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• Would someone please explain Octree Collisions to me?

  - by A-Type

  I've been reading everything I can find on the subject and I feel like the pieces are just about to fall into place, but I just can't quite get it. I'm making a space game, where collisions will occur between planets, ships, asteroids, and the sun. Each of these objects can be subdivided into 'chunks', which I have implemented to speed up rendering (the vertices can and will change often at runtime, so I've separated the buffers). These subdivisions also have bounding primitives to test for collision. All of these objects are made of blocks (yeah, it's that kind of game). Blocks can also be tested for rough collisions, though they do not have individual bounding primitives for memory reasons. I think the rough testing seems to be sufficient, though. So, collision needs to be fairly precise; at block resolution. Some functions rely on two blocks colliding. And, of course, attacking specific blocks is important. Now what I am struggling with is filtering my collision pairs. As I said, I've read a lot about Octrees, but I'm having trouble applying it to my situation as many tutorials are vague with very little code. My main issues are: Are Octrees recalculated each frame, or are they stored in memory and objects are shuffled into different divisions as they move? Despite all my reading I still am not clear on this... the vagueness of it all has been frustrating. How far do Octrees subdivide? Planets in my game are quite large, while asteroids are smaller. Do I subdivide to the size of the planet, or asteroid (where planet is in multiple divisions)? Or is the limit something else entirely, like number of elements in the division? Should I load objects into the octrees as 'chunks' or in the whole, then break into chunks later? This could be specific to my implementation, I suppose. I was going to ask about how big my root needed to be, but I did manage to find this question, and the second answer seems sufficient for me. I'm afraid I don't really get what he means by adding new nodes and doing subdivisions upon adding new objects, probably because I'm confused about whether the tree is maintained in memory or recalculated per-frame.

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• WebCenter Customer Spotlight: Guizhou Power Grid Company

  - by me

  Author: Peter Reiser - Social Business Evangelist, Oracle WebCenter  Solution SummaryGuizhou Power Grid Company is responsible for power grid planning, construction, management, and power distribution in Guizhou Province, serving 39 million people. Giuzhou has 49,823 employees and an annual revenue of over $5 Billion. The business objectives were to consolidate information contained in disparate systems into a single knowledge repository and provide a safe and efficient way for staff and managers to access, query, share, manage, and store business information. Guizhou Power Grid Company saved more than US$693,000 in storage costs, reduced  average search times from 180 seconds to 5 seconds and solved 80% to 90% of technology and maintenance issues by searching the Oracle WebCenter Content management system. Company OverviewA wholly owned subsidiary of China Southern Power Grid Company Limited, Guizhou Power Grid Company is responsible for power grid planning, construction, management, and power distribution in Guizhou Province, serving 39 million people. Giuzhou has 49,823 employees and an annual revenue of over $5 Billion. Business ChallengesThe business objectives were to consolidate information contained in disparate systems, such as the customer relationship management and power grid management systems, into a single knowledge repository and provide a safe and efficient way for staff and managers to access, query, share, manage, and store business information. Solution DeployedGuizhou Power Grid Company  implemented Oracle WebCenter Content to build a content management system that enabled the secure, integrated management and storage of information, such as documents, records, images, Web content, and digital assets. The content management solution was integrated with the power grid, customer service, maintenance, and other business systems, as well as the corporate Web site. Business Results Saved more than US$693,000 in storage costs and shortened the material distribution time by integrating the knowledge management solution with the power grid, customer service, maintenance, and other business systems, as well as the corporate Web site Enabled staff to search 31,650 documents using catalogs, multidimensional attributes, and knowledge maps, reducing average search times from 180 seconds to 5 seconds and saving approximately 1,539 hours in annual search time Gained comprehensive document management, format transformation, security, and auditing capabilities Enabled users to upload new documents and supervisors to check the accuracy of these documents online, resulting in improved information quality control Solved 80% to 90% of technology and maintenance issues by searching the Oracle content management system for information, ensuring IT staff can respond quickly to users’ technical problems Improved security by using role-based access controls to restrict access to confidential documents and information Supported the efficient classification of corporate knowledge by using Oracle’s metadata functions to collect, tag, and archive documents, images, Web content, and digital assets “We chose Oracle WebCenter Content, as it is an outstanding integrated content management platform. It has allowed us to establish a system to access, query, share, manage, and store our corporate assets. This has laid a solid foundation for Guizhou Power Grid Company to improve management practices.” Luo Sixi, Senior Information Consultant, Guizhou Power Grid Company Additional Information Guizhou Power Grid Company Customer Snapshot Oracle WebCenter Content

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• best way to "introduce" OOP/OOD to team of experienced C++ engineers

  - by DXM

  I am looking for an efficient way, that also doesn't come off as an insult, to introduce OOP concepts to existing team members? My teammates are not new to OO languages. We've been doing C++/C# for a long time so technology itself is familiar. However, I look around and without major infusion of effort (mostly in the form of code reviews), it seems what we are producing is C code that happens to be inside classes. There's almost no use of single responsibility principle, abstractions or attempts to minimize coupling, just to name a few. I've seen classes that don't have a constructor but get memset to 0 every time they are instantiated. But every time I bring up OOP, everyone always nods and makes it seem like they know exactly what I'm talking about. Knowing the concepts is good, but we (some more than others) seem to have very hard time applying them when it comes to delivering actual work. Code reviews have been very helpful but the problem with code reviews is that they only occur after the fact so to some it seems we end up rewriting (it's mostly refactoring, but still takes lots of time) code that was just written. Also code reviews only give feedback to an individual engineer, not the entire team. I am toying with the idea of doing a presentation (or a series) and try to bring up OOP again along with some examples of existing code that could've been written better and could be refactored. I could use some really old projects that no one owns anymore so at least that part shouldn't be a sensitive issue. However, will this work? As I said most people have done C++ for a long time so my guess is that a) they'll sit there thinking why I'm telling them stuff they already know or b) they might actually take it as an insult because I'm telling them they don't know how to do the job they've been doing for years if not decades. Is there another approach which would reach broader audience than a code review would, but at the same time wouldn't feel like a punishment lecture? I'm not a fresh kid out of college who has utopian ideals of perfectly designed code and I don't expect that from anyone. The reason I'm writing this is because I just did a review of a person who actually had decent high-level design on paper. However if you picture classes: A - B - C - D, in the code B, C and D all implement almost the same public interface and B/C have one liner functions so that top-most class A is doing absolutely all the work (down to memory management, string parsing, setup negotiations...) primarily in 4 mongo methods and, for all intents and purposes, calls almost directly into D. Update: I'm a tech lead(6 months in this role) and do have full support of the group manager. We are working on a very mature product and maintenance costs are definitely letting themselves be known.

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• Why can't a blendShader sample anything but the current coordinate of the background image?

  - by Triynko

  In Flash, you can set a DisplayObject's blendShader property to a pixel shader (flash.shaders.Shader class). The mechanism is nice, because Flash automatically provides your Shader with two input images, including the background surface and the foreground display object's bitmap. The problem is that at runtime, the shader doesn't allow you to sample the background anywhere but under the current output coordinate. If you try to sample other coordinates, it just returns the color of the current coordinate instead, ignoring the coordinates you specified. This seems to occur only at runtime, because it works properly in the Pixel Bender toolkit. This limitation makes it impossible to simulate, for example, the Aero Glass effect in Windows Vista/7, because you cannot sample the background properly for blurring. I must mention that it is possible to create the effect in Flash through manual composition techniques, but it's hard to determine when it actually needs updated, because Flash does not provide information about when a particular area of the screen or a particular display object needs re-rendered. For example, you may have a fixed glass surface with objects moving underneath it that don't dispatch events when they move. The only alternative is to re-render the glass bar every frame, which is inefficient, which is why I am trying to do it through a blendShader so Flash determines when it needs rendered automatically. Is there a technical reason for this limitation, or is it an oversight of some sort? Does anyone know of a workaround, or a way I could provide my manual composition implementation with information about when it needs re-rendered? The limitation is mentioned with no explanation in the last note in this page: http://help.adobe.com/en_US/as3/dev/WSB19E965E-CCD2-4174-8077-8E5D0141A4A8.html It says: "Note: When a Pixel Bender shader program is run as a blend in Flash Player or AIR, the sampling and outCoord() functions behave differently than in other contexts.In a blend, a sampling function will always return the current pixel being evaluated by the shader. You cannot, for example, use add an offset to outCoord() in order to sample a neighboring pixel. Likewise, if you use the outCoord() function outside a sampling function, its coordinates always evaluate to 0. You cannot, for example, use the position of a pixel to influence how the blended images are combined."

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• How to suggest using an ORM instead of stored procedures?

  - by Wayne M

  I work at a company that only uses stored procedures for all data access, which makes it very annoying to keep our local databases in sync as every commit we have to run new procs. I have used some basic ORMs in the past and I find the experience much better and cleaner. I'd like to suggest to the development manager and rest of the team that we look into using an ORM Of some kind for future development (the rest of the team are only familiar with stored procedures and have never used anything else). The current architecture is .NET 3.5 written like .NET 1.1, with "god classes" that use a strange implementation of ActiveRecord and return untyped DataSets which are looped over in code-behind files - the classes work something like this: class Foo { public bool LoadFoo() { bool blnResult = false; if (this.FooID == 0) { throw new Exception("FooID must be set before calling this method."); } DataSet ds = // ... call to Sproc if (ds.Tables[0].Rows.Count > 0) { foo.FooName = ds.Tables[0].Rows[0]["FooName"].ToString(); // other properties set blnResult = true; } return blnResult; } } // Consumer Foo foo = new Foo(); foo.FooID = 1234; foo.LoadFoo(); // do stuff with foo... There is pretty much no application of any design patterns. There are no tests whatsoever (nobody else knows how to write unit tests, and testing is done through manually loading up the website and poking around). Looking through our database we have: 199 tables, 13 views, a whopping 926 stored procedures and 93 functions. About 30 or so tables are used for batch jobs or external things, the remainder are used in our core application. Is it even worth pursuing a different approach in this scenario? I'm talking about moving forward only since we aren't allowed to refactor the existing code since "it works" so we cannot change the existing classes to use an ORM, but I don't know how often we add brand new modules instead of adding to/fixing current modules so I'm not sure if an ORM is the right approach (too much invested in stored procedures and DataSets). If it is the right choice, how should I present the case for using one? Off the top of my head the only benefits I can think of is having cleaner code (although it might not be, since the current architecture isn't built with ORMs in mind so we would basically be jury-rigging ORMs on to future modules but the old ones would still be using the DataSets) and less hassle to have to remember what procedure scripts have been run and which need to be run, etc. but that's it, and I don't know how compelling an argument that would be. Maintainability is another concern but one that nobody except me seems to be concerned about.

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• My co-worker has not been doing such a good job for the past decade. What do I do? [closed]

  - by stijn

  Possible Duplicate: How do I approach a coworker about his or her code quality? I started working with him almost a decade ago and back then I had never really programmed before, being a young hardware engineer. Right now however I have made quite some progress in all areas being part of software design and i am much, much more skilled than my co-worker who is 15 years older and has been programming more than twice as long. He is super nice and definitely smart enough, but lately his lack of skill and performance are starting to drag me down because we're more and more working on the same codebase. And soon we are going to do a quite ambitious start from scratch creating a whole new hard/software system. I feel it is time to address all issues now, but i do not know how to start. Here are some of the things that I would like to see him improve on: no consistent usage of style, spaces nor tabs (eg if(something ) a =b ) adds newlines around pieces of code to make it easier to read, then commits those with messages like 'no changes made' overall commit messages are useless and so are most of the comments, if there are any (eg 'remove solves for bug Rik' if Rik reported a bug). There is no function/class documentation. lots of spelling errors, in both English and native language, which sometimes are mixed 6/7/8 level deep deep nesting is no exception, a lot of functions start with one level already like if(ptr!=Null){ even when ptr is the result of allocation via new in the constructor numerous source files have over 10k lines of those lines, a major part is simply a result of copy-pasting functionality instead of using a function. This includes copying comments so we end up with 50 occurrences of var=NULL; //TODO TEST this!!!!!!! another part is hundreds of lines of dead code knows what versioning does, yet comments out old code and places new code underneath it when making changes coding skills are below par, especially for the type of rather high precision applications we do. Yet somehow, after a lot of trying and testing, stuff starts to work. But then breaks again some time later because every change casues a waterfall effect. violates every single item in the C++ FAQ lite, practices every bad practice I can think of still doesn't know how to properly use the debugger, but spends hours inspecting messy logfiles in notepad on a tiny laptop screen. Does not make any adjustments to the settings of the software he uses. Never uses keyboard shortcuts. does not seem to progress or learn new things at all. Work rather slow, mostly due to the lack of planning and incorrect usage of tools. How does one deal with this? For starters, how do I make him aware of all these problems? Should I tell the staff about it? And the next step, how to get him to learn new things and adopt another way of working?

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• Reference Data Management

  - by rahulkamath

  Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} table.MsoTableColorfulListAccent2 {mso-style-name:"Colorful List - Accent 2"; mso-tstyle-rowband-size:1; mso-tstyle-colband-size:1; mso-style-priority:72; mso-style-unhide:no; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-tstyle-shading:#F8EDED; mso-tstyle-shading-themecolor:accent2; mso-tstyle-shading-themetint:25; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri","sans-serif"; color:black; mso-themecolor:text1;} table.MsoTableColorfulListAccent2FirstRow {mso-style-name:"Colorful List - Accent 2"; mso-table-condition:first-row; mso-style-priority:72; mso-style-unhide:no; mso-tstyle-shading:#9E3A38; mso-tstyle-shading-themecolor:accent2; mso-tstyle-shading-themeshade:204; mso-tstyle-border-bottom:1.5pt solid white; mso-tstyle-border-bottom-themecolor:background1; color:white; mso-themecolor:background1; mso-ansi-font-weight:bold; mso-bidi-font-weight:bold;} table.MsoTableColorfulListAccent2LastRow {mso-style-name:"Colorful List - Accent 2"; mso-table-condition:last-row; mso-style-priority:72; mso-style-unhide:no; mso-tstyle-shading:white; mso-tstyle-shading-themecolor:background1; mso-tstyle-border-top:1.5pt solid black; mso-tstyle-border-top-themecolor:text1; color:#9E3A38; mso-themecolor:accent2; mso-themeshade:204; mso-ansi-font-weight:bold; mso-bidi-font-weight:bold;} table.MsoTableColorfulListAccent2FirstCol {mso-style-name:"Colorful List - Accent 2"; mso-table-condition:first-column; mso-style-priority:72; mso-style-unhide:no; mso-ansi-font-weight:bold; mso-bidi-font-weight:bold;} table.MsoTableColorfulListAccent2LastCol {mso-style-name:"Colorful List - Accent 2"; mso-table-condition:last-column; mso-style-priority:72; mso-style-unhide:no; mso-ansi-font-weight:bold; mso-bidi-font-weight:bold;} table.MsoTableColorfulListAccent2OddColumn {mso-style-name:"Colorful List - Accent 2"; mso-table-condition:odd-column; mso-style-priority:72; mso-style-unhide:no; mso-tstyle-shading:#EFD3D2; mso-tstyle-shading-themecolor:accent2; mso-tstyle-shading-themetint:63; mso-tstyle-border-top:cell-none; mso-tstyle-border-left:cell-none; mso-tstyle-border-bottom:cell-none; mso-tstyle-border-right:cell-none; mso-tstyle-border-insideh:cell-none; mso-tstyle-border-insidev:cell-none;} table.MsoTableColorfulListAccent2OddRow {mso-style-name:"Colorful List - Accent 2"; mso-table-condition:odd-row; mso-style-priority:72; mso-style-unhide:no; mso-tstyle-shading:#F2DBDB; mso-tstyle-shading-themecolor:accent2; mso-tstyle-shading-themetint:51;} Reference Data Management Oracle Data Relationship Management (DRM) has always been extremely powerful as an Enterprise MDM solution that can help manage changes to master data in a way that influences enterprise structure, whether it be mastering chart of accounts to enable financial transformation, or revamping organization structures to drive business transformation and operational efficiencies, or mastering sales territories in light of rapid fire acquisitions that require frequent sales territory refinement, equitable distribution of leads and accounts to salespersons, and alignment of budget/forecast with results to optimize sales coverage. Increasingly, DRM is also being utilized by Oracle customers for reference data management, an emerging solution space that deserves some explanation. What is reference data? Reference data is a close cousin of master data. While master data may be more rapidly changing, requires consensus building across stakeholders and lends structure to business transactions, reference data is simpler, more slowly changing, but has semantic content that is used to categorize or group other information assets – including master data – and give them contextual value. The following table contains an illustrative list of examples of reference data by type. Reference data types may include types and codes, business taxonomies, complex relationships & cross-domain mappings or standards. Types & Codes Taxonomies Relationships / Mappings Standards Transaction Codes Industry Classification Categories and Codes, e.g., North America Industry Classification System (NAICS) Product / Segment; Product / Geo Calendars (e.g., Gregorian, Fiscal, Manufacturing, Retail, ISO8601) Lookup Tables (e.g., Gender, Marital Status, etc.) Product Categories City à State à Postal Codes Currency Codes (e.g., ISO) Status Codes Sales Territories (e.g., Geo, Industry Verticals, Named Accounts, Federal/State/Local/Defense) Customer / Market Segment; Business Unit / Channel Country Codes (e.g., ISO 3166, UN) Role Codes Market Segments Country Codes / Currency Codes / Financial Accounts Date/Time, Time Zones (e.g., ISO 8601) Domain Values Universal Standard Products and Services Classification (UNSPSC), eCl@ss International Classification of Diseases (ICD) e.g., ICD9 à IC10 mappings Tax Rates Why manage reference data? Reference data carries contextual value and meaning and therefore its use can drive business logic that helps execute a business process, create a desired application behavior or provide meaningful segmentation to analyze transaction data. Further, mapping reference data often requires human judgment. Sample Use Cases of Reference Data Management Healthcare: Diagnostic Codes The reference data challenges in the healthcare industry offer a case in point. Part of being HIPAA compliant requires medical practitioners to transition diagnosis codes from ICD-9 to ICD-10, a medical coding scheme used to classify diseases, signs and symptoms, causes, etc. The transition to ICD-10 has a significant impact on business processes, procedures, contracts, and IT systems. Since both code sets ICD-9 and ICD-10 offer diagnosis codes of very different levels of granularity, human judgment is required to map ICD-9 codes to ICD-10. The process requires collaboration and consensus building among stakeholders much in the same way as does master data management. Moreover, to build reports to understand utilization, frequency and quality of diagnoses, medical practitioners may need to “cross-walk” mappings -- either forward to ICD-10 or backwards to ICD-9 depending upon the reporting time horizon. Spend Management: Product, Service & Supplier Codes Similarly, as an enterprise looks to rationalize suppliers and leverage their spend, conforming supplier codes, as well as product and service codes requires supporting multiple classification schemes that may include industry standards (e.g., UNSPSC, eCl@ss) or enterprise taxonomies. Aberdeen Group estimates that 90% of companies rely on spreadsheets and manual reviews to aggregate, classify and analyze spend data, and that data management activities account for 12-15% of the sourcing cycle and consume 30-50% of a commodity manager’s time. Creating a common map across the extended enterprise to rationalize codes across procurement, accounts payable, general ledger, credit card, procurement card (P-card) as well as ACH and bank systems can cut sourcing costs, improve compliance, lower inventory stock, and free up talent to focus on value added tasks. Specialty Finance: Point of Sales Transaction Codes and Product Codes In the specialty finance industry, enterprises are confronted with usury laws – governed at the state and local level – that regulate financial product innovation as it relates to consumer loans, check cashing and pawn lending. To comply, it is important to demonstrate that transactions booked at the point of sale are posted against valid product codes that were on offer at the time of booking the sale. Since new products are being released at a steady stream, it is important to ensure timely and accurate mapping of point-of-sale transaction codes with the appropriate product and GL codes to comply with the changing regulations. Multi-National Companies: Industry Classification Schemes As companies grow and expand across geographies, a typical challenge they encounter with reference data represents reconciling various versions of industry classification schemes in use across nations. While the United States, Mexico and Canada conform to the North American Industry Classification System (NAICS) standard, European Union countries choose different variants of the NACE industry classification scheme. Multi-national companies must manage the individual national NACE schemes and reconcile the differences across countries. Enterprises must invest in a reference data change management application to address the challenge of distributing reference data changes to downstream applications and assess which applications were impacted by a given change.

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• With AMD style modules in JavaScript is there any benefit to namespaces?

  - by gman

  Coming from C++ originally and seeing lots of Java programmers doing the same we brought namespaces to JavaScript. See Google's closure library as an example where they have a main namespace, goog and under that many more namespaces like goog.async, goog.graphics But now, having learned the AMD style of requiring modules it seems like namespaces are kind of pointless in JavaScript. Not only pointless but even arguably an anti-pattern. What is AMD? It's a way of defining and including modules that removes all direct dependencies. Effectively you do this // some/module.js define([ 'name/of/needed/module', 'name/of/someother/needed/module', ], function( RefToNeededModule, RefToSomeOtherNeededModule) { ...code... return object or function }); This format lets the AMD support code know that this module needs name/of/needed/module.js and name/of/someother/needed/module.js loaded. The AMD code can load all the modules and then, assuming no circular dependencies, call the define function on each module in the correct order, record the object/function returned by the module as it calls them, and then call any other modules' define function with references to those modules. This seems to remove any need for namespaces. In your own code you can call the reference to any other module anything you want. For example if you had 2 string libraries, even if they define similar functions, as long as they follow the AMD pattern you can easily use both in the same module. No need for namespaces to solve that. It also means there's no hard coded dependencies. For example in Google's closure any module could directly reference another module with something like var value = goog.math.someMathFunc(otherValue) and if you're unlucky it will magically work where as with AMD style you'd have to explicitly include the math library otherwise the module wouldn't have a reference to it since there are no globals with AMD. On top of that dependency injection for testing becomes easy. None of the code in the AMD module references things by namespace so there is no hardcoded namespace paths, you can easily mock classes at testing time. Is there any other point to namespaces or is that something that C++ / Java programmers are bringing to JavaScript that arguably doesn't really belong?

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• Incorrect results for frustum cull

  - by DeadMG

  Previously, I had a problem with my frustum culling producing too optimistic results- that is, including many objects that were not in the view volume. Now I have refactored that code and produced a cull that should be accurate to the actual frustum, instead of an axis-aligned box approximation. The problem is that now it never returns anything to be in the view volume. As the mathematical support library I'm using does not provide plane support functions, I had to code much of this functionality myself, and I'm not really the mathematical type, so it's likely that I've made some silly error somewhere. As follows is the relevant code: class Plane { public: Plane() { r0 = Math::Vector(0,0,0); normal = Math::Vector(0,1,0); } Plane(Math::Vector p1, Math::Vector p2, Math::Vector p3) { r0 = p1; normal = Math::Cross((p2 - p1), (p3 - p1)); } Math::Vector r0; Math::Vector normal; }; This class represents one plane as a point and a normal vector. class Frustum { public: Frustum( const std::array<Math::Vector, 8>& points ) { planes[0] = Plane(points[0], points[1], points[2]); planes[1] = Plane(points[4], points[5], points[6]); planes[2] = Plane(points[0], points[1], points[4]); planes[3] = Plane(points[2], points[3], points[6]); planes[4] = Plane(points[0], points[2], points[4]); planes[5] = Plane(points[1], points[3], points[5]); } Plane planes[6]; }; The points are passed in order where (the inverse of) each bit of the index of each point indicates whether it's the left, top, and back of the frustum, respectively. As such, I just picked any three points where they all shared one bit in common to define the planes. My intersection test is as follows (based on this): bool Intersects(Math::AABB lhs, const Frustum& rhs) const { for(int i = 0; i < 6; i++) { Math::Vector pvertex = lhs.TopRightFurthest; Math::Vector nvertex = lhs.BottomLeftClosest; if (rhs.planes[i].normal.x <= -0.0f) { std::swap(pvertex.x, nvertex.x); } if (rhs.planes[i].normal.y <= -0.0f) { std::swap(pvertex.y, nvertex.y); } if (rhs.planes[i].normal.z <= -0.0f) { std::swap(pvertex.z, nvertex.z); } if (Math::Dot(rhs.planes[i].r0, nvertex) < 0.0f) { return false; } } return true; } Also of note is that because I'm using a left-handed co-ordinate system, I wrote my Cross function to return the negative of the formula given on Wikipedia. Any suggestions as to where I've made a mistake?

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• Inline template efficiency

  - by Darryl Gove

  I like inline templates, and use them quite extensively. Whenever I write code with them I'm always careful to check the disassembly to see that the resulting output is efficient. Here's a potential cause of inefficiency. Suppose we want to use the mis-named Leading Zero Detect (LZD) instruction on T4 (this instruction does a count of the number of leading zero bits in an integer register - so it should really be called leading zero count). So we put together an inline template called lzd.il looking like: .inline lzd lzd %o0,%o0 .end And we throw together some code that uses it: int lzd(int); int a; int c=0; int main() { for(a=0; a<1000; a++) { c=lzd(c); } return 0; } We compile the code with some amount of optimisation, and look at the resulting code: $ cc -O -xtarget=T4 -S lzd.c lzd.il $ more lzd.s .L77000018: /* 0x001c 11 */ lzd %o0,%o0 /* 0x0020 9 */ ld [%i1],%i3 /* 0x0024 11 */ st %o0,[%i2] /* 0x0028 9 */ add %i3,1,%i0 /* 0x002c */ cmp %i0,999 /* 0x0030 */ ble,pt %icc,.L77000018 /* 0x0034 */ st %i0,[%i1] What is surprising is that we're seeing a number of loads and stores in the code. Everything could be held in registers, so why is this happening? The problem is that the code is only inlined at the code generation stage - when the actual instructions are generated. Earlier compiler phases see a function call. The called functions can do all kinds of nastiness to global variables (like 'a' in this code) so we need to load them from memory after the function call, and store them to memory before the function call. Fortunately we can use a #pragma directive to tell the compiler that the routine lzd() has no side effects - meaning that it does not read or write to memory. The directive to do that is #pragma no_side_effect(<routine name), and it needs to be placed after the declaration of the function. The new code looks like: int lzd(int); #pragma no_side_effect(lzd) int a; int c=0; int main() { for(a=0; a<1000; a++) { c=lzd(c); } return 0; } Now the loop looks much neater: /* 0x0014 10 */ add %i1,1,%i1 ! 11 ! { ! 12 ! c=lzd(c); /* 0x0018 12 */ lzd %o0,%o0 /* 0x001c 10 */ cmp %i1,999 /* 0x0020 */ ble,pt %icc,.L77000018 /* 0x0024 */ nop

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• Why would I learn C++11, having known C and C++?

  - by Shahbaz

  I am a programmer in C and C++, although I don't stick to either language and write a mixture of the two. Sometimes having code in classes, possibly with operator overloading, or templates and the oh so great STL is obviously a better way. Sometimes use of a simple C function pointer is much much more readable and clear. So I find beauty and practicality in both languages. I don't want to get into the discussion of "If you mix them and compile with a C++ compiler, it's not a mix anymore, it's all C++" I think we all understand what I mean by mixing them. Also, I don't want to talk about C vs C++, this question is all about C++11. C++11 introduces what I think are significant changes to how C++ works, but it has introduced many special cases that change how different features behave in different circumstances, placing restrictions on multiple inheritance, adding lambda functions, etc. I know that at some point in the future, when you say C++ everyone would assume C++11. Much like when you say C nowadays, you most probably mean C99. That makes me consider learning C++11. After all, if I want to continue writing code in C++, I may at some point need to start using those features simply because my colleagues have. Take C for example. After so many years, there are still many people learning and writing code in C. Why? Because the language is good. What good means is that, it follows many of the rules to create a good programming language. So besides being powerful (which easy or hard, almost all programming languages are), C is regular and has few exceptions, if any. C++11 however, I don't think so. I'm not sure that the changes introduced in C++11 are making the language better. So the question is: Why would I learn C++11? Update: My original question in short was: "I like C++, but the new C++11 doesn't look good because of this and this and this. However, deep down something tells me I need to learn it. So, I asked this question here so that someone would help convince me to learn it." However, the zealous people here can't tolerate pointing out a flaw in their language and were not at all constructive in this manner. After the moderator edited the question, it became more like a "So, how about this new C++11?" which was not at all my question. Therefore, in a day or too I am going to delete this question if no one comes up with an actual convincing argument. P.S. If you are interested in knowing what flaws I was talking about, you can edit my question and see the previous edits.

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• How do I maintain a really poorly written code base?

  - by onlineapplab.com

  Recently I got hired to work on existing web application because of NDA I'm not at liberty to disclose any details but this application is working online in sort of a beta testing stage before official launch. We have a few hundred users right now but this number is supposed to significantly increase after official launch. The application is written in PHP (but it is irrelevant to my question) and is running on a dual xeon processor standalone server with severe performance problems. I have seen a lot of bad PHP code but this really sets new standards, especially knowing how much time and money was invested in developing it. it is as badly coded as possible there is PHP, HTML, SQL mixed together and code is repeated whenever it is necessary (especially SQL queries). there are not any functions used, not mentioning any OOP there are four versions of the app (desktop, iPhone, Android + other mobile) each version has pretty much the same functionality but was created by copying the whole code base, so now there are some differences between each version and it is really hard to maintain the database is really badly designed, which is causing severe performance problems also for fixing some errors in PHP code there is a lot of database triggers used which are updating data on SELECT and on INSERT so any testing is a nightmare Basically, any sin of a bad programming you can imagine is there for example it is not only possible to use SQL injections in literally every place but you can log into app if you use a login which doesn't exist and an empty password. The team which created this app is not working on it any more and there is an outsourced team which suggested that there are some problems but was never willing to deal with the elephant in the room partially because they've got a very comfortable contract and partially due to lack of skills (just my opinion). My job was supposed to be fixing some performance problems and extending existing functionality but first thing I was asked to do was a review of the existing code base. I've made my review and it was quite a shock for the management but my conclusions were after some time finally confirmed by other programmers. Management made it clear that it is not possible to start rewriting this app from scratch (which in my opinion should be done). We have to maintain its operable state and at the same time fix performance errors and extend the functionality. My question is, as I don't want just to patch the existing code, how to transform this into properly written app while keeping the existing code working at the same time? My plan is: Unify four existing versions into common code base (fixing only most obvious errors). Redesign db and use triggers to populate it with data (so data will be maintained in two formats at the same time) All new functionality will be written as separate project. Step by step transfer existing functionality into the new project After some time everything will be in the new project Some explanation about #2, right now it is practically impossible to make any updates in existing db any change requires reviewing whole code and making changes in many places. Is such plan feasible at all? Another solution is to walk away and leave the headache to someone else.

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• What shall I include in a 10 week web technologies course?

  - by Iain

  In September I will be teaching a university module on web technologies. This session will be available to 1st year (freshman) students who don't necessarily have any programming knowledge or know how the web works. In the 2nd semester I will be teaching Flash, which is my specialism, so I know exactly what I am going to teach, but in the 1st semester I will be teaching them web standards technologies - HTML, CSS, JS, jQuery, PHP and MySQL. Where I need advice is how to proportion the emphasis for each part, and which parts of each technology to cover. Another real issue I'm struggling with is how much of the bad old ways should I teach them? Do they need to know about bold as well as strong, etc. UPDATE: based, on your feedback I will only be teaching the latest version of everything - CSS3, HTML5 etc. I'm not sure exactly how long the semester will be but I'm guessing about 10-12 weeks. Each session is a 2 hour lab. Obviously there's only so much I can cover in that time and it will be up to the students to go a research this stuff properly on W3 schools etc. My ideas so far were: Lesson 0 - Course intro and overview of the current tech landscape. What is out there, what will we be learning, what won't we. What is a web server, URL etc. Looking at different example websites and discussing how they work. Lesson 1 - HTML basics (head, body, title, img, table, a, lists, h1, strong etc) Lesson 2 - CSS for styling and layout - fonts, webfonts, float etc Lesson 3 - Intro to programming JS (variables, loops, conditionals, functions) Lesson 4 - more JS programming fundamentals, DOM manipulation Lesson 5 - jQuery - making things fly about and look cool Lesson 6 - XML and Ajax Lesson 7 - PHP basics - syntax, server-side principles Lesson 8 - PHP and MySQL - forms, logins, saving user info Lesson 9 - don't know Lesson 10 - don't know Please let me know if you think this is the right order, what have I missed, how to use any spare sessions etc. Thanks :) UPDATE BASED ON RESPONSES: Thanks for all your responses - some great stuff. To be absolutely clear, this is not a computer science course, it is a practical module on a creative technology course. The emphasis definitely has to be on making cool things work rather than understanding how the backbone of the internet works. That can come later, if the students are interested. At the end of the module I would like the students to be able to produce a web page or pages that does something cool, using some or all of the technologies I cover. Many of these topics are of course far beyond the scope of a 2 hour session, however I do not have the option of reducing the syllabus, I will just have to explain what the technology does and encourage the student to research it in their own time.

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• Microsoft and Application Architectures

  Microsoft has dealt with several kinds of application architectures to include but not limited to desktop applications, web applications, operating systems, relational database systems, windows services, and web services. Because of the size and market share of Microsoft, virtually every modern language works with or around a Microsoft product. Some of the languages include: Visual Basic, VB.Net, C#, C++, C, ASP.net, ASP, HTML, CSS, JavaScript, Java and XML. From my experience, Microsoft strives to maintain an n-tier application standard where an application is comprised of multiple layers that perform specific functions, for example: presentation layer, business layer, data access layer are three general layers that just about every formally structured application contains. The presentation layer contains anything to do with displaying information to the screen and how it appears on the screen. The business layer is the middle man between the presentation layer and data access layer and transforms data from the data access layer in to useable information to be stored later or sent to an output device through the presentation layer. The data access layer does as its name implies, it allows the business layer to access data from a data source like MS SQL Server, XML, or another data source. One of my favorite technologies that Microsoft has come out with recently is the .Net Framework. This framework allows developers to code an application in multiple languages and compiles them in to one intermediate language called the Common Language Runtime (CLR). This allows VB and C# developers to work seamlessly together as if they were working in the same project. The only real disadvantage to using the .Net Framework is that it only natively runs on Microsoft operating systems. However, Microsoft does control a majority of the operating systems currently installed on modern computers and servers, especially with personal home computers. Given that the Microsoft .Net Framework is so flexible it is an ideal for business to develop applications around it as long as they wanted to commit to using Microsoft technologies and operating systems in the future. I have been a professional developer for about 9+ years now and have seen the .net framework work flawlessly in just about every instance I have used it. In addition, I have used it to develop web applications, mobile phone applications, desktop applications, web service applications, and windows service applications to name a few.

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• Changes to the LINQ-to-StreamInsight Dialect

  - by Roman Schindlauer

  In previous versions of StreamInsight (1.0 through 2.0), CepStream<> represents temporal streams of many varieties: Streams with ‘open’ inputs (e.g., those defined and composed over CepStream<T>.Create(string streamName) Streams with ‘partially bound’ inputs (e.g., those defined and composed over CepStream<T>.Create(Type adapterFactory, …)) Streams with fully bound inputs (e.g., those defined and composed over To*Stream – sequences or DQC) The stream may be embedded (where Server.Create is used) The stream may be remote (where Server.Connect is used) When adding support for new programming primitives in StreamInsight 2.1, we faced a choice: Add a fourth variety (use CepStream<> to represent streams that are bound the new programming model constructs), or introduce a separate type that represents temporal streams in the new user model. We opted for the latter. Introducing a new type has the effect of reducing the number of (confusing) runtime failures due to inappropriate uses of CepStream<> instances in the incorrect context. The new types are: IStreamable<>, which logically represents a temporal stream. IQStreamable<> : IStreamable<>, which represents a queryable temporal stream. Its relationship to IStreamable<> is analogous to the relationship of IQueryable<> to IEnumerable<>. The developer can compose temporal queries over remote stream sources using this type. The syntax of temporal queries composed over IQStreamable<> is mostly consistent with the syntax of our existing CepStream<>-based LINQ provider. However, we have taken the opportunity to refine certain aspects of the language surface. Differences are outlined below. Because 2.1 introduces new types to represent temporal queries, the changes outlined in this post do no impact existing StreamInsight applications using the existing types! SelectMany StreamInsight does not support the SelectMany operator in its usual form (which is analogous to SQL’s “CROSS APPLY” operator): static IEnumerable<R> SelectMany<T, R>(this IEnumerable<T> source, Func<T, IEnumerable<R>> collectionSelector) It instead uses SelectMany as a convenient syntactic representation of an inner join. The parameter to the selector function is thus unavailable. Because the parameter isn’t supported, its type in StreamInsight 1.0 – 2.0 wasn’t carefully scrutinized. Unfortunately, the type chosen for the parameter is nonsensical to LINQ programmers: static CepStream<R> SelectMany<T, R>(this CepStream<T> source, Expression<Func<CepStream<T>, CepStream<R>>> streamSelector) Using Unit as the type for the parameter accurately reflects the StreamInsight’s capabilities: static IQStreamable<R> SelectMany<T, R>(this IQStreamable<T> source, Expression<Func<Unit, IQStreamable<R>>> streamSelector) For queries that succeed – that is, queries that do not reference the stream selector parameter – there is no difference between the code written for the two overloads: from x in xs from y in ys select f(x, y) Top-K The Take operator used in StreamInsight causes confusion for LINQ programmers because it is applied to the (unbounded) stream rather than the (bounded) window, suggesting that the query as a whole will return k rows: (from win in xs.SnapshotWindow() from x in win orderby x.A select x.B).Take(k) The use of SelectMany is also unfortunate in this context because it implies the availability of the window parameter within the remainder of the comprehension. The following compiles but fails at runtime: (from win in xs.SnapshotWindow() from x in win orderby x.A select win).Take(k) The Take operator in 2.1 is applied to the window rather than the stream: Before After (from win in xs.SnapshotWindow() from x in win orderby x.A select x.B).Take(k) from win in xs.SnapshotWindow() from b in     (from x in win     orderby x.A     select x.B).Take(k) select b Multicast We are introducing an explicit multicast operator in order to preserve expression identity, which is important given the semantics about moving code to and from StreamInsight. This also better matches existing LINQ dialects, such as Reactive. This pattern enables expressing multicasting in two ways: Implicit Explicit var ys = from x in xs          where x.A > 1          select x; var zs = from y1 in ys          from y2 in ys.ShiftEventTime(_ => TimeSpan.FromSeconds(1))          select y1 + y2; var ys = from x in xs          where x.A > 1          select x; var zs = ys.Multicast(ys1 =>     from y1 in ys1     from y2 in ys1.ShiftEventTime(_ => TimeSpan.FromSeconds(1))     select y1 + y2; Notice the product translates an expression using implicit multicast into an expression using the explicit multicast operator. The user does not see this translation. Default window policies Only default window policies are supported in the new surface. Other policies can be simulated by using AlterEventLifetime. Before After xs.SnapshotWindow(     WindowInputPolicy.ClipToWindow,     SnapshotWindowInputPolicy.Clip) xs.SnapshotWindow() xs.TumblingWindow(     TimeSpan.FromSeconds(1),     HoppingWindowOutputPolicy.PointAlignToWindowEnd) xs.TumblingWindow(     TimeSpan.FromSeconds(1)) xs.TumblingWindow(     TimeSpan.FromSeconds(1),     HoppingWindowOutputPolicy.ClipToWindowEnd) Not supported … LeftAntiJoin Representation of LASJ as a correlated sub-query in the LINQ surface is problematic as the StreamInsight engine does not support correlated sub-queries (see discussion of SelectMany). The current syntax requires the introduction of an otherwise unsupported ‘IsEmpty()’ operator. As a result, the pattern is not discoverable and implies capabilities not present in the server. The direct representation of LASJ is used instead: Before After from x in xs where     (from y in ys     where x.A > y.B     select y).IsEmpty() select x xs.LeftAntiJoin(ys, (x, y) => x.A > y.B) from x in xs where     (from y in ys     where x.A == y.B     select y).IsEmpty() select x xs.LeftAntiJoin(ys, x => x.A, y => y.B) ApplyWithUnion The ApplyWithUnion methods have been deprecated since their signatures are redundant given the standard SelectMany overloads: Before After xs.GroupBy(x => x.A).ApplyWithUnion(gs => from win in gs.SnapshotWindow() select win.Count()) xs.GroupBy(x => x.A).SelectMany(     gs =>     from win in gs.SnapshotWindow()     select win.Count()) xs.GroupBy(x => x.A).ApplyWithUnion(gs => from win in gs.SnapshotWindow() select win.Count(), r => new { r.Key, Count = r.Payload }) from x in xs group x by x.A into gs from win in gs.SnapshotWindow() select new { gs.Key, Count = win.Count() } Alternate UDO syntax The representation of UDOs in the StreamInsight LINQ dialect confuses cardinalities. Based on the semantics of user-defined operators in StreamInsight, one would expect to construct queries in the following form: from win in xs.SnapshotWindow() from y in MyUdo(win) select y Instead, the UDO proxy method is referenced within a projection, and the (many) results returned by the user code are automatically flattened into a stream: from win in xs.SnapshotWindow() select MyUdo(win) The “many-or-one” confusion is exemplified by the following example that compiles but fails at runtime: from win in xs.SnapshotWindow() select MyUdo(win) + win.Count() The above query must fail because the UDO is in fact returning many values per window while the count aggregate is returning one. Original syntax New alternate syntax from win in xs.SnapshotWindow() select win.UdoProxy(1) from win in xs.SnapshotWindow() from y in win.UserDefinedOperator(() => new Udo(1)) select y -or- from win in xs.SnapshotWindow() from y in win.UdoMacro(1) select y Notice that this formulation also sidesteps the dynamic type pitfalls of the existing “proxy method” approach to UDOs, in which the type of the UDO implementation (TInput, TOuput) and the type of its constructor arguments (TConfig) need to align in a precise and non-obvious way with the argument and return types for the corresponding proxy method. UDSO syntax UDSO currently leverages the DataContractSerializer to clone initial state for logical instances of the user operator. Initial state will instead be described by an expression in the new LINQ surface. Before After xs.Scan(new Udso()) xs.Scan(() => new Udso()) Name changes ShiftEventTime => AlterEventStartTime: The alter event lifetime overload taking a new start time value has been renamed. CountByStartTimeWindow => CountWindow

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• Techniques to re-factor garbage and maintain sanity?

  - by Incognito

  So I'm sitting down to a nice bowl of c# spaghetti, and need to add something or remove something... but I have challenges everywhere from functions passing arguments that doesn't make sense, someone who doesn't understand data structures abusing strings, redundant variables, some comments are red-hearings, internationalization is on a per-every-output-level, SQL doesn't use any kind of DBAL, database connections are left open everywhere... Are there any tools or techniques I can use to at least keep track of the "functional integrity" of the code (meaning my "improvements" don't break it), or a resource online with common "bad patterns" that explains a good way to transition code? I'm basically looking for a guidebook on how to spin straw into gold. Here's some samples from the same 500 line function: protected void DoSave(bool cIsPostBack) { //ALWAYS a cPostBack cIsPostBack = true; SetPostBack("1"); string inCreate ="~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~"; parseValues = new string []{"","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","",""}; if (!cIsPostBack) { //....... //.... //.... if (!cIsPostBack) { } else { } //.... //.... strHPhone = StringFormat(s1.Trim()); s1 = parseValues[18].Replace(encStr," "); strWPhone = StringFormat(s1.Trim()); s1 = parseValues[11].Replace(encStr," "); strWExt = StringFormat(s1.Trim()); s1 = parseValues[21].Replace(encStr," "); strMPhone = StringFormat(s1.Trim()); s1 = parseValues[19].Replace(encStr," "); //(hundreds of lines of this) //.... //.... SQL = "...... lots of SQL .... "; SqlCommand curCommand; curCommand = new SqlCommand(); curCommand.Connection = conn1; curCommand.CommandText = SQL; try { curCommand.ExecuteNonQuery(); } catch {} //.... } I've never had to refactor something like this before, and I want to know if there's something like a guidebook or knowledgebase on how to do this sort of thing, finding common bad patterns and offering the best solutions to repair them. I don't want to just nuke it from orbit,

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• Profiling Startup Of VS2012 &ndash; Ants Profiler

  - by Alois Kraus

  I just downloaded ANTS Profiler 7.4 to check how fast it is and how deep I can analyze the startup of Visual Studio 2012. The Pro version which is useful does cost 445€ which is ok. To measure a complex system I decided to simply profile VS2012 (Update 1) on my older Intel 6600 2,4GHz with 3 GB RAM and a 32 bit Windows 7. Ants Profiler is really easy to use. So lets try it out. The Ants Profiler does want to start the profiled application by its own which seems to be rather common. I did choose Method Level timing of all managed methods. In the configuration menu I did want to get all call stacks to get full details. Once this is configured you are ready to go.   After that you can select the Method Grid to view Wall Clock Time in ms. I hate percentages which are on by default because I do want to look where absolute time is spent and not something else.   From the Method Grid I can drill down to see where time is spent in a nice and I can look at the decompiled methods where the time is spent. This does really look nice. But did you see the size of the scroll bar in the method grid? Although I wanted all call stacks I do get only about 4 pages of methods to drill down. From the scroll bar count I would guess that the profiler does show me about 150 methods for the complete VS startup. This is nonsense. I will never find a bottleneck in VS when I am presented only a fraction of the methods that were actually executed. I have also tried in the configuration window to also profile the extremely trivial functions but there was no noticeable difference. It seems that the Ants Profiler does filter away way too many details to be useful for bigger systems. If you want to optimize a CPU bound operation inside NUnit then Ants Profiler is with its line level timings a very nice tool to work with. But for bigger stuff it is certainly not usable. I also do not like that I must start the profiled application from the profiler UI. This makes it hard to profile processes which are started by some other process. Next: JetBrains dotTrace

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• Self-Executing Anonymous Function vs Prototype

  - by Robotsushi

  In Javascript there are a few clearly prominent techniques for create and manage classes/namespaces in javascript. I am curious what situations warrant using one technique vs. the other. I want to pick one and stick with it moving forward. I write enterprise code that is maintained and shared across multiple teams, and I want to know what is the best practice when writing maintainable javascript ? I tend to prefer Self-Executing Anonymous Functions however I am curious what the community vote is on these techniques. Prototype : function obj() { } obj.prototype.test = function() { alert('Hello?'); }; var obj2 = new obj(); obj2.test(); Self-Closing Anonymous Function : //Self-Executing Anonymous Function (function( skillet, $, undefined ) { //Private Property var isHot = true; //Public Property skillet.ingredient = "Bacon Strips"; //Public Method skillet.fry = function() { var oliveOil; addItem( "\t\n Butter \n\t" ); addItem( oliveOil ); console.log( "Frying " + skillet.ingredient ); }; //Private Method function addItem( item ) { if ( item !== undefined ) { console.log( "Adding " + $.trim(item) ); } } }( window.skillet = window.skillet || {}, jQuery )); //Public Properties console.log( skillet.ingredient ); //Bacon Strips //Public Methods skillet.fry(); //Adding Butter & Fraying Bacon Strips //Adding a Public Property skillet.quantity = "12"; console.log( skillet.quantity ); //12 //Adding New Functionality to the Skillet (function( skillet, $, undefined ) { //Private Property var amountOfGrease = "1 Cup"; //Public Method skillet.toString = function() { console.log( skillet.quantity + " " + skillet.ingredient + " & " + amountOfGrease + " of Grease" ); console.log( isHot ? "Hot" : "Cold" ); }; }( window.skillet = window.skillet || {}, jQuery )); //end of skillet definition try { //12 Bacon Strips & 1 Cup of Grease skillet.toString(); //Throws Exception } catch( e ) { console.log( e.message ); //isHot is not defined } I feel that I should mention that the Self-Executing Anonymous Function is the pattern used by the jQuery team. Update When I asked this question I didn't truly see the importance of what I was trying to understand. The real issue at hand is whether or not to use new to create instances of your objects or to use patterns which do not require constructors of the use of the new keyword. I added my own answer, because in my opinion we should make use of patterns which don't use the new keyword. For more information please see my answer.

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• How to apply effects that occur (or change) over time to characters in a game?

  - by Joshua Harris

  So assume that I have a system that applies Effects to Characters like so: public class Character { private Collection<Effect> _effects; public void AddEffect (Effect e) { e.ApplyTo(this); _effects.Add(e); } public void RemoveEffect (Effect e) { e.RemoveFrom(this); _effects.Remove(e); } } public interface Effect { public void ApplyTo (Character character); public void RemoveFrom (Character character); } Example Effect: Armor Buff for 5 seconds. void someFunction() { // Do Stuff ... Timer armorTimer = new Timer(5 seconds); ArmorBuff armorbuff = new ArmorBuff(); character.AddEffect(armorBuff); armorTimer.Start(); // Do more stuff ... } // Some where else in code public void ArmorTimer_Complete() { character.RemoveEffect(armorBuff); } public class ArmorBuff implements Effect { public void applyTo(Character character) { character.changeArmor(20); } public void removeFrom(Character character) { character.changeArmor(-20); } } Ok, so this example would buff the Characters armor for 5 seconds. Easy to get working. But what about effects that change over the duration of the effect being applied. Two examples come to mind: Damage Over Time: 200 damage every second for 3 seconds. I could mimic this by applying an Effect that lasts for 1 second and has a counter set to 3, then when it is removed it could deal 200 damage, clone itself, decrement the counter of the clone, and apply the clone to the character. If it repeats this until the counter is 0, then you got a damage over time ability. I'm not a huge fan of this approach, but it does describe the behavior exactly. Degenerating Speed Boost: Gain a speed boost that degrades over 3 seconds until you return to your normal speed. This is a bit harder. I can basically do the same thing as above except having timers set to some portion of a second, such that they occur fast enough to give the appearance of degenerating smoothly over time (even though they are really just stepping down incrementally). I feel like you could get away with only 12 steps over a second (maybe less, I would have to test it and see), but this doesn't seem very elegant to me. The only other way to implement this effect would be to change the system so that the Character checks the _effects collection for effects that alter any of the properties any time that they are being used. I could handle this in functions like getCurrentSpeed() and getCurrentArmor(), but you can imagine how much of a hassle it would be to have that kind of overhead every time you want to do a calculation with movement speed (which would be every time you move your character). Is there a better way to deal with these kinds of effects or events?

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• Nautilus ignores / misinterprets view size

  - by BlueZero4

  I noticed that a lot of my folders had suddenly switched to higher view sizes than I had specificied. I was assuming that somehow nautilus had suddenly decided to create per-folder entries for said folders with incorrect view sizes. So I found this question: How to reset all per-folder view settings in nautilus? I found the folder specified in the answer (~/.local/share/gvfs-metadata) and found that it was actually important to delete the files INSIDE the folder, because for some reason deleting the folder itself didn't work for some reason. After doing that, I discovered that the odd setting was for the default view settings, not for a handful of files. Nautilus actually handles the per-folder settings like it should, but it ignores the global folder settings. I want Nautilus to, by default, display all non-specified folders as compact view, 50%. My folders are using the compact setting like I want, but they are not down to 50%. At a guess, they are at 100%. Altering the view size of the icon view can set the compact view to 33%, but I'm not sure by what mechanism this functions. I haven't extensively tested the other view sizes because I don't plan on using them much at all. Next I looked up questions like How do I reset nautilus to the default configuration? I'm expecting the problem to be a corrupted config file or something of the sort, so I hunted down directories like ~/.nautilus, ~/.gconf/apps/nautilus, and ~/.gnome2/nautilus. (I don't have a ~/.nautilus directory, so I'm assuming that's only for older versions.) I attempted to remove the contents of each, but I can't seem to force Nautilus back to default configuration settings. Actually viewing Nautilus's preferences in GConf made the settings look like they were what I wanted them to be, which is odd. I'd like to force Nautilus to default settings, basically. Though if something else will fix it, I'll take it too. I'm not interested in doing a full uninstall, reinstall of Nautilus if I don't have to. ==EDIT1== Turns out that Nautilus just writes the settings in GConf for the heck of it. Nautilus only really uses the settings that it stores in DConf. I did gsettings reset-recursively org.gnome.nautilus, which actually did reset Nautilus to default, but it still doesn't like my view size settings.

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• A little gem from MPN&ndash;FREE online course on Architectural Guidance for Migrating Applications to Windows Azure Platform

  - by Eric Nelson

  I know a lot of technical people who work in partners (ISVs, System Integrators etc). I know that virtually none of them would think of going to the Microsoft Partner Network (MPN) learning portal to find some deep and high quality technical content. Instead they would head to MSDN, Channel 9, msdev.com etc. I am one of those people :-) Hence imagine my surprise when i stumbled upon this little gem Architectural Guidance for Migrating Applications to Windows Azure Platform (your company and hence your live id need to be a member of MPN – which is free to join). This is first class stuff – and represents about 4 hours which is really 8 if you stop and ponder :) Course Structure The course is divided into eight modules.  Each module explores a different factor that needs to be considered as part of the migration process. Module 1:  Introduction:  This section provides an introduction to the training course, highlighting the values of the Windows Azure Platform for developers. Module 2:  Dynamic Environment: This section goes into detail about the dynamic environment of the Windows Azure Platform. This session will explain the difference between current development states and the Windows Azure Platform environment, detail the functions of roles, and highlight development considerations to be aware of when working with the Windows Azure Platform. Module 3:  Local State: This session details the local state of the Windows Azure Platform. This section details the different types of storage within the Windows Azure Platform (Blobs, Tables, Queues, and SQL Azure). The training will provide technical guidance on local storage usage, how to write to blobs, how to effectively use table storage, and other authorization methods. Module 4:  Latency and Timeouts: This session goes into detail explaining the considerations surrounding latency, timeouts and how to assess an IT portfolio. Module 5:  Transactions and Bandwidth: This session details the performance metrics surrounding transactions and bandwidth in the Windows Azure Platform environment. This session will detail the transactions and bandwidth costs involved with the Windows Azure Platform and mitigation techniques that can be used to properly manage those costs. Module 6:  Authentication and Authorization: This session details authentication and authorization protocols within the Windows Azure Platform. This session will detail information around web methods of authorization, web identification, Access Control Benefits, and a walkthrough of the Windows Identify Foundation. Module 7:  Data Sensitivity: This session details data considerations that users and developers will experience when placing data into the cloud. This section of the training highlights these concerns, and details the strategies that developers can take to increase the security of their data in the cloud. Module 8:  Summary Provides an overall review of the course.

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• Write and fprintf for file I/O

  - by Darryl Gove

  fprintf() does buffered I/O, where as write() does unbuffered I/O. So once the write() completes, the data is in the file, whereas, for fprintf() it may take a while for the file to get updated to reflect the output. This results in a significant performance difference - the write works at disk speed. The following is a program to test this: #include <fcntl.h #include <unistd.h #include <stdio.h #include <stdlib.h #include <errno.h #include <stdio.h #include <sys/time.h #include <sys/types.h #include <sys/stat.h static double s_time; void starttime() { s_time=1.0*gethrtime(); } void endtime(long its) { double e_time=1.0*gethrtime(); printf("Time per iteration %5.2f MB/s\n", (1.0*its)/(e_time-s_time*1.0)*1000); s_time=1.0*gethrtime(); } #define SIZE 10*1024*1024 void test_write() { starttime(); int file = open("./test.dat",O_WRONLY|O_CREAT,S_IWGRP|S_IWOTH|S_IWUSR); for (int i=0; i<SIZE; i++) { write(file,"a",1); } close(file); endtime(SIZE); } void test_fprintf() { starttime(); FILE* file = fopen("./test.dat","w"); for (int i=0; i<SIZE; i++) { fprintf(file,"a"); } fclose(file); endtime(SIZE); } void test_flush() { starttime(); FILE* file = fopen("./test.dat","w"); for (int i=0; i<SIZE; i++) { fprintf(file,"a"); fflush(file); } fclose(file); endtime(SIZE); } int main() { test_write(); test_fprintf(); test_flush(); } Compiling and running I get 0.2MB/s for write() and 6MB/s for fprintf(). A large difference. There's three tests in this example, the third test uses fprintf() and fflush(). This is equivalent to write() both in performance and in functionality. Which leads to the suggestion that fprintf() (and other buffering I/O functions) are the fastest way of writing to files, and that fflush() should be used to enforce synchronisation of the file contents.

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• Enabling Attachments in Oracle Forms

  - by Manoj Madhusoodanan

  In this blog I will demonstrate how we can enable attachments in Oracle Form. The user ask is to capture a job description which will be along text. Oracle Apps has a feature called attachments, through some easy setup we can enable attachments in forms. We will be going to addresscustomer ask through this feature. Step 1 : Identify Form Name First thing you have to do is to identify the form to enable attachment. In this scenario form will be PERWSDJT ( Job form in HRMS ). Step 2 :  Identify Document Entity exists or not. If exists then do nothing otherwise create new. Step 3 : Create Document Categories. Here I will create a category Job Description with Default Data Type Long Text and Application Human Resources.Onceit is done I will assign this to Create Job form. Step: 3 Query Attachment Functions for PERWSDJT. Click on Categories and add Job Description.Make sure enabled check box is checked. v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} Normal 0 false false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Step 4 : Turn off HR:Use Standard Attachments profile option. Output Go to Work Structures > Job > Description

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• How is fundamental mathematics efficiently evaluated by programming languages?

  - by Korvin Szanto

  As I get more and more involved with the theory behind programming, I find myself fascinated and dumbfounded by seemingly simple things.. I realize that my understanding of the majority of fundamental processes is justified through circular logic Q: How does this work? A: Because it does! I hate this realization! I love knowledge, and on top of that I love learning, which leads me to my question (albeit it's a broad one). Question: How are fundamental mathematical operators assessed with programming languages? How have current methods been improved? Example var = 5 * 5; My interpretation: $num1 = 5; $num2 = 5; $num3 = 0; while ($num2 > 0) { $num3 = $num3 + $num1; $num2 = $num2 - 1; } echo $num3; This seems to be highly inefficient. With Higher factors, this method is very slow while the standard built in method is instantanious. How would you simulate multiplication without iterating addition? var = 5 / 5; How is this even done? I can't think of a way to literally split it 5 into 5 equal parts. var = 5 ^ 5; Iterations of iterations of addition? My interpretation: $base = 5; $mod = 5; $num1 = $base; while ($mod > 1) { $num2 = 5; $num3 = 0; while ($num2 > 0) { $num3 = $num3 + $num1; $num2 = $num2 - 1; } $num1 = $num3; $mod -=1; } echo $num3; Again, this is EXTREMELY inefficient, yet I can't think of another way to do this. This same question extends to all mathematical related functions that are handled automagically.

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• F# Project Euler Problem 1

  - by MarkPearl

  Every now and then I give project Euler a quick browse. Since I have been playing with F# I have found it a great way to learn the basics of the language. Today I thought I would give problem 1 an attempt… Problem 1 If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23. Find the sum of all the multiples of 3 or 5 below 1000. My F# Solution I broke this problem into two functions… 1) be able to generate a collection of numbers that are multiples of a number but but are smaller than another number. let GenerateMultiplesOfXbelowY X Y = X |> Seq.unfold (fun i -> if (i<Y) then Some(i, i+X) else None) I then needed something that generated collections for multiples of 3 & 5 and then removed any duplicates. Once this was done I would need to sum these all together to get a result. I found the Seq object to be extremely useful to achieve this… let Multiples = Seq.append (GenerateMultiplesOfXbelowY 3 1000) (GenerateMultiplesOfXbelowY 5 1000) |> Seq.distinct |> Seq.fold(fun acc a -> acc + a) 0 |> Console.WriteLine |> Console.ReadLine My complete solution was … open System let GenerateMultiplesOfXbelowY X Y = X |> Seq.unfold (fun i -> if (i<Y) then Some(i, i+X) else None) let Multiples = Seq.append (GenerateMultiplesOfXbelowY 3 1000) (GenerateMultiplesOfXbelowY 5 1000) |> Seq.distinct |> Seq.fold(fun acc a -> acc + a) 0 |> Console.WriteLine |> Console.ReadLine   Which seemed to generate the correct result in a relatively short period of time although I am sure I will get some comments from the experts who know of some intrinsic method to achieve all of this in one method call.

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