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• Firmware/driver for Broadcom wifi card, PowerBook G4 running Ubuntu 12.04 [duplicate]

  - by user107831

  This question already has an answer here: How to Install Broadcom Wireless Drivers 40 answers This is my first time working with Ubuntu (or Linux), so please be patient. I am running Ubuntu 12.04-powerpc "Precise Pangolin" on a Mac PowerBook G4 with 1.67GHz processor. The firmware/driver for the wifi card is missing. For reasons not worth explaining, I cannot physically plug the computer into the network. I have another computer, a MacBook Pro running OSX, from which I can download files and port them by USB thumb drive. The wifi card in the PowerBook G4 is by Broadcom. The chip is BCM4306, rev. 3. The PCI number is 14e4:4302. I have downloaded b43-fwcutter_015-14_powerpc.deb and dropped it into the Home folder on the Ubuntu machine. However, it will not install. When I double-click, it opens with Ubuntu SoftwareCenter, but the "Install" button is inactive: I can't click it. There's a message beside the inactive button saying, "An older version of 'b43-fwcutter' is available in your normal software channels. Only install this file if you trust the origin." If I "right-click" the .deb file and open with Archive Manager, it shows me the "DEBIAN" and "usr" folders, but I'm unsure what to do from there...and fairly certain this is not the right way to do things. Maybe I have the wrong version of b43-fwcutter for my machine/version of Ubuntu? The documentation for this problem is a mess. It refers to all sorts of out-of-date Ubuntu versions and to an array of different "cutter" and firmware files. Maybe I'd be able to figure this out if I were a more seasoned Ubuntu user, but I have no idea why Sofware Center won't let me do the install. I would be VERY grateful for an explanation of how to get the wifi card working on this machine again. Thank you!

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• Automated backups for Windows Azure SQL Database

  - by Greg Low

  One of the questions that I've often been asked is about how you can backup databases in Windows Azure SQL Database. What we have had access to was the ability to export a database to a BACPAC. A BACPAC is basically just a zip file that contains a bunch of metadata along with a set of bcp files for each of the tables in the database. Each table in the database is exported one after the other, so this does not produce a transactionally-consistent backup at a specific point in time. To get a transactionally-consistent copy, you need a database that isn't in use.The easiest way to get a database that isn't in use is to use CREATE DATABASE AS COPY OF. This creates a new database as a transactionally-consistent copy of the database that you are copying. You can then use the export options to get a consistent BACPAC created.Previously, I've had to automate this process by myself. Given there was also no SQL Agent in Azure, I used a job in my on-premises SQL Server to do this, using a linked server configuration.Now there's a much simpler way. Windows Azure SQL Database now supports an automated export function. On the Configuration tab for the database, you need to enable the Automated Export function. You can configure how often the operation is performed for you, and which storage account will be used for the backups.It's important to consider the cost impacts of this as well. You are charged for how ever many databases are on your server on a given day. So if you enable a daily backup, you will double your database costs. Do not schedule the backups just before midnight UTC, as that could cause you to have three databases each day instead of one.This is a much needed addition to the capabilities. Scott Guthrie also posted about some other notable changes today, including a preview of a new premium offering for SQL Database. In addition to the Web and Business editions, there will now be a Premium edition that has reserved (rather than shared) resources. You can read about it all in Scott's post here: http://weblogs.asp.net/scottgu/archive/2013/07/23/windows-azure-july-updates-sql-database-traffic-manager-autoscale-virtual-machines.aspx

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• C++ and system exceptions

  - by Abyx

  Why standard C++ doesn't respect system (foreign or hardware) exceptions? E.g. when null pointer dereference occurs, stack isn't unwound, destructors aren't called, and RAII doesn't work. The common advice is "to use system API". But on certain systems, specifically Win32, this doesn't work. To enable stack unwinding for this C++ code // class Foo; // void bar(const Foo&); bar(Foo(1, 2)); one should generate something like this C code Foo tempFoo; Foo_ctor(&tempFoo); __try { bar(&tempFoo); } __finally { Foo_dtor(&tempFoo); } Foo_dtor(&tempFoo); and it's impossible to implement this as C++ library. Upd: Standard doesn't forbid handling system exceptions. But it seems that popular compilers like g++ doesn't respect system exceptions on any platforms just because standard doesn't require this. The only thing that I want - is to use RAII to make code readable and program reliable. I don't want to put hand-crafted try\finally around every call to unknown code. For example in this reusable code, AbstractA::foo is such unknown code: void func(AbstractA* a, AbstractB* b) { TempFile file; a->foo(b, file); } Maybe one will pass to func such implementation of AbstractA, which every Friday will not check if b is NULL, so access violation will happen, application will terminate and temporary file will not be deleted. How many months uses will suffer because of this issue, until either author of func or author of AbstractA will do something with it? Related: Is `catch(...) { throw; }` a bad practice?

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• Is there an excuse for short variable names?

  - by KChaloux

  This has become a large frustration with the codebase I'm currently working in; many of our variable names are short and undescriptive. I'm the only developer left on the project, and there isn't documentation as to what most of them do, so I have to spend extra time tracking down what they represent. For example, I was reading over some code that updates the definition of an optical surface. The variables set at the start were as follows: double dR, dCV, dK, dDin, dDout, dRin, dRout dR = Convert.ToDouble(_tblAsphere.Rows[0].ItemArray.GetValue(1)); dCV = convert.ToDouble(_tblAsphere.Rows[1].ItemArray.GetValue(1)); ... and so on Maybe it's just me, but it told me essentially nothing about what they represented, which made understanding the code further down difficult. All I knew was that it was a variable parsed out specific row from a specific table, somewhere. After some searching, I found out what they meant: dR = radius dCV = curvature dK = conic constant dDin = inner aperture dDout = outer aperture dRin = inner radius dRout = outer radius I renamed them to essentially what I have up there. It lengthens some lines, but I feel like that's a fair trade off. This kind of naming scheme is used throughout a lot of the code however. I'm not sure if it's an artifact from developers who learned by working with older systems, or if there's a deeper reason behind it. Is there a good reason to name variables this way, or am I justified in updating them to more descriptive names as I come across them?

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• Object pools for efficient resource management

  - by GameDevEnthusiast

  How can I avoid using default new() to create each object? My previous demo had very unpleasant framerate hiccups during dynamic memory allocations (usually, when arrays are resized), and creating lots of small objects which often contain one pointer to some DirectX resource seems like an awful lot of waste. I'm thinking about: Creating a master look-up table to refer to objects by handles (for safety & ease of serialization), much like EntityList in source engine Creating a templated object pool, which will store items contiguously (more cache-friendly, fast iteration, etc.) and the stored elements will be accessed (by external systems) via the global lookup table. The object pool will use the swap-with-last trick for fast removal (it will invoke the object's ~destructor first) and will update the corresponding indices in the global table accordingly (when growing/shrinking/moving elements). The elements will be copied via plain memcpy(). Is it a good idea? Will it be safe to store objects of non-POD types (e.g. pointers, vtable) in such containers? Related post: Dynamic Memory Allocation and Memory Management

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• Loadbalancing Questions

  - by Van Holtz

  I have been learning networking for about 4 months. Wrote a single standalone Multiplayer server and succeeded with authoritative approach. Now I want to extend it by splitting the single server into clusters to allow even more players to log in to avoid latency issues. Now I have protyped the Loadbalancing server and its running pretty good so far. This is my architecture, I have a master server which acts as a proxy, every sub servers(chat, login, game) connect to the master server as well as all the clients. when a client connects, Client Request: Send Request - MS(Master) - Decides which SS(SubServer) to forward to - Forwards Request to SS - SS - Analyze Message - Send Response to MS - Decides which Client to forward to - Forwards Response to Client Well, it looks like its going through lots of stages. it takes double the time to process the message than a single server approach. i feel like my model isnt the best or i may be wrong. is there any better model or the one they use in professional games? I still want a Master-SubServer approach. I just want to clarify that I'm going in the right direction before writing all my codes. Thanks for any answer :)

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• Perfomance of 8 bit operations on 64 bit architechture

  - by wobbily_col

  I am usually a Python / Database programmer, and I am considering using C for a problem. I have a set of sequences, 8 characters long with 4 possible characters. My problem involves combining sets of these sequences and filtering which sets match a criteria. The combinations of 5 run into billions of rows and takes around an hour to run. So I can represent each sequence as 2 bytes. If I am working on a 64 bit architechture will I gain any advantage by keeping these data structures as 2 bytes when I generate the combinations, or will I be as well storing them as 8 bytes / double ? (64 bit = 8 x 8) If I am on a 64 bit architecture, all registers will be 64 bit, so in terms of operations that shouldn´t be any faster (please correct me if I am wrong). Will I gain anything from the smaller storage requirements - can I fit more combinations in memory, or will they all take up 64 bits anyway? And finally, am I likley to gain anything coding in C. I have a first version, which stores the sequence as a small int in a MySQL database. It then self joins the tabe to itself a number of times in order to generate all the possible combinations. The performance is acceptable, depending on how many combinations are generated. I assume the database must involve some overhead.

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• How to configure Logitech Marble trackball

  - by user27189

  You can configure it using xinput. I tested this in 11.10 and it works very nicely. This selection is from "Ubuntuwiki" Avoid using Hal for this release because it has known issues. Put the following into terminal, using gedit: Edit $HOME/bin/trackball.sh using this command: gedit $HOME/bin/trackball.sh Then paste this into the file: #!/bin/bash dev="Logitech USB Trackball" we="Evdev Wheel Emulation" xinput set-int-prop "$dev" "$we Button" 8 8 xinput set-int-prop "$dev" "$we" 8 1 # xinput set-int-prop "$dev" "$we" 8 1 # xinput set-int-prop "$dev" "$we Button" 8 9 # xinput set-int-prop "$dev" "$we X Axis" 8 6 7 # xinput set-int-prop "$dev" "$we Y Axis" 8 4 5 # xinput set-int-prop "$dev" "Drag Lock Buttons" 8 8 Make sure trackball.sh begins with #!/bin/bash. Make the script executable by running this: chmod +x $HOME/bin/trackball.sh` Add the following lines to $HOME/.bashrc, using gedit $HOME/.bashrc and put this in the file even if it is empty: xmodmap $HOME/.Xmodmap > /dev/null 2>&1 $HOME/bin/trackball.sh Edit $HOME/.Xmodmap using: gedit $HOME/.Xmodmap pointer = 1 8 3 4 5 6 7 9 Log out and back in and viola!

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• PHP Battle System for RPG game

  - by Jay

  I posted this a while ago on stackoverflow, they thought it would be better place here, I agree. Essentially I know what I want to accomplish, and I have something to the effect of what I want but I am not satisfied with it. Here's the problem. Each user has some states: STR (how hard they hit), DEF (dodging/blocking attacks), SPD (when they can strike), and STAMINA (basically their endurance in game, if this runs out they can no longer fight and lose) What I need is something like this: UserA Stats: STR: 1,000 DEF: 2500 SPD: 2000 (HP: 1000/1000) UserB Stats: STR: 1,500 DEF: 500 SPD: 4000 (HP: 1000/1000) Because the second user has double the speed, he lands twice the amount of hits on the first user, before he gets hit. Because he has less strength than the first users defence, he will do no, to little damage. This is how the battle would theoretically go: UserB strikes UserA for 0 damage UserB strikes UserA for 0 damage UserA strikes UserB for 500 damage UserB strikes UserA for 0 damage UserB strikes UserA for 0 damage UserA strikes UserB for 500 damage, and sends him to the hospital! I was using this code, which is buggy, and not efficient, I just need a better way to do this: http://pastebin.com/15LiQQuJ Oh, and if anyone has some good ideas on how to improve the concept that would be cool too! It's not that elaborate so I'll be thinking of all sorts of things to make it more dynamic. Thanks.

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• Are web application usability issues equal to website usability issues?

  - by Kor

  I've been reading two books about web usability issues and tests (Rocket Surgery Made Easy¹ and Prioritizing Web Usability²) and they claim some strategies and typical problems about website usability and how to lead them. However, I want to do a web application, and I think I lost track of what I am trying to solve. These two books claim to work with raw websites (e-commerce, business sites, even intranet), but I'm not sure if everything about web usability is applicable to web application usability. They sure talk about always having available (and usable) the Back button, to focus on short information rather than big amounts of text, etc., but they could be inaccurate in deeper problems that may be easier (or just skippable) in regular websites. Has anybody some experience in this field and could tell me if both web applications and websites share their usability issues? Thanks in advance Edit: Quoting Wikipedia, a website is a collection of related web pages containing images, videos or other digital assets, and a web application is an application that is accessed over a network such as the Internet or an intranet. To sum up, both shows/lets you search/produce information but websites are "simple" in interaction and keep the classics of websites (one-click actions) and the other one is closer to desktop applications in the meaning of their uses and ways of interaction (double click, modal windows, asynchronous calls [to keep you in the same "environment" instead of reloading it] etc.). I don't know if this clarifies the difference. Edit 2: Quoting @Victor and myself, a website is anything running in your browser, but a web application is somewhat running in your browser that could be running in your desktop, with similar behaviors and features. Gmail is a web application that could replace Outlook. GDocs could replace Office. Grooveshark could replace your music player, etc.

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• Burg Custom Icons work only with specific themes

  - by el10780

  I have made a custom icon for burg loader for my Lenovo Recovery Partition.I have made 3 icons : large_qdrive.png (128 X 128 pixels) small_qdrive.png (24 X 24 pixels) grey_qdrive.png (128 x 128 pixels) The .png icons that I created I made them using gimp from a qdrive.ico file that I found in the Lenovo Recovery Partition. I transferred the icons to the /boot/burg/themes/icons folder and I added to the class list of the grey,large,small and the hover files the following lines : -qdrive { image = "$$/large_qdrive.png" } in the large file -qdrive { image = "$$/small_qdrive.png" } in the small file -qdrive { image = "$$/grey_qdrive.png" } in the grey file -qdrive { image = "$$/grey_qdrive.png:$$/large_qdrive.png" } in the hover file I ran sudo update-burg and after that I modified the following line in the burg.cfg file : menuentry "Windows 7 (loader) (on /dev/sda2)" --class windows --class os { to menuentry "Windows 7 (loader) (on /dev/sda2)" --class qdrive --class os { and I also tried to change the title for the Lenovo Recovery Partition,so I tried this as well: menuentry "Lenovo Recovery Partition (on /dev/sda2)" --class qdrive --class os { None of this tries enforced actually burg loader to use the custom icon that I made and I can't figure out why. I have to mention also that there are a few themes that I have installed in burg which actually are able to use the small_qdrive.png icon that I made,but all the others which use either the large_qdrive.png or the grey_qdrive.png weren't able to use the custom icons. I have double checked for typos in all the files that I have created or I modified,so I am pretty sure that I haven't misspelled anything. I have checked also the title of the custom icons that I made and neither of them have a typo. I have looked also if there are any other folder that the themes might use to retrieve the icons,but it seems that all of them except for **Fortune** theme,which I downloaded from OMG!UBUNTU,use the icons folder which is located in /boot/burg/themes/icons I tried to add the custom icons to the icons folder of the theme **Fortune**,but still nothing happened.

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• Procurement Community Live Chat December 13th on Implementing AME with Purchase Orders

  - by LuciaC

  Do you still have questions on setting up the Approval Management Engine (AME) for Purchase Orders after attending the AME Webcast? Or maybe you are new to this topic and need more information?  Don’t miss our Procurement Community Live Chat on December 13th from 7:00 am to 11:00 am EST. Proactive Support and Development will be available to answer questions.You can access the main Oracle Communities page at http://communities.oracle.com (If you are enrolled, the Procurement community will be listed on your left.   If you're not already enrolled in the Procurement community, you can do so by clicking on the link Edit Subscriptions). OR you can use these alternative steps:From "My Oracle Support" as follows:    Log into My Oracle Support.    Click on the 'Community' link at the top of the page.    Click in 'Find a Community' field and enter Procurement.    Double click on Procurement in the list.    Click on the 'Create a Community Post' button and submit your question.Then in the ‘Procurement Featured Discussions’ section, drill down on the following thread and post your question.  We are looking forward to hearing from you!

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• How to Pin Any File to the Start Screen in Windows 8

  - by Taylor Gibb

  By default Windows 8 only allows you to pin a few file types to the Start Screen. Read on to find out how you can change that by editing the registry. How to Pin Any File to the Start Screen in Windows 8 Press the Win + R keyboard combination to open a run box, then type notepad and press enter. When notepad opens, paste the following into the new document: Windows Registry Editor Version 5.00 [HKEY_CLASSES_ROOT\*\shell\pintostartscreen] “MUIVerb”=”@shell32.dll,-51201″ “NeverDefault”=”" “Description”=”@shell32.dll,-51202″ “MultiSelectModel”=”Single” [HKEY_CLASSES_ROOT\*\shell\pintostartscreen\command] “DelegateExecute”=”{470C0EBD-5D73-4d58-9CED-E91E22E23282}” Then click on the File menu item and select save as… Before you go any further, change the Save as type to All Files. Then give your file a name ending in .reg and click Save. PinToStartHack.reg To use the hack, just double click on the .reg file you just created. When you are prompted about whether you want to continue, click Yes. Now you can pin any file to the Start Screen. Undo the Change If you ever wish to undo the change, press the Win + R keyboard combination and type regedit, then press enter. Then drill down into: HKEY_CLASSES_ROOT\*\shell\ Finally delete the pintostartscreen key. That’s all there is to it. How to Factory Reset Your Android Phone or Tablet When It Won’t Boot Our Geek Trivia App for Windows 8 is Now Available Everywhere How To Boot Your Android Phone or Tablet Into Safe Mode

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• Is there an excuse for excessively short variable names?

  - by KChaloux

  This has become a large frustration with the codebase I'm currently working in; many of our variable names are short and undescriptive. I'm the only developer left on the project, and there isn't documentation as to what most of them do, so I have to spend extra time tracking down what they represent. For example, I was reading over some code that updates the definition of an optical surface. The variables set at the start were as follows: double dR, dCV, dK, dDin, dDout, dRin, dRout dR = Convert.ToDouble(_tblAsphere.Rows[0].ItemArray.GetValue(1)); dCV = convert.ToDouble(_tblAsphere.Rows[1].ItemArray.GetValue(1)); ... and so on Maybe it's just me, but it told me essentially nothing about what they represented, which made understanding the code further down difficult. All I knew was that it was a variable parsed out specific row from a specific table, somewhere. After some searching, I found out what they meant: dR = radius dCV = curvature dK = conic constant dDin = inner aperture dDout = outer aperture dRin = inner radius dRout = outer radius I renamed them to essentially what I have up there. It lengthens some lines, but I feel like that's a fair trade off. This kind of naming scheme is used throughout a lot of the code however. I'm not sure if it's an artifact from developers who learned by working with older systems, or if there's a deeper reason behind it. Is there a good reason to name variables this way, or am I justified in updating them to more descriptive names as I come across them?

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• The tale of how the PowerShell CmdLets got installed with Azure SDK 1.4

  - by Enrique Lima

  I installed the Azure SDK 1.4 while rebuilding my laptop and ran the installation for the Windows Azure Service Management PowerShell CmdLets. Kicked off the installation script for the WASM PowerShell CmdLets by locating the path to which WASM PowerShell CmdLets was deployed to. Double clicked the startHere command. It will then open the WASM installation dialog. Click Next. Click Next. Notice the red x next to the Azure SDK 1.3, the problem is I have SDK 1.4 Here is the workaround, I go back to the location of the deployed WASM sources. Go into the setup path, then scripts>dependencies>check. Now, locate the CheckAzureSDK.ps1 file, and right-click, then edit. This is the content in the ps1 file, it check for the specific version of the Azure SDK, in this case, it is looking for version 1.3.11133.0038. We need for it to check for version 1.4.20227.1419 Now, save your ps1 file, go back to the open WASM install dialog, and click rescan. This time it should pass, then click next. A Command prompt window will appear, click any key. This completes the installation, click Close.

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• A short but intense GCC Gathering in London

  - by user817571

  About one week ago I joined in London many long time GCC friends and acquaintances for a gathering organized by Google (in particular I guess should be thanked Diego and Ian). Only a weekend, and I wasn't able to attend on Sunday morning, but a very good occasion to raise some issues in a very relaxed way, in particular those at the border between areas of competence, which are the most difficult to discuss during the normal work days. If you are interested in a general overview and some notes this is a good link: http://gcc.gnu.org/wiki/GCCGathering2011 As you may easily guess, the third topic is mine, which I managed to have up quite early on Friday morning thanks to the votes of some good friends like Dodji (the ordering of the topics resulted from democratic voting on Friday evening!). I learned a lot from the discussion: for example that certainly the new C++11 'final' should be exploited largely in the c++ front-end; the various reasons why devirtualization can be quite trick (but I'm really confident that Martin and Honza are going to make a good progress also basing on a set of short testcases which I promised to collect); that, as explained by Ian, the gold linker already implements the nice --icf (Identical Code Folding) facility, which some friends of mine are definitely going to like (however, see: http://sourceware.org/bugzilla/show_bug.cgi?id=12919). I also enjoyed the observations made by Lawrence, where he remarked that in C+11 we are going to see more pointer iterations implicitly produced by the new range-based for-loop and we really want to make sure the loop optimizers are able to deal with those as well as loops explicitly using a counter. All in all, I really hope we are going to do it again!

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• Floating point undesireable in highly critical code?

  - by Kirt Undercoffer

  Question 11 in the Software Quality section of "IEEE Computer Society Real-World Software Engineering Problems", Naveda, Seidman, lists fp computation as undesirable because "the accuracy of the computations cannot be guaranteed". This is in the context of computing acceleration for an emergency braking system for a high speed train. This thinking seems to be invoking possible errors in small differences between measurements of a moving object but small differences at slow speeds aren't a problem (or shouldn't be), small differences between two measurements at high speed are irrelevant - can there be a problem with small roundoff errors during deceleration for an emergency braking system? This problem has been observed with airplane braking systems resulting in hydroplaning but could this actually happen in the context of a high speed train? The concern about fp errors seems to not be well-founded in this context. Any insight? The fp is used for acceleration so perhaps the concern is inching over a speed limit? But fp should be just fine if they use a double in whatever implementation language. The actual problem in the text states: During the inspection of the code for the emergency braking system of a new high speed train (a highly critical, real-time application), the review team identifies several characteristics of the code. Which of these characteristics are generally viewed as undesirable? The code contains three recursive functions (well that one is obvious). The computation of acceleration uses floating point arithmetic. All other computations use integer arithmetic. The code contains one linked list that uses dynamic memory allocation (second obvious problem). All inputs are checked to determine that they are within expected bounds before they are used.

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• Sources of NetBeans Gradle Plugin

  - by Geertjan

  Here is where you can find the sources of the latest and greatest NetBeans Gradle plugin: http://java.net/projects/nb-api-samples/sources/api-samples/show/versions/7.1/misc/GradleSupport To use it, download the sources above, open the sources into the IDE (which must be 7.1.1 or above), then you'll have a NetBeans module. Right-click it to run the module into a new instance of NetBeans IDE. In the Options window's Miscellaneous tab, there's a Gradle subtab for setting the Gradle location. In the New File dialog, in the Other category, you'll find a template named "Empty Gradle file". Make sure to name it "build" and to put it in the root directory of the application (by leaving the Folder field empty, you're specifying it should be created in the root directory). You'll then be able to expand the build.gradle file: Double-click a task to run it. When you open the file, it opens in the Groovy editor, if the Groovy editor is installed. When you make changes in the file, the list of tasks, shown above, is automatically recreated. It's at a really early stage of development and it would be great if developers out there would be interested in adding more features to it.

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• forward motion car physics - gradual slow

  - by spartan2417

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

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• Handling Types for Real and Complex Matrices in a BLAS Wrapper

  - by mga

  I come from a C background and I'm now learning OOP with C++. As an exercise (so please don't just say "this already exists"), I want to implement a wrapper for BLAS that will let the user write matrix algebra in an intuitive way (e.g. similar to MATLAB) e.g.: A = B*C*D.Inverse() + E.Transpose(); My problem is how to go about dealing with real (R) and complex (C) matrices, because of C++'s "curse" of letting you do the same thing in N different ways. I do have a clear idea of what it should look like to the user: s/he should be able to define the two separately, but operations would return a type depending on the types of the operands (R*R = R, C*C = C, R*C = C*R = C). Additionally R can be cast into C and vice versa (just by setting the imaginary parts to 0). I have considered the following options: As a real number is a special case of a complex number, inherit CMatrix from RMatrix. I quickly dismissed this as the two would have to return different types for the same getter function. Inherit RMatrix and CMatrix from Matrix. However, I can't really think of any common code that would go into Matrix (because of the different return types). Templates. Declare Matrix<T> and declare the getter function as T Get(int i, int j), and operator functions as Matrix *(Matrix RHS). Then specialize Matrix<double> and Matrix<complex>, and overload the functions. Then I couldn't really see what I would gain with templates, so why not just define RMatrix and CMatrix separately from each other, and then overload functions as necessary? Although this last option makes sense to me, there's an annoying voice inside my head saying this is not elegant, because the two are clearly related. Perhaps I'm missing an appropriate design pattern? So I guess what I'm looking for is either absolution for doing this, or advice on how to do better.

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• How can I assign actions to all my mouse buttons?

  - by Torben Gundtofte-Bruun

  I have a mouse with lots of buttons, but it's not a mainstream make like Logitech. For Windows, I have a driver that lets me assign actions like close-window (Ctrl+W) or next-tab (Ctrl+Tab), but I don't have a Linux driver. Since Linux is so flexible, I thought perhaps there is a general way to do this, regardless of brand? Update: Based on input from Cyrex, I installed and ran sudo apt-get install btnx which found several but not all mouse buttons. Found: left, right, wheel, wheelclick, thumb fwd, thumb back. Not found: wheel left, wheel right, thumb middle button. Vendor ID is 0x04d9, Model ID is 0xa015. Update 2: In SystemPrefsMouse there's a lightbulb icon for testing double-click speed. Every working button can turn the bulb on&off, but the missing buttons can't. It would seem that Ubuntu isn't aware of these buttons and thus doesn't register their clicks. I guess I need to hunt for a driver, though a mainstream mouse is probably the easier way.

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• what are some good interview questions for a position that consists of reviewing code for security vulnerabilities?

  - by John Smith

  The position is an entry-level position that consists of reading C++ code and identifying lines of code that are vulnerable to buffer overflows, out-of-bounds reads, uncontrolled format strings, and a bunch of other CWE's. We don't expect the average candidate to be knowledgeable in the area of software security nor do we expect him or her to be an expert computer programmer; we just expect them to be able to read the code and correctly identify vulnerabilities. I guess I could ask them the typical interview questions: reverse a string, print a list of prime numbers, etc, but I'm not sure that their ability to write code under pressure (or lack thereof) tells me anything about their ability to read code. Should I instead focus on testing their knowledge of C++? Ask them if they understand what a pointer is and how bitwise operators work? My only concern about asking that kind of question is that I might unfairly weed out people who don't happen to have the knowledge but have the ability to acquire it. After all, it's not like they will be writing a single line of code, and it's not like we are looking only for people who already know C++, since we are willing to train the right candidate. (It is true that I could ask those questions only to those candidates who claim to know C++, but I'd like to give the same "test" to everyone.) Should I just focus on trying to get an idea of their level of intelligence? In other words, should I get them to talk and pay attention to the way they articulate their thoughts, and so on?

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• Why do memory-managed languages retain the `new` keyword?

  - by Channel72

  The new keyword in languages like Java, Javascript, and C# creates a new instance of a class. This syntax seems to have been inherited from C++, where new is used specifically to allocate a new instance of a class on the heap, and return a pointer to the new instance. In C++, this is not the only way to construct an object. You can also construct an object on the stack, without using new - and in fact, this way of constructing objects is much more common in C++. So, coming from a C++ background, the new keyword in languages like Java, Javascript, and C# seemed natural and obvious to me. Then I started to learn Python, which doesn't have the new keyword. In Python, an instance is constructed simply by calling the constructor, like: f = Foo() At first, this seemed a bit off to me, until it occurred to me that there's no reason for Python to have new, because everything is an object so there's no need to disambiguate between various constructor syntaxes. But then I thought - what's really the point of new in Java? Why should we say Object o = new Object();? Why not just Object o = Object();? In C++ there's definitely a need for new, since we need to distinguish between allocating on the heap and allocating on the stack, but in Java all objects are constructed on the heap, so why even have the new keyword? The same question could be asked for Javascript. In C#, which I'm much less familiar with, I think new may have some purpose in terms of distinguishing between object types and value types, but I'm not sure. Regardless, it seems to me that many languages which came after C++ simply "inherited" the new keyword - without really needing it. It's almost like a vestigial keyword. We don't seem to need it for any reason, and yet it's there. Question: Am I correct about this? Or is there some compelling reason that new needs to be in C++-inspired memory-managed languages like Java, Javascript and C#?

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• When module calling gets ugly

  - by Pete

  Has this ever happened to you? You've got a suite of well designed, single-responsibility modules, covered by unit tests. In any higher-level function you code, you are (95% of the code) simply taking output from one module and passing it as input to the next. Then, you notice this higher-level function has turned into a 100+ line script with multiple responsibilities. Here is the problem. It is difficult (impossible) to test that script. At least, it seems so. Do you agree? In my current project, all of the bugs came from this script. Further detail: each script represents a unique solution, or algorithm, formed by using different modules in different ways. Question: how can you remedy this situation? Knee-jerk answer: break the script up into single-responsibility modules. Comment on knee-jerk answer: it already is! Best answer I can come up with so far: create higher-level connector objects which "wire" modules together in particular ways (take output from one module, feed it as input to another module). Thus if our script was: FooInput fooIn = new FooInput(1, 2); FooOutput fooOutput = fooModule(fooIn); Double runtimevalue = getsomething(fooOutput.whatever); BarInput barIn = new BarInput( runtimevalue, fooOutput.someOtherValue); BarOutput barOut = barModule(BarIn); It would become with a connector: FooBarConnectionAlgo fooBarConnector = new fooBarConnector(fooModule, barModule); FooInput fooIn = new FooInput(1, 2); BarOutput barOut = fooBarConnector(fooIn); So the advantage is, besides hiding some code and making things clearer, we can test FooBarConnectionAlgo. I'm sure this situation comes up a lot. What do you do?

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• Architecture a for a central renderer rather than self-rendering

  - by The Communist Duck

  For the architectural side of rendering, there's two main ways: having each object render itself, and having a single renderer which renders everything. I'm currently aiming for the second idea, for the following reasons: The list can be sorted to only use shaders once. Else each object would have to bind the shader, because it's not sure if it's active. The objects could be sorted and grouped. Easier to swap APIs. With a few macro lines, it can be easy to swap between a DirectX renderer and an OpenGL renderer (not a reason for my project, but still a good point) Easier to manage rendering code Of course, if anyone has strong recommendations for the first method, I will listen to them. But I was wondering how make this work. First idea The renderer has a list of pointers to the renderable components of each entity, which register themselves on RenderCompoent creation. However, I'm worrying that this may end up as a lot of extra pointer weight. But I can sort the list of pointers every so often. Second idea The entire list of entities is passed to the renderer each render call. The renderer then sorts the list (each call, or maybe once?) and gets what it wants. That's a lot of passing and/or sorting, however. Other ideas ??? PROFIT Anyone got ideas? Thank you.

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