, Java SE compatible runtime environments are available for popular embedded ARM/Intel/PowerPC configurations that could theoretically host this software too. As compared to other JVM language projects, the Magik integration differs in that it represents a serious commercial entity betting a sizable part of its business on the success of this effort.  Expect to see announcements not only from General Electric, but other organizations as they realize the benefits of utilizing the Java Virtual Machine.

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• How would you gather client's data on Google App Engine without using Datastore/Backend Instances too much?

  - by ruslan

  I'm relatively new to StackExchange and not sure if it's appropriate place to ask design question. Site gives me a hint "The question you're asking appears subjective and is likely to be closed". Please let me know. Anyway.. One of the projects I'm working on is online survey engine. It's my first big commercial project on Google App Engine. I need your advice on how to collect stats and efficiently record them in DataStore without bankrupting me. Initial requirements are: After user finishes survey client sends list of pairs [ID (int) + PercentHit (double)]. This list shows how close answers of this user match predefined answers of reference answerers (which identified by IDs). I call them "target IDs". Creator of the survey wants to see aggregated % for given IDs for last hour, particular timeframe or from the beginning of the survey. Some surveys may have thousands of target/reference answerers. So I created entity public class HitsStatsDO implements Serializable { @Id transient private Long id; transient private Long version = (long) 0; transient private Long startDate; @Parent transient private Key parent; // fake parent which contains target id @Transient int targetId; private double avgPercent; private long hitCount; } But writing HitsStatsDO for each target from each user would give a lot of data. For instance I had a survey with 3000 targets which was answered by ~4 million people within one week with 300K people taking survey in first day. Even if we assume they were answering it evenly for 24 hours it would give us ~1040 writes/second. Obviously it hits concurrent writes limit of Datastore. I decided I'll collect data for one hour and save that, that's why there are avgPercent and hitCount in HitsStatsDO. GAE instances are stateless so I had to use dynamic backend instance. There I have something like this: // Contains stats for one hour private class Shard { ReadWriteLock lock = new ReentrantReadWriteLock(); Map<Integer, HitsStatsDO> map = new HashMap<Integer, HitsStatsDO>(); // Key is target ID public void saveToDatastore(); public void updateStats(Long startDate, Map<Integer, Double> hits); } and map with shard for current hour and previous hour (which doesn't stay here for long) private HashMap<Long, Shard> shards = new HashMap<Long, Shard>(); // Key is HitsStatsDO.startDate So once per hour I dump Shard for previous hour to Datastore. Plus I have class LifetimeStats which keeps Map<Integer, HitsStatsDO> in memcached where map-key is target ID. Also in my backend shutdown hook method I dump stats for unfinished hour to Datastore. There is only one major issue here - I have only ONE backend instance :) It raises following questions on which I'd like to hear your opinion: Can I do this without using backend instance ? What if one instance is not enough ? How can I split data between multiple dynamic backend instances? It hard because I don't know how many I have because Google creates new one as load increases. I know I can launch exact number of resident backend instances. But how many ? 2, 5, 10 ? What if I have no load at all for a week. Constantly running 10 backend instances is too expensive. What do I do with data from clients while backend instance is dead/restarting? Thank you very much in advance for your thoughts.

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• Should data structures be integrated into the language (as in Python) or be provided in the standard library (as in Java)?

  - by Anto

  In Python, and most likely many other programming languages, common data structures can be found as an integrated part of the core language with their own dedicated syntax. If we put LISP's integrated list syntax aside, I can't think of any other languages that I know which provides some kind of data structure above the array as an integrated part of their syntax, though all of them (but C, I guess) seem to provide them in the standard library. From a language design perspective, what are your opinions on having a specific syntax for data structures in the core language? Is it a good idea, and does the purpose of the language (etc.) change how good this could be of a choice? Edit: I'm sorry for (apparently) causing some confusion about which data structures I mean. I talk about the basic and commonly used ones, but still not the most basic ones. This excludes trees (too complex, uncommon), stacks (too seldom used), arrays (too simple) but includes e.g. sets, lists and hashmaps.

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• Handy Javascript array Extensions &ndash; distinct()

  - by Liam McLennan

  The following code adds a method to javascript arrays that returns a distinct list of values. Array.prototype.distinct = function() { var derivedArray = []; for (var i = 0; i < this.length; i += 1) { if (!derivedArray.contains(this[i])) { derivedArray.push(this[i]) } } return derivedArray; }; and to demonstrate: alert([1,1,1,2,2,22,3,4,5,6,7,5,4].distinct().join(',')); This produces 1,2,22,3,4,5,6,7

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• Alternatives to NSMutableArray for storing 2D grid - iOS Cocos2d

  - by SundayMonday

  I'm creating a grid-based iOS game using Cocos2d. Currently the grid is stored in an NSMutableArray that contains other NSMutableArrays (the latter are rows in the grid). This works ok and performance so far is pretty good. However the syntax feels bulky and the indexing isn't very elegant (using CGPoints, would prefer integer indices). I'm looking for an alternative. What are some alternatives data structures for 2D arrays in this situation? In my game it's very common to add and remove rows from the bottom of the grid. So the grid might start off 10x10, grow to 17x10, shrink to 8x10 and then finally end with 2x10. Note the column count is constant. I've consider using a vector<vector<Object*>>. Also I'm vaguely aware of some type of "fast array" or similar offered by Cocos2d. I'd just like to learn about best practices from other developers!

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• Using multiple indexes with buffer objects in OpenTK

  - by Rushyo

  I've got multiple buffers in OpenGL holding data on position, normals and texcoords. I also have an equal number of buffers holding distinct index data for each of those buffers. I quite like this format (indvidual indexes for each buffer) utilised by COLLADA since it strikes me as optimally efficient at accessing each buffer. I've set up pointers to the relevant data arrays using VertexPointer, NormalPointer, etc however I have no way to assign pointers to the index buffers since DrawElements appear to only look at one ElementArrayBuffer. Can I utilise multiple indices some way or will I be better off using a different technique which can support this? I'd prefer to keep the distinct indices if at all possible.

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• 25. Treffen der FraOSUG am 18. September 2012

  - by uligraef

  Zum 25. Treffen der FraOSUG (Frankfurter Open Solaris / Solaris / Oracle Solaris Users Group) treffen wir uns erstmals in den Räumlichkeiten der Geschäftstelle in Dreieich. Wann? 18. September 2012, 18:00 - 21:00 Uhr Wo? Oracle, Geschäftsstelle Frankfurt, Robert Bosch Str. 5, 63303 Dreieich Agenda: Begrüßung Optimale Datenkompression kleiner Datenmengen mit Suffix Arrays Nachdem neulich Interesse bekundet wurde wird hier der Vortrag vom mrmcd12 wiederholt.(Ulrich Gräf) Roundtable: ZFS Performance -- Die Diskussion zum Vortrag vom letzten Mal (Alle) Diskussion(alle)  Anmeldung bitte mit Doodle . Mehr siehe auf der FraOSUG Homepage.

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• How can I gather client's data on Google App Engine without using Datastore/Backend Instances too much?

  - by ruslan

  One of the projects I'm working on is online survey engine. It's my first big commercial project on Google App Engine. I need your advice on how to collect stats and efficiently record them in DataStore without bankrupting me. Initial requirements are: After user finishes survey client sends list of pairs [ID (int) + PercentHit (double)]. This list shows how close answers of this user match predefined answers of reference answerers (which identified by IDs). I call them "target IDs". Creator of the survey wants to see aggregated % for given IDs for last hour, particular timeframe or from the beginning of the survey. Some surveys may have thousands of target/reference answerers. So I created entity public class HitsStatsDO implements Serializable { @Id transient private Long id; transient private Long version = (long) 0; transient private Long startDate; @Parent transient private Key parent; // fake parent which contains target id @Transient int targetId; private double avgPercent; private long hitCount; } But writing HitsStatsDO for each target from each user would give a lot of data. For instance I had a survey with 3000 targets which was answered by ~4 million people within one week with 300K people taking survey in first day. Even if we assume they were answering it evenly for 24 hours it would give us ~1040 writes/second. Obviously it hits concurrent writes limit of Datastore. I decided I'll collect data for one hour and save that, that's why there are avgPercent and hitCount in HitsStatsDO. GAE instances are stateless so I had to use dynamic backend instance. There I have something like this: // Contains stats for one hour private class Shard { ReadWriteLock lock = new ReentrantReadWriteLock(); Map<Integer, HitsStatsDO> map = new HashMap<Integer, HitsStatsDO>(); // Key is target ID public void saveToDatastore(); public void updateStats(Long startDate, Map<Integer, Double> hits); } and map with shard for current hour and previous hour (which doesn't stay here for long) private HashMap<Long, Shard> shards = new HashMap<Long, Shard>(); // Key is HitsStatsDO.startDate So once per hour I dump Shard for previous hour to Datastore. Plus I have class LifetimeStats which keeps Map<Integer, HitsStatsDO> in memcached where map-key is target ID. Also in my backend shutdown hook method I dump stats for unfinished hour to Datastore. There is only one major issue here - I have only ONE backend instance :) It raises following questions on which I'd like to hear your opinion: Can I do this without using backend instance ? What if one instance is not enough ? How can I split data between multiple dynamic backend instances? It hard because I don't know how many I have because Google creates new one as load increases. I know I can launch exact number of resident backend instances. But how many ? 2, 5, 10 ? What if I have no load at all for a week. Constantly running 10 backend instances is too expensive. What do I do with data from clients while backend instance is dead/restarting?

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• Breaking up a large PHP object used to abstract the database. Best practices?

  - by John Kershaw

  Two years ago it was thought a single object with functions such as $database->get_user_from_id($ID) would be a good idea. The functions return objects (not arrays), and the front-end code never worries about the database. This was great, until we started growing the database. There's now 30+ tables, and around 150 functions in the database object. It's getting impractical and unmanageable and I'm going to be breaking it up. What is a good solution to this problem? The project is large, so there's a limit to the extent I can change things. My current plan is to extend the current object for each table, then have the database object contain these. So, the above example would turn into (assume "user" is a table) $database->user->get_user_from_id($ID). Instead of one large file, we would have a file for every table.

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• Solving a probabilistic problem

  - by ????????????

  So I am interested in Computational Investing and came across this problem on a wiki page: Write a program to discover the answer to this puzzle:"Let's say men and women are paid equally (from the same uniform distribution). If women date randomly and marry the first man with a higher salary, what fraction of the population will get married?" I don't have much knowledge in probability theory, so I'm not really sure how to implement this in code. My thinking: Populate two arrays(female,male) with random salary values from a uniform distribution. Randomly pair one female and one male array element and see if condition of higher salary is met. If it is, increment a counter. Divide counter by population and get percentage. Is this the correct logic? Do woman continually date until there is no males left with higher salaries than women?

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• Associative array challenges, or examples?

  - by Aerovistae

  I understand well when and how to use an associative array, but I'm trying to teach a friend to program and I'm having some trouble with this particular concept. I need a good set of problems whose solutions are best implemented through the use of maps/hashes/associative arrays/dictionaries. I googled all over and couldn't find any. I was hoping someone might know of some, or perhaps get a community wiki sort of answer. That way I can say, here's our problem, and here's how we could effectively solve it through the use of an associative array... It's one of those cases where when I'm programming and I run into a situation that calls for a dictionary, I recognize it, but I can't seem to make up any such situations to use for a demonstration.

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• Minimum team development sizes

  - by MarkPearl

  Disclaimer - these are observations that I have had, I am not sure if this follows the philosophy of scrum, agile or whatever, but most of these insights were gained while implementing a scrum scenario. Two is a partnership, three starts a team For a while I thought that a team was anything more than one and that scrum could be effective methodology with even two people. I have recently adjusted my thinking to a scrum team being a minimum of three, so what happened to two and what do you call it? For me I consider a group of two people working together a partnership - there is value in having a partnership, but some of the dynamics and value that you get from having a team is lost with a partnership. Avoidance of a one on one confrontation The first dynamic I see missing in a partnership is the team motivation to do better and how this is delivered to individuals that are not performing. Take two highly motivated individuals and put them together and you will typically see them continue to perform. Now take a situation where you have two individuals, one performing and one not and the behaviour is totally different compared to a team of three or more individuals. With two people, if one feels the other is not performing it becomes a one on one confrontation. Most people avoid confrontations and so nothing changes. Compare this to a situation where you have three people in a team, 2 performing and 1 not the dynamic is totally different, it is no longer a personal one on one confrontation but a team concern and people seem more willing to encourage the individual not performing and express their dissatisfaction as a team if they do not improve. Avoiding the effects of Tuckman’s Group Development Theory If you are not familiar with Tuckman’s group development theory give it a read (http://en.wikipedia.org/wiki/Tuckman's_stages_of_group_development) In a nutshell with Tuckman’s theory teams go through these stages of Forming, Storming, Norming & Performing. You want your team to reach and remain in the Performing stage for as long as possible - this is where you get the most value. When you have a partnership of two and you change the individuals in the partnership you basically do a hard reset on the partnership and go back to the beginning of Tuckman’s model each time. This has a major effect on the performance of a team and what they can deliver. What I have seen is that you reduce the effects of Tuckman's theory the more individuals you have in the team (until you hit the maximum team size in which other problems kick in). While you will still experience Tuckman's theory with a team of three, the impact will be greatly reduced compared to two where it is guaranteed every time a change occurs. It's not just in the numbers, it's in the people One final comment - while the actual numbers of a team do play a role, the individuals in the team are even more important - ideally you want to keep individuals working together for an extended period. That doesn't mean that you never change the individuals in a team, or that once someone joins a team they are stuck there - there is value in an individual moving from team to team and getting cross pollination, but the period of time that an individual moves should be in month's or years, not days or weeks. Why? So why is it important to know this? Why is it important to know how a team works and what motivates them? I have been asking myself this question for a while and where I am at right now is this… the aim is to achieve the stage where the sum of the total (team) is greater than the sum of the parts (team members). This is why we form teams and why understanding how they work is a challenge and also extremely stimulating.

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• How to restruct RAID 10?

  - by user276851

  We would like to alter the partition without losing data. Here is the sketch of the plan. I am wondering if it is doable using mdadm; and if so, please kindly point some reference on how to carry out the following steps. For RAID 10, there are four disks used. (1 2)(3 4) The idea is to work on 1 and 3 while keeping 2 and 4 as backup. 1: break RAID 10 into two arrays of RAID 0 => (1 3) (2 4) (how to?) 2: re-partition and format (1 3) 3: copy data from (2 4) to (1 3) 4: re-partition and format (2 4) exactly as (1 3) 5: join (2 4) with (1 3) to form RAID 10 (how to?) Does it sound doable? Thanks a lot! Add: It looks like this guy (drumfile) is doing something similar, but lack of enough detail.

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• How to make the switch to C++11?

  - by Overv

  I've been programming in C++ for a while now, but mostly thinks centered around the low-level features of C++. By that I mean mostly working with pointers and raw arrays. I think this behavior is known as using C++ as C with classes despite me only having tried C recently for the first time. I was pleasantly surprised how languages like C# and Java hide these details away in convenient standard library classes like Dictionaries and Lists. I'm aware that the C++ standard library has many convenience containers like vectors, maps and strings as well and C++11 only adds to this by having std:: array and ranged loops. How do I best learn to make use of these modern language features and which are suitable for which moments? Is it correct that software engineering in C++ nowadays I'd mostly free of manual memory management? Lastly, which compiler should I use to make the most of the new standard? Visual Studio has excellent debugging tools, but even VS2012 seems to have terrible C++11 support.

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• Passing data between engine layers

  - by spaceOwl

  I am building a software system (game engine with networking support ) that is made up of (roughly) these layers: Game Layer Messaging Layer Networking Layer Game related data is passed to the messaging layer (this could be anything that is game specific), where they are to be converted to network specific messages (which are then serialized to byte arrays). I'm looking for a way to be able to convert "game" data into "network" data, such that no strong coupling between these layers will exist. As it looks now, the Messaging layer sits between both layers (game and network) and "knows" both of them (it contains Converter objects that know how to translate between data objects of both layers back and forth). I am not sure this is the best solution. Is there a good design for passing objects between layers? I'd like to learn more about the different options.

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• Extreme Makeover, Phone Edition: Comcasts xfinity

  Mobile Makeover For many companies the first foray into Windows Phone 7 (WP7) may be in porting their existing mobile apps. It is tempting to simply transfer existing functionality, avoiding the additional design costs. Readdressing business needs and taking advantage of the WP7 platform can reduce cost and is essential to a successful re-launch. To better understand the advantage of new development lets examine a conceptual upgrade of Comcasts existing mobile app. Before Comcast has a great mobile app that provides several key features. The ability to browse the lineup using a guide, a client for Comcast email accounts, On Demand gallery, and much more. We will leverage these and build on them using some of the incredible WP7 features.   After With the proliferation of DVRs (Digital Video Recorders) and a variety of media devices (TV, PC, Mobile) content providers are challenged to find creative ways to build their brands. Every client touch point must provide both value added services as well as opportunities for marketing and up-sale; WP7 makes it easy to focus on those opportunities. The new app is an excellent vehicle for presenting Comcasts newly rebranded TV, Voice, and Internet services. These services now fly under the banner of xfinity and have been expanded to provide the best experience for Comcast customers. The Windows Phone 7 app will increase the surface area of this service revolution.   The home menu is simplified and highlights Comcasts Triple Play: Voice, TV, and Internet. The inbox has been replaced with a messages view, and message management is handled by a WP7 hub. The hub presents emails, tweets, and IMs from Comcast and other viewers the user follows on Twitter.  The popular view orders shows based on the users viewing history and current cable package. The first show Glee is both popular and participating in a conceptual co-marketing effort, so it receives prime positioning. The second spot goes to a hit show on a premium channel, in this example HBOs The Pacific, encouraging viewers to upgrade for this premium content. The remaining spots are ordered based on viewing history and popularity. Tapping the play button moves the user to the theatre where they can watch previews or full episodes streaming from Fancast. Tapping an extra presents the user with show details as well as interactive content that may be included as part of co-marketing efforts. Co-Marketing with Dynamic Content The success of Comcasts services are tied to the success of the networks and shows it purveys, making co-marketing efforts essential. In this concept FOX is co-marketing its popular show Glee. A customized panorama is updated with the latest gleeks tweets, streaming HD episodes, and extras featuring photos and video of the cast. If WP7 apps can be dynamically extended with web hosted .xap files, including sandboxed partner experiences would enable interactive features such as the Gleek Peek, in which a viewer can select a character from a panorama to view the actors profile. This dynamic inline experience has a tailored appeal to aspiring creatives and is technically possible with Windows Phone 7.   Summary The conceptual Comcast mobile app for Windows Phone 7 highlights just a few of the incredible experiences and business opportunities that can be unlocked with this latest mobile solution. It is critical that organizations recognize and take full advantage of these new capabilities. Simply porting existing mobile applications does not leverage these powerful tools; re-examining existing applications and upgrading them to Windows Phone 7 will prove essential to the continued growth and success of your brand.Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Handy Javascript array Extensions &ndash; contains(&hellip;)

  - by Liam McLennan

  This javascript adds a method to javascript arrays that returns a boolean indicating if the supplied object is an element of the array Array.prototype.contains = function(item) { for (var i = 0; i < this.length; i += 1) { if (this[i] === item) { return true; } } return false; }; To test alert([1,1,1,2,2,22,3,4,5,6,7,5,4].contains(2)); // true alert([1,1,1,2,2,22,3,4,5,6,7,5,4].contains(99)); // false

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• How can be data oriented programming applied for GUI system?

  - by Miro

  I've just learned basics of Data oriented programming design, but I'm not very familiar with that yet. I've also read Pitfalls of Object Oriented Programming GCAP 09. It seems that data oriented programming is much better idea for games, than OOP. I'm just creating my own GUI system and it's completely OOP. I'm thinking if is data oriented programming design applicable for structured things like GUI. The main problem I see is that every type widget has different data, so I can hardly group them into arrays. Also every type of widget renders differently so I still need to call virtual functions.

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• When to use functional programming approach and when not? (in Java)

  - by john smith optional

  let's assume I have a task to create a Set of class names. To remove duplication of .getName() method calls for each class, I used org.apache.commons.collections.CollectionUtils and org.apache.commons.collections.Transformer as follows: Snippet 1: Set<String> myNames = new HashSet<String>(); CollectionUtils.collect( Arrays.<Class<?>>asList(My1.class, My2.class, My3.class, My4.class, My5.class), new Transformer() { public Object transform(Object o) { return ((Class<?>) o).getName(); } }, myNames); An alternative would be this code: Snippet 2: Collections.addAll(myNames, My1.class.getName(), My2.class.getName(), My3.class.getName(), My4.class.getName(), My5.class.getName()); So, when using functional programming approach is overhead and when it's not and why? Isn't my usage of functional programming approach in snippet 1 is an overhead and why?

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