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  • Pixels - A cry for some insight

    - by CarrotFile
    I'm pretty new to web developing and I'd love some clarification. Although reading more than one book on the topic, I cannot seem to wrap my head around the pixel concept. I encounter problems with this issue when trying to use CSS and pixel units for design that fits different screen sizes. To my understanding a pixel is the most basic unit used by a monitor in order to compose an image on the screen. So if me resolution is 800 by 600, everything on my screen is rendered using those 800*600 basic building blocks. If I were to enlarge my screen resolution, 3 things would accrue: A. The basic image building block(the pixel) would shrink in size B. The pixels would move close together C. Well, more pixels would now be available All these combined lead to a sharper(depending on the viewing distance) and more detail enabling image. Well so far so good. Here is were I start getting lost: To my knowledge a pixel is not a physical, real object. Monitors are not embedded with a few thousand pixels. I am drawn to this conclusion because anyone can change his screen's resolution, making a pixel on his screen bigger or smaller, and adding or subtracting the amount of total pixels on screen. Adding to that, I have herd that different monitors have different pixel densities. For example Apple's retina monitors. Taking all of the above as my knowledge base, These are my questions: If a pixel has no real world constant size, what does comparing different pixel densities matter? Each screen company can define it's own pixel concept and declare the higher density. What does a bigger pixel density mean? Say we take two screens with the same physical dimensions, but with a different pixel density, am I to assert that the main difference would be the larger density screen being able to display a higher max resolution? Or am I to assert that given the same resolution on both monitors, the higher density one would display a sharper, smaller image? If a pixel is not a fixed size within one monitor, is it a fixed size between the same resolution on two different monitors? For example, would two different monitors, set to the same resolution, be comprised of same size, same quantity pixels? I'd love some help (:

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  • Point line collision reaction

    - by user4523
    I am trying to program point line segment collision detection and reaction. I am doing this for fun and to learn. The point moves (it has a velocity, and can be controlled by the user), whilst the lines are strait and stationary. The lines are not axis aligned. Everything is in 2D. It is quite straight forward to work out if a collision has occurred. For each frame, the point moves from A to B. AB is a line, and if it crosses the line segment, a collision has occurred (or will occur) and I am able to work out the point of intersection (poi). The problem I am having is with the reaction. Ideally I would like the point to be prevented from moving across the line. In one frame, I can move the point back to the poi (or only alow it to move as far as the poi), and alter the velocity. The problem I am having with this approach (I think) is that, next frame the user may try to cross the line again. Although the point is on the poi, the point may not be exactly on the line. Since it is not axis aligned, I think there is always some subtle rounding issue (A float representation of a point on a line might be rounded to a point that is slightly on one side or the other). Because of this, next frame the path might not intersect the line (because it can start on the other side and move away from it) and the point is effectively allowed to cross the line. Firstly, does the analysis sound correct? Having accepted (maybe) that I cannot always exactly position the point on the line, I tried to move the point away from the line slightly (either along the normal to the line, or along the path vector). I then get a problem at edges. Attempting to fix one collision by moving the point away from the line (even slightly) can cause it to cross another line (one shape I am dealing with is a star, with sharp corners). This can mean that the solution to one collision inadvertently creates another collision, which is ignored. Again, does this sound correct? Anyway, whatever I try, I am having difficulty with edges, and the point is occasionally able to penetrate the polygons and cross lines, which is undesirable. Whilst I can find a lot of information about collision detection on the web (and on this site) I can find precious little information on collision reaction. Does any one know of any good point line collision reaction tutorials? Or is my approach too flawed/over complicated?

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  • How to deal with fellow programmer who likes to delegate task with lack any support from boss [closed]

    - by Rudy
    I have a problem with my fellow programmer. We are currently working together in a small project that need to be shipped every 2 weeks. She has a tendency to ask for help for every issues that she is facing. Whether it's a compile error, algorithm problem or even sync/merge issue that caused by herself. She does not even bother to check Google or try to find out by herself. I can be asked to help her for 5-10 times a day. Everyday her husband keeps calling (4-6 times a day), and most of the code that has been delivered by her are actually incorrect. Today she framed me for sending the wrong delivery product. She went home after lunch on the delivery day without telling PM and other team member on that day and her code she commited does not work at all. It's not even tested. I have no choice to roll back her code and cleaning her code just for sake to able to run the product. I have warned her about her defective codes for almost 3 iterations. She said when she was not around I should be able to test her module for her. I snapped and yelled that I am not her slave and directly reported to my boss. However, my boss is not a person that can manage and care about software quality. What is the most important thing to my boss is delivery of product, whether it tested or not. He can even asked us to deliver something that not even tested by QA to the client, on the next day. Most of our suggestion is not followed by him. He even asked me to apologize to her because I snapped. I am tired of the whole situation. This kind of thing keeps repeated. I do have saving to be able to survive for 6 months and the idea of resigning is keep haunting. There is nothing else that can be learned in my current job and I had been in a better environment than this. What should I do with the situation?

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  • Innovation for Retailers

    - by David Dorf
    One of my main objectives for this blog is to point out emerging technologies and how they might apply to the retail industry.  But ideas are just the beginning; retailers either have to rely on vendors or have their own lab to explore these ideas and see which ones work.  (A healthy dose of both is probably the best solution.)  The Nordstrom Innovation Lab is a fine example of dedicating resources to cultivate ideas and test prototypes. The video below, from 2011, is a case study in which the team builds an iPad app that helps customers purchase sunglasses in the store.  Customers take pictures of themselves wearing different sunglasses, then can do side-by-side comparisons. There are a few interesting take-aways from their process.  First, they are working in the store alongside employees and customers.  There's no concept of documenting all the requirements then building the product.  Instead, they work closely with those that will be using the app in order to fully understand what's needed.  When they find an issue, they change the software onsite and try again.  This iterative prototyping ensures their product hits the mark.  Feels like Extreme Programming if you recall that movement. Second, they have time-boxed the project to one week.  Either it works or it doesn't, and either way they've only expended a week's worth of resources.  Innovation always entails failure, and those that succeed are often good at detecting failure quickly then adjusting.  Fail fast and fail often. Third, its not always about technology.  I was impressed they used paper designs to walk through user stories and help understand the needs of the customer.  Pen and paper is the innovator's most powerful tool. Our Retail Applied Research (RAR) team uses some of these concepts in our development process.  (Calling it a process is probably overkill.)  We try to give life to concepts quickly so the rest of organization can help us decide if we're heading the right direction.  It takes many failures before finding a successful product.

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  • Capture a Query Executed By An Application Or User Against a SQL Server Database in Less Than a Minute

    - by Compudicted
    At times a Database Administrator, or even a developer is required to wear a spy’s hat. This necessity oftentimes is dictated by a need to take a glimpse into a black-box application for reasons varying from a performance issue to an unauthorized access to data or resources, or as in my most recent case, a closed source custom application that was abandoned by a deserted contractor without source code. It may not be news or unknown to most IT people that SQL Server has always provided means of back-door access to everything connecting to its database. This indispensible tool is SQL Server Profiler. This “gem” is always quietly sitting in the Start – Programs – SQL Server <product version> – Performance Tools folder (yes, it is for performance analysis mostly, but not limited to) ready to help you! So, to the action, let’s start it up. Once ready click on the File – New Trace button, or using Ctrl-N with your keyboard. The standard connection dialog you have seen in SSMS comes up where you connect the standard way: One side note here, you will be able to connect only if your account belongs to the sysadmin or alter trace fixed server role. Upon a successful connection you must be able to see this initial dialog: At this stage I will give a hint: you will have a wide variety of predefined templates: But to shorten your time to results you would need to opt for using the TSQL_Grouped template. Now you need to set it up. In some cases, you will know the principal’s login name (account) that needs to be monitored in advance, and in some (like in mine), you will not. But it is VERY helpful to monitor just a particular account to minimize the amount of results returned. So if you know it you can already go to the Event Section tab, then click the Column Filters button which would bring a dialog below where you key in the account being monitored without any mask (or whildcard):  If you do not know the principal name then you will need to poke around and look around for things like a config file where (typically!) the connection string is fully exposed. That was the case in my situation, an application had an app.config (XML) file with the connection string in it not encrypted: This made my endeavor very easy. So after I entered the account to monitor I clicked on Run button and also started my black-box application. Voilà, in a under a minute of time I had the SQL statement captured:

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  • Collaborative work (small team) - Best practices

    - by LEM01
    I'm currently working in a very small team of programmers (2-3) and I'm looking for advices/best practices on how to organise our work. We're all working on the same application using PHP. Today we're kind of all working on our way. Today situation: List item that have to be worked on by each dev 1/week. What has to be done is defined at a high functional level (ex: Build the search engine for this product..) Commit / merge our individual branches (git) every week before the next meeting No real dev rules, no code review No test written (aouutch) Problems faced: Code quality issue: discovering someone else code is sometime tough (inline, variable+function+class names, spaces, comments..) Changes in already existing classes (impact on someone else work) Responsibility of each dev unclear: after getting someone else code and discover something messy, should I make the change? Should he make the change? How to plan those things,... What I'm looking for: Basically I'm looking into structuring the way we develop things in order to avoid frustration and improve overall quality. How to define coding standards (naming convention, code rules...)? Do you you any validation script to make sure code is valid before committing? Do you think that defining an architect role in the team is needed? Someone that would actually define what has to be developed during the next phase. By defining interfaces or class descriptions that have to be written. (Does it make sense in such a small team?) Today we're losing time into understanding what others did or tried to do, we're also losing time in discussion like "you should have done it that way! Why is this class doing that and not that..? Shouldn't we have a embedded class rather that this set of data...". I'm looking into a work process, maybe with more defined responsibilities and process in order to improve our performance. If you have experience, advices, best practices or anything to share that we could benefit from it will be much appreciated! Thanks a lot for your time!

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  • Why is everything crashing?

    - by Kopkins
    I've been using Ubuntu for a while now and I love it, I wouldn't think of using another OS unless I can't fix this issue. The install I'm on is only around a month and a half old. I'm running 12.04 64bit on a 8,1 MBP. Up until around 2 weeks ago everything was running smoothly. Around then applications started crashing and weird things started happening. At first I thought it was just certain applications. The first thing to start giving me trouble was compiz. Occasionally compiz will stop decorating windows and lost many other functionalities. running compiz --replace fixes this, but I don't feel like doing it usually once a day. The other thing with this is that after running compiz --replace, my conky window gets lost somewhere and so I run killall conky && conky -c .conkyrc. But this isn't with just a couple applications, it seems like it is proliferating through my system. Last week fontforge started crashing while doing whatever task. So I ended up unable to finish what I was working on to completeness. Didn't find a fix. Today rhythmbox started crashing. Whenever I try to play anything, Rhythmbox becomes unresponsive and needs to be forced to close. When I try to do certain things with the disk utility, it crashes. I get the Ubuntu has experienced an internal error message much more often than I would like. Frequently applications stop appearing in the launcher. Wine almost never does anymore. After not being active for a little while, thunderbird can only fetch my mail after restarting wireless, sudo rmmod b43 && sudo modprobe b43 Occasionally some of my startup apps don't start. What is my best option here? Could they be bugs? I don't want to submit a ton of vague bug reports. Reinstall? switch OS? Thank you to anyone who responds. Kopkins

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  • Why are MVC & TDD not employed more in game architecture?

    - by secoif
    I will preface this by saying I haven't looked a huge amount of game source, nor built much in the way of games. But coming from trying to employ 'enterprise' coding practices in web apps, looking at game source code seriously hurts my head: "What is this view logic doing in with business logic? this needs refactoring... so does this, refactor, refactorrr" This worries me as I'm about to start a game project, and I'm not sure whether trying to mvc/tdd the dev process is going to hinder us or help us, as I don't see many game examples that use this or much push for better architectural practices it in the community. The following is an extract from a great article on prototyping games, though to me it seemed exactly the attitude many game devs seem to use when writing production game code: Mistake #4: Building a system, not a game ...if you ever find yourself working on something that isn’t directly moving your forward, stop right there. As programmers, we have a tendency to try to generalize our code, and make it elegant and be able to handle every situation. We find that an itch terribly hard not scratch, but we need to learn how. It took me many years to realize that it’s not about the code, it’s about the game you ship in the end. Don’t write an elegant game component system, skip the editor completely and hardwire the state in code, avoid the data-driven, self-parsing, XML craziness, and just code the damned thing. ... Just get stuff on the screen as quickly as you can. And don’t ever, ever, use the argument “if we take some extra time and do this the right way, we can reuse it in the game”. EVER. is it because games are (mostly) visually oriented so it makes sense that the code will be weighted heavily in the view, thus any benefits from moving stuff out to models/controllers, is fairly minimal, so why bother? I've heard the argument that MVC introduces a performance overhead, but this seems to me to be a premature optimisation, and that there'd more important performance issues to tackle before you worry about MVC overheads (eg render pipeline, AI algorithms, datastructure traversal, etc). Same thing regarding TDD. It's not often I see games employing test cases, but perhaps this is due to the design issues above (mixed view/business) and the fact that it's difficult to test visual components, or components that rely on probablistic results (eg operate within physics simulations). Perhaps I'm just looking at the wrong source code, but why do we not see more of these 'enterprise' practices employed in game design? Are games really so different in their requirements, or is a people/culture issue (ie game devs come from a different background and thus have different coding habits)?

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  • Separating logic and data in browser game

    - by Tesserex
    I've been thinking this over for days and I'm still not sure what to do. I'm trying to refactor a combat system in PHP (...sorry.) Here's what exists so far: There are two (so far) types of entities that can participate in combat. Let's just call them players and NPCs. Their data is already written pretty well. When involved in combat, these entities are wrapped with another object in the DB called a Combatant, which gives them information about the particular fight. They can be involved in multiple combats at once. I'm trying to write the logic engine for combat by having combatants injected into it. I want to be able to mock everything for testing. In order to separate logic and data, I want to have two interfaces / base classes, one being ICombatantData and the other ICombatantLogic. The two implementers of data will be one for the real objects stored in the database, and the other for my mock objects. I'm now running into uncertainties with designing the logic side of things. I can have one implementer for each of players and NPCs, but then I have an issue. A combatant needs to be able to return the entity that it wraps. Should this getter method be part of logic or data? I feel strongly that it should be in data, because the logic part is used for executing combat, and won't be available if someone is just looking up information about an upcoming fight. But the data classes only separate mock from DB, not player from NPC. If I try having two child classes of the DB data implementer, one for each entity type, then how do I architect that while keeping my mocks in the loop? Do I need some third interface like IEntityProvider that I inject into the data classes? Also with some of the ideas I've been considering, I feel like I'll have to put checks in place to make sure you don't mismatch things, like making the logic for an NPC accidentally wrap the data for a player. Does that make any sense? Is that a situation that would even be possible if the architecture is correct, or would the right design prohibit that completely so I don't need to check for it? If someone could help me just layout a class diagram or something for this it would help me a lot. Thanks. edit Also useful to note, the mock data class doesn't really need the Entity, since I'll just be specifying all the parameters like combat stats directly instead. So maybe that will affect the correct design.

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  • Best way to determine surface normal for a group of pixels?

    - by Paul Renton
    One of my current endeavors is creating a 2D destructible terrain engine for iOS Cocos2D (See https://github.com/crebstar/PWNDestructibleTerrain ). It is in an infant stages no doubt, but I have made significant progress since starting a couple weeks ago. However, I have run into a bit of a performance road block with calculating surface normals. Note: For my destructible terrain engine, an alpha of 0 is considered to not be solid ground. The method posted below works just great given small rectangles, such as n < 30. Anything above 30 causes a dip in the frame rate. If you approach 100x100 then you might as well read a book while the sprite attempts to traverse the terrain. At the moment this is the best I can come up with for altering the angle on a sprite as it roams across terrain (to get the angle for a sprite's orientation just take dot product of 100 * normal * (1,0) vector). -(CGPoint)getAverageSurfaceNormalAt:(CGPoint)pt withRect:(CGRect)area { float avgX = 0; float avgY = 0; ccColor4B color = ccc4(0, 0, 0, 0); CGPoint normal; float len; for (int w = area.size.width; w >= -area.size.width; w--) { for (int h = area.size.height; h >= -area.size.height; h--) { CGPoint pixPt = ccp(w + pt.x, h + pt.y); if ([self pixelAt:pixPt colorCache:&color]) { if (color.a != 0) { avgX -= w; avgY -= h; } // end inner if } // end outer if } // end inner for } // end outer for len = sqrtf(avgX * avgX + avgY * avgY); if (len == 0) { normal = ccp(avgX, avgY); } else { normal = ccp(avgX/len, avgY/len); } // end if return normal; } // end get My problem is I have sprites that require larger rectangles in order for their movement to look realistic. I considered doing a cache of all surface normals, but this lead to issues of knowing when to recalculate the surface normals and these calculations also being quite expensive (also how large should the blocks be?). Another smaller issue is I don't know how to properly treat the case when length is = 0. So I am stuck... Any advice from the community would be greatly appreciated! Is my method the best possible one? Or should I rethink the algorithm? I am new to game development and always looking to learn new tips and tricks.

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  • How to avoid oscillation by async event based systems?

    - by inf3rno
    Imagine a system where there are data sources which need to be kept in sync. A simple example is model - view data binding by MVC. Now I intend to describe these kind of systems with data sources and hubs. Data sources are publishing and subscribing for events and hubs are relaying events to data sources. By handling an event a data source will change it state described in the event. By publishing an event the data source puts its current state to the event, so other data sources can use that information to change their state accordingly. The only problem with this system, that events can be reflected from the hub or from the other data sources, and that can put the system into an infinite oscillation (by async or infinite loop by sync). For example A -- data source B -- data source H -- hub A -> H -> A -- reflection from the hub A -> H -> B -> H -> A -- reflection from another data source By sync it is relatively easy to solve this issue. You can compare the current state with the event, and if they are equal, you don't change the state and raise the same event again. By async I could not find a solution yet. The state comparison does not work by async event handling because there is eventual consistency, and new events can be published in an inconsistent state causing the same oscillation. For example: A(*->x) -> H -> B(y->x) -- can go parallel with B(*->y) -> H -> A(x->y) -- so first A changes to x state while B changes to y state -- then B changes to x state while A changes to y state -- and so on for eternity... What do you think is there an algorithm to solve this problem? If there is a solution, is it possible to extend it to prevent oscillation caused by multiple hubs, multiple different events, etc... ? update: I don't think I can make this work without a lot of effort. I think this problem is just the same as we have by syncing multiple databases in a distributed system. So I think what I really need is constraints if I want to prevent this problem in an automatic way. What constraints do you suggest?

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  • "You are missing the following 32-bit libraries, and Steam may not run: libc.so.6" The common fixes don't work,

    - by M_Steam_User
    So I know this is a problem that has been asked around a lot, but I've tried a bunch of solutions with no success. I'm running Ubuntu 12.04 (64 bit), and I just installed it yesterday. This is my first time working with linux. The error is: You are missing the following 32-bit libraries, and Steam may not run: libc.so.6 Things I've tried. First, I had downloaded from the steam website. I uninstalled it, and tried again from the ubuntu software centre. sudo apt-get update sudo apt-get install ia32-libs sudo apt-get upgrade This installed a bunch of the 32 bit libraries, but did not fix the issue. This seems like the major fix for most people. The direct approach of sudo apt-get install libc.so.6 returns this: Reading package lists... Done Building dependency tree Reading state information... Done E: Unable to locate package libc.so.6 E: Couldn't find any package by regex 'libc.so.6' I guess libc.so.6 isn't a package, just a single file or something? I also tried gksudo gedit /etc/ld.so.conf.d/steam.conf Added these two lines, those the second one was all ready in the file, but copied over: /usr/lib32 /usr/lib/i386-linux-gnu/mesa Then executed: sudo ldconfig But nothing seemed to happen, steam still doesn't work. So, I feel like it is more likely that I have the library and steam isn't looking in the right place. One thing I've seen is people usually reference /usr/local/lib/ for your library locations. However, I can't find where to cd into /usr/, it isn't in my home folder. If /usr/ is the home folder, there is only a /.local folder which only has /share, no lib anywhere. Sorry for my linux ignorance. I appreciate any help, I honestly have no idea how to confirm I have the library and point steam to it, or if that is even the right thing to do. Edit: Tried this, not entirely sure what it means ~$ ls -l /lib32/libc* -rwxr-xr-x 1 root root 1721832 Sep 30 11:06 /lib32/libc-2.15.so -rw-r--r-- 1 root root 185928 Sep 30 11:06 /lib32/libcidn-2.15.so lrwxrwxrwx 1 root root 15 Sep 30 11:06 /lib32/libcidn.so.1 -> libcidn-2.15.so -rw-r--r-- 1 root root 34316 Sep 30 11:06 /lib32/libcrypt-2.15.so lrwxrwxrwx 1 root root 16 Sep 30 11:06 /lib32/libcrypt.so.1 -> libcrypt-2.15.so lrwxrwxrwx 1 root root 12 Sep 30 11:06 /lib32/libc.so.6 -> libc-2.15.so

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  • reference list for non-IT driven algorithmic patterns

    - by Quicker
    I am looking for a reference list for non-IT driven algorithmic patterns (which still can be helped with IT implementations of IT). An Example List would be: name; short desc; reference Travelling Salesman; find the shortest possible route on a multiple target path; http://en.wikipedia.org/wiki/Travelling_salesman_problem Ressource Disposition (aka Regulation); Distribute a limited/exceeding input on a given number output receivers based on distribution rules; http://database-programmer.blogspot.de/2010/12/critical-analysis-of-algorithm-sproc.html If there is no such list, but you instantly think of something specific, please 'put it on the desk'. Maybe I can compile something out of the input I get here (actually I am very frustrated as I did not find any such list via research by myself). Details on Scoping: I found it very hard to formulate what I want in a way everything is out that I do not need (which may be the issue why I did not find anything at google). There is a database centric definition for what I am looking for in the section 'Processes' of the second example link. That somehow fits, but the database focus sort of drifts away from the pattern thinking, which I have in mind. So here are my own thoughts around what's in and what's out: I am NOT looking for a foundational algo ref list, which is implemented as basis for any programming language. Eg. the php reference describes substr and strlen. That implements algos, but is not what I am looking for. the problem the algo does address would even exist, if there were no computers (or other IT components) the main focus of the algo is NOT to help other algo's chances are high, that there are implementions of the solution or any workaround without any IT support out there in the world however the algo could be benefitialy implemented/fully supported by a software application = means: the problem of the algo has to be addressed anyway, but running an algo implementation with software automates the process (that is why I posted it on stackoverflow and not somewhere else) typically such algo implementations have more than one input field value and more than one output field value - which implies it could not be implemented as simple function (which is fixed to produce not more than one output value) in a normalized data model often times such algo implementation outputs span accross multiple rows (sometimes multiple tables), whereby the number of output rows depends on the input paraters and rows in the table(s) at start time - which implies that any algo implementation/procedure must interact with a database (read and/or write) I am mainly looking for patterns, not for specific implementations. Example: The Travelling Salesman assumes any coordinates, however it does not say: You need a table targets with fields x and y. - however sometimes descriptions are focussed on examples with specific implementations very much - no worries, as long as the pattern gets clear

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  • Java @Contented annotation to help reduce false sharing

    - by Dave
    See this posting by Aleksey Shipilev for details -- @Contended is something we've wanted for a long time. The JVM provides automatic layout and placement of fields. Usually it'll (a) sort fields by descending size to improve footprint, and (b) pack reference fields so the garbage collector can process a contiguous run of reference fields when tracing. @Contended gives the program a way to provide more explicit guidance with respect to concurrency and false sharing. Using this facility we can sequester hot frequently written shared fields away from other mostly read-only or cold fields. The simple rule is that read-sharing is cheap, and write-sharing is very expensive. We can also pack fields together that tend to be written together by the same thread at about the same time. More generally, we're trying to influence relative field placement to minimize coherency misses. Fields that are accessed closely together in time should be placed proximally in space to promote cache locality. That is, temporal locality should condition spatial locality. Fields accessed together in time should be nearby in space. That having been said, we have to be careful to avoid false sharing and excessive invalidation from coherence traffic. As such, we try to cluster or otherwise sequester fields that tend to written at approximately the same time by the same thread onto the same cache line. Note that there's a tension at play: if we try too hard to minimize single-threaded capacity misses then we can end up with excessive coherency misses running in a parallel environment. Theres no single optimal layout for both single-thread and multithreaded environments. And the ideal layout problem itself is NP-hard. Ideally, a JVM would employ hardware monitoring facilities to detect sharing behavior and change the layout on the fly. That's a bit difficult as we don't yet have the right plumbing to provide efficient and expedient information to the JVM. Hint: we need to disintermediate the OS and hypervisor. Another challenge is that raw field offsets are used in the unsafe facility, so we'd need to address that issue, possibly with an extra level of indirection. Finally, I'd like to be able to pack final fields together as well, as those are known to be read-only.

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  • StringBuffer behavior in LWJGL

    - by Michael Oberlin
    Okay, I've been programming in Java for about ten years, but am entirely new to LWJGL. I have a specific problem whilst attempting to create a text console. I have built a class meant to abstract input polling to it, which (in theory) captures key presses from the Keyboard object and appends them to a StringBuilder/StringBuffer, then retrieves the completed string after receiving the ENTER key. The problem is, after I trigger the String return (currently with ESCAPE), and attempt to print it to System.out, I consistently get a blank line. I can get an appropriate string length, and I can even sample a single character out of it and get complete accuracy, but it never prints the actual string. I could swear that LWJGL slipped some kind of thread-safety trick in while I wasn't looking. Here's my code: static volatile StringBuffer command = new StringBuffer(); @Override public void chain(InputPoller poller) { this.chain = poller; } @Override public synchronized void poll() { //basic testing for modifier keys, to be used later on boolean shift = false, alt = false, control = false, superkey = false; if(Keyboard.isKeyDown(Keyboard.KEY_LSHIFT) || Keyboard.isKeyDown(Keyboard.KEY_RSHIFT)) shift = true; if(Keyboard.isKeyDown(Keyboard.KEY_LMENU) || Keyboard.isKeyDown(Keyboard.KEY_RMENU)) alt = true; if(Keyboard.isKeyDown(Keyboard.KEY_LCONTROL) || Keyboard.isKeyDown(Keyboard.KEY_RCONTROL)) control = true; if(Keyboard.isKeyDown(Keyboard.KEY_LMETA) || Keyboard.isKeyDown(Keyboard.KEY_RMETA)) superkey = true; while(Keyboard.next()) if(Keyboard.getEventKeyState()) { command.append(Keyboard.getEventCharacter()); } if (Framework.isConsoleEnabled() && Keyboard.isKeyDown(Keyboard.KEY_ESCAPE)) { System.out.println("Escape down"); System.out.println(command.length() + " characters polled"); //works System.out.println(command.toString().length()); //works System.out.println(command.toString().charAt(4)); //works System.out.println(command.toString().toCharArray()); //blank line! System.out.println(command.toString()); //blank line! Framework.disableConsole(); } //TODO: Add command construction and console management after that } } Maybe the answer's obvious and I'm just feeling tired, but I need to walk away from this for a while. If anyone sees the issue, please let me know. This machine is running the latest release of Java 7 on Ubuntu 12.04, Mate desktop environment. Many thanks.

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  • Frame rate on one of two machines running same code seems to be capped at 60 for no reason

    - by dennmat
    ISSUE I recently moved a project from my laptop to my desktop(machine info below). On my laptop the exact same code displays the fps(and ms/f) correctly. On my desktop it does not. What I mean by this is on the laptop it will display 300 fps(for example) where on my desktop it will show only up to 60. If I add 100 objects to the game on the laptop I'll see my frame rate drop accordingly; the same test on the desktop results in no change and the frames stay at 60. It takes a lot(~300) entities before I'll see a frame drop on the desktop, then it will descend. It seems as though its "theoretical" frames would be 400 or 500 but will never actually get to that and only do 60 until there's too much to handle at 60. This 60 frame cap is coming from no where. I'm not doing any frame limiting myself. It seems like something external is limiting my loop iterations on the desktop, but for the last couple days I've been scratching my head trying to figure out how to debug this. SETUPS Desktop: Visual Studio Express 2012 Windows 7 Ultimate 64-bit Laptop: Visual Studio Express 2010 Windows 7 Ultimate 64-bit The libraries(allegro, box2d) are the same versions on both setups. CODE Main Loop: while(!abort) { frameTime = al_get_time(); if (frameTime - lastTime >= 1.0) { lastFps = fps/(frameTime - lastTime); lastTime = frameTime; avgMspf = cumMspf/fps; cumMspf = 0.0; fps = 0; } /** DRAWING/UPDATE CODE **/ fps++; cumMspf += al_get_time() - frameTime; } Note: There is no blocking code in the loop at any point. Where I'm at My understanding of al_get_time() is that it can return different resolutions depending on the system. However the resolution is never worse than seconds, and the double is represented as [seconds].[finer-resolution] and seeing as I'm only checking for a whole second al_get_time() shouldn't be responsible. My project settings and compiler options are the same. And I promise its the same code on both machines. My googling really didn't help me much, and although technically it's not that big of a deal. I'd really like to figure this out or perhaps have it explained, whichever comes first. Even just an idea of how to go about figuring out possible causes, because I'm out of ideas. Any help at all is greatly appreciated.

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  • TechEd 2010 Day Three: The Database Designer (Isn't)

    - by BuckWoody
    Yesterday at TechEd 2010 here in New Orleans I worked the front-booth, answering general SQL Server questions for the masses. I was actually a little surprised to find most of the questions I got were from folks that wanted to know more about Stream Insight and Master Data Services. In past conferences I've been asked a lot of "free consulting" questions, about problems folks have had from older products. I don't mind that a bit - in fact, I'm always happy to help in any way I can. But this time people are really interested in the new features in the product, and I like that they are thinking ahead, not just having to solve problems in production. My presentation was on "Database Design in an Hour". We had the usual fun, and SideShow Bob made an appearance - I kid you not. The guy in the back of the room looked just like Sideshow Bob, so I quickly held a "bes thair" contest, and he won. Duing the presentation, I explain the tools you can use to design databases. I also explain that the "Database Designer" tool in SQL Server Management Studio (SSMS) isn't truly a desinger - it uses non-standard notation, doesn't have a meta-data dictionary, and worst of all, it works at the physical level. In other words, whatever you do in SSMS will automatically change the field/table/relationship structures in the database. We fixed this in SSMS 2008 and higher by adding an option to block that, but the tool is not a good design function nonetheless. To be fair, no one I know of at Microsoft recommends that it is - but I was shocked to hear so many developers in the room defending it as a good tool. I think the main issue for someone who doesn't have to work with Relational Systems a great deal is that it can be difficult to figure out Foreign Keys. The syntax makes them look "backwards", so it's just easier to grab a field and place it on the table you want to point to. There are options. You can download a couple of free tools (CA has a community edition of ER-WIN, Quest has one, and Embarcadero also has one) and if you design more than one or two databases a year, it may be worth buying a true design tool. For years I used Visio, but we changed it so that it doesn't forward-engineer (create the DDL) any more, so it isn't a true design tool either. So investigate those free and not-so-free tools. You'll find they help you in your job - but stay away from the Database Designer in SSMS. Or I'll send Sideshow Bob over there to straighten you out. Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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  • JCP.next.3: time to get to work

    - by Patrick Curran
    As I've previously reported in this blog, we planned three JSRs to improve the JCP’s processes and to meet our members’ expectations for change. The first - JCP.next.1, or more formally JSR 348: Towards a new version of the Java Community Process - was completed in October 2011. This focused on a small number of simple but important changes to make our process more transparent and to enable broader participation. We're already seeing the benefits of these changes as new and existing JSRs adopt the new requirements. However, because we wanted to complete this JSR quickly we deliberately postponed a number of more complex items, including everything that would require modifying the JSPA (the legal agreement that members sign when they join the organization) to a follow-on JSR. The second JSR (JSR 355: JCP Executive Committee Merge) is in progress now and will complete later this year. This JSR is even simpler than the first, and is focused solely on merging the two Executive Committees into one for greater efficiency and to encourage synergies between the Java ME and Java SE platforms. Continuing the momentum to move Java and the JCP forward we have just filed the third JSR (JCP.next.3) as JSR 358: A major revision of the Java Community Process. This JSR will modify the JSPA as well as the Process Document, and will tackle a large number of complex issues, many of them postponed from JSR 348. For these reasons we expect to spend a considerable amount of time working on it - at least a year, and probably more. The current version of the JSPA was created back in 2002, although some minor changes were introduced in 2005. Since then the organization and the environment in which we operate have changed significantly, and it is now time to revise our processes to ensure that they meet our current needs. We have a long list of topics to be considered, including the role of independent implementations (those not derived from the Reference Implementation), licensing and open source, ensuring that our new transparency requirements are implemented correctly, compatibility policy and TCKs, the role of individual members, patent policy, and IP flow. The Expert Group for JSR 358, as with all process-change JSRs, consists of all members of the Executive Committees. Even though the JSR has just been filed we started discussions on the various topics several months ago (see the EC's meeting minutes for details) and our EC members - including the new members who joined within the last year or two - are actively engaged. Now it's your opportunity to get involved. As required by version 2.8 of our Process (introduced with JSR 348) we will conduct all our business in the open. We have a public java.net project where you can follow and participate in our work. All of our deliberations will be copied to a public Observer mailing list, we'll track our issues on a public Issue Tracker, and all our documents (meeting agendas and minutes, task lists, working drafts) will be published in our Document Archive. We're just getting started, but we do want your input. Please visit us on java.net where you can learn how to participate. Let's get to work...

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  • NVIDIA Additional Drivers Empty - maximum resolution 640x480 - Driver disappears

    - by Hannibal
    EDIT: Optimus card. For resolution please read this thread: "You do not appear to be using the nvidia x server"(screenshot included) And this: Ubuntu 11.10 problem with Nvidia Thanks! I know, I know yet another NVIDIA question. So I did all the research. I uninstalled and installed nvidia-settings and drivers and nvidia-current from PPE repositories which are the most updated ones. I executed nvidia-xconfig. I have two major problems. One: Additional Drivers setting is empty! It doesn't contain any driver although one is installed. I have executed apt-get update too. But still the list is empty. Two: If I execute nvidia-xconfig it will properly configure an xorg.conf file. I restart but the maximum resolution I got is 640x480. I tried the xrandr but I can't add any resolution to display LVDS1. Some weird error occurs. So I can't add a proprietary driver and I can't boot in with the xorg file created by Nvidia... What can I do? With some work ( unistall nvidia-current and install libgl1-mesa-glx I was able to activate some kind of usage of my card because the resolution got better... and I added bumbelbee to because I have multiple video cards... ) but still the list is empty. I don't know what to do at this point??!!! Also: this is the most important part. When I first installed my ubuntu yesterday 11.10 one I saw the driver!! The driver was there... And then I ofc updated every package from internet.. And after that it was gone. And I can't bring it back. So there must be something wrong with one of the updates. But which???? Thanks for any extra info you can provide! I'm really desperate to solve this issue.

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  • Using extension methods to decrease the surface area of a C# interface

    - by brian_ritchie
    An interface defines a contract to be implemented by one or more classes.  One of the keys to a well-designed interface is defining a very specific range of functionality. The profile of the interface should be limited to a single purpose & should have the minimum methods required to implement this functionality.  Keeping the interface tight will keep those implementing the interface from getting lazy & not implementing it properly.  I've seen too many overly broad interfaces that aren't fully implemented by developers.  Instead, they just throw a NotImplementedException for the method they didn't implement. One way to help with this issue, is by using extension methods to move overloaded method definitions outside of the interface. Consider the following example: .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: Consolas, "Courier New", Courier, Monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } 1: public interface IFileTransfer 2: { 3: void SendFile(Stream stream, Uri destination); 4: } 5:   6: public static class IFileTransferExtension 7: { 8: public static void SendFile(this IFileTransfer transfer, 9: string Filename, Uri destination) 10: { 11: using (var fs = File.OpenRead(Filename)) 12: { 13: transfer.SendFile(fs, destination); 14: } 15: } 16: } 17:   18: public static class TestIFileTransfer 19: { 20: static void Main() 21: { 22: IFileTransfer transfer = new FTPFileTransfer("user", "pass"); 23: transfer.SendFile(filename, new Uri("ftp://ftp.test.com")); 24: } 25: } In this example, you may have a number of overloads that uses different mechanisms for specifying the source file. The great part is, you don't need to implement these methods on each of your derived classes.  This gives you a better interface and better code reuse.

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  • URL slugs: ideal length, and the real SEO effects of these slugs

    - by tattvamasi
    this question is addressed widely on SO and outside it, but for some reason, instead of taking it as a good load of great advice, all this information is confusing me. ** Problem ** I already had, on one of my sites, "prettified" urls. I had taken out the query strings, rewritten the URLS, and the link was short enough for me, but had a problem: the ID of the item or post in the URL isn't good for users. One of the users asked is there's a way to get rid of numbers, and I thought it was better for users to just see a clue of the page content in the URL. ** Solution ** With this in mind, I am trying with a section of the site.Armed with 301 redirects, some parsing work, and a lot of patience, I have added the URL slugs to some blog entries, and the slug of the URL reports the title of the article (something close to http://example.com/my-news/terribly-boring-and-long-url-that-replaces-the-number-I-liked-so-much/ ** Problems after Solution ** The problem, as I see it, is that now the URL of those blog articles is very descriptive for sure, but it is also impossible to remember. So, this brings me to the same issue I had with my previous problem: if numbers say nothing and can't be remembered, what's the use of these slugs? I prefer to see http://example.com/my-news/1/ than http://example.com/my-news/terribly-boring-and-long-url-that-replaces-the-number-I-liked-so-much/ To avoid forcing my user to memorize my URLS, I have added a script that finds the closest match to the URL you type, and redirects there. This is something I like, because the page now acts as a sort of little search engine, and users can play with the URLS to find articles. ** Open questions ** I still have some open questions, and don't seem to be able to find an answer, because answers tend to contradict one another. 1) How many characters should an URL ideally be long? I've read the magic number 115 and am sticking to that, but am not sure. 2) Is this really good for SEO? One of those blog articles I have redirected, with ID number in the URL and all, ranked second on Google. I've just found this question, and the answer seems to be consistent with what I think URL slug and SEO - structure (but see this other question with the opposite opinion) 3) To make a question with a specific example, would this URL risk to be penalized? Is it acceptable? Is it too long? StackOverflow seems to have comparably long URLs, but I'm not sure it's a winning strategy in my case. I just wanted to facilitate my users without running into Google's algorithms.

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  • Registering domain during Christmas holidays

    - by arkascha
    One of the domain names I tried to register previously has been blocked by a domain grabber two days prior to my own attempt. That was about 1 year ago. The attempt to buy the domain from that person failed due to a totally exaggerated price. So I dropped the issue and watched the domain (offered at sedo.com). As expected there were no more offers, the domain was not sold. Now I learn from the whois database that the registration of that domain name ends on 25 Dec 2012 (Christmas holiday). This raises two questions for me, I fail to find reliable answers on the internet. So maybe someone experienced here can drop a statement or a hint: Is it reasonable that the domain name in question really will be free again when that date mentioned in the whois database up to when the domain is registered has passed? I certainly know that the registration can be prolonged, that is not what I mean. I expect (hope) that that domain grabber does not extend the registration, since it costs money and effort and he failed to sell the domain. Provided this is the case and the domain registration is not prolonged, is that date mentioned reliable? Or might it just be some 'default' date? I would like to try to register that domain name as soon as it is unregistered. Since that domain grabber registered that domain only two days before my own registration attempt I would like to prevent such annoying interference next time. So I ask myself: is it possible to register a domain name on a holiday? I mean not to send an email to my provider to do so on that day or before, but to actually have to process taking place as not to wait for 1-2 days after the unregistration? My own provider which I am very happy with does not offer such service on a holiday (which is perfectly understandable). They are 'still checking' if they can offer something automatic. I researched and did not find an answer to the question if that is possible at all. Is an automatic registration attempt on a holiday possible? Where can I do that? Is that reliable?

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  • Operation times out trying to SSH outside LAN i.e. from internet to LAN no connection is established

    - by Pelle L
    I run Ubuntu 12.04 and have no success connecting with SSH from "Internet". The router is a TL-MR3420 which is set up to forward requests to one of the NIC's on ubuntu machine (which has in total 3 NICs). I can SSH from a client on the "local" network/LAN. The forward mechanism in the router seems to work. If I stop SSH service on the Ubuntu machine and instead start one on the windows machine - it works like a charm. I do not use the Std port 22 but that shouldn't be an issue as far as I understand - sine it works on the same port on the win machine. Since my public IS isn't static I use a dynDNS service but as said earlier the same setup works from the win machine. The router is located on 192.168.0.1 The Ubuntu NICs has the following IP: eth2 192.168.0.100 , eth1 192.168.0.101 , eth0 192.168.0.102 and I have forwarded the "outside" request to 192.168.0.100 In regards for firewall settings on the Ubuntu machine I have disabled the ufw and the command ufw status give status: inactive. I don't now it this is relevant information but teh command iptables --list give: Chain INPUT (policy ACCEPT) target prot opt source destination Chain FORWARD (policy ACCEPT) target prot opt source destination Chain OUTPUT (policy ACCEPT) target prot opt source destination I have tried to catch traffic with help of wireshark (a tool I'm not too used to use) and it seems as a few (3?) "requests" actually reaches the NIC but ... nothing happens. The syslog does not show any entries during these attempts. Perhaps it could be some routing issues but I have reached my level of competence and are stuck ... all help and support to get this sorted out is much appreciated. I'm new to Linux so please do not assume I have a configuration that is correct - but as I wrote earlier - if the client that initiate SSH is on the LAN it all works. PS:I have also tried to get VPN (PPP) working from Internet with no success - once again VPN works on the windows machine ... so my best guess is that this is related to how the ubuntu machine handles (IP) traffic and not the TL-MR3420 router or other network issues.

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  • How do I prevent ISPs from killing downloads of files in mid-transfer?

    - by Gorchestopher H
    I run a small website with a few users, low traffic, mostly to share personal mp3 files with a small community. Depending on their ISP, my users can't always download or stream larger files. By larger I mean larger than 1MB. Essentially the host either stops sending, or the client stops receiving. One of the links along the connection chain simply ends its connection before the transfer completes Trace-route shows no connection issues. There are no connection issues with short transfers that don't take more than a few seconds. It's these 10 second transfers that just end up ending. Just doing a straight download with a direct link can yield this error if you have the wrong ISP. Strangely enough, this is most common with users with ISPs who are essentially independent providers that buy service via a fiber link. Unfortunately these providers aren't very knowledgeable, are unable to do any testing, and insist it's a problem with the host. I have gotten my host to transfer my site to different servers of their, to the same effect. Nearly identical sites (affiliate sites actually) experience no such issue. What can I be doing to further troubleshoot this matter? How can I prove that someone is dropping the ball, and identify who that party is? Can I do a 5Mb traceroute? EDIT Maybe I can clear up some misconceptions with my question: The files are not very large. They are simply over 2Mb. The users do not have "slow" connections, they are at least 5mbps. This "time out" happens very quickly, in the realm of 5 seconds, so I don't know if it's a timeout or not. The user often gets 1 or 2Mb in this chunk of time. I have tried streaming with a flash player. I have tried saving the target. Forcing the download. I have tried allowing the browser to stream the file. I have tried different browsers (FF, IE, Chrome). Users are able to download identical files when on different hosts.

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  • Multi-threaded JOGL Problem

    - by moeabdol
    I'm writing a simple OpenGL application in Java that implements the Monte Carlo method for estimating the value of PI. The method is pretty easy. Simply, you draw a circle inside a unit square and then plot random points over the scene. Now, for each point that is inside the circle you increment the counter for in points. After determining for all the random points wither they are inside the circle or not you divide the number of in points over the total number of points you have plotted all multiplied by 4 to get an estimation of PI. It goes something like this PI = (inPoints / totalPoints) * 4. This is because mathematically the ratio of a circle's area to a square's area is PI/4, so when we multiply it by 4 we get PI. My problem doesn't lie in the algorithm itself; however, I'm having problems trying to plot the points as they are being generated instead of just plotting everything at once when the program finishes executing. I want to give the application a sense of real-time display where the user would see the points as they are being plotted. I'm a beginner at OpenGL and I'm pretty sure there is a multi-threading feature built into it. Non the less, I tried to manually create my own thread. Each worker thread plots one point at a time. Following is the psudo-code: /* this part of the code exists in display() method in MyCanvas.java which extends GLCanvas and implements GLEventListener */ // main loop for(int i = 0; i < number_of_points; i++){ RandomGenerator random = new RandomGenerator(); float x = random.nextFloat(); float y = random.nextFloat(); Thread pointThread = new Thread(new PointThread(x, y)); } gl.glFlush(); /* this part of the code exists in run() method in PointThread.java which implements Runnable */ void run(){ try{ gl.glPushMatrix(); gl.glBegin(GL2.GL_POINTS); if(pointIsIn) gl.glColor3f(1.0f, 0.0f, 0.0f); // red point else gl.glColor3f(0.0f, 0.0f, 1.0f); // blue point gl.glVertex3f(x, y, 0.0f); // coordinates gl.glEnd(); gl.glPopMatrix(); }catch(Exception e){ } } I'm not sure if my approach to solving this issue is correct. I hope you guys can help me out. Thanks.

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