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• What is the best Java numerical method package?

  - by Bob Cross

  I am looking for a Java-based numerical method package that provides functionality including: Solving systems of equations using different numerical analysis algorithms. Matrix methods (e.g., inversion). Spline approximations. Probability distributions and statistical methods. In this case, "best" is defined as a package with a mature and usable API, solid performance and numerical accuracy. Edit: derick van brought up a good point in that cost is a factor. I am heavily biased in favor of free packages but others may have a different emphasis.

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• Google maps spatial reference system

  - by JavaRocky

  What is Google map's spatial reference system using when you enter a lat, long into the maps search bar? I've found hints that it might be WGS84 but after converting to that coordinate system, nothing shows up when i paste the coordinates into the google maps search box. I am converting from GDA MGA 56. Sample: Input MGA56 coords: 336301, 6253363 Expected WGS86 coords: -33.8473340793201, 151.230631835944 I get: 16834916.928327594 -4008321.1020318186 Spatial coord systems: EPSG:28356 for MGA56 EPSG:900913 for WGS86 (google maps) I am using geotools to do the transform: CoordinateReferenceSystem crsMga56 = CRS.parseWKT(mga56); CoordinateReferenceSystem crsGmaps = CRS.parseWKT(gmaps); Coordinate coordinate = new Coordinate(336301, 6253363); Point point = new GeometryFactory().createPoint(coordinate); MathTransform transform = CRS.findMathTransform(crsMga56, crsGmaps); Geometry geometry = JTS.transform(point, transform); I know the transform is not correct, as when i use an online tool it gives me the correct coords. http://www.environment.gov.au/cgi-bin/transform/mga2geo%5Fgda.pl?east=336301&north=6253363&zone=56

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• How should I structure my git commits?

  - by int3

  I'm trying to contribute to open source software for the first time, but I'm pretty inexperienced with version control systems. In particular, right now I want to make a number of changes to different parts of the code, but I'm not sure if the maintainer would want to integrate all of them into the master repository. However, the changes I'll be making are independent, i.e. they affect different parts of the file, or parts of different files. How should I go about making the changes? If I make a string of commits on the same branch, will the maintainer be able to pick and choose what he wants from the individual commit? E.g. can he patch in the changes I made in my second commit while ignoring the first one? Or should I make each change in a separate branch?

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• What is the best way to interoperably serialize a message?

  - by iwein

  I'm considering message serialization support for spring-integration. This would be useful for various wire level transports to implement guaranteed delivery, but also to allow interoperability with other messaging systems (e.g. through AMQP). The fundamental problem that arises is that a message containing Java object in it's payload and headers should be converted to a byte[] and/or written to a stream. Java's own serialization is clearly not going to cut it because that is not interoperable. My preference would be to create an interface that allows the user to implement the needed logic for all Objects that take part in serialization. Is this a sensible idea and what would the interface look like? Is there a standard interoperable way to serialize Objects that would make sense in this context?

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• How can I get read-ahead bytes?

  - by Bruno Martinez

  Operating systems read from disk more than what a program actually requests, because a program is likely to need nearby information in the future. In my application, when I fetch an item from disk, I would like to show an interval of information around the element. There's a trade off between how much information I request and show, and speed. However, since the OS already reads more than what I requested, accessing these bytes already in memory is free. What API can I use to find out what's in the OS caches? Alternatively, I could use memory mapped files. In that case, the problem reduces to finding out whether a page is swapped to disk or not. Can this be done in any common OS?

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• Again, what version control system to choose?

  - by Ivan

  Please excuse me for probably a newbie hundred-times-chewed question. I have no experience with version control systems except of using Visual Source Safe in a project done by 2 people sitting in front of each other (which has shown VSS quite sack of boulders, not anything useful). Right now I am looking to grok-in using some modern VCS. Here are the preferences in descending priority order: Platform-agnostic. Pretty pleasant to use With Visual Studio 2010 on Windows as well as With NetBeans 6.9 and Eclipse 3.6 on Linux and Mac. Convenient and efficient for mutually-dependent projects done by teams of 1-10 and consisting of files of quite a diverse selection of types. Including early-stage projects with unstable design and experimenting. Modern. As fresh and future-technology-feature-rich as possible. Free & open-source. Should I take a closer look at SVN, Mercurial, GIT, Bazaar, or something else?

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• Database storage for high sample rate data in web app

  - by Jim

  I've got multiple sensors feeding data to my web app. Each channel is 5 samples per second and the data gets uploaded bundled together in 1 minute json messages (containing 300 samples). The data will be graphed using flot at multiple zoom levels from 1 day to 1 minute. I'm using Amazon SimpleDB and I'm currently storing the data in the 1 minute chunks that I receive it in. This works well for high zoom levels, but for full days there will be simply be too many rows to retrieve. The idea I've currently got is that every hour I can crawl through the data and collect together 300 samples for the last hour and store them in an hour Domain (table if you like). Does this sound like a reasonable solution? How have others implemented the same sort of systems?

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• Parsing XML stream in ASP.NET 3.5

  - by Ranjit

  Hi All, I am trying to build an ASP.NET 3.5 application based on XML streams from a legacy systems. My issue is once I get the XML I have to built menus and sub menus from the XML as well filter data(XML stream) based on the menu selection without making roundtrip to the Data store(legacy system). Right now I have a DAL which will get the XML stream in the form of XDocument.I was able to built the first level Menu Items, but not the sub Menu Items based on the selection in the Main Menu and then the final content based on the sub menu selection, all this without making a round trip. Is there a way to do this in-memory. Please suggest. thank you. Ranjit

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• Worst side effects from chars signedness. (Explanation of signedness effects on chars and casts)

  - by JustSmith

  I frequently work with libraries that use char when working with bytes in C++. The alternative is to define a "Byte" as unsigned char but that not the standard they decided to use. I frequently pass bytes from C# into the C++ dlls and cast them to char to work with the library. When casting ints to chars or chars to other simple types what are some of the side effects that can occur. Specifically, when has this broken code that you have worked on and how did you find out it was because of the char signedness? Lucky i haven't run into this in my code, used a char signed casting trick back in an embedded systems class in school. I'm looking to better understand the issue since I feel it is relevant to the work I am doing.

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• Email form isn't sending

  - by Jonathan

  Hi I have an email form that isn't sending out an email to the recipient or a copy to the client. The form can be found at www.kelcos.co.uk/contact and the files associated with this are: /index.php /jquery.js /sendemail.php /submitform.php /thanks.php /verify.php I have used this form on other websites http://www.bowlesgreen.co.uk/contact/ and http://www.arbortectreecare.co.uk/contact/ and it works fine - the only difference is that these other sites use my usual hosting provider and for the one that won't send I'm working through the clients hosting provider, which I can only presume is what is causing the problem. I have contacted the hosting and so far we have eliminated a few things such as: 'The limitation to our systems is that the emails sent using scripts will be blocked if they are not going to or coming from an email address setup on the web hosting account. - so I am now sending the form to an a kelcos.co.uk address, but still no joy. PHP/ASP was originally disabled, but now has been activated the mail() script is enabled I would really appreciated any advise any of you could offer. Thanks

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• Service Layer Pattern - Could we avoid the service layer on a specific case?

  - by lidermin

  Hi, we are trying to implement an application using the Service Layer Pattern cause our application needs to connect to other multiple applications too, and googling on the web, we found this link of a demonstrative graphic for the "right" way of apply the pattern: martinfowler.com - Service Layer Pattern But now we have a question: what if our system needs to implement some business logic, only for our application (like some maintenance data for the system itself) that we don't need to share with other systems. Based on this graphic: As it seems, it will be unnecesary to implement a service layer just for that; it will be more practical to avoid the service layer, and just go from User Interface to the Business Layer (for example). What should be the right way in this case to implement the Service Layer Pattern? What do you suggest us for a scenario like the one I told you? Thanks in advance.

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• How to allow for modular development while still running in same JVM?

  - by Marcus

  Our current app runs in a single JVM. We are now splitting up the app into separate logical services where each service runs in its own JVM. The split is being done to allow a single service to be modified and deployed without impacting the entire system. This reduces the need to QA the entire system - just need to QA the interaction with the service being changed. For interservice communication we use a combination of REST, an MQ system bus, and database views. What I don't like about this: REST means we have to marshal data to/from XML DB views couple the systems together which defeats the whole concept of separate services MQ / system bus is added complexity There is inevitably some code duplication between services You have set up n JBoss server configurations, we have to do n number of deployments, n number of set up scripts, etc, etc. Is there a better way to structure an internal application to allow modular development and deployment while allowing the app to run in a single JVM (and achieving the associated benefits)?

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• Netlink user-space and kernel-space communication

  - by sasayins

  Hi, I am learning programming in embedded systems using Linux as my main platform. And I want to create a Device Event Management Service. This service is a user-space application/daemon that will detect if a connected hardware module triggered an event. But my problem is I don't know where should I start. I read about Netlink implementation for userspace-kernelspace communication and it seems its a good idea but not sure if it is the best solution. But I read that the UDEV device manager uses Netlink to wait a "uevent" from the kernel space but it is not clear for me how to do that. I read about polling sysfs but it seems it is not a good idea to poll filesystem. What do you think the implementation that should I use in my service? Should I use netlink(hard/no clue how to) or just polling the sysfs(not sure if it works)? Thanks

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• Solutions for redundant server and client code?

  - by Fragsworth

  In our system, the code which exists on the client side (in Flash and Javascript) mirrors the code that exists on the server side (e.g. in Python or PHP), normally with respect to the models, the methods available for those models, and the unit tests written for them. This becomes a problem in systems where you want to minimize data transfer (e.g. multiplayer games). I do not want to write the same code and unit tests redundantly for both the client and server, but I don't know of any standard solutions to deal with this. Basically, I want a language/compiler which can produce models and methods for three main languages: Actionscript, Javascript, and any server language. Does something like this exist?

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• Is "non breaking change" a common term in revision control?

  - by mafutrct

  Non breaking change is a term used to describe minor contributions which are supposed to not break anything and is abbreviated as NBC. Typical example include formatting a source file or adding a comment - it really, really should not break the build (of course there are always exceptional cases). Is this a common term in revision control talk? I'm especially asking those familiar with RC systems. I use "NBC" on occasion but I never heard anyone else using it so I wondered... (btw: Don't trust wikipedia as a source on this)

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• GUI system architecture?

  - by topright

  I'm designing GUI (graphical user interface) system for a game engine (C++). Idea is to create a heirarchy of GUI controllers like Focusable, Hoverable, Dragable etc. Every GUI component can attach multiple controllers, they modify component's behaviour. I think it gives flexible system and protects from code duplication. Different instances of the same GUI class can have different complex behaviours (may be, even change it dynamically), so this approach looks practical. The other choice is to add focused, hovered, dragged etc. flags in the base GUI component class. It looks like overhead and not that flexible. Another solution is to use Decorator pattern and wrap objects with FocusDecorator, HoverDecorator etc. Maintaining such system looks a bit harder. Question: What are pitfalls in my solution? May be you have seen a better approaches in GUI systems? What are the best ways of implementing such flexible complex system?

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• Python - which multi platform GUI framework to use?

  - by Iacopo

  Hi, I've written a Python GUI application and made it run on Linux, Windows and Mac. The framework I'm using is PyGtk. The final result is not really good: the application looks horrible on Mac, and it is not really 'native' neither on Windows. Furthermore on Mac the windows' behavior is sometimes wrong, with modal dialogs appearing below the main windows. I've explored other frameworks and I've found that a porting may be really hard: PyQt it is huge, difficult to install and to distribute under Mac; PyGui is poor: I need tables and tree views at least; wxPython state explicitly that you have to use a custom python build for Mac Tkinter: didn't check it, only have the impression that it is obsolete I know this question may appear similar to http://stackoverflow.com/questions/394039/which-python-gui-framework but in that thread the portability issue is not really taken in account. Windows and Mac are a must, since most of my user have that systems. Can you also suggest some books?

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• Generating Dynamic web pages without server side scripting

  - by Microkernel

  Hi guys, I am trying to control a media device which has lot of multimedia content that it can play using another device(remote control device) like an ipad connected to the LAN. (UPnP) I want the media device to be able to send the content listing to the remote device so that it will be rendered as a webpage on the remote controller. And actions on the webpages needs to be sent to the the device as commands to execute (like play, pause, next etc). The media device is an embedded device, hence can't have any server side scripting, all has to be done on the client side. I want the page rendered to be HTML5. So, is it possible to generate dynamic HTML5 pages using just client side scripting? Thanks a lot. I am an embedded systems developer hence clueless about the web designing stuff.

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• Allow for modular development while still running in same JVM?

  - by Marcus

  Our current app runs in a single JVM. We are now splitting up the app into separate logical services where each service runs in its own JVM. The split is being done to allow a single service to be modified and deployed without impacting the entire system. This reduces the need to QA the entire system - just need to QA the interaction with the service being changed. For inter service communication we use a combination of REST, an MQ system bus, and database views. What I don't like about this: REST means we have to marshal data to/from XML DB views couple the systems together which defeats the whole concept of separate services MQ / system bus is added complexity There is inevitably some code duplication between services You have set up n JBoss server configurations, we have to do n number of deployments, n number of set up scripts, etc, etc. Is there a better way to structure an internal application to allow modular development and deployment while allowing the app to run in a single JVM (and achieving the associated benefits)?

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• When and why will an OS initialise memory to 0xCD, 0xDD, etc. on malloc/free/new/delete?

  - by LeopardSkinPillBoxHat

  I know that the OS will sometimes initialise memory with certain patterns such as 0xCD and 0xDD. What I want to know is when and why this happens. When Is this specific to the compiler used? Do malloc/new and free/delete work in the same way with regard to this? Is it platform specific? Will it occur on other operating systems, such as Linux or VxWorks? Why My understanding is this only occurs in Win32 debug configuration, and it is used to detect memory overruns and to help the compiler catch exceptions. Can you give any practical examples as to how this initialisation is useful? I remember reading something (maybe in Code Complete 2) that it is good to initialise memory to a known pattern when allocating it, and certain patterns will trigger interrupts in Win32 which will result in exceptions showing in the debugger. How portable is this?

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• Which format does static library (*.lib) files use? Where can I find "Official" specifications of *.

  - by claws

  Just now I found that static libraries in *nix systems, in other words *.a libraries are nothing but archives of relocatables(*.o files) in ar fromat. What about static libraries(*.lib files) in windows? Which format are they in? I found an article: http://www.microsoft.com/msj/0498/hood0498.aspx which explains *.lib file structure. But Where can I find "Official" specifications of *.lib file structure/format? Other than ar.exe of mingw is there any tool from Microsoft which extracts relocatable objects of *.lib & *.a files? EDIT: I wonder why I'm unable to get to this question. If there are no official specifications. Then how does the compiler ('linker' to be more correct) writers work with *.LIB files?

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• Editing "Time to display recovery options when needed" timeout value using a program

  - by chandra

  Hi all, I want to edit the timeout value of 'Time to display recovery options when needed' without using the UI display option. To navigate, Right click on 'Mycomputer' - Properties - Advanced tab - click on SETTINGS of 'Startup and recovery' = 2nd displayed check box. The value thought to be in c:\boot.ini file, but it has value of other timeout 'Time to display other operating systems'. After some searching, i found that 'c:\windows\bootstat.dat' file holds the timeout value for 'Time to display recovery options when needed'... but, i am not able to decode the .dat file or edit that file.. any suggestions would he helpful for me.. Thanks in advance

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• How do I give a jQuery Element a fixed position on the page. In other words absolute positioning of a jQuery element.

  - by Stephanie

  <script type="text/javascript"> $(function() { $('a.StackedSystem').hover(function(e) { var html = '<div id="StackedSysteminfo">'; html += '<div id="StackedSystemTxt"> ETTER utilizes the latest technologies for our booster systems, including PLC-Based controls complete with touch-screen panel user interfaces (HMI). The base package includes the gray scale screen as shown; color screens are also available. The PLC not only provides a cleaner interface but provides additional features like automatic logging and time/date stamping of all alarms and shut-downs. Great for trouble-shooting.'; html += ''; $('body').append(html).children('#info').hide().fadeIn(400); }, function() { $('#StackedSysteminfo').remove(); }); });

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• Best practices or tools for installing a MS SQL database

  - by Maestro1024

  Best practices or tools for installing a MS SQL database I have a MS SQL database designed with the MS SQL GUI database editor/Visual Studio. What is the best way to "install" that database on other systems. Said another way how should I ship this thing? I know I can save the scripts and set the primary/foreign keys with T-SQL but I suspect their is something better. I guess you could have people restore from backup but that does not seem very professional. What other choices are there and what are the pluses and minuses?

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• Perform manual test, automate after - or never?

  - by dotnetdev

  In my current company, we have one tester. Having spoken to this tester, she says that in testing, before implementing any automation systems, the scripts (steps to take) are manually written and performed (performed at least once). Is this the way things work in testing? To make me laugh, this has been done in this case, yet no automation. It makes me laugh to see the lead tester perform loads of different combinations of usernames and passwords for a login form (which she is not overly keen on having automated) when I could easily automate that (but politics in the company won't allow that). This doesn't seem like the environment where a junior tester (not me, I'm a SDET) cannot learn anything. Thanks

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