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• How-To Backup, Swap, and Update Your Wii Game Saves

  - by Jason Fitzpatrick

  Whether you want to backup your game saves because you’ve worked so hard on them or you want to import game saves precisely so you don’t have to work so hard, we’ve got you covered. Image adapted from icon set by GasClown. There are a multitude of reasons you might want to export and import game saves from your Wii including: saving the progress on your favorite games before sending in your Wii for service, copying the progress to a friend’s or your secondary Wii, and importing saved games from the web or your friend’s Wii so that you don’t have to bust your ass to unlock all the specialty items yourself. (Here’s looking at you Mario Kart and House of the Dead: Overkill.) Latest Features How-To Geek ETC How To Create Your Own Custom ASCII Art from Any Image How To Process Camera Raw Without Paying for Adobe Photoshop How Do You Block Annoying Text Message (SMS) Spam? How to Use and Master the Notoriously Difficult Pen Tool in Photoshop HTG Explains: What Are the Differences Between All Those Audio Formats? How To Use Layer Masks and Vector Masks to Remove Complex Backgrounds in Photoshop Bring Summer Back to Your Desktop with the LandscapeTheme for Chrome and Iron The Prospector – Home Dash Extension Creates a Whole New Browsing Experience in Firefox KinEmote Links Kinect to Windows Why Nobody Reads Web Site Privacy Policies [Infographic] Asian Temple in the Snow Wallpaper 10 Weird Gaming Records from the Guinness Book

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• Drawing lines in 3D space

  - by DeadMG

  When attempting to draw a line in 3D space with D3DPT_LINELIST, then Direct3D gives me an error about an invalid vertex declaration, saying that it cannot be converted to an FVF. I am using the same vertex declaration and shader/stream setup as for my D3DPT_TRIANGLELIST rendering which works absolutely correctly. How can I use D3DPT_LINELIST to render some lines in 3D space? Edit: Oopsie, forgot my codeses. Here's my raw Draw call. D3DCALL(device->SetStreamSource(1, PerBoneBuffer.get(), 0, sizeof(PerInstanceData))); D3DCALL(device->SetStreamSourceFreq(1, D3DSTREAMSOURCE_INSTANCEDATA | 1)); D3DCALL(device->SetStreamSource(0, LineVerts, 0, sizeof(D3DXVECTOR3))); D3DCALL(device->SetStreamSourceFreq(0, D3DSTREAMSOURCE_INDEXEDDATA | lines.size())); D3DCALL(device->SetIndices(LineIndices)); PerInstanceData* data; std::vector<Wide::Render::Line*> lines_vec(lines.begin(), lines.end()); D3DCALL(PerBoneBuffer->Lock(0, lines.size() * sizeof(PerInstanceData), reinterpret_cast<void**>(&data), D3DLOCK_DISCARD)); std::for_each(lines.begin(), lines.end(), [&](Wide::Render::Line* ptr) { data->Color = D3DXColor(ptr->Colour); D3DXMATRIXA16 Translate, Scale, Rotate; D3DXMatrixTranslation(&Translate, ptr->Start.x, ptr->Start.y, ptr->Start.z); D3DXMatrixScaling(&Scale, ptr->Scale, 1, 1); D3DXMatrixRotationQuaternion(&Rotate, &D3DQuaternion(ptr->Rotation)); data->World = Scale * Rotate * Translate; }); D3DCALL(PerBoneBuffer->Unlock()); D3DCALL(device->DrawIndexedPrimitive(D3DPRIMITIVETYPE::D3DPT_LINELIST, 0, 0, 2, 0, 1)); Here's my vertex declaration: D3DVERTEXELEMENT9 BasicMeshVertices[] = { {0, 0, D3DDECLTYPE_FLOAT3, D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_POSITION, 0}, {1, 0, D3DDECLTYPE_FLOAT4, D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_TEXCOORD, 0}, {1, 16, D3DDECLTYPE_FLOAT4, D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_TEXCOORD, 1}, {1, 32, D3DDECLTYPE_FLOAT4, D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_TEXCOORD, 2}, {1, 48, D3DDECLTYPE_FLOAT4, D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_TEXCOORD, 3}, {1, 64, D3DDECLTYPE_FLOAT4, D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_COLOR, 0}, D3DDECL_END() }; The LineIndices are just 0, 1 and the LineVerts are just {0,0,0} and {1,0,0}, to represent a unit 3D line along the X axis.

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• Internet Explorer 9 Preview 2 link + webcasts for developers

  - by Eric Nelson

  At Web Directions last week in London (10th and 11th June 2010) I promised several folks I would put up a blog post to more information on IE 9.0. True to my word (albeit a little later than I had hoped), here is what I was thinking of: Install First up, Install Preview 2 and try out the demos I was showing at the conference. Remember that IE9 Preview installs side by side with IE8/7 etc. It is not a beta nor is it intended to be a full browser. It is a … preview :-)   Including good old SVG-oids :-) Learn And then check out the following webcasts which were recorded in March this year at MIX: In-Depth Look At Internet Explorer 9 Presenter:  Ted Johnson & John Hrvatin VisitMIX URL: http://live.visitmix.com/MIX10/Sessions/CL28 Slides: Download Videos: MP4 Small WMV Large WMV High Performance Best Practices For Web Sites Presenter: Jason Weber VisitMIX URL: http://live.visitmix.com/MIX10/Sessions/CL29 Slides: Download Videos: MP4 Small WMV Large WMV HTML5: Cross Browser Best Practices Presenter: Tony Ross VisitMIX URL: http://live.visitmix.com/MIX10/Sessions/CL27 Slides: Download Videos: MP4 Small WMV Large WMV Internet Explorer Developer Tools Presenter: Jon Seitel VisitMIX URL: http://live.visitmix.com/MIX10/Sessions/FT51 Slides: Download Videos: MP4 Small WMV Large WMV SVG: The Past, Present And Future of Vector Graphics For The Web Presenter: Patrick Dengler, Doug Schepers VisitMIX URL: http://live.visitmix.com/MIX10/Sessions/EX30 Slides: Download Videos: MP4 Small WMV Large WMV Day 2 Keynote containing IE9 Presenter: Dean Hachamovitch VisitMIX URL: http://live.visitmix.com/MIX10/Sessions/KEY02 Slides: Download Videos: MP4 Small WMV Large WMV

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• LWJGL Determining whether or not a polygon is on-screen.

  - by Brandon oubiub

  Not sure whether this is an LWJGL or math question. I want to check whether a shape is on-screen, so that I don't have to render it if it isn't. First of all, is there any simple way to do this that I am overlooking? Like some method or something that I haven't found? I'm going to assume there isn't. I tried using my trigonometry skills, but it is hard to do this because of how glRotate also distorts the image a little for perspective and realism. Or, is there any way to easily determine if a ray starting from the camera, and going outward in a straight line intersects a shape? (I can probably do it with my math skillz, but is there an easier way?) By the way, I can easily determine the angle at which the camera is facing around the x and y axis. EDIT: Or, possibly, I could get the angles of a vector from the camera to the object, and compare those angles to my camera angles. But I have a feeling that the distorts from glRotate and glTranslate would be an issue. I'll try it though.

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• jerky walljump in unity rigidbody2d

  - by Lilz Votca Love

  hey there i know people have encountered issues with it before i looked upon the different solutions provided but i couldnt get any fix at all.im making a 2d game and am stuck with the walljump.i detect the wall wonderfully i also detect the jump and it works the player jumps off the wall when facing right with the use of rigidbody.addforce(new vector2(-1,2)*jumpforce) now when jumping on the oposite wall using the same vector with the sign in x axis changed to 1,the player jumps too but it goes more in the y axis than it should.Here is an image to show you the curves it(the player) follows. check the following url to see the behaviour https://scontent-b-mad.xx.fbcdn.net/hphotos-xpf1/t1.0-9/1470386_10152415957141154_156025539179003805_n.jpg voila the green one is happennig when player faces right and the other one happens when he is not here is the section of code if (wall) { if (wallJump) { if (facingRight) { rigidbody2D.velocity = Vector2.zero; flip (); rigidbody2D.AddForce (new Vector2 (-1f, 2f) * Jumpforce / 1.5f); Debug.Log ("saut mural gauche" + new Vector2 (-1f, 2f) * Jumpforce / 1.5f); } else { rigidbody2D.velocity = Vector2.zero; flip (); rigidbody2D.AddForce (new Vector2 (1f, 2f) * Jumpforce / 1.5f); Debug.Log ("saut mural droit--" + new Vector2 (Mathf.Sign (1f), 2f) * Jumpforce / 1.5f + "jump" + jump); } } } else { wallJump = false; } here the code is not optimized yet but i assure you it works so guys any help would be so awesome!! thanks

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• Camera Collision inside the room model

  - by sanddy

  I am having a problem in Calculating the camera collision for my Room model which consists of sofa, tables and other models. The users shall be moving the camera front, back, rotating so i need to make sure that the camera does not collide with any of the models with in the room. I have treated all my models inside the room by BoundingBox[] and the camera by BoundingSphere. So, far i have implemented collision by looking into the tutorial from http://www.toymaker.info/Games/XNA/html/xna_model_collisions.html which was great. But, I guess the problem lies in the Transformation part. I debugged and found some points to be at Vector(-XXX,-XXX,-XXX) where X is digit. Also i found my radius of some models where too large(in thousand, i just looked into its radius value before converting to BoundingBox). Do I need to scale the model for collision??? Below are my code:- On My LoadContent(): Matrix[] transforms = new Matrix[myModel.Bones.Count]; myModel.CopyAbsoluteBoneTransformsTo(transforms); int index = 0; box = new List<BoundingBox>(); BoundingBox worldModel = Utility.CalculateBoundingBox(myModel); foreach (ModelMesh mesh in myModel.Meshes) { Vector3[] obb = new Vector3[8]; worldModel.GetCorners(obb); Vector3[] asdf = (Vector3[])obb.Clone(); Vector3.Transform(obb, ref transforms[mesh.ParentBone.Index], obb); BoundingBox worldBox = BoundingBox.CreateFromPoints(obb); box.Add(worldBox); index++; } On CameraPosition Update: BoundingSphere bs = new BoundingSphere(this.cameraPos, 5.0f); if (RoomWalkthrough.Utility.CheckCollision(bs, bb)) { // Do Something } Please Help.

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• The next next C++ [closed]

  - by Roger Pate

  It's entirely too early for speculation on what C++ will be like after C++0x, but idle hands make for wild predictions. What features would you find useful and why? Is there anything in another language that would fit nicely into the state of C++ after 0x? What should be considered for the next TC and TR? (Mostly TR, as the TC would depend more on what actually becomes the next standard.) Export was removed, rather than merely deprecated, in 0x. (It remains a keyword.) What other features carry so much baggage to also be more harmful than helpful? ISO Standards' process I'm not involved in the C++ committee, but it's also a mystery, unfortunately, to most programmers using C++. A few things worth keeping in mind: There will be 10 years between standards, barring extremely exceptional circumstances. The standard can get "bug fixes" in the form of a Technical Corrigendum. This happened to C++98 with TC1, named C++03. It fixed "simple" issues such as making the explicit guarantee that std::vector stores items contiguously, which was always intended. The committee can issue reports which can add to the language. This happened to C++98/03 with TR1 in 2005, which introduced the std::tr1 namespace.

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• Bad DMA/do_IRQ errors on suspend/resume, with occasional freezing

  - by Steve Kroon

  Every time I suspend or resume my laptop (Dell Latitude E6520, bought this year), I get 2 messages of the form displayed on the console just before shutting down/starting up: [ 407.107610] ehci_hcd 0000:00:1d.0: dma_pool_free buffer-128, f6f18000/36f18000 (bad dma) On occasion, I get a message of the form: [ 3753.979066] do_IRQ: 0.177 No irq handler for vector (irq -1) On occasion, my machine freezes with a flashing Caps Lock button when suspending, after which I need to do a hard shutdown. This never happened before the messages started appearing (a while back), and I think it never happens without a do_IRQ message appearing (although I'm not sure about that). [There's nothing in the owner's manual on a flashing Caps Lock button; apparently it may be a kernel panic if the scroll lock also flashes, but the laptop doesn't have a scroll lock light, and there's no message on the console saying kernel panic.] Are these bad DMA/do IRQ messages serious, and what can I do to investigate/troubleshoot them and the freezing? Edit: I've also now received the following error messages a few times: [246943.023908] JBD: I/O error detected when updating journal superblock for sdb1. [246943.023958] Buffer I/O error on device sdb1, logical block 0 [246943.023996] EXT3-fs (sdb1): I/O error while writing superblock Edit: Output of dmesg at http://pastebin.com/ra7MTQEj ; contents of /var/log/kern.log at http://pastebin.com/i6jf0Md9 Edit: the output of some smartctl (-a, -x, --log=error, --log=xerror) instructions is available at http://paste.ubuntu.com/1088488/ . Edit (31/8/2012): Output of dmesg|grep -i ehci available at http://paste.ubuntu.com/1177246/ .

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• A Look Inside JSR 360 - CLDC 8

  - by Roger Brinkley

  If you didn't notice during JavaOne the Java Micro Edition took a major step forward in its consolidation with Java Standard Edition when JSR 360 was proposed to the JCP community. Over the last couple of years there has been a focus to move Java ME back in line with it's big brother Java SE. We see evidence of this in JCP itself which just recently merged the ME and SE/EE Executive Committees into a single Java Executive Committee. But just before that occurred JSR 360 was proposed and approved for development on October 29. So let's take a look at what changes are now being proposed. In a way JSR 360 is returning back to the original roots of Java ME when it was first introduced. It was indeed a subset of the JDK 4 language, but as Java progressed many of the language changes were not implemented in the Java ME. Back then the tradeoff was still a functionality, footprint trade off but the major market was feature phones. Today the market has changed and CLDC, while it will still target feature phones, will have it primary emphasis on embedded devices like wireless modules, smart meters, health care monitoring and other M2M devices. The major changes will come in three areas: language feature changes, library changes, and consolidating the Generic Connection Framework.  There have been three Java SE versions that have been implemented since JavaME was first developed so the language feature changes can be divided into changes that came in JDK 5 and those in JDK 7, which mostly consist of the project Coin changes. There were no language changes in JDK 6 but the changes from JDK 5 are: Assertions - Assertions enable you to test your assumptions about your program. For example, if you write a method that calculates the speed of a particle, you might assert that the calculated speed is less than the speed of light. In the example code below if the interval isn't between 0 and and 1,00 the an error of "Invalid value?" would be thrown. private void setInterval(int interval) { assert interval > 0 && interval <= 1000 : "Invalid value?" } Generics - Generics add stability to your code by making more of your bugs detectable at compile time. Code that uses generics has many benefits over non-generic code with: Stronger type checks at compile time. Elimination of casts. Enabling programming to implement generic algorithms. Enhanced for Loop - the enhanced for loop allows you to iterate through a collection without having to create an Iterator or without having to calculate beginning and end conditions for a counter variable. The enhanced for loop is the easiest of the new features to immediately incorporate in your code. In this tip you will see how the enhanced for loop replaces more traditional ways of sequentially accessing elements in a collection. void processList(Vector<string> list) { for (String item : list) { ... Autoboxing/Unboxing - This facility eliminates the drudgery of manual conversion between primitive types, such as int and wrapper types, such as Integer.  Hashtable<Integer, string=""> data = new Hashtable<>(); void add(int id, String value) { data.put(id, value); } Enumeration - Prior to JDK 5 enumerations were not typesafe, had no namespace, were brittle because they were compile time constants, and provided no informative print values. JDK 5 added support for enumerated types as a full-fledged class (dubbed an enum type). In addition to solving all the problems mentioned above, it allows you to add arbitrary methods and fields to an enum type, to implement arbitrary interfaces, and more. Enum types provide high-quality implementations of all the Object methods. They are Comparable and Serializable, and the serial form is designed to withstand arbitrary changes in the enum type. enum Season {WINTER, SPRING, SUMMER, FALL}; } private Season season; void setSeason(Season newSeason) { season = newSeason; } Varargs - Varargs eliminates the need for manually boxing up argument lists into an array when invoking methods that accept variable-length argument lists. The three periods after the final parameter's type indicate that the final argument may be passed as an array or as a sequence of arguments. Varargs can be used only in the final argument position. void warning(String format, String... parameters) { .. for(String p : parameters) { ...process(p);... } ... } Static Imports -The static import construct allows unqualified access to static members without inheriting from the type containing the static members. Instead, the program imports the members either individually or en masse. Once the static members have been imported, they may be used without qualification. The static import declaration is analogous to the normal import declaration. Where the normal import declaration imports classes from packages, allowing them to be used without package qualification, the static import declaration imports static members from classes, allowing them to be used without class qualification. import static data.Constants.RATIO; ... double r = Math.cos(RATIO * theta); Annotations - Annotations provide data about a program that is not part of the program itself. They have no direct effect on the operation of the code they annotate. There are a number of uses for annotations including information for the compiler, compiler-time and deployment-time processing, and run-time processing. They can be applied to a program's declarations of classes, fields, methods, and other program elements. @Deprecated public void clear(); The language changes from JDK 7 are little more familiar as they are mostly the changes from Project Coin: String in switch - Hey it only took us 18 years but the String class can be used in the expression of a switch statement. Fortunately for us it won't take that long for JavaME to adopt it. switch (arg) { case "-data": ... case "-out": ... Binary integral literals and underscores in numeric literals - Largely for readability, the integral types (byte, short, int, and long) can also be expressed using the binary number system. and any number of underscore characters (_) can appear anywhere between digits in a numerical literal. byte flags = 0b01001111; long mask = 0xfff0_ff08_4fff_0fffl; Multi-catch and more precise rethrow - A single catch block can handle more than one type of exception. In addition, the compiler performs more precise analysis of rethrown exceptions than earlier releases of Java SE. This enables you to specify more specific exception types in the throws clause of a method declaration. catch (IOException | InterruptedException ex) { logger.log(ex); throw ex; } Type Inference for Generic Instance Creation - Otherwise known as the diamond operator, the type arguments required to invoke the constructor of a generic class can be replaced with an empty set of type parameters (<>) as long as the compiler can infer the type arguments from the context.  map = new Hashtable<>(); Try-with-resource statement - The try-with-resources statement is a try statement that declares one or more resources. A resource is an object that must be closed after the program is finished with it. The try-with-resources statement ensures that each resource is closed at the end of the statement.  try (DataInputStream is = new DataInputStream(...)) { return is.readDouble(); } Simplified varargs method invocation - The Java compiler generates a warning at the declaration site of a varargs method or constructor with a non-reifiable varargs formal parameter. Java SE 7 introduced a compiler option -Xlint:varargs and the annotations @SafeVarargs and @SuppressWarnings({"unchecked", "varargs"}) to supress these warnings. On the library side there are new features that will be added to satisfy the language requirements above and some to improve the currently available set of APIs.  The library changes include: Collections update - New Collection, List, Set and Map, Iterable and Iteratator as well as implementations including Hashtable and Vector. Most of the work is too support generics String - New StringBuilder and CharSequence as well as a Stirng formatter. The javac compiler  now uses the the StringBuilder instead of String Buffer. Since StringBuilder is synchronized there is a performance increase which has necessitated the wahat String constructor works. Comparable interface - The comparable interface works with Collections, making it easier to reuse. Try with resources - Closeable and AutoCloseable Annotations - While support for Annotations is provided it will only be a compile time support. SuppressWarnings, Deprecated, Override NIO - There is a subset of NIO Buffer that have been in use on the of the graphics packages and needs to be pulled in and also support for NIO File IO subset. Platform extensibility via Service Providers (ServiceLoader) - ServiceLoader interface dos late bindings of interface to existing implementations. It helpe to package an interface and behavior of the implementation at a later point in time.Provider classes must have a zero-argument constructor so that they can be instantiated during loading. They are located and instantiated on demand and are identified via a provider-configuration file in the METAINF/services resource directory. This is a mechansim from Java SE. import com.XYZ.ServiceA; ServiceLoader<ServiceA> sl1= new ServiceLoader(ServiceA.class); Resources: META-INF/services/com.XYZ.ServiceA: ServiceAProvider1 ServiceAProvider2 ServiceAProvider3 META-INF/services/ServiceB: ServiceBProvider1 ServiceBProvider2 From JSR - I would rather use this list I think The Generic Connection Framework (GCF) was previously specified in a number of different JSRs including CLDC, MIDP, CDC 1.2, and JSR 197. JSR 360 represents a rare opportunity to consolidated and reintegrate parts that were duplicated in other specifications into a single specification, upgrade the APIs as well provide new functionality. The proposal is to specify a combined GCF specification that can be used with Java ME or Java SE and be backwards compatible with previous implementations. Because of size limitations as well as the complexity of the some features like InvokeDynamic and Unicode 6 will not be included. Additionally, any language or library changes in JDK 8 will be not be included. On the upside, with all the changes being made, backwards compatibility will still be maintained. JSR 360 is a major step forward for Java ME in terms of platform modernization, language alignment, and embedded support. If you're interested in following the progress of this JSR see the JSR's java.net project for details of the email lists, discussions groups.

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• Using orientation to calculate position on Windows Phone 7

  - by Lavinski

  I'm using the motion API and I'm trying to figure out a control scheme for the game I'm currently developing. What I'm trying to achive is for a orienation of the device to correlate directly to a position. Such that tilting the phone forward and to the left represents the top left position and back to the right would be the bottom right position. Photos to make it clearer (the red dot would be the calculated position). Forward and Left Back and Right Now for the tricky bit. I also have to make sure that the values take into account left landscape and right landscape device orientations (portrait is the default so no calculations would be needed for it). Has anyone done anything like this? Notes: I've tried using the yaw, pitch, roll and Quaternion readings. Sample: // Get device facing vector public static Vector3 GetState() { lock (lockable) { var down = Vector3.Forward; var direction = Vector3.Transform(down, state); switch (Orientation) { case Orientation.LandscapeLeft: return Vector3.TransformNormal(direction, Matrix.CreateRotationZ(-rightAngle)); case Orientation.LandscapeRight: return Vector3.TransformNormal(direction, Matrix.CreateRotationZ(rightAngle)); } return direction; } }

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• Solving Big Problems with Oracle R Enterprise, Part I

  - by dbayard

  Abstract: This blog post will show how we used Oracle R Enterprise to tackle a customer’s big calculation problem across a big data set. Overview: Databases are great for managing large amounts of data in a central place with rigorous enterprise-level controls.  R is great for doing advanced computations.  Sometimes you need to do advanced computations on large amounts of data, subject to rigorous enterprise-level concerns.  This blog post shows how Oracle R Enterprise enables R plus the Oracle Database enabled us to do some pretty sophisticated calculations across 1 million accounts (each with many detailed records) in minutes. The problem: A financial services customer of mine has a need to calculate the historical internal rate of return (IRR) for its customers’ portfolios.  This information is needed for customer statements and the online web application.  In the past, they had solved this with a home-grown application that pulled trade and account data out of their data warehouse and ran the calculations.  But this home-grown application was not able to do this fast enough, plus it was a challenge for them to write and maintain the code that did the IRR calculation. IRR – a problem that R is good at solving: Internal Rate of Return is an interesting calculation in that in most real-world scenarios it is impractical to calculate exactly.  Rather, IRR is a calculation where approximation techniques need to be used.  In this blog post, we will discuss calculating the “money weighted rate of return” but in the actual customer proof of concept we used R to calculate both money weighted rate of returns and time weighted rate of returns.  You can learn more about the money weighted rate of returns here: http://www.wikinvest.com/wiki/Money-weighted_return First Steps- Calculating IRR in R We will start with calculating the IRR in standalone/desktop R.  In our second post, we will show how to take this desktop R function, deploy it to an Oracle Database, and make it work at real-world scale.  The first step we did was to get some sample data.  For a historical IRR calculation, you have a balances and cash flows.  In our case, the customer provided us with several accounts worth of sample data in Microsoft Excel.      The above figure shows part of the spreadsheet of sample data.  The data provides balances and cash flows for a sample account (BMV=beginning market value. FLOW=cash flow in/out of account. EMV=ending market value). Once we had the sample spreadsheet, the next step we did was to read the Excel data into R.  This is something that R does well.  R offers multiple ways to work with spreadsheet data.  For instance, one could save the spreadsheet as a .csv file.  In our case, the customer provided a spreadsheet file containing multiple sheets where each sheet provided data for a different sample account.  To handle this easily, we took advantage of the RODBC package which allowed us to read the Excel data sheet-by-sheet without having to create individual .csv files.  We wrote ourselves a little helper function called getsheet() around the RODBC package.  Then we loaded all of the sample accounts into a data.frame called SimpleMWRRData. Writing the IRR function At this point, it was time to write the money weighted rate of return (MWRR) function itself.  The definition of MWRR is easily found on the internet or if you are old school you can look in an investment performance text book.  In the customer proof, we based our calculations off the ones defined in the The Handbook of Investment Performance: A User’s Guide by David Spaulding since this is the reference book used by the customer.  (One of the nice things we found during the course of this proof-of-concept is that by using R to write our IRR functions we could easily incorporate the specific variations and business rules of the customer into the calculation.) The key thing with calculating IRR is the need to solve a complex equation with a numerical approximation technique.  For IRR, you need to find the value of the rate of return (r) that sets the Net Present Value of all the flows in and out of the account to zero.  With R, we solve this by defining our NPV function: where bmv is the beginning market value, cf is a vector of cash flows, t is a vector of time (relative to the beginning), emv is the ending market value, and tend is the ending time. Since solving for r is a one-dimensional optimization problem, we decided to take advantage of R’s optimize method (http://stat.ethz.ch/R-manual/R-patched/library/stats/html/optimize.html). The optimize method can be used to find a minimum or maximum; to find the value of r where our npv function is closest to zero, we wrapped our npv function inside the abs function and asked optimize to find the minimum.  Here is an example of using optimize: where low and high are scalars that indicate the range to search for an answer.   To test this out, we need to set values for bmv, cf, t, emv, tend, low, and high.  We will set low and high to some reasonable defaults. For example, this account had a negative 2.2% money weighted rate of return. Enhancing and Packaging the IRR function With numerical approximation methods like optimize, sometimes you will not be able to find an answer with your initial set of inputs.  To account for this, our approach was to first try to find an answer for r within a narrow range, then if we did not find an answer, try calling optimize() again with a broader range.  See the R help page on optimize()  for more details about the search range and its algorithm. At this point, we can now write a simplified version of our MWRR function.  (Our real-world version is  more sophisticated in that it calculates rate of returns for 5 different time periods [since inception, last quarter, year-to-date, last year, year before last year] in a single invocation.  In our actual customer proof, we also defined time-weighted rate of return calculations.  The beauty of R is that it was very easy to add these enhancements and additional calculations to our IRR package.)To simplify code deployment, we then created a new package of our IRR functions and sample data.  For this blog post, we only need to include our SimpleMWRR function and our SimpleMWRRData sample data.  We created the shell of the package by calling: To turn this package skeleton into something usable, at a minimum you need to edit the SimpleMWRR.Rd and SimpleMWRRData.Rd files in the \man subdirectory.  In those files, you need to at least provide a value for the “title” section. Once that is done, you can change directory to the IRR directory and type at the command-line: The myIRR package for this blog post (which has both SimpleMWRR source and SimpleMWRRData sample data) is downloadable from here: myIRR package Testing the myIRR package Here is an example of testing our IRR function once it was converted to an installable package: Calculating IRR for All the Accounts So far, we have shown how to calculate IRR for a single account.  The real-world issue is how do you calculate IRR for all of the accounts?This is the kind of situation where we can leverage the “Split-Apply-Combine” approach (see http://www.cscs.umich.edu/~crshalizi/weblog/815.html).  Given that our sample data can fit in memory, one easy approach is to use R’s “by” function.  (Other approaches to Split-Apply-Combine such as plyr can also be used.  See http://4dpiecharts.com/2011/12/16/a-quick-primer-on-split-apply-combine-problems/). Here is an example showing the use of “by” to calculate the money weighted rate of return for each account in our sample data set.  Recap and Next Steps At this point, you’ve seen the power of R being used to calculate IRR.  There were several good things: R could easily work with the spreadsheets of sample data we were given R’s optimize() function provided a nice way to solve for IRR- it was both fast and allowed us to avoid having to code our own iterative approximation algorithm R was a convenient language to express the customer-specific variations, business-rules, and exceptions that often occur in real-world calculations- these could be easily added to our IRR functions The Split-Apply-Combine technique can be used to perform calculations of IRR for multiple accounts at once. However, there are several challenges yet to be conquered at this point in our story: The actual data that needs to be used lives in a database, not in a spreadsheet The actual data is much, much bigger- too big to fit into the normal R memory space and too big to want to move across the network The overall process needs to run fast- much faster than a single processor The actual data needs to be kept secured- another reason to not want to move it from the database and across the network And the process of calculating the IRR needs to be integrated together with other database ETL activities, so that IRR’s can be calculated as part of the data warehouse refresh processes In our next blog post in this series, we will show you how Oracle R Enterprise solved these challenges.

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• How can I resolve collisions at different speeds, depending on the direction?

  - by Raven Dreamer

  I have, for all intents and purposes, a Triangle class that objects in my scene can collide with (In actuality, the right side of a parallelogram). My collision detection and resolution code works fine for the purposes of preventing a gameobject from entering into the space of the Triangle, instead directing the movement along the edge. The trouble is, the maximum speed along the x and y axis is not equivalent in my game, and moving along the Y axis (up or down) should take twice as long as an equivalent distance along the X axis (left or right). Unfortunately, these speeds apply to the collision resolution too, and movement along the blue path above progresses twice as fast. What can I do in my collision resolution to make sure that the speedlimit for Y axis movement is obeyed in the latter case? Collision Resolution for this case below (vecInput and velocity are the position and velocity vectors of the game object): // y = mx+c // solve for y. M = 2, x = input's x coord, c = rightYIntercept lowY = 2*vecInput.x + parag.rightYIntercept ; ... else { // y = mx+c // vecInput.y = 2(x) + RightYIntercept // (vecInput.y - RightYIntercept) / 2 = x; //if velocity.Y (positive) greater than velocity.X (negative) //pushing from bottom, so push right. if(velocity.y > -1*velocity.x) { //change the input vector's x position to match the //y position on the shape's edge. Formula for line: Y = MX+C // M is 2, C is rightYIntercept, y is the input y, solve for X. vecInput = new Vector2((vecInput.y - parag.rightYIntercept)/2, vecInput.y); Debug.Log("adjusted rightwards"); } else { vecInput = new Vector2( vecInput.x, lowY); Debug.Log("adjusted downwards"); } }

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• What is a technique for 2D ray-box intersection that is suitable for old console hardware?

  - by DJCouchyCouch

  I'm working on a Sega Genesis homebrew game (it has a 7mhz 68000 CPU). I'm looking for a way to find the intersection between a particle sprite and a background tile. Particles are represented as a point with a movement vector. Background tiles are 8 x 8 pixels, with an (X,Y) position that is always located at a multiple of 8. So, really, I need to find the intersection point for a ray-box collision; I need to find out where along the edge of the tile the ray/particle hits. I have these two hard constraints: I'm working with pixel locations (integers). Floating point is too expensive. It doesn't have to be super exact, just close enough. Multiplications, divisions, dot products, et cetera, are incredibly expensive and are to be avoided. So I'm looking for an efficient algorithm that would fit those constraints. Any ideas? I'm writing it in C, so that would work, but assembly should be good as well.

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• Sprites rendering blurry with velocity

  - by ashes999

  After adding velocity to my game, I feel like my textures are twitching. I thought it was just my eyes, until I finally captured it in a screenshot: The one on the left is what renders in my game; the one on the right is the original sprite, pasted over. (This is a screenshot from Photoshop, zoomed in 6x.) Notice the edges are aliasing -- it looks almost like sub-pixel rendering. In fact, if I had not forced my sprites (which have position and velocity as ints) to draw using integer values, I would swear that MonoGame is drawing with floating point values. But it isn't. What could be the cause of these things appearing blurry? It doesn't happen without velocity applied. To be precise, my SpriteComponent class has a Vector2 Position field. When I call Draw, I essentially use new Vector2((int)Math.Round(this.Position.X), (int)Math.Round(this.Position.Y)) for the position. I had a bug before where even stationary objects would jitter -- that was due to me using the straight Position vector and not rounding the values to ints. If I use Floor/Ceiling instead of round, the sprite sinks/hovers (one pixel difference either way) but still draws blurry.

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• Make an object slide around an obstacle

  - by Isaiah

  I have path areas set up in a game I'm making for canvas/html5 and have got it working to keep the player within these areas. I have a function isOut(boundary, x, y) that returns true if the point is outside the boundary. What I do is check only the new position x/y separately with the corresponding old position x/y. Then if each one is out I assign them the past value from the frame before. The old positions are kept in a variable from a closure I made. like this: opos = [x,y];//old position npos = [x,y];//new position if(isOut(bound, npos[0], opos[1])){ npos[0] = opos[0]; //assign it the old x position } if(isOut(bound, opos[0], npos[1])){ npos[1] = opos[1]; //assign it the old y position } It looks nice and works good at certain angles, but if your boundary has diagonal regions it results in jittery motion. What's happening is the y pos exits the area while x doesn't and continues pushing the player to the side, once it has moved the player to the side a bit the player can move forward and then the y exits again and the whole process repeats. Anyone know how I may be able to achieve a smoother slide? I have access to the player's velocity vector, the angle, and the speed(when used with the angle). I can move the play with either angle/speed or x/yvelocities as I've built in backups to translate one to the other if either have been altered manually.

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• MVC and individual elements of the model under a common base class

  - by Stewart

  Admittedly my experience of using the MVC pattern is limited. It might be argued that I don't really separate the V from the C, though I keep the M separate from the VC to the extent I can manage. I'm considering the scenario in which the application's model includes a number of elements that have a common base class. For example, enemy characters in a video game, or shape types in a vector graphics app. The view wants to render these elements. Of course, the different subclasses call for different rendering. The problem is that the elements are part of the model. Rendering them is conceptually part of the view. But how they are to be rendered depends on parameters of both: Attributes and state of the element are parameters of the model User settings are parameters of the view - and to support multiple platforms and/or view modes, different views may be used What's your preferred way of dealing with this? Put the rendering code in the model classes, passing in any view parameters? Put the rendering code in the view, using a switch or similar to select the right rendering for the model element type? Have some intermediate classes as a model-view interface, of which the model will create objects on demand and the view will then render them? Something else?

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• How do I classify using SVM Classifier in Matlab?

  - by Gomathi

  I'm on a project of liver tumor segmentation and classification. I used Region Growing and FCM for liver and tumor segmentation respectively. Then, I used Gray Level Co-occurence matrix for texture feature extraction. I have to use Support Vector Machine for Classification. But I don't know how to normalize the feature vectors. Can anyone tell how to program it in Matlab? To the GLCM program, I gave the tumor segmented image as input. Was I correct? If so, I think, then, my output will also be correct. I gave the parameters exactly as in the example provided in the documentation itself. The output I obtained was stats = autoc: [1.857855266614132e+000 1.857955341199538e+000] contr: [5.103143332457753e-002 5.030548650257343e-002] corrm: [9.512661919561399e-001 9.519459060378332e-001] corrp: [9.512661919561385e-001 9.519459060378338e-001] cprom: [7.885631654779597e+001 7.905268525471267e+001] cshad: [1.219440700252286e+001 1.220659371449108e+001] dissi: [2.037387269065756e-002 1.935418927908687e-002] energ: [8.987753042491253e-001 8.988459843719526e-001] entro: [2.759187341212805e-001 2.743152140681436e-001] homom: [9.930016927881388e-001 9.935307908219834e-001] homop: [9.925660617240367e-001 9.930960070222014e-001] maxpr: [9.474275457490587e-001 9.474466930429607e-001] sosvh: [1.847174384255155e+000 1.846913030238459e+000] savgh: [2.332207337361002e+000 2.332108469591401e+000] svarh: [6.311174784234007e+000 6.314794324825067e+000] senth: [2.663144677055123e-001 2.653725436772341e-001] dvarh: [5.103143332457753e-002 5.030548650257344e-002] denth: [7.573115918713391e-002 7.073380266499811e-002] inf1h: [-8.199645492654247e-001 -8.265514568489666e-001] inf2h: [5.643539051044213e-001 5.661543271625117e-001] indnc: [9.980238521073823e-001 9.981394883569174e-001] idmnc: [9.993275086521848e-001 9.993404634013308e-001] The thing is, I run the program for three images. But all three gave me the same output. When I used graycoprops() stat = Contrast: 4.721877658740964e+005 Correlation: -3.282870417955449e-003 Energy: 8.647689474127760e-006 Homogeneity: 8.194621855726478e-003 stat = Contrast: 2.817160447307697e+004 Correlation: 2.113032196952781e-005 Energy: 4.124904827799189e-004 Homogeneity: 2.513567163994905e-002 stat = Contrast: 7.086638436309059e+004 Correlation: 2.459637878221028e-002 Energy: 4.640677159445994e-004 Homogeneity: 1.158305728309460e-002 The images are:

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• Collision within a poly

  - by G1i1ch

  For an html5 engine I'm making, for speed I'm using a path poly. I'm having trouble trying to find ways to get collision with the walls of the poly. To make it simple I just have a vector for the object and an array of vectors for the poly. I'm using Cartesian vectors and they're 2d. Say poly = [[550,0],[169,523],[-444,323],[-444,-323],[169,-523]], it's just a pentagon I generated. The object that will collide is object, object.pos is it's position and object.vel is it's velocity. They're both 2d vectors too. I've had some success to get it to find a collision, but it's just black box code I ripped from a c++ example. It's very obscure inside and all it does though is return true/false and doesn't return what vertices are collided or collision point, I'd really like to be able to understand this and make my own so I can have more meaningful collision. I'll tackle that later though. Again the question is just how does one find a collision to walls of a poly given you know the poly vertices and the object's position + velocity? If more info is needed please let me know. And if all anyone can do is point me to the right direction that's great.

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• Does F# kill C++?

  - by MarkPearl

  Okay, so the title may be a little misleading… but I am currently travelling and so have had very little time and access to resources to do much fsharping – this has meant that I am right now missing my favourite new language. I was interested to see this post on Stack Overflow this evening concerning the performance of the F# language. The person posing the question asked 8 key points about the F# language, namely… How well does it do floating-point? Does it allow vector instructions How friendly is it towards optimizing compilers? How big a memory foot print does it have? Does it allow fine-grained control over memory locality? Does it have capacity for distributed memory processors, for example Cray? What features does it have that may be of interest to computational science where heavy number processing is involved? Are there actual scientific computing implementations that use it? Now, I don’t have much time to look into a decent response and to be honest I don’t know half of the answers to what he is asking, but it was interesting to see what was put up as an answer so far and would be interesting to get other peoples feedback on these questions if they know of anything other than what has been covered in the answer section already.

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• Building View Matrix in Direct3D11

  - by Balls

  Am I doing it right? I converted this. m_ViewMatrix = XMMatrixLookAtLH(XMLoadFloat3(&m_Position), lookAtVector, upVector); to this one. XMVECTOR vz = XMVector3Normalize( lookAtVector - XMLoadFloat3(&m_Position) ); XMVECTOR vx = XMVector3Normalize( XMVector3Cross( upVector, vz ) ); XMVECTOR vy = XMVector3Cross( vz, vx ); m_ViewMatrix.r[0] = vx; m_ViewMatrix.r[1] = vy; m_ViewMatrix.r[2] = vz; m_ViewMatrix.r[3] = XMLoadFloat3(&m_Position); m_ViewMatrix.r[0].m128_f32[3] = 0.0f; m_ViewMatrix.r[1].m128_f32[3] = 0.0f; m_ViewMatrix.r[2].m128_f32[3] = 0.0f; m_ViewMatrix.r[3].m128_f32[3] = 1.0f; m_ViewMatrix = XMMatrixInverse( &XMMatrixDeterminant(m_ViewMatrix), m_ViewMatrix ); Everything looks fine when I run it. Another question is, I saw on this site(http://webglfactory.blogspot.com/2011/06/how-to-create-view-matrix.html) that he subtracted lookat from position in his vector vz. I tried it but gave me wrong view matrix. Can anyone check my code. I'm studying linear algebra right now. Sucks my course doesn't have one. Thank you, Balls

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• Collision Detection with SAT: False Collision for Diagonal Movement Towards Vertical Tile-Walls?

  - by Macks

  Edit: Problem solved! Big thanks to Jonathan who pointed me in the right direction. Sean describes the method I used in a different thread. Also big thanks to him! :) Here is how I solved my problem: If a collision is registered by my SAT-method, only fire the collision-event on my character if there are no neighbouring solid tiles in the direction of the returned minimum translation vector. I'm developing my first tile-based 2D-game with Javascript. To learn the basics, I decided to write my own "game engine". I have successfully implemented collision detection using the separating axis theorem, but I've run into a problem that I can't quite wrap my head around. If I press the [up] and [left] arrow-keys simultaneously, my character moves diagonally towards the upper left. If he hits a horizontal wall, he'll just keep moving in x-direction. The same goes for [up] and [left] as well as downward-diagonal movements, it works as intended: http://i.stack.imgur.com/aiZjI.png Diagonal movement works fine for horizontal walls, for both left and right-movement However: this does not work for vertical walls. Instead of keeping movement in y-direction, he'll just stop as soon as he "enters" a new tile on the y-axis. So for some reason SAT thinks my character is colliding vertically with tiles from vertical walls: http://i.stack.imgur.com/XBEKR.png My character stops because he thinks that he is colliding vertically with tiles from the wall on the right. This only occurs, when: Moving into top-right direction towards the right wall Moving into top-left direction towards the left wall Bottom-right and bottom-left movement work: the character keeps moving in y-direction as intended. Is this inherited from the way SAT works or is there a problem with my implementation? What can I do to solve my problem? Oh yeah, my character is displayed as a circle but he's actually a rectangular polygon for the collision detection. Thank you very much for your help.

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• What is wrong with my game loop/mechanic?

  - by elias94xx

  I'm currently working on a 2d sidescrolling game prototype in HTML5 canvas. My implementations so far include a sprite, vector, loop and ticker class/object. Which can be viewed here: http://elias-schuett.de/apps/_experiments/2d_ssg/js/ So my game essentially works well on todays lowspec PC's and laptops. But it does not on an older win xp machine I own and on my Android 2.3 device. I tend to get ~10 FPS with these devices which results in a too high delta value, which than automaticly gets fixed to 1.0 which results in a slow loop. Now I know for a fact that there is a way to implement a super smooth 60 or 30 FPS loop on both devices. Best example would be: http://playbiolab.com/ I don't need all the chunk and debugging technology impact.js offers. I could even write a super simple game where you just control a damn square and it still wouldn't run on a equally fast 30 or 60 fps. Here is the Loop class/object I'm using. It requires a requestAnimationFrame unify function. Both devices I've tested my game on support requestAnimationFrame, so there is no interval fallback. var Loop = function(callback) { this.fps = null; this.delta = 1; this.lastTime = +new Date; this.callback = callback; this.request = null; }; Loop.prototype.start = function() { var _this = this; this.request = requestAnimationFrame(function(now) { _this.start(); _this.delta = (now - _this.lastTime); _this.fps = 1000/_this.delta; _this.delta = _this.delta / (1000/60) > 2 ? 1 : _this.delta / (1000/60); _this.lastTime = now; _this.callback(); }); }; Loop.prototype.stop = function() { cancelAnimationFrame(this.request); };

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• forward motion car physics - gradual slow

  - by spartan2417

  Im having trouble creating realistic car movements in xna 4. Right now i have a car going forward and hitting a terminal velocity which is fine but when i release the up key i need to the car to slow down gradually and then come to a stop. Im pretty sure this is easy code but i cant seem to get it to work the code - update if (Keyboard.GetState().IsKeyDown(Keys.Up)) { double elapsedTime = gameTime.ElapsedGameTime.Milliseconds; CalcTotalForce(); Acceleration = Vector2.Divide(CalcTotalForce(), MASS); Velocity = Vector2.Add(Velocity, Vector2.Multiply(Acceleration, (float)(elapsedTime))); Position = Vector2.Add(Position, Vector2.Multiply(Velocity, (float)(elapsedTime))); } added functions public Vector2 CalcTraction() { //Traction force = vector direction * engine force return Vector2.Multiply(forwardDirection, ENGINE_FORCE); } public Vector2 CalcDrag() { //Drag force = constdrag * velocity * speed return Vector2.Multiply(Vector2.Multiply(Velocity, DRAG_CONST), Velocity.Y); } public Vector2 CalcRoll() { //roll force = const roll * velocity return Vector2.Multiply(Velocity, ROLL_CONST); } public Vector2 CalcTotalForce() { //total force = traction + (-drag) + (-rolling) return Vector2.Add(CalcTraction(), Vector2.Add(-CalcDrag(), -CalcRoll())); } anyone have any ideas?

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• How do I create a third Person View using DXUTCamera in DX10?

  - by David

  I am creating a 3d flying game and using DXUTCamera for my view. I can get the camera to take on the characters position, But I would like to view my character in the 3rd person. Here is my code for first person view: //Put the camera on the object. D3DXVECTOR3 viewerPos; D3DXVECTOR3 lookAtThis; D3DXVECTOR3 up ( 5.0f, 1.0f, 0.0f ); D3DXVECTOR3 newUp; D3DXMATRIX matView; //Set the viewer's position to the position of the thing. viewerPos.x = character->x; viewerPos.y = character->y; viewerPos.z = character->z; // Create a new vector for the direction for the viewer to look character->setUpWorldMatrix(); D3DXVECTOR3 newDir, lookAtPoint; D3DXVec3TransformCoord(&newDir, &character->initVecDir, &character->matAllRotations); // set lookatpoint D3DXVec3Normalize(&lookAtPoint, &newDir); lookAtPoint.x += viewerPos.x; lookAtPoint.y += viewerPos.y; lookAtPoint.z += viewerPos.z; g_Camera.SetViewParams(&viewerPos, &lookAtPoint); So does anyone have an ideas how I can move the camera to the third person view? preferably timed so there is a smooth action in the camera movement. (I'm hoping I can just edit this code instead of bringing in another camera class)

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• C++ Iterator lifetime and detecting invalidation

  - by DK.

  Based on what's considered idiomatic in C++11: should an iterator into a custom container survive the container itself being destroyed? should it be possible to detect when an iterator becomes invalidated? are the above conditional on "debug builds" in practice? Details: I've recently been brushing up on my C++ and learning my way around C++11. As part of that, I've been writing an idiomatic wrapper around the uriparser library. Part of this is wrapping the linked list representation of parsed path components. I'm looking for advice on what's idiomatic for containers. One thing that worries me, coming most recently from garbage-collected languages, is ensuring that random objects don't just go disappearing on users if they make a mistake regarding lifetimes. To account for this, both the PathList container and its iterators keep a shared_ptr to the actual internal state object. This ensures that as long as anything pointing into that data exists, so does the data. However, looking at the STL (and lots of searching), it doesn't look like C++ containers guarantee this. I have this horrible suspicion that the expectation is to just let containers be destroyed, invalidating any iterators along with it. std::vector certainly seems to let iterators get invalidated and still (incorrectly) function. What I want to know is: what is expected from "good"/idiomatic C++11 code? Given the shiny new smart pointers, it seems kind of strange that STL allows you to easily blow your legs off by accidentally leaking an iterator. Is using shared_ptr to the backing data an unnecessary inefficiency, a good idea for debugging or something expected that STL just doesn't do? (I'm hoping that grounding this to "idiomatic C++11" avoids charges of subjectivity...)

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