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• Do I need the 'w' component in my Vector class?

  - by bobobobo

  Assume you're writing matrix code that handles rotation, translation etc for 3d space. Now the transformation matrices have to be 4x4 to fit the translation component in. However, you don't actually need to store a w component in the vector do you? Even in perspective division, you can simply compute and store w outside of the vector, and perspective divide before returning from the method. For example: // post multiply vec2=matrix*vector Vector operator*( const Matrix & a, const Vector& v ) { Vector r ; // do matrix mult r.x = a._11*v.x + a._12*v.y ... real w = a._41*v.x + a._42*v.y ... // perspective divide r /= w ; return r ; } Is there a point in storing w in the Vector class?

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• What are the differences between programming languages? [closed]

  - by Omega

  Once upon a time, I heard from someone the only difference between programming languages is the syntax I wanted to deny it - to say that there are other fundamental aspects that truly set a language apart from others than just syntax. But I couldn't... So, can you? Whenever I search Google for something like "differences between programming languages", the results tend to be debates between two specific languages (I'd like something more general) - however, some of the aspects that people seemed to debate the most were: Object-Oriented Method/Operator overloading (I actually see this rather related to syntax) Garbage-Collection (While it seems like a good difference, for some reason it doesn't seem that "fundamental") What important aspects other than syntax can you think of?

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• Creating a new variable versus assigning an existing one

  - by rwallace

  Which is more common, creating a new variable versus assigning an existing variable (field, array element etc - anything that syntactically uses the assignment operator)? The reason I ask is that I'm designing a new language, and wondering which of these two operations should get the shorter syntax. It's not intended to be a pure functional language, or the question wouldn't arise, so I'd ideally like to count usage across large existing code bases in procedural and object-oriented languages like C, C++ and Java, though as far as I can see there isn't an easy way to do this automatically, and going by memory and eyeball, neither is obviously more common than the other.

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• how can i find my usb2rs232 driver

  - by mefmef

  i have a device that is correctly connected to my PC . but i could not see it in /dev . what does it means? is it because of not installing my drive? $ /dev ls before connecting my device: agpgart mei sda1 tty28 tty59 ttyS30 autofs mem sda2 tty29 tty6 ttyS31 block net sda5 tty3 tty60 ttyS4 bsg network_latency sda6 tty30 tty61 ttyS5 btrfs-control network_throughput serial tty31 tty62 ttyS6 bus null sg0 tty32 tty63 ttyS7 char oldmem shm tty33 tty7 ttyS8 console parport0 snapshot tty34 tty8 ttyS9 core port snd tty35 tty9 ttyUSB0 cpu ppp stderr tty36 ttyprintk uinput cpu_dma_latency psaux stdin tty37 ttyS0 urandom disk ptmx stdout tty38 ttyS1 usbmon0 dri pts tty tty39 ttyS10 usbmon1 ecryptfs ram0 tty0 tty4 ttyS11 usbmon2 fb0 ram1 tty1 tty40 ttyS12 vcs fd ram10 tty10 tty41 ttyS13 vcs1 full ram11 tty11 tty42 ttyS14 vcs2 fuse ram12 tty12 tty43 ttyS15 vcs3 hidraw0 ram13 tty13 tty44 ttyS16 vcs4 hpet ram14 tty14 tty45 ttyS17 vcs5 input ram15 tty15 tty46 ttyS18 vcs6 kmsg ram2 tty16 tty47 ttyS19 vcsa log ram3 tty17 tty48 ttyS2 vcsa1 loop0 ram4 tty18 tty49 ttyS20 vcsa2 loop1 ram5 tty19 tty5 ttyS21 vcsa3 loop2 ram6 tty2 tty50 ttyS22 vcsa4 loop3 ram7 tty20 tty51 ttyS23 vcsa5 loop4 ram8 tty21 tty52 ttyS24 vcsa6 loop5 ram9 tty22 tty53 ttyS25 vga_arbiter loop6 random tty23 tty54 ttyS26 zero loop7 rfkill tty24 tty55 ttyS27 lp0 rtc tty25 tty56 ttyS28 mapper rtc0 tty26 tty57 ttyS29 mcelog sda tty27 tty58 ttyS3 $ /dev ls after connecting my device: agpgart mei sda1 tty28 tty59 ttyS30 autofs mem sda2 tty29 tty6 ttyS31 block net sda5 tty3 tty60 ttyS4 bsg network_latency sda6 tty30 tty61 ttyS5 btrfs-control network_throughput serial tty31 tty62 ttyS6 bus null sg0 tty32 tty63 ttyS7 char oldmem shm tty33 tty7 ttyS8 console parport0 snapshot tty34 tty8 ttyS9 core port snd tty35 tty9 ttyUSB0 cpu ppp stderr tty36 ttyprintk ttyUSB1 cpu_dma_latency psaux stdin tty37 ttyS0 uinput disk ptmx stdout tty38 ttyS1 urandom dri pts tty tty39 ttyS10 usbmon0 ecryptfs ram0 tty0 tty4 ttyS11 usbmon1 fb0 ram1 tty1 tty40 ttyS12 usbmon2 fd ram10 tty10 tty41 ttyS13 vcs full ram11 tty11 tty42 ttyS14 vcs1 fuse ram12 tty12 tty43 ttyS15 vcs2 hidraw0 ram13 tty13 tty44 ttyS16 vcs3 hpet ram14 tty14 tty45 ttyS17 vcs4 input ram15 tty15 tty46 ttyS18 vcs5 kmsg ram2 tty16 tty47 ttyS19 vcs6 log ram3 tty17 tty48 ttyS2 vcsa loop0 ram4 tty18 tty49 ttyS20 vcsa1 loop1 ram5 tty19 tty5 ttyS21 vcsa2 loop2 ram6 tty2 tty50 ttyS22 vcsa3 loop3 ram7 tty20 tty51 ttyS23 vcsa4 loop4 ram8 tty21 tty52 ttyS24 vcsa5 loop5 ram9 tty22 tty53 ttyS25 vcsa6 loop6 random tty23 tty54 ttyS26 vga_arbiter loop7 rfkill tty24 tty55 ttyS27 zero lp0 rtc tty25 tty56 ttyS28 mapper rtc0 tty26 tty57 ttyS29 mcelog sda tty27 tty58 ttyS3

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• Disable log rotation for apache or move file location

  - by vittocia

  I need to change the log retention for apache, currently is seems to be running on the default from logrotate.conf which is weekly. It creates 'access_log.1' 'access_log.2' and so on for each week. The problem is it deletes the last log file every week, 'access_log.5', I need the logs to keep going infinitely instead of the last log being deleted every week. It seems to be running on the default value from logrotate.conf - I don't want to change the default values held in that file, so I assume there is a way to change the retention using the /etc/logrotate.d/httpd file? the contents are as follows: /var/log/httpd/*log { missingok notifempty sharedscripts postrotate /sbin/service httpd reload > /dev/null 2>/dev/null || true endscript } what can I add/change to stop the last log being deleted every week?

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• How to correctly set permisions for all subfolders and files

  - by Saeid87

  I am following the guide to install TinyOS on Ubuntu 12.04 I have done up to step 3, But I am not sure if I have done the step 3 correctly. Because by doing the step 4 I get the permission error : saeid@saeid-Satellite-C660:~$ tos-install-jni /usr/bin/tos-install-jni: 13: [: =: unexpected operator Installing 32-bit Java JNI code in /usr/lib/jvm/java-6-openjdk-i386/jre/lib/i386 ... install: cannot create regular file `/usr/lib/jvm/java-6-openjdk-i386/jre/lib/i386/libgetenv.so': Permission denied Can you please tell me what would be the actual commands for step 3? What I have to replace with following lines?: /opt/tinyos-2.x files: chown -R /opt/tinyos-2.x Change the permissions on any serial (/dev/ttyS), usb (/dev/tts/usb, /dev/ttyUSB), or parallel (/dev/parport) devices you are going to use: chmod 666 /dev/ I mean how would you do those steps in your ubuntu?

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• How do functional languages handle a mocking situation when using Interface based design?

  - by Programmin Tool

  Typically in C# I use dependency injection to help with mocking; public void UserService { public UserService(IUserQuery userQuery, IUserCommunicator userCommunicator, IUserValidator userValidator) { UserQuery = userQuery; UserValidator = userValidator; UserCommunicator = userCommunicator; } ... public UserResponseModel UpdateAUserName(int userId, string userName) { var result = UserValidator.ValidateUserName(userName) if(result.Success) { var user = UserQuery.GetUserById(userId); if(user == null) { throw new ArgumentException(); user.UserName = userName; UserCommunicator.UpdateUser(user); } } ... } ... } public class WhenGettingAUser { public void AndTheUserDoesNotExistThrowAnException() { var userQuery = Substitute.For<IUserQuery>(); userQuery.GetUserById(Arg.Any<int>).Returns(null); var userService = new UserService(userQuery); AssertionExtensions.ShouldThrow<ArgumentException>(() => userService.GetUserById(-121)); } } Now in something like F#: if I don't go down the hybrid path, how would I test workflow situations like above that normally would touch the persistence layer without using Interfaces/Mocks? I realize that every step above would be tested on its own and would be kept as atomic as possible. Problem is that at some point they all have to be called in line, and I'll want to make sure everything is called correctly.

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• The rule of 5 - to use it or not?

  - by VJovic

  The rule of 3 (the rule of 5 in the new c++ standard) states : If you need to explicitly declare either the destructor, copy constructor or copy assignment operator yourself, you probably need to explicitly declare all three of them. But, on the other hand, the Martin's "Clean Code" advises to remove all empty constructors and destructors (page 293, G12:Clutter) : Of what use is a default constructor with no implementation? All it serves to do is clutter up the code with meaningless artifacts. So, how to handle these two opposite opinions? Should empty constructors/destructors really be implemented?

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• T-SQL Tuesday: What kind of Bookmark are you using?

  - by Kalen Delaney

  I’m glad there is no minimum length requirement for T-SQL Tuesday blog posts , because this one will be short. I was in the classroom for almost 11 hours today, and I need to be back tomorrow morning at 7:30. Way long ago, back in SQL 2000 (or was it earlier?) when a query indicated that SQL Server was going to use a nonclustered index to get row pointers, and then look up those rows in the underlying table, the plan just had a very linear look to it. The operator that indicated going from the nonclustered...(read more)

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• Most appropriate diagram for GUI button design?

  - by JustADude

  What is the most appropriate diagram for GUI button design? Specifically, I have numerous buttons that will be changing color based on state information from operator input and input from various subcomponents and sensors. I would like to use UML or some other type of design diagrams to be able to capture the color transition. Some folks have suggested sequence diagrams, but I haven't been able to find any good examples that show how to incorporate this design artifact. I would really like to head in this direction to help developers. Thanks a ton for feedback and insights.

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• DOMDocument programming: a lot of little dilemmas, how to solve them?

  - by Peter Krauss

  I need elegance and performance: how to decide by the "best implementation" for each DOM algorithm that I face. This simple "DOMNodeList grouper" illustrate many little dilemmas: use iterator_to_array or "populate an array", when not all items need to be copied. use clone operator, cloneNode method or import method? use parentNode::method() or documentElement::method? (see here) first removeChild or first replaceChild, no avoids "side effects"? ... My position, today, is only "do an arbitrary choice and follow it in all implementations" (like a "Convention over configuration" principle)... But, there are another considerations? About performance, there are some article showing benchmarks? PS: this is a generic DOM question, any language (PHP, Javascript, Python, etc.) have the problem.

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• File Activation in Windows RT

  - by jdanforth

  The code sample for file activation on MSDN is lacking some code so a simple way to pass the file clicked to your MainPage could be: protected override void OnFileActivated(FileActivatedEventArgs args) {     var page = new Frame();     page.Navigate(typeof(MainPage));     Window.Current.Content = page;       var p = page.Content as MainPage;     if (p != null) p.FileEvent = args;     Window.Current.Activate(); } And in MainPage: public MainPage() {     InitializeComponent();     Loaded += MainPageLoaded; } void MainPageLoaded(object sender, RoutedEventArgs e) {     if (FileEvent != null && FileEvent.Files.Count > 0)     {         //… do something with file     } }

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• Information I need to know as a Java Developer [on hold]

  - by Woy

  I'm a java developer. I'm trying to get more knowledge to become a better programmer. I've listed a number of technologies to learn. Instead of what I've listed, what technologies would you suggest to learn as well for a Junior Java Developer? I realize, there's a lot of things to study. Java: - how a garbage collector works - resource management - network programming - TCP/IP HTTP - transactions, - consistency: interfaces, classes collections, hash codes, algorithms, comp. complexity concurrent programming: synchronizing, semafores steam management metability: thread-safety byte code manipulations, reflections, Aspect-Oriented Programming as base to understand frameworks such as Spring etc. Web stack: servlets, filters, socket programming Libraries: JDK, GWT, Apache Commons, Joda-Time, Dependency Injections: Spring, Nano Tools: IDE: very good knowledge - debugger - profiler - web analyzers: Wireshark, firebugs - unit testing SQL/Databases: Basics SELECTing columns from a table Aggregates Part 1: COUNT, SUM, MAX/MIN Aggregates Part 2: DISTINCT, GROUP BY, HAVING + Intermediate JOINs, ANSI-89 and ANSI-92 syntax + UNION vs UNION ALL x NULL handling: COALESCE & Native NULL handling Subqueries: IN, EXISTS, and inline views Subqueries: Correlated ITH syntax: Subquery Factoring/CTE Views Advanced Topics Functions, Stored Procedures, Packages Pivoting data: CASE & PIVOT syntax Hierarchical Queries Cursors: Implicit and Explicit Triggers Dynamic SQL Materialized Views Query Optimization: Indexes Query Optimization: Explain Plans Query Optimization: Profiling Data Modelling: Normal Forms, 1 through 3 Data Modelling: Primary & Foreign Keys Data Modelling: Table Constraints Data Modelling: Link/Corrollary Tables Full Text Searching XML Isolation Levels Entity Relationship Diagrams (ERDs), Logical and Physical Transactions: COMMIT, ROLLBACK, Error Handling

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• Most common parts of a SELECT SQL query?

  - by jnrbsn

  I'm writing a function that generates a SELECT SQL query. (I'm not looking for a tool that already does this.) My function currently takes the following arguments which correspond to different parts of the SELECT query (the base table name is already known): where order fields joins group limit All of these arguments will be optional so that the function generates something like this by default: SELECT * FROM `table_name` I want to order the arguments so that the most often used parts of a SELECT query are first. That way the average call to the function will use as few of the arguments as possible rather than passing a null value or something like that to skip an argument. For example, if someone wanted to use the 1st and 3rd arguments but not the rest, they might have to pass a null value as the 2nd argument in order to skip it. So, for general purpose use, how should I order the arguments? Edit: To be more precise, out of the query parts I listed above, what is the order from most used to least used? Also, I'm not looking for solutions that allow me to not have to specify the order. Edit #2: The "fields" argument will default to "*" (i.e all fields/columns).

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• Does MS Access update the data on the clipboard from a query when the data in the database changes?

  - by leeand00

  I was just debugging a macro in MS Access, and when it hit the breakpoint ran a query and I copied the data from it to the clipboard. Some of the values were null before stepping to the next step, then I ran the next step which ran a query which changed the data I had on the clipboard. I then pasted the data and the values that were null before had been changed by the query...leading to a rather large WTF on my part when I pasted the data. So my question is, does MSAccess update the data on the clipboard when it changes in the database? That's the only explanation I have for what occurred there.

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• Serial Port ttyUSB0

  - by Alex

  I picked up a USB serial null modem cable, so that I can connect up to a headless linux box. As a quick test, I plugged the device into the usb null modem, and the other end I connected to a windows pc. I opened up a terminal on the windows side, with 115200 8N1. On the linux side I opened minicom with the same params. MY problem is that I can type one way from the pc and see the text on the linux minicom side. If I type on the linux side it doesnt show on the pc side. If I reverse the cable it reverses the process. I bet this is a simple issue but I haven't dealt with serial comms in ages. Thanks

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• From the Coalface - 3 - Work as hard as you can to be as lazy as you can!

  - by TATWORTH

  The saga of the Change Log A recent conversation reminded me of the need for change logs within a database, to record when various change scripts were run. Creating such the required table is simple. A typical table for this consists of: Id - identity Integer primary key ChangeFileName - NVARCHAR(128) to hold the name of the file run. DateAdded - DateTime non-null with default value of getutcdate() Purpose - NVARCHAR(128) Rerunnable - Bit non-null default 0. By good design of the table only two data values normally need to be supplied. Two stored procedures, one for inserting data and one to list in reverse sequence the log complete the database essentials. The complete implementation can be found in the CommonData solution at http://CommonData.CodePlex.Com By including a call the add Change Log stored procedure, each script can log its name and purpose for posterity. The scripts that were applied to say the UAT system and their sequence of application can be readily identified for running on the Live system. Formatting XML XML is often produced as one continous string with no embedded CR/LF. To get it into human readable form, open it in visual studio, swap to another tab and back and click the format document button. The XML will then be nicely formatted!

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• Showing an Action on a TopComponent Node

  - by Geertjan

  Let's say you want to extend the tools in NetBeans IDE, specifically for TopComponents. When the user right-clicks in the Projects window (or Files window or Favorites window) on a Java class that extends TopComponent, a menu item should be available for branding the TopComponent. What "branding" entails is, at this stage, a secondary question. The primary question, from an implementation point of view, is "how do I create an action that is only shown when the user right-clicks on a TopComponent?" Here's the solution, in NetBeans IDE 7.2 (the "lazy" attribute, here set to false, is new in 7.2): import com.sun.source.tree.ClassTree; import com.sun.source.util.TreePathScanner; import java.awt.event.ActionEvent; import java.io.IOException; import javax.lang.model.element.Element; import javax.lang.model.element.TypeElement; import javax.swing.AbstractAction; import javax.swing.Action; import javax.swing.JOptionPane; import org.netbeans.api.java.source.CompilationController; import org.netbeans.api.java.source.CompilationInfo; import org.netbeans.api.java.source.JavaSource; import org.netbeans.api.java.source.JavaSource.Phase; import org.netbeans.api.java.source.Task; import org.openide.awt.ActionID; import org.openide.awt.ActionReference; import org.openide.awt.ActionReferences; import org.openide.awt.ActionRegistration; import org.openide.awt.DynamicMenuContent; import org.openide.loaders.DataObject; import org.openide.util.ContextAwareAction; import org.openide.util.Exceptions; import org.openide.util.Lookup; import org.openide.util.NbBundle.Messages; import org.openide.util.Utilities; @ActionID(     category = "Tools", id = "org.tc.customizer.BrandTopComponentAction") @ActionRegistration(     displayName = "#CTL_BrandTopComponentAction",     lazy = false) @ActionReferences({     @ActionReference(path = "Loaders/text/x-java/Actions", position = 150) }) @Messages("CTL_BrandTopComponentAction=Brand") public final class BrandTopComponentAction extends AbstractAction implements ContextAwareAction {     private final DataObject dobj;     public BrandTopComponentAction() {         this(Utilities.actionsGlobalContext());     }     public BrandTopComponentAction(Lookup context) {         super(Bundle.CTL_BrandTopComponentAction());         this.dobj = context.lookup(DataObject.class);         //Enable the menu item only if we're dealing with a TopComponent         JavaSource javaSource = JavaSource.forFileObject(dobj.getPrimaryFile());         try {             javaSource.runUserActionTask(new ScanForTopComponentTask(this), true);         } catch (IOException ex) {             Exceptions.printStackTrace(ex);         }         //Hide the menu item if it isn't enabled:         putValue(DynamicMenuContent.HIDE_WHEN_DISABLED, true);     }     @Override     public void actionPerformed(ActionEvent ev) {         JOptionPane.showMessageDialog(null, "Hurray, I am a TopComponent!");         //Now add your code for showing a dialog,         //where the dialog will display UI for branding the TopComponent somehow         //and retrieve those branding values         //and then change the TopComponent class accordingly.     }     @Override     public Action createContextAwareInstance(Lookup actionContext) {         return new BrandTopComponentAction(actionContext);     }     private static class ScanForTopComponentTask implements Task<CompilationController> {         private final BrandTopComponentAction action;         private ScanForTopComponentTask(BrandTopComponentAction action) {             this.action = action;         }         @Override         public void run(CompilationController compilationController) throws Exception {             compilationController.toPhase(Phase.ELEMENTS_RESOLVED);             new MemberVisitor(compilationController, action).scan(                     compilationController.getCompilationUnit(), null);         }     }     private static class MemberVisitor extends TreePathScanner<Void, Void> {         private CompilationInfo info;         private final AbstractAction action;         public MemberVisitor(CompilationInfo info, AbstractAction action) {             this.info = info;             this.action = action;         }         @Override         public Void visitClass(ClassTree t, Void v) {             Element el = info.getTrees().getElement(getCurrentPath());             if (el != null) {                 TypeElement te = (TypeElement) el;                 if (te.getSuperclass().toString().equals("org.openide.windows.TopComponent")){                     action.setEnabled(true);                 } else {                     action.setEnabled(false);                 }             }             return null;         }     } } The code above is the result of combining various tutorials found on the NetBeans Platform Learning Trail.

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• Trouble running multiple Firefox versions on OS X Lion

  - by politicus

  I am trying to use two versions of Firefox (11 and 13) on OS X Lion. I don't especially want to run two versions at the same time. I want to be able to run the version 11 when I choose the version 11 via the profile manager. The same for the version 13. Every time, I want to launch the version 11, the launcher launches the version 13... When I select the version 11 via the profile manager, Firefox 13 is launched. I created 2 automators apps (FF11.app and FF13.app) to launch Firefox : /Applications/Firefox11.app/Contents/MacOS/firefox-bin -no-remote -P FF11 & /dev/null & /Applications/Firefox13.app/Contents/MacOS/firefox-bin -no-remote -P FF13 & /dev/null & Any help would be greatly appreciated. Thanks in advance.

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• Enemy collision detection with movie clips

  - by user18080

  I have created multiple movieclips with animations within them. It is an obstacle avoidance game and I cannot seem to be able to get my enemies to contact my playableCharacter. The enemies I have created are each embedded on certain levels of my game. I have created an array, enemiesArray to have each of my enemies placed within it. Here is the code for that: //step 1: make sure array exists if(enemiesArray!=null && enemiesArray.length!=0) { //step 2: check all enemies against villain for(var i:int = 0;i < enemiesArray.length; i++) { //step 3: check for collision if(villain.hitTestObject(enemiesArray[i])) { //step 4: do stuff trace("HIT!"); removeChild(enemiesArray[i]); enemiesArray.splice(i,1); removeChild(villain); villain = null; } } } What I am unsure of is whether or not my enemiesArray is actually holding the movieclips I have suggested. If it was, this code would be tracing back a "HIT" for every time I ran into an enemy and would kill my character. It is not doing that however. I am thinking I have to push my movieclips into my array but I don't know how to do that or where for that matter. Any and all help would be much appreciated.

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• EC2 Amazon Linux AMI MySQL CPU @ 62% When Idle?

  - by Jeff

  I am running MySQL on an Amazon Linux AMI. There is nothing connected to it. There are no connections and no other applications running that use MySQL. It is completely idle, but yet, top is reporting that mysql is using 62% of the CPU? Why is this happening and how do I fix it? Cpu(s): 0.2%us, 0.2%sy, 0.0%ni, 97.8%id, 0.0%wa, 0.0%hi, 0.0%si, 1.7%st Mem: 1738504k total, 390708k used, 1347796k free, 56888k buffers Swap: 917500k total, 0k used, 917500k free, 229804k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 2959 mysql 20 0 466m 39m 5244 S 62.2 2.3 4:00.67 mysqld 1 root 20 0 19252 1504 1212 S 0.0 0.1 0:00.20 init 2 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kthreadd There are no connections... mysql> show processlist; +----+------+-----------+------+---------+------+-------+------------------+ | Id | User | Host | db | Command | Time | State | Info | +----+------+-----------+------+---------+------+-------+------------------+ | 5 | root | localhost | NULL | Query | 0 | NULL | show processlist | +----+------+-----------+------+---------+------+-------+------------------+

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• Sys.WebForms.PageRequestManagerServerErrorException: An entity object cannot be referenced by multiple instances of IEntityChangeTracker [closed]

  - by Mingebag

  `Story: I have a strange error when I try to save something I got this error message An entity object cannot be referenced by multiple instances of IEntityChangeTracker. I really don’t know what that is and why is it appear, it appears only when I try to save something my insert and update is working, only when I try to save something in db from my Telerik grid if (this.annualVacationList != null) { List<AnnualVacation> vacationToSave = this.annualVacationList; IEnumerable<AnnualVacation> existing = paramUser.AnnualVacations; foreach (AnnualVacation toSave in vacationToSave) { AnnualVacation existingItem = existing.Where(x => x.AnnualVacationId == toSave.AnnualVacationId).SingleOrDefault(); if (existingItem == null) { ctx.AddToAnnualVacations(toSave); } else { existingItem.FromDate = toSave.FromDate; existingItem.ToDate = toSave.ToDate; existingItem.WorkingTime = toSave.WorkingTime; existingItem.VacationDays = toSave.VacationDays; } } } ctx.SaveChanges(); } After debugging I have seen that the code brake down in the Project.Name.Designer.cs ..... O.o public void AddToAnnualVacations(AnnualVacation annualVacation) { base.AddObject("AnnualVacations", annualVacation); }

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• How can I use an object pool for optimization in AndEngine?

  - by coder_For_Life22

  I have read up on a tutorial that allows you to reuse sprites that are re-added to the scene such as bullets from a gun or any other objects using an ObjectPool. In my game i have a variation of sprites about 6 all together with different textures. This is how the object pool is set up with its own class extending Java's GenericPool class public class BulletPool extends GenericPool<BulletSprite> { private TextureRegion mTextureRegion; public BulletPool(TextureRegion pTextureRegion) { if (pTextureRegion == null) { // Need to be able to create a Sprite so the Pool needs to have a TextureRegion throw new IllegalArgumentException("The texture region must not be NULL"); } mTextureRegion = pTextureRegion; } /** * Called when a Bullet is required but there isn't one in the pool */ @Override protected BulletSprite onAllocatePoolItem() { return new BulletSprite(mTextureRegion); } /** * Called when a Bullet is sent to the pool */ @Override protected void onHandleRecycleItem(final BulletSprite pBullet) { pBullet.setIgnoreUpdate(true); pBullet.setVisible(false); } /** * Called just before a Bullet is returned to the caller, this is where you write your initialize code * i.e. set location, rotation, etc. */ @Override protected void onHandleObtainItem(final BulletSprite pBullet) { pBullet.reset(); } } As you see here it takes a TextureRegion parameter. The only problem i am facing with this is that i need to have 6 different sprites recycled and reused in the ObjectPool. This ObjectPool is set up to only use one TextureRegion. Any idea's or suggestions on how to do this?

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• Keeping the wireless connected.

  - by casr

  I’m running OpenBSD on a computer which is connected via wireless to the network. It is a well supported NIC and I’ve had no problems with it from a hardware perspective. Unfortunately my wireless access point occasionally loves to forget it’s settings. I then have to help it remember. However, in this intervening time my OpenBSD box drops the connection and then does not automatically reconnect. I have alleviated my problems by running this simple script in the background: #!/bin/sh while [ 1 ] do ping -c1 192.168.1.254 > /dev/null if [ $? = 1 ] then sh /etc/netstart ral0 > /dev/null fi sleep 30 done [Ping the access point. If there is no response attempt to reconnect.] It seems to me to be a very suboptimal solution. Has anyone else come across a better way?

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• Are sequence designs appropriate for GUI button design?

  - by JustADude

  Specifically, I have numerous buttons that will be changing color based on state information from operator input and input from various subcomponents and sensors. I would like to use UML or some other type of design diagrams to be able to capture the color transition. Some folks have suggested sequence diagrams, but I haven't been able to find any good examples that show how to incorporate this design artifact. I would really like to head in this direction to help developers. Are sequence designs in fact, appropriate, or is there a more appropriate design?

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