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  • How can I use "IF statements" in a postgres trigger

    - by Dan B
    I have a trigger function that I only want to fire on certain instances of INSERTS, in this case, if do_backup = true. If it fires in all instances, I get an infinite loop. The logic seems pretty simple to me, and the rest of the function works. But the trigger function does not seem to register my conditional and always runs, even when backup = true. CREATE OR REPLACE FUNCTION table_styles_backup() RETURNS TRIGGER AS $table_styles_backup$ DECLARE ... do_backup boolean; BEGIN SELECT backup INTO do_backup FROM table_details WHERE id=NEW.table_meta_id; IF (do_backup = true) THEN ... INSERT INTO table_styles_versions ( ... ) VALUES ( ... ); END IF; RETURN NULL; END; $table_styles_backup$ LANGUAGE plpgsql; CREATE TRIGGER table_styles_backup AFTER INSERT ON table_styles FOR EACH ROW EXECUTE PROCEDURE table_styles_backup();

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  • c++ - FIFO implementation

    - by Narek
    While implementing a FIFO I have used the following structure: struct Node { T info_; Node* link_; Node(T info, Node* link=0): info_(info), link_(link) {} }; I think this a well known trick for lots of STL containers (for example for List). Is this a good practice? What it means for compiler when you say that Node has a member with a type of it's pointer? Is this a kind of infinite loop? And finally, if this is a bad practice, how I could implement a better FIFO.

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  • PHP - turning register globals off, what is the best way to go about fixing the code?

    - by user187809
    I am working on a old code base, where programmers assumed that register_globals will always be on. Hence variables are used without $_GET or $_POST prefix, pretty much in every page (the code base is huge, hundreds of scripts). I tried turning it off, but the very first script (login script) goes on an infinite loop. I understand that going through one script at a time, and one line at a time and fixing the variables is probably the only option (adding the prefix $_GET or $_POST as the case may be). Has anyone does this before? How did you go about doing it? Any advice?

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  • Java concurrency - Should block or yield?

    - by teto
    Hi, I have multiple threads each one with its own private concurrent queue and all they do is run an infinite loop retrieving messages from it. It could happen that one of the queues doesn't receive messages for a period of time (maybe a couple seconds), and also they could come in big bursts and fast processing is necessary. I would like to know what would be the most appropriate to do in the first case: use a blocking queue and block the thread until I have more input or do a Thread.yield()? I want to have as much CPU resources available as possible at a given time, as the number of concurrent threads may increase with time, but also I don't want the message processing to fall behind, as there is no guarantee of when the thread will be reescheduled for execution when doing a yield(). I know that hardware, operating system and other factors play an important role here, but setting that aside and looking at it from a Java (JVM?) point of view, what would be the most optimal?

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  • floating point exception in C++ code !

    - by mekasperasky
    #include<stdio.h> #include<math.h> int main () { FILE *fp; fp=fopen("output","w"); float t,y=0,x=0,e=5,f=1,w=1; for (t=0;t<10;t=t+0.01) { if( y==inf && y== nan) break; fprintf(fp,"%lf\t%lf\n",y,x); y = y + ((e*(1 - x*x)*y) - x + f*cos(w*t))*t; x = x + y*t; } return (0); } why is the ouput giving infinite and NAN values?

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  • .BAT Switches Parsing

    - by giiYanJ
    Erm.. I'm working with a switches parsing in BAT files, which goes like this: <commands> -a -b -x -y -z -u abc ...... The user may input a lot of switch, or none. So I used looped shift to make parsing infinite switches possible: :loop IF "%1"=="-a" ... SHIFT GOTO loop But when the script ends, I always get cmd executing the switches and showing up error like '-n' is not recognized as an internal... So, someone got any idea? Thanks a lot... P/S: Make solution sticks with BAT script if possible as using other language may cause dependencies problem as this script is aimed on ANY computer with Windows. Finally, thanks again =) EDIT: Tried shf301 suggestion, i found out that I used DEL %0 to delete itself but it seems the %0 is shifted into the arguments because of the SHIFT command.

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  • why Haskell can deduce [] type in this function

    - by Sili
    rho x = map (((flip mod) x).(\a -> a^2-1)) (rho x) This function will generate an infinite list. And I tested in GHCi, the function type is *Main> :t rho rho :: Integral b => b -> [b] If I define a function like this fun x = ((flip mod) x).(\a -> a^2-1) The type is *Main> :t fun fun :: Integral c => c -> c -> c My question is, how can Haskell deduce the function type to b - [b]? We don't have any [] type data in this function. Thanks!

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  • Mathematica Programming Language&ndash;An Introduction

    - by JoshReuben
    The Mathematica http://www.wolfram.com/mathematica/ programming model consists of a kernel computation engine (or grid of such engines) and a front-end of notebook instances that communicate with the kernel throughout a session. The programming model of Mathematica is incredibly rich & powerful – besides numeric calculations, it supports symbols (eg Pi, I, E) and control flow logic.   obviously I could use this as a simple calculator: 5 * 10 --> 50 but this language is much more than that!   for example, I could use control flow logic & setup a simple infinite loop: x=1; While [x>0, x=x,x+1] Different brackets have different purposes: square brackets for function arguments:  Cos[x] round brackets for grouping: (1+2)*3 curly brackets for lists: {1,2,3,4} The power of Mathematica (as opposed to say Matlab) is that it gives exact symbolic answers instead of a rounded numeric approximation (unless you request it):   Mathematica lets you define scoped variables (symbols): a=1; b=2; c=a+b --> 5 these variables can contain symbolic values – you can think of these as partially computed functions:   use Clear[x] or Remove[x] to zero or dereference a variable.   To compute a numerical approximation to n significant digits (default n=6), use N[x,n] or the //N prefix: Pi //N -->3.14159 N[Pi,50] --> 3.1415926535897932384626433832795028841971693993751 The kernel uses % to reference the lastcalculation result, %% the 2nd last, %%% the 3rd last etc –> clearer statements: eg instead of: Sqrt[Pi+Sqrt[Sqrt[Pi+Sqrt[Pi]]] do: Sqrt[Pi]; Sqrt[Pi+%]; Sqrt[Pi+%] The help system supports wildcards, so I can search for functions like so: ?Inv* Mathematica supports some very powerful programming constructs and a rich function library that allow you to do things that you would have to write allot of code for in a language like C++.   the Factor function – factorization: Factor[x^3 – 6*x^2 +11x – 6] --> (-3+x) (-2+x) (-1+x)   the Solve function – find the roots of an equation: Solve[x^3 – 2x + 1 == 0] -->   the Expand function – express (1+x)^10 in polynomial form: Expand[(1+x)^10] --> 1+10x+45x^2+120x^3+210x^4+252x^5+210x^6+120x^7+45x^8+10x^9+x^10 the Prime function – what is the 1000th prime? Prime[1000] -->7919 Mathematica also has some powerful graphics capabilities:   the Plot function – plot the graph of y=Sin x in a single period: Plot[Sin[x], {x,0,2*Pi}] you can also plot 3D surfaces of functions using Plot3D function

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  • SQL SERVER – A Puzzle – Fun with NULL – Fix Error 8117

    - by pinaldave
    During my 8 years of career, I have been involved in many interviews. Quite often, I act as the  interview. If I am the interviewer, I ask many questions – from easy questions to difficult ones. When I am the interviewee, I frequently get an opportunity to ask the interviewer some questions back. Regardless of the my capacity in attending the interview, I always make it a point to ask the interviewer at least one question. What is NULL? It’s always fun to ask this question during interviews, because in every interview, I get a different answer. NULL is often confused with false, absence of value or infinite value. Honestly, NULL is a very interesting subject as it bases its behavior in server settings. There are a few properties of NULL that are universal, but the knowledge about these properties is not known in a universal sense. Let us run this simple puzzle. Run the following T-SQL script: SELECT SUM(data) FROM (SELECT NULL AS data) t It will return the following error: Msg 8117, Level 16, State 1, Line 1 Operand data type NULL is invalid for sum operator. Now the error makes it very clear that NULL is invalid for sum Operator. Frequently enough, I have showed this simple query to many folks whom I came across. I asked them if they could modify the subquery and return the result as NULL. Here is what I expected: Even though this is a very simple looking query, so far I’ve got the correct answer from only 10% of the people to whom I have asked this question. It was common for me to receive this kind of answer – convert the NULL to some data type. However, doing so usually returns the value as 0 or the integer they passed. SELECT SUM(data) FROM (SELECT ISNULL(NULL,0) AS data) t I usually see many people modifying the outer query to get desired NULL result, but that is not allowed in this simple puzzle. This small puzzle made me wonder how many people have a clear understanding about NULL. Well, here is the answer to my simple puzzle. Just CAST NULL AS INT and it will return the final result as NULL: SELECT SUM(data) FROM (SELECT CAST(NULL AS INT) AS data) t Now that you know the answer, don’t you think it was very simple indeed? This blog post is especially dedicated to my friend Madhivanan who has written an excellent blog post about NULL. I am confident that after reading the blog post from Madhivanan, you will have no confusion regarding NULL in the future. Read: NULL, NULL, NULL and nothing but NULL. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Puzzle, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Digital Storage for Airline Entertainment

    - by Bill Evjen
    by Thomas Coughlin Common flash memory cards The most common flash memory products currently in use are SD cards and derivative products (e.g. mini and micro-SD cards) Some compact flash used for professional applications (such as DSLR cameras) Evolution of leading flash formats Standardization –> market expansion Market expansion –> volume iNAND –> focus is on enabling embedded X3 iSSD –> ideal for thin form factor devices Flash memory applications Phones are the #1 user of flash memory Flash memory is used as embedded and removable storage in many mobile applications Flash memory is being used in computers as USB sticks and SSDs Possible use of flash memory in computer combined with HDDs (hybrid HDDs and paired or dual storage computers) It can be a removable card or an embedded card These devices can only handle a specific number of writes Flash memory reads considerably quicker than hard drives Hybrid and dual storage in computers SSDs can provide fast performance but they are expensive HDDs can provide cheap storage but they are relatively slow Combining some flash memory with a HDD can provide costs close to those of HDDs and performance close to flash memory Seagate Momentus XT hybrid HDD Various dual storage offerings putting flash memory with HDDs Other common flash memory devices USB sticks All forms and colors Used for moving files around Some sold with content on them (Sony Movies on USB sticks) Solid State Drives (SSDs) Floating Gate Flash Memory Cell When a bit is programmed, electrons are stored upon the floating gate This has the effect of offsetting the charge on the control gate of the transistor If there is no charge upon the floating gate, then the control gate’s charge determines whether or not a current flows through the channel A strong charge on the control gate assumes that no current flows. A weak charge will allow a strong current to flow through. Similar to HDDs, flash memory must provide: Bit error correction Bad block management NAND and NOR memories are treated differently when it comes to managing wear In many NOR-based systems no management is used at all, since the NOR is simply used to store code, and data is stored in other devices. In this case, it would take a near-infinite amount of time for wear to become an issue since the only time the chip would see an erase/write cycle is when the code in the system is being upgraded, which rarely if ever happens over the life of a typical system. NAND is usually found in very different application than is NOR Flash memory wears out This is expected to get worse over time Retention: Disappearing data Bits fade away Retention decreases with increasing read/writes Bits may change when adjacent bits are read Time and traffic are concerns Controllers typically groom read disturb errors Like DRAM refresh Increases erase/write frequency Application characteristics Music – reads high / writes very low Video – r high / writes very low Internet Cache – r high / writes low On airplanes Many consumers now have their own content viewing devices – do they need the airlines? Is there a way to offer more to consumers, especially with their own viewers Additional special content tie into airplane network access to electrical power, internet Should there be fixed embedded or removable storage for on-board airline entertainment? Is there a way to leverage personal and airline viewers and content in new and entertaining ways?

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  • Now Shipping! NetAdvantage for .NET 2010 Volume 3!

    The new NetAdvantage Ultimate includes all four Line of Business user interface control sets for ASP .NET, Windows Forms, WPF and Silverlight plus two advanced Data Visualization UI control sets for WPF and Silverlight. With six NetAdvantage products in one robust package, Infragistics® gives you hundreds of controls and infinite development possibilities. Unified XAML Product Strategy-Share Code, Get More Controls In the 10.3 release, Infragistics continues to deliver code parity between the XAML platforms, WPF and Silverlight. In the line of business toolsets, Infragistics introduces the new xamSchedule™, full-featured, Outlook® 2010-style schedule controls, and the new xamDataTree™, a data bound tree view that comfortably handles tens of thousands of tree nodes. Mimicking our Silverlight Drag and Drop Framework, the WPF Drag and Drop Framework CTP empowers you to add your own rich touches to your applications. Track Users' Behaviors New to all NetAdvantage Silverlight controls is the Infragistics Analytics Framework (IGAF), which empowers you to track user behavior in RIAs running on Silverlight 4. Building on the Microsoft® Silverlight Analytics Framework, with IGAF you can analyze the user's behaviors to ensure the experience you want to deliver. NetAdvantage for Windows Forms--New Office® 2010 Ribbon and Application Menu 2010 Create new experiences with Windows Forms. Now with Office 2010 styling, NetAdvantage for Windows Forms has new features such as Microsoft® Office 2010 ribbon and enhanced Infragistics.Excel to export the contents of the high performance WinGrid™ into Microsoft Excel® 2010. The new Windows Message Support enables Infragistics standalone editor controls to process numerous Windows® OS messages, allowing them to respond just like native controls to changes in the Windows environment. Create Faster Web 2.0 Experiences with NetAdvantage for ASP .NET Infragistics continues to push the envelope to deliver the fastest ASP .NET WebForms controls available on the market. Our lightning fast ASP .NET grids are now enhanced with XPS/PDF Exporting and Summary Rows. This release also includes support for jQuery Templating (as a CTP) within our WebDataGrid™ and WebDataTree™ controls allowing you to quickly cut down overall page size. Deliver Business Intelligence with Power, Flexibility and the Office 2010 Experience NetAdvantage for WPF Data Visualization and NetAdvantage for Silverlight Data Visualization help you deliver flexible, powerful and usable end user experiences in Business Intelligence applications. Both suites include the Pivot Grid that delivers the full power of online analytical processing (OLAP) to present multi-dimensional data, sliced and diced in cross-tabulated form for end users to drill down into, interact with and easily extract meaning from the data. Mapping Made Easy 10.3 marks the official release of the WPF Data Visualization xamMap™ control to map anything and everything from geographic to geo-spacial mapping data. Map layers allow you to add successive levels of detail, navigational panes for panning in all directions, color swatch panes that facilitate value scales like Choropleth shading, and scale panes allowing users to zoom-in and out. Both toolsets introduce the first of many relationship maps! With the xamOrgChart™ CTP you can map out organizational charts of up to 50K employees, competitive brackets (think World Cup) and any other relational, organizational map your application needs. http://www.infragistics.com span.fullpost {display:none;}

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  • Game of Phones

    - by Carlos Chang
    Game  of  Phones There’s an excellent DZone article titled: 2014 Guide to Mobile Development. It’s loaded with excellent information including some results from a mobile related survey to more than 1000 IT professionals. Without giving away too much, these highlights should convince you to read the entire article.  Web and Hybrid apps are gaining tons of traction particularly in the enterprise. If you want to better understand the differences between Web, Native and Hybrid, this article has you covered. Enterprise developers are increasingly more interested in cross platform tools. Makes sense right?  I mean, unless you have infinite resources (e.g. Facebook) and can afford to write native apps to every platform, finding something that can meet your needs for iOS and Android makes sense.  And toss in the possibility of Windows Phone …and oh, just to be current, the addition of Apple’s new mobile language, Swift, to add to Objective C.. and oh boy.  Why not check out cross platform tools? BTW, don’t  forget testing on each platform, and maintenance and the next versions of the app. It’s not one and done. If you’re successful, you’re never done. Various mobile vendors are represented and many provide some great information.  Oracle's own Suhas Uliyar, VP of Mobile Strategy, represented with some great insights into the challenges of mobile back end integration (SOA, mBaaS, etc.) and moving from "mobile first" to a mobile plus world. BTW, Suhas was recently named Top 100 Wireless Technology Experts for 2014 by Today's Wireless World magazine.  And if your not yet convinced, DZone did a very nice job with their mobile infographic stylized after the insanely popular series, Game of Thrones.  Even though there were no dragons illustrated, worth the price of admission just for that.   Check it out here.

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  • How to load stacking chunks on the fly?

    - by Brettetete
    I'm currently working on an infinite world, mostly inspired by minecraft. A Chunk consists of 16x16x16 blocks. A block(cube) is 1x1x1. This runs very smoothly with a ViewRange of 12 Chunks (12x16) on my computer. Fine. When I change the Chunk height to 256 this becomes - obviously - incredible laggy. So what I basically want to do is stacking chunks. That means my world could be [8,16,8] Chunks large. The question is now how to generate chunks on the fly? At the moment I generate not existing chunks circular around my position (near to far). Since I don't stack chunks yet, this is not very complex. As important side note here: I also want to have biomes, with different min/max height. So in Biome Flatlands the highest layer with blocks would be 8 (8x16) - in Biome Mountains the highest layer with blocks would be 14 (14x16). Just as example. What I could do would be loading 1 Chunk above and below me for example. But here the problem would be, that transitions between different bioms could be larger than one chunk on y. My current chunk loading in action For the completeness here my current chunk loading "algorithm" private IEnumerator UpdateChunks(){ for (int i = 1; i < VIEW_RANGE; i += ChunkWidth) { float vr = i; for (float x = transform.position.x - vr; x < transform.position.x + vr; x += ChunkWidth) { for (float z = transform.position.z - vr; z < transform.position.z + vr; z += ChunkWidth) { _pos.Set(x, 0, z); // no y, yet _pos.x = Mathf.Floor(_pos.x/ChunkWidth)*ChunkWidth; _pos.z = Mathf.Floor(_pos.z/ChunkWidth)*ChunkWidth; Chunk chunk = Chunk.FindChunk(_pos); // If Chunk is already created, continue if (chunk != null) continue; // Create a new Chunk.. chunk = (Chunk) Instantiate(ChunkFab, _pos, Quaternion.identity); } } // Skip to next frame yield return 0; } }

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  • Will polishing my current project be a better learning experience than starting a new one?

    - by Alejandro Cámara
    I started programming many years ago. Now I'm trying to make games. I have read many recommendations to start cloning some well known games like galaga, tetris, arkanoid, etc. I have also read that I should go for the whole game (including menus, sound, score, etc.). Yesterday I finished the first complete version of my arkanoid clone. But it is far from over. I can still work on it for months (I program as a hobby in my free time) implementing a screen resolution switcher, remap of the control keys, power-ups falling from broken bricks, and a huge etc. But I do not want to be forever learning how to clone ONE game. I have the urge to get to the next clone in order to apply some design ideas I have come upon while developing this arkanoid clone (at the same time I am reading the GoF book and much source code from Ludum Dare 21 game contest). So the question is: Should I keep improving the arkanoid clone until it has all the features the original game had? or should I move to the next clone (there are almost infinite games to clone) and start mending the things I did wrong with the previous clone? This can be a very subjective question, so please restrain the answers to the most effective way to learn how to make my own games (not cloning someone ideas). Thank you! CLARIFICATION In order to clarify what I have implemented I make this list: Features implemented: Bouncing capabilities (the ball bounces on walls, on bricks, and on the bar). Sounds when bouncing on bricks and the bar, and when the player wins or loses. Basic title menu (new game and exit only). Also in-game menu and win/lose menus. Only three levels, but the map system is so easy I do not think it will teach me much (am I wrong?). Features not-implemented: Power-ups when breaking the bricks. Complex bricks (with more than one "hit point" and invincible). Better graphics (I am not really good at it). Programming polishing (use more intensively the design patterns). Here's a link to its (minimal) webpage: http://blog.acamara.es/piperine/ I kind of feel ashamed to show it, so please do not hit me too hard :-) My question was related to the not-implemented features. I wondered what was the fastest (optimal) path to learn. 1) implement the not-implemented features in this project which is getting big, or 2) make a new game which probably will teach me those lessons and new ones. ANSWER I choose @ashes999 answer because, in my case, I think I should polish more and try to "ship" the game. I think all the other answers are also important to bear in mind, so if you came here having the same question, before taking a rush decision read all the discussion. Thank you all!

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  • TDC: The Developer's Conference Day One

    - by Tori Wieldt
    The Developer's Conference (TDC) kicked off Wednesday in São Paulo, Brazil. With over 3000 developers in attendance over five days, it is the premier multi-community developer conference in Brazil, organized by Globalcode. Yara Senger, one of the organizers said, "We like to say multi-community rather than multi-technology because it is interesting and benefical when various communities get together. They learn so much from each other!" TDC includes tracks on Java and several other technologies, including SOA, Python, Ruby, mobile and digital TV. In the mobile track, developers who create a Java ME app will get a Nokia S40 phone!New this year at TDC is the Java University track, sponsored by Oracle.  It is aimed at university students and professionals who are new to Java. The lectures are introductory level, with an educational focus and practical exercises. The Java track and other tracks, such as SOA, mobile and Digital TV, are getting lots of help from the expertise of Brazilian JUGS members. Thanks to GoJava, JavaBahia, JavaNoroeste and SouJava!Carlos Fernando, one of the coordinators on the Digital TV track, said "My goal is to teach developers the basics of digital TV, and show them the tools used to build interactive TV applications." Fernando explained the concept of "the second screen:" that many people watch TV and have second smart device (tablet or smartphone) with them, and this creates many opportunities for developers. For example, while watching TV, a viewer can get extra content (interviews, behind the scenes) on their tablet. More interestingly, while watching their favorite TV show a viewer likes an outfit one of the actors is wearing, their smartphone can tell them where they can buy it nearby, or they can order it online immediately. Fernando exclaimed, "The opportunities for developers are nearly infinite in the area of digital TV!" At the TDC opening keynote, Debora Palermo, Oracle University country manager for Brazil, reminded attendees that Java is present in many devices, from simple to complex, and knowledge of this platform can open many doors in the labor market. She explained Oracle's Workforce Development Program (WDP), managed by Oracle University, which allows educational institutions to deliver Oracle training. WDP allows for easy and low-cost access to Oracle training in local communities across the world. "Oracle University is committed to creating the next generation of Java developers, and WDP can make that happen," Palermo said. As of March 2012, Oracle University is partnering with Globalcode to offer WDP. Students can earn official Oracle Course Certifications, a great way to learn Java.Brazilian developers that cannot attend TDC can watch live streaming.

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  • Basis of definitions

    - by Yttrill
    Let us suppose we have a set of functions which characterise something: in the OO world methods characterising a type. In mathematics these are propositions and we have two kinds: axioms and lemmas. Axioms are assumptions, lemmas are easily derived from them. In C++ axioms are pure virtual functions. Here's the problem: there's more than one way to axiomatise a system. Given a set of propositions or methods, a subset of the propositions which is necessary and sufficient to derive all the others is called a basis. So too, for methods or functions, we have a desired set which must be defined, and typically every one has one or more definitions in terms of the others, and we require the programmer to provide instance definitions which are sufficient to allow all the others to be defined, and, if there is an overspecification, then it is consistent. Let me give an example (in Felix, Haskell code would be similar): class Eq[t] { virtual fun ==(x:t,y:t):bool => eq(x,y); virtual fun eq(x:t, y:t)=> x == y; virtual fun != (x:t,y:t):bool => not (x == y); axiom reflex(x:t): x == x; axiom sym(x:t, y:t): (x == y) == (y == x); axiom trans(x:t, y:t, z:t): implies(x == y and y == z, x == z); } Here it is clear: the programmer must define either == or eq or both. If both are defined, the definitions must be equivalent. Failing to define one doesn't cause a compiler error, it causes an infinite loop at run time. Defining both inequivalently doesn't cause an error either, it is just inconsistent. Note the axioms specified constrain the semantics of any definition. Given a definition of == either directly or via a definition of eq, then != is defined automatically, although the programmer might replace the default with something more efficient, clearly such an overspecification has to be consistent. Please note, == could also be defined in terms of !=, but we didn't do that. A characterisation of a partial or total order is more complex. It is much more demanding since there is a combinatorial explosion of possible bases. There is an reason to desire overspecification: performance. There also another reason: choice and convenience. So here, there are several questions: one is how to check semantics are obeyed and I am not looking for an answer here (way too hard!). The other question is: How can we specify, and check, that an instance provides at least a basis? And a much harder question: how can we provide several default definitions which depend on the basis chosen?

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  • 2D Grid Map Connectivity Check (avoiding stack overflow)

    - by SombreErmine
    I am trying to create a routine in C++ that will run before a more expensive A* algorithm that checks to see if two nodes on a 2D grid map are connected or not. What I need to know is a good way to accomplish this sequentially rather than recursively to avoid overflowing the stack. What I've Done Already I've implemented this with ease using a recursive algorithm; however, depending upon different situations it will generate a stack overflow. Upon researching this, I've come to the conclusion that it is overflowing the stack because of too many recursive function calls. I am sure that my recursion does not enter an infinite loop. I generate connected sets at the beginning of the level, and then I use those connected sets to determine connectivity on the fly later. Basically, the generating algorithm starts from left-to-right top-to-bottom. It skips wall nodes and marks them as visited. Whenever it reaches a walkable node, it recursively checks in all four cardinal directions for connected walkable nodes. Every node that gets checked is marked as visited so they aren't handled twice. After checking a node, it is added to either a walls set, a doors set, or one of multiple walkable nodes sets. Once it fills that area, it continues the original ltr ttb loop skipping already-visited nodes. I've also looked into flood-fill algorithms, but I can't make sense of the sequential algorithms and how to adapt them. Can anyone suggest a better way to accomplish this without causing a stack overflow? The only way I can think of is to do the left-to-right top-to-bottom loop generating connected sets on a row basis. Then check the previous row to see if any of the connected sets are connected and then join the sets that are. I haven't decided on the best data structures to use for that though. I also just thought about having the connected sets pre-generated outside the game, but I wouldn't know where to start with creating a tool for that. Any help is appreciated. Thanks!

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  • Now Shipping! NetAdvantage for .NET 2010 Volume 3!

    The new NetAdvantage Ultimate includes all four Line of Business user interface control sets for ASP .NET, Windows Forms, WPF and Silverlight plus two advanced Data Visualization UI control sets for WPF and Silverlight. With six NetAdvantage products in one robust package, Infragistics® gives you hundreds of controls and infinite development possibilities. Unified XAML Product Strategy-Share Code, Get More Controls In the 10.3 release, Infragistics continues to deliver code parity between the XAML platforms, WPF and Silverlight. In the line of business toolsets, Infragistics introduces the new xamSchedule™, full-featured, Outlook® 2010-style schedule controls, and the new xamDataTree™, a data bound tree view that comfortably handles tens of thousands of tree nodes. Mimicking our Silverlight Drag and Drop Framework, the WPF Drag and Drop Framework CTP empowers you to add your own rich touches to your applications. Track Users' Behaviors New to all NetAdvantage Silverlight controls is the Infragistics Analytics Framework (IGAF), which empowers you to track user behavior in RIAs running on Silverlight 4. Building on the Microsoft® Silverlight Analytics Framework, with IGAF you can analyze the user's behaviors to ensure the experience you want to deliver. NetAdvantage for Windows Forms--New Office® 2010 Ribbon and Application Menu 2010 Create new experiences with Windows Forms. Now with Office 2010 styling, NetAdvantage for Windows Forms has new features such as Microsoft® Office 2010 ribbon and enhanced Infragistics.Excel to export the contents of the high performance WinGrid™ into Microsoft Excel® 2010. The new Windows Message Support enables Infragistics standalone editor controls to process numerous Windows® OS messages, allowing them to respond just like native controls to changes in the Windows environment. Create Faster Web 2.0 Experiences with NetAdvantage for ASP .NET Infragistics continues to push the envelope to deliver the fastest ASP .NET WebForms controls available on the market. Our lightning fast ASP .NET grids are now enhanced with XPS/PDF Exporting and Summary Rows. This release also includes support for jQuery Templating (as a CTP) within our WebDataGrid™ and WebDataTree™ controls allowing you to quickly cut down overall page size. Deliver Business Intelligence with Power, Flexibility and the Office 2010 Experience NetAdvantage for WPF Data Visualization and NetAdvantage for Silverlight Data Visualization help you deliver flexible, powerful and usable end user experiences in Business Intelligence applications. Both suites include the Pivot Grid that delivers the full power of online analytical processing (OLAP) to present multi-dimensional data, sliced and diced in cross-tabulated form for end users to drill down into, interact with and easily extract meaning from the data. Mapping Made Easy 10.3 marks the official release of the WPF Data Visualization xamMap™ control to map anything and everything from geographic to geo-spacial mapping data. Map layers allow you to add successive levels of detail, navigational panes for panning in all directions, color swatch panes that facilitate value scales like Choropleth shading, and scale panes allowing users to zoom-in and out. Both toolsets introduce the first of many relationship maps! With the xamOrgChart™ CTP you can map out organizational charts of up to 50K employees, competitive brackets (think World Cup) and any other relational, organizational map your application needs. http://www.infragistics.com span.fullpost {display:none;}

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  • Methodology to understanding JQuery plugin & API's developed by third parties

    - by Taoist
    I have a question about third party created JQuery plug ins and API's and the methodology for understanding them. Recently I downloaded the JQuery Masonry/Infinite scroll plug in and I couldn't figure out how to configure it based on the instructions. So I downloaded a fully developed demo, then manually deleted everything that wouldn't break the functionality. The code that was left allowed me to understand the plug in much greater detail than the documentation. I'm now having a similar issue with a plug in called JQuery knob. http://anthonyterrien.com/knob/ If you look at the JQuery Knob readme file it says this is working code: $(function() { $('.dial') .trigger( 'configure', { "min":10, "max":40, "fgColor":"#FF0000", "skin":"tron", "cursor":true } ); }); But as far as I can tell it isn't at all. The read me also says the Plug in uses Canvas. I am wondering if I am suppose to wrap this code in a canvas context or if this functionality is already part of the plug in. I know this kind of "question" might not fit in here but I'm a bit confused on the assumptions around reading these kinds of documentation and thought I would post the query regardless. Curious to see if this is due to my "newbi" programming experience or if this is something seasoned coders also fight with. Thank you. Edit In response to Tyanna's reply. I modified the code and it still doesn't work. I posted it below. I made sure that I checked the Google Console to insure the basics were taken care of, such as not getting a read-error on the library. <!DOCTYPE html> <meta charset="UTF-8"> <title>knob</title> <link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.7.2/themes/hot-sneaks/jquery-ui.css" type="text/css" /> <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.js" charset="utf-8"></script> <script src="https://ajax.googleapis.com/ajax/libs/jqueryui/1.8.21/jquery-ui.min.js"></script> <script src="js/jquery.knob.js"></script> <div id="button1">test </div> <script> $(function() { $("#button1").click(function () { $('.dial').trigger( 'configure', { "min":10, "max":40, "fgColor":"#FF0000", "skin":"tron", "cursor":true } ); }); }); </script>

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  • What is the best way to implement collision detection using Bullet physics engine and a track generated from a curve?

    - by tigrou
    I am developing a small racing game were the track is generated from a curve. As said above, the track is generated, but not infinite. The track of one level could fit with no problem in memory and will contain a reasonably small amount of triangles. For collisions, I would like to use Bullet physics engine and know what is the best way to handle collisions with the track efficiently. NOTE : The track will be stored as a static rigid body (mass = 0). The player will be represented by a sphere shape for collisions. Here is some possibilities i have in mind : Create one rigid body, then, put all triangles of the track (except non collidable stuff) into it. Result : 1 body with many triangles (eg : 30000 triangles) Split the track into several sections (eg: 10 sections). Then, for each section, create a rigid body and put corresponding triangles in it. Result : small amount of bodies with relatively small amount of triangles (eg : 1500 triangles per section). Split the track into many sub-sections (eg : 1200 sections). Here one subsection = very small step when generating the curve. Again for each sub-section, create a body and put triangles in it. Result : many bodies with very small amount of triangles (eg : 20 triangles). Advantage : it could be possible to "extra data" to each of the subsection, that could be used when handling collisions. Same as 2, but only put sections N and N+1 in physics engine (where N = current section where the player is). When player reach section N+1, unload section N and load section N+2 and so on... Issue : harder to implement, problems if the player suddenly "jump" from one section to another (eg : player fly away from section N, and fall on section N + 4 that was underneath : no collision handled, player will fall into void ) Same as 4, but with many sub-sections. Issues : since subsections are very small there will be constantly new bodies added and removed to physics engine at runtime. Possibilities for player to accidently skip some sections and fall into the void are higher than 4.

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  • Threads slowing down application and not working properly

    - by Belgin
    I'm making a software renderer which does per-polygon rasterization using a floating point digital differential analyzer algorithm. My idea was to create two threads for rasterization and have them work like so: one thread draws each even scanline in a polygon and the other thread draws each odd scanline, and they both start working at the same time, but the main application waits for both of them to finish and then pauses them before continuing with other computations. As this is the first time I'm making a threaded application, I'm not sure if the following method for thread synchronization is correct: First of all, I use two global variables to control the two threads, if a global variable is set to 1, that means the thread can start working, otherwise it must not work. This is checked by the thread running an infinite loop and if it detects that the global variable has changed its value, it does its job and then sets the variable back to 0 again. The main program also uses an empty while to check when both variables become 0 after setting them to 1. Second, each thread is assigned a global structure which contains information about the triangle that is about to be rasterized. The structures are filled in by the main program before setting the global variables to 1. My dilemma is that, while this process works under some conditions, it slows down the program considerably, and also it fails to run properly when compiled for Release in Visual Studio, or when compiled with any sort of -O optimization with gcc (i.e. nothing on screen, even SEGFAULTs). The program isn't much faster by default without threads, which you can see for yourself by commenting out the #define THREADS directive, but if I apply optimizations, it becomes much faster (especially with gcc -Ofast -march=native). N.B. It might not compile with gcc because of fscanf_s calls, but you can replace those with the usual fscanf, if you wish to use gcc. Because there is a lot of code, too much for here or pastebin, I created a git repository where you can view it. My questions are: Why does adding these two threads slow down my application? Why doesn't it work when compiling for Release or with optimizations? Can I speed up the application with threads? If so, how? Thanks in advance.

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  • DD-WRT: DNSMasq expand-hosts not working

    - by Craig Walker
    I have a Linksys router running DD-WRT (Firmware: DD-WRT v24-sp2 (09/08/09) mini). I have it successfully resolving the DNS names for my DHCP-assigned systems, but only when I fully-qualify those domains. This is despite using the "expand-hosts" DNSMasq additional option, which is supposed to activate this precise function. Here's my dnsmasq.conf: interface=br0 resolv-file=/tmp/resolv.dnsmasq domain=example.com dhcp-leasefile=/tmp/dnsmasq.leases dhcp-lease-max=51 dhcp-option=lan,3,10.77.0.5 dhcp-authoritative dhcp-range=lan,10.77.0.100,10.77.0.149,255.255.0.0,1440m dhcp-host=00:1A:A0:1D:82:5A,astatichostname,10.77.1.40,infinite expand-hosts (FYI: example.com and astatichostname are placeholders for the real-deal names I use. My network uses 10.77.0.0/16; my router is on 10.77.0.5.) Results: > nslookup astatichostname 10.77.0.5 Server: 10.77.0.5 Address: 10.77.0.5#53 ** server can't find astatichostname: NXDOMAIN > nslookup astatichostname.example.com 10.77.0.5 Server: 10.77.0.5 Address: 10.77.0.5#53 Name: astatichostname.example.com Address: 10.77.1.40 Is there something else that could be tripping up expand-host in DNSMasq?

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  • Can't get my OpenVpn client to connect

    - by Larry
    Hi Guys, I am trying to setup a test vpn between my home desktop and my laptop. So far I have got the server on the desktop to connect fine but I can not get my laptop to finish the connection. I have tried several different configurations and they all give me the same result. Obviously it has nothing to do with my Client configuration but possibly something on my laptop? Here is the message I get in the log when it stops then times out and restarts. Mon Oct 18 20:10:55 2010 UDPv4 link local: [undef] Mon Oct 18 20:10:55 2010 UDPv4 link remote: 74.190.29.236:1194 Mon Oct 18 20:11:55 2010 TLS Error: TLS key negotiation failed to occur within 60 seconds (check your network connectivity) Mon Oct 18 20:11:55 2010 TLS Error: TLS handshake failed here are my configurations server.ovpn port 1194 proto udp dev tun ca ca.crt cert server.crt key server.key dh dh1024.pem server 10.8.0.1 255.255.255.252 ifconfig-pool-persist ipp.txt push "route 10.0.0.1 255.255.255.0" push "dhcp-option WINS 10.0.0.5" push "dhcp-option DNS 10.0.0.5" push "dhcp-option DOMAIN acme.com.local" keepalive 10 120 comp-lzo max-clients 1 persist-key persist-tun status openvpn-status.log verb 3 LArry.ovpn client proto udp dev tun remote doublel.hopto.org 1194 resolv-retry infinite nobind persist-key persist-tun ca ca.crt cert client1.crt key client1.key comp-lzo verb 3 dev tun local 206.162.148.9 remote 134.28.54.2 ifconfig 192.168.99.1 192.168.99.2 route 10.0.0.0 255.0.0.0 192.168.99.2 I just need a simple vpn for one user. Am I headed down the right path? Thanks, Larry

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  • openvpn TCP/UDP slow SSH/SMB performance

    - by Petr Latal
    I have question about strange behavior of my openVPN configuration on Debian lenny. I have 2 server configs (one proto tcp-server based and one proto udp based). ISP bandwidth is 7Mbit/7Mbit. When I uses proto tcp-server my download server rate is fine around 6,4 Mbit/s, but upload rate is about 3Mbit/s. When I uses proto udp, my download server rate is around 3Mbit/s and upload rate around 6,4Mbit/s. I tried to handle the MTU, MSSFIX and cipher on/off on server and client configs to synchronize rates, but without solution. Here is TCP based SERVER config: mode server tls-server port 1194 proto tcp-server dev tap0 ifconfig 11.10.15.1 255.255.255.0 ifconfig-pool 11.10.15.2 11.10.15.20 255.255.255.0 push "route 192.168.1.0 255.255.255.0" push "dhcp-option DNS 192.168.1.200" push "route-gateway 11.10.15.1" push "dhcp-option WINS 192.168.1.200" route-up /etc/openvpn/routeup.sh duplicate-cn ca /etc/openvpn/ca.crt cert /etc/openvpn/server.crt key /etc/openvpn/server.key dh /etc/openvpn/dh2048.pem log-append /var/log/openvpn.log status /var/run/vpn.status 10 user nobody group nogroup keepalive 10 120 comp-lzo verb 3 script-security 3 plugin /usr/lib/openvpn/openvpn-auth-pam.so system-auth persist-tun persist-key mssfix cipher BF-CBC Here is UDP based SERVER config: port 1194 proto udp dev tun0 local xx.xx.xx.xx server 11.10.15.0 255.255.255.0 ca /etc/openvpn/ca.crt cert /etc/openvpn/server.crt key /etc/openvpn/server.key dh /etc/openvpn/dh2048.pem log-append /var/log/openvpn.log status /var/run/vpn.status 10 user nobody group nogroup keepalive 10 120 comp-lzo verb 3 duplicate-cn script-security 3 plugin /usr/lib/openvpn/openvpn-auth-pam.so system-auth persist-tun persist-key tun-mtu 1500 mssfix 1212 client-to-client ifconfig-pool-persist ipp.txt Here is TCP/UDP based windows CLIENT config: remote xx.xx.xx.xx --socket-flags TCP_NODELAY tls-client port 1194 proto tcp-client #proto udp dev tap #dev tun pull ca ca.crt cert latis.crt key latis.key mute 0 comp-lzo adaptive verb 3 resolv-retry infinite nobind persist-key auth-user-pass auth-nocache script-security 2 mssfix cipher BF-CBC

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  • Problems setting up a VPN: can connect but can't ping anyone

    - by Fernando
    This is my first time setting a VPN. Clients can connect but can't ping other machines. This is certainly a route problem but i can't find the right way to configure it. Here is a sample example of the two LANS i want to connect: So, i want machines from 192.168.1.0/24 being able to connect with 192.168.0.0/24 as if they were on the same network. For the VPN network, i would like to use the 10.0.0.0/24 range. Here is my server.conf: proto udp port 1194 dev tun server 10.0.0.0 255.255.255.0 push "route 192.168.0.0 255.255.255.0 192.168.0.1" push "dhcp-option DNS 192.168.0.1" push "dhcp-option WINS 192.168.0.1" comp-lzo keepalive 10 120 float max-clients 10 persist-key persist-tun log-append /var/log/openvpn.log verb 6 tls-server dh /etc/openvpn/keys/dh1024.pem ca /etc/openvpn/keys/ca.crt cert /etc/openvpn/keys/server.crt key /etc/openvpn/keys/server.key tls-auth /etc/openvpn/keys/mykey.key 0 status /var/log/openvpn.stats And one of my clients 192.168.1.2: client dev tap proto udp remote my.no-ip.address 1194 route 192.168.1.0 255.0.0.0 192.168.1.1 3 resolv-retry infinite nobind persist-key persist-tun ca "C:\\Program Files\\OpenVPN\\easy-rsa\\keys\\ca.crt" cert "C:\\Program Files\\OpenVPN\\easy-rsa\\keys\\test1.crt" key "C:\\Program Files\\OpenVPN\\easy-rsa\\keys\\test1.key" tls-auth "C:\\Program Files\\OpenVPN\\easy-rsa\\keys\\mykey.key" 1 ns-cert-type server cipher BF-CBC comp-lzo verb 1 What exactly i am doing wrong? All machines can connect to openvpn but the ping doesn't work. At the client log i see the following error: Wed Feb 16 09:43:23 2011 OpenVPN ROUTE: OpenVPN needs a gateway parameter for a --route option and no default was specified by either --route-gateway or --ifconfig options Wed Feb 16 09:43:23 2011 OpenVPN ROUTE: failed to parse/resolve route for host/network: 10.0.0.1 Thanks!

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