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  • Algorithm for procedural city generation?

    - by Zove Games
    I am planning on making a (simple) procedural city generator using Java. I need ideas on whan algorithm to use for the layout, and the actual buildings. The city will mostly have skyscrapers, not really much complex stuff. For the layout I already have a simple algorithm implemented: Create a Map with java.awt.Point keys and Integer values. Fill it with all the points in the city's bounds with the value as -1 (unnassigned) Shuffle the map, and assign the 1st 10 of the keys IDs (from 1-10) Loop until all points have IDs: Loop though all points: Assign points next to an assigned point IDs of the point next to them, if 2 or more points border the point, then randomly choose which ID the point will get. You will end up with 10 random regions. Make roads bordering these regions. Fill the inside of each region with a randomly spaced and randomly rotated grid PROBLEM: This is not the fastest way to do it. What algorithm should I use for the layout. And what should I use to make each building's design? I don't even know how I'm going to do that yet (fractals maybe). I just need some ideas, not actual code.

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  • Advanced TSQL training

    - by Dave Ballantyne
    Over the past few years, Ive had it on my to do list to write and deliver and full-scale SQLServer training course and not just an hour long bite size session at user groups and conferences.  To me, SQLServer development is not just knowing and remembering the syntax of commands.  Sometimes I semi-jest that i have “Written a merge statement without looking up the syntax”, but I know from my interactions on and off line that I am far from alone in this.  In any case we have an awesome tool in the internet which is great at looking things up. When developing SQL Server based solutions,  of more importance is knowing the internals of the engine.  SQL Server is a complex piece of software and we need to be able to understand to a fairly low level ( you can always dive deeper ) the choices that it makes and why it makes them in order to deliver performant, reliable, predictable and scalable systems to our customers and end-users. This is the view i shall be taking over two days in March (19th and 20th) in London and ,TBH, one I dont see taken often enough. Early bird discounts are available until 31Dec. Full details of the course and a high level view of the bullet points we shall be covering are available at the Technitrain site ( http://tinyurl.com/TSQLTraining )

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  • ArchBeat Link-o-Rama for November 6, 2012

    - by Bob Rhubart
    OAM/OVD JVM Tuning | @FusionSecExpert Vinay from the Oracle Fusion Middleware Architecture Group (the infamous A-Team) shares a process for analyzing and improving performance in Oracle Virtual Directory and Oracle Access Manager. Architects Matter: Making sense of the people who make sense of enterprise IT Why do architects matter? Oracle Enterprise Architect Eric Stephens suggests that you ask yourself that question the next time you take the elevator to the Oracle offices on the 45th floor of the Willis Tower in Chicago, Illinois (or any other skyscraper, for that matter). If you had to take the stairs to get to those offices, who would you blame? "You get the picture," he says. "Architecture is essential for any necessarily complex structure, be it a building or an enterprise." (Read the article...) SOA Galore: New Books for Technical Eyes Only Shake up up your technical skills with this trio of new technical books from community members covering SOA and BPM. Thought for the Day "It goes against the grain of modern education to teach students to program. What fun is there to making plans, acquiring discipline, organizing thoughts, devoting attention to detail, and learning to be self critical?" — Alan Perlis (April 1, 1922 – February 7, 1990) Source: SoftwareQuotes.com

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  • Search multiple tables

    - by gilden
    I have developed a web application that is used mainly for archiving all sorts of textual material (documents, references to articles, books, magazines etc.). There can be any given number of archive tables in my system, each with its own schema. The schema can be changed by a moderator through the application (imagine something similar to a really dumbed down version of phpMyAdmin). Users can search for anything from all of the tables. By using FULLTEXT indexes together with substring searching (fields which do not support FULLTEXT indexing) the script inserts the results of a search to a single table and by ordering these results by the similarity measure I can fairly easily return the paginated results. However, this approach has a few problems: substring searching can only count exact results the 50% rule applies to all tables separately and thus, mysql may not return important matches or too naively discards common words. is quite expensive in terms of query numbers and execution time (not an issue right now as there's not a lot of data yet in the tables). normalized data is not even searched for (I have different tables for categories, languages and file attatchments). My planned solution Create a single table having columns similar to id, table_id, row_id, data Every time a new row is created/modified/deleted in any of the data tables this central table also gets updated with the data column containing a concatenation of all the fields in a row. I could then create a single index for Sphinx and use it for doing searches instead. Are there any more efficient solutions or best practises how to approach this? Thanks.

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  • Call DB Stored Procedure using @NamedStoredProcedureQuery Injection

    - by anwilson
    Oracle Database Stored Procedure can be called from EJB business layer to perform complex DB specific operations. This approach will avoid overhead from frequent network hits which could impact end-user result. DB Stored Procedure can be invoked from EJB Session Bean business logic using org.eclipse.persistence.queries.StoredProcedureCall API. Using this approach requires more coding to handle the Session and Arguments of the Stored Procedure, thereby increasing effort on maintenance. EJB 3.0 introduces @NamedStoredProcedureQuery Injection to call Database Stored Procedure as NamedQueries. This blog will take you through the steps to call Oracle Database Stored Procedure using @NamedStoredProcedureQuery.EMP_SAL_INCREMENT procedure available in HR schema will be used in this sample.Create Entity from EMPLOYEES table.Add @NamedStoredProcedureQuery above @NamedQueries to Employees.java with definition as given below - @NamedStoredProcedureQuery(name="Employees.increaseEmpSal", procedureName = "EMP_SAL_INCREMENT", resultClass=void.class, resultSetMapping = "", returnsResultSet = false, parameters = { @StoredProcedureParameter(name = "EMP_ID", queryParameter = "EMPID"), @StoredProcedureParameter(name = "SAL_INCR", queryParameter = "SALINCR")} ) Observe how Stored Procedure's arguments are handled easily in  @NamedStoredProcedureQuery using @StoredProcedureParameter.Expose Entity Bean by creating a Session Facade.Business method need to be added to Session Bean to access the Stored Procedure exposed as NamedQuery. public void salaryRaise(Long empId, Long salIncrease) throws Exception { try{ Query query = em.createNamedQuery("Employees.increaseEmpSal"); query.setParameter("EMPID", empId); query.setParameter("SALINCR", salIncrease); query.executeUpdate(); } catch(Exception ex){ throw ex; } } Expose business method through Session Bean Remote Interface. void salaryRaise(Long empId, Long salIncrease) throws Exception; Session Bean Client is required to invoke the method exposed through remote interface.Call exposed method in Session Bean Client main method. final Context context = getInitialContext(); SessionEJB sessionEJB = (SessionEJB)context.lookup("Your-JNDI-lookup"); sessionEJB.salaryRaise(new Long(200), new Long(1000)); Deploy Session BeanRun Session Bean Client.Salary of Employee with Id 200 will be increased by 1000.

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  • Trying to wrap my head around class structure for domain-specific language

    - by svaha
    My work is mostly in embedded systems programming in C, and the proper class structure to pull this off eludes me. Currently we communicate via C# and Visual Basic with a large collection of servos, pumps, and sensors via a USB-to-CAN hid device. Right now, it is quite cumbersome to communicate with the devices. To read the firmware version of controller number 1 you would use: SendCan(Controller,1,ReadFirmwareVersion) or SendCan(8,1,71) This sends three bytes on the CAN bus: (8,1,71) Connected to controllers are various sensors. SendCan(Controller,1,PassThroughCommand,O2Sensor,2,ReadO2) would tell Controller number 1 to pass a command to O2 Sensor number 2 to read O2 by sending the bytes 8,1,200,16,2,0 I would like to develop a domain-specific language for this setup. Instead of commands issued like they are currently, commands would be written like this: Controller1.SendCommand.O2Sensor2.ReadO2 to send the bytes 8,1,200,16,0 What's the best way to do this? Some machines have 20 O2 Sensors, others have 5 controllers, so the numbers and types of controllers and sensors, pumps, etc. aren't static.

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  • Quadcopters Play Catch [Video]

    - by Jason Fitzpatrick
    Working like a group of hive-minded bees, these quadcopters come off as almost playful with their ball throwing antics. Courtesy of the folks at the Swiss Federal Institute of Technology in Zurich’s Institute for Dynamic Systems and Control, we’re treated to a video of three quadcopters playing catch in the research facility’s Flying Machine Area. They explain the processes demonstrated in the video: This video shows three quadrocopters cooperatively tossing and catching a ball with the aid of an elastic net. To toss the ball, the quadrocopters accelerate rapidly outward to stretch the net tight between them and launch the ball up. Notice in the video that the quadrocopters are then pulled forcefully inward by the tension in the elastic net, and must rapidly stabilize in order to avoid a collision. Once recovered, the quadrotors cooperatively position the net below the ball in order to catch it. Because they are coupled to each other by the net, the quadrocopters experience complex forces that push the vehicles to the limits of their dynamic capabilities. To exploit the full potential of the vehicles under these circumstances requires several novel algorithms, including: HTG Explains: How Antivirus Software Works HTG Explains: Why Deleted Files Can Be Recovered and How You Can Prevent It HTG Explains: What Are the Sys Rq, Scroll Lock, and Pause/Break Keys on My Keyboard?

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  • Get the Latest Security Inside Out Newsletter, October Edition

    - by Troy Kitch
    The latest October edition of the Security Inside Out newsletter is now available and covers the following important security news: Securing Oracle Database 12c: A Technical Primer The new multitenant architecture of Oracle Database 12c calls for adopting an updated approach to database security. In response, Oracle security experts have written a new book that is expected to become a key resource for database administrators. Find out how to get a complimentary copy.  Read More HIPAA Omnibus Rule Is in Effect: Are You Ready? On September 23, 2013, the HIPAA Omnibus Rule went into full effect. To help Oracle’s healthcare customers ready their organizations for the new requirements, law firm Ballard Spahr LLP and the Oracle Security team hosted a webcast titled “Addressing the Final HIPAA Omnibus Rule and Securing Protected Health Information.” Find out three key changes affecting Oracle customers.  Read More The Internet of Things: A New Identity Management Paradigm By 2020, it’s predicted there will be 50 billion devices wirelessly connected to the internet, from consumer products to highly complex industrial and manufacturing equipment and processes. Find out the key challenges of protecting identity and data for the new paradigm called the Internet of Things.  Read More

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  • Should a software developer get a yearly equipment budget?

    - by CrazyDart
    I am looking at a new position with a new company. I have talked to some people in the past (in general, not at this company) that they had been given a yearly budget to buy new computer stuff to keep up to date. Now why I feel this question is worth asking here is that Joel comes right out and says an employer should pay for the best equipment money can buy... within reason of course. From The Joel Test: 12 Steps to Better Code 9. Do you use the best tools money can buy? Writing code in a compiled language is one of the last things that still can't be done instantly on a garden variety home computer... Top notch development teams don't torture their programmers. Even minor frustrations caused by using underpowered tools add up, making programmers grumpy and unhappy. And a grumpy programmer is an unproductive programmer... Does anyone know if the industry has such a standard to offer an allowance or budget? I have never worked for a company like this, but I am thinking I should toss this in the ring for negotiations. Seems reasonable. How do bigger companies like MS, Google, and Apple handle this? If you say yes, give a range... I have been told numbers from $5k to $10k. Seems high to me, but hey I would gladly take it.

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  • Is it okay to use a language that isn't supported by your company for some tasks?

    - by systempuntoout
    I work for a company that supports several languages: COBOL, VB6, C# and Java. I use those languages for my primary work, but I often find myself to coding some minor programs (e.g. scripts) in Python because I found it to be the best tool for that type of task. For example: An analyst gives me a complex CSV file to populate some DB tables, so I would use Python to parse it and create a DB script. What's the problem? The main problem I see is that a few parts of these quick & dirty scripts are slowly gaining importance and: My company does not support Python They're not version controlled (I back them up in another way) My coworkers do not know Python The analysts have even started referencing them in email ("launch the script that exports..."), so they are needed more often than I initially thought. I should add that these scripts are just utilities that are not part of the main project; they simply help to get trivial tasks done in less time. For my own small tasks they help a lot. In short, if I were a lottery winner to be in a accident, my coworkers would need to keep the project alive without those scripts; they would spend more time in fixing CSV errors by hand for example. Is this a common scenario? Am I doing something wrong? What should I do?

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  • How can # of unique visitors be more than # of visits?

    - by Dallas
    I am confused as heck. When looking at a few individual pages, I am seeing weird results I hope someone can help explain. I am doing manual standard reports, and not creating or using a widget. For each of the two tests below, the metrics I am using are visits (not visitors) and unique visitors. I am using Page as my primary dimension and Page Title as secondary. I am filtering to include certain Pages. Example 1 - Looking at a single page... I see 731 unique visitors and 169 visits. How is this possible? Does google just flip them around for some reason? Example 2 - Looking at several pages combined... If you examine the timeline below , you can see that the numbers are all over the place. How is it possible to have more unique visitors than visits? What am I missing? I would suspect that if things were just flipped around, then I should still see one line that is always below the other line. Anyone clue me in to what may be happening here? I also notice that the visits column (just out of view) adds up to the total, but the unique visitors column clearly doesn't.

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  • Oracle EZConnect in Mediawiki

    - by raindog308
    Mediawiki supports Oracle and I'm trying to configure it in the installer. The installers says you can use EZConnect...something like: user/pass@//server.example.com/dbname or since the installer has fields elsewhere for user/pass server.example.com/dbname The installer includes a link to the EZConnect docs: http://docs.oracle.com/cd/E11882_01/network.112/e10836/naming.htm. All the examples in that doc include a forward slash. But every combination I've tried results in an error like this: Invalid database TNS "sever.example.com/service_name". Use only ASCII letters (a-z, A-Z), numbers (0-9), underscores (_) and dots (.). I can't find any examples of EZConnect that don't include a forward slash. That error is from Mediawiki, not Oracle. I'm tailing the listener log and there is no connection made - Medaiwiki is returning an error without trying to connect. I'm using php OCI8 with the Oracle instant client. I don't have a tnsnames.ora setup for this client - which is kind of the point of EZConnect. I did write a test php script that connects via oci_connect just fine. Has anyone configured Mediawiki to use Oracle with EZConnect? If so, what did you use in the installer?

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  • Static / Shared Helper Functions vs Built-In Methods

    - by Nathan
    This is a simple question but a design consideration that I often run across in my day to day development work. Lets say that you have a class that represents some kinds of collection. Public Class ModifiedCustomerOrders Public Property Orders as List(Of ModifiedOrders) End Class Within this class you do all kinds of important work, such as combining many different information sources and, eventually, build the Modified Customer Orders. Now, you have different processes that consume this class, each of which needs a slightly different slice of the ModifiedCustomerOrders items. To enable this, you want to add filtering functionality. How do you go about this? Do you: Add Filtering calls to the ModifiedCustomerOrders class so that you can say: MyOrdersClass.RemoveCanceledOrders() Create a Static / Shared "tooling" class that allows you to call: OrdersFilters.RemoveCanceledOrders(MyOrders) Create an extension method to accomplish the same feat as #2 but with less typing: MyOrders.RemoveCanceledOrders() Create a "Service" method that handles the getting of Orders as appropriate to the calling function, while using one of the previous approaches "under the hood". OrdersService.GetOrdersForProcessA() Others? I tend to prefer the tooling / extension method approaches as they make testing a little bit simpler. Although I dependency inject all my sourcing data into the ModifiedCustomerOrders, having it as part of the class makes it a little bit more complicated to test. Typically, I choose to use extension methods where I am doing parameterless transformations / filters. As they get more complex, I will move it into a static class instead. Thoughts on this approach? How would you approach it?

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  • Unable to start Ubuntu 12.04. The system is running in low-graphics

    - by kaleidoscpicsoul
    I am a newbie to Ubuntu. I installed Ubuntu 12.04 using a USB Stick and it was running all fine for a few weeks and this error popped up. According to one of my friend, the best way was to re-install Ubuntu. Being from a non unix background i thought the same too and after the second install it happened again, but only this time was much quicker, in 3 days. I don't want to re-install Ubuntu every time this happens. I am a complete newbie to Linux which means that i am really bad at using terminal. I know there are other people who fixed this issue using this very same forum, but unfortunately the answers provided are too complex for me to understand. Please let me know how to do this. Things I want to let you know: I would need help step by step if that is alright with you. After i get the error i get the options and i click exit to console login I get the following message in a black screen (which i think is a command line sort of thing): * Stopping save kernel messages [OK] apache2: Could not reliably determine the server's fully qualified domain name,using 127.0.1.1 for ServerName [OK] * Starting web server apache2 and a blinking cursor. So basically it looks like a dead end for my non unixy eye. And one final thing is before this issue had happened i had tried configuring Python to Apache2. For that i had uninstalled and installed LAMP server several time and edited the configuration files too. I don't know if this really is a concern, but I don't know.. I have a USB with Ubuntu 12.04 in it so i can install it anytime. (But i want to know what the issue is rather than running away) . I migrated to Ubuntu from Windows and i have no plans to go back. I think that's from my side. Please let me know if there are any questions.

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  • Where did I write that code ?

    - by Tarun Arora
    Every been in that situation when you desperately need to find that code you checked into TFS a few days back but just can’t remember what team project, what branch, what solution or what file you checked it into. Well you are not alone… Only if there was a way to efficiently search for files and text with in TFS. It is possible… You need to get your hands on Agent Ransack… This is a stand a lone tool that does not integrate with TFS but gives you the capability to search through text files effortlessly. Agent Ransack searches through files, text or otherwise, fast and efficiently. When searching the contents of files for code, or other text, Agent Ransack displays the text found so you can quickly browse the results without having to separately open each file! Agent Ransack is free for both Personal and Commercial use and can be Download from here.   Set the Look In directory of the Ransack search tool to your TFS Workspace and type the text you would like to scan for, you can limit the search by narrowing down the filter path or the name of the file. Found text is shown with highlighted keywords so you don't need to waste time opening each file looking for the right information.         The regular expression wizard helps you build regular expressions for complex pattern matching searches         You even have the option of searching by modified, created or last accessed date          Export your results to a file for importing into other apps or for sharing with others          Agent Ransack also provides search support for popular Office formats including Office 2007 and OpenOffice Next time you are looking for that illusive line of code whether it is a method declaration, function call, or algorithm that you checked into TFS, use Agent Ransack for a quick search.

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  • New whitepaper: Evolution from the Traditional Data Center to Exalogic: An Operational Perspective

    - by Javier Puerta
    IT organizations are struggling with the need to balance the day-to-day concerns of data center management against the business level requirements to deliver long-term value. This balancing act has proven difficult and inefficient: systems and application management tools are resource intensive and traditional infrastructure management architectures have developed over time on a project by project basis. These traditional management systems consist of multiple tools that require administrators to waste time performing too many steps to handle routine administrative tasks. Operational efficiency and agility in your enterprise are directly linked to the capabilities provided by the management layer across the entire stack, from the application, middleware, operating system, compute, network and storage. Only when this end to end capability is provided will we experience the full benefit of a scalable, efficient, responsive and secure datacenter. Managing Exalogic is substantially less complex and error prone than managing traditional systems built from individually sourced, multi-vendor components because Exalogic is designed to be administered and maintained as a single, integrated system (Figure 1). It is at the forefront of the industry-wide shift away from costly and inferior one-off platforms toward private clouds and Engineered Systems. Read the full whitepaper "Evolution from the Traditional Data Center to Exalogic: An Operational Perspective". Full document is available for download at the Exadata Partner Community Collaborative Workspace (for community members only - if you get an error message, please register for the Community first).

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  • New Whitepaper: Evolution from the Traditional Data Center to Exalogic: An Operational Perspective

    - by Javier Puerta
    IT organizations are struggling with the need to balance the day-to-day concerns of data center management against the business level requirements to deliver long-term value. This balancing act has proven difficult and inefficient: systems and application management tools are resource intensive and traditional infrastructure management architectures have developed over time on a project by project basis. These traditional management systems consist of multiple tools that require administrators to waste time performing too many steps to handle routine administrative tasks. Operational efficiency and agility in your enterprise are directly linked to the capabilities provided by the management layer across the entire stack, from the application, middleware, operating system, compute, network and storage. Only when this end to end capability is provided will we experience the full benefit of a scalable, efficient, responsive and secure datacenter. Managing Exalogic is substantially less complex and error prone than managing traditional systems built from individually sourced, multi-vendor components because Exalogic is designed to be administered and maintained as a single, integrated system (Figure 1). It is at the forefront of the industry-wide shift away from costly and inferior one-off platforms toward private clouds and Engineered Systems. Read the full whitepaper "Evolution from the Traditional Data Center to Exalogic: An Operational Perspective". Full document is available for download at the Exadata Partner Community Collaborative Workspace (for community members only - if you get an error message, please register for the Community first).

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  • Should I always encapsulate an internal data structure entirely?

    - by Prog
    Please consider this class: class ClassA{ private Thing[] things; // stores data // stuff omitted public Thing[] getThings(){ return things; } } This class exposes the array it uses to store data, to any client code interested. I did this in an app I'm working on. I had a ChordProgression class that stores a sequence of Chords (and does some other things). It had a Chord[] getChords() method that returned the array of chords. When the data structure had to change (from an array to an ArrayList), all client code broke. This made me think - maybe the following approach is better: class ClassA{ private Thing[] things; // stores data // stuff omitted public Thing[] getThing(int index){ return things[index]; } public int getDataSize(){ return things.length; } public void setThing(int index, Thing thing){ things[index] = thing; } } Instead of exposing the data structure itself, all of the operations offered by the data structure are now offered directly by the class enclosing it, using public methods that delegate to the data structure. When the data structure changes, only these methods have to change - but after they do, all client code still works. Note that collections more complex than arrays might require the enclosing class to implement even more than three methods just to access the internal data structure. Is this approach common? What do you think of this? What downsides does it have other? Is it reasonable to have the enclosing class implement at least three public methods just to delegate to the inner data structure?

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  • The better way to ask for input?

    - by Skippy
    I am wondering which is the best way to go with java code. I need to create a class with simple prompts for input.. I have tried using both classes and cannot work out the particular benefits for each. Is this because I am still in the early stages of programming or are there situations that will occur as it becomes more complex?? import java.util.Scanner; public class myClass { Scanner stdin = new Scanner(System.in); public String getInput(String prompt) { System.out.print(prompt); return stdin.nextLine(); } ... or import java.io.*; public class myClass { public static void main(String[] args) throws IOException { BufferedReader stdin = new BufferedReader (new InputStreamReader (System.in)); System.out.print("Input something: "); String name = stdin.readLine(); I know these examples are showing different methods within these classes, but thought this might serve well for the discussion. I'm really not sure which site is the best to ask this on.

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  • Connecting two monitors at the corners

    - by fastmultiplication
    I am using two separate X screens on two monitors and I would like them to be connected at the lower right corner. That is, if you move to the lower right corner of screen0 the mouse should appear at the upper left of screen1. I do not want an entire edge of each monitor to be permeable to the mouse. I modified the xorg.conf file like so: Section "ServerLayout" Identifier "Layout0" Screen 0 "Screen0" 0 0 Screen 1 "Screen1" Relative "Screen0" 1200 1000 InputDevice "Keyboard0" "CoreKeyboard" InputDevice "Mouse0" "CorePointer" EndSection (screen 0's resolution is 1280x1024) so there is a bit of overlap. However whenever I move the mouse to the bottom of screen0, the pointer appears at the upper left of screen1. And, the entire top of screen1 is permeable to the mouse and brings it to the lower left corner of screen0. I have tried various numbers in following the "relative" statement - if I put 1280 1024 the mouse does not cross over at all. If I use 1280 1023 the entire right side of screen0 is permeable. I haven't been able to find any documentation about how to explicitly tell the mouse where to crossover - is there some? It seems that xorg is being really aggressive in guessing where the mouse crossover should take place. Does anyone know how to do this? Thanks!

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  • Context switches much slower in new linux kernels

    - by Michael Goldshteyn
    We are looking to upgrade the OS on our servers from Ubuntu 10.04 LTS to Ubuntu 12.04 LTS. Unfortunately, it seems that the latency to run a thread that has become runnable has significantly increased from the 2.6 kernel to the 3.2 kernel. In fact the latency numbers we are getting are hard to believe. Let me be more specific about the test. We have a program that has two threads. The first thread gets the current time (in ticks using RDTSC) and then signals a condition variable once a second. The second thread waits on the condition variable and wakes up when it is signaled. It then gets the current time (in ticks using RDTSC). The difference between the time in the second thread and the time in the first thread is computed and displayed on the console. After this the second thread waits on the condition variable once more. So, we get a thread to thread signaling latency measurement once a second as a result. In linux 2.6.32, this latency is somewhere on the order of 2.8-3.5 us, which is reasonable. In linux 3.2.0, this latency is somewhere on the order of 40-100 us. I have excluded any differences in hardware between the two host hosts. They run on identical hardware (dual socket X5687 {Westmere-EP} processors running at 3.6 GHz with hyperthreading, speedstep and all C states turned off). We are changing the affinity to run both threads on physical cores of the same socket (i.e., the first thread is run on Core 0 and the second thread is run on Core 1), so there is no bouncing of threads on cores or bouncing/communication between sockets. The only difference between the two hosts is that one is running Ubuntu 10.04 LTS with kernel 2.6.32-28 (the fast context switch box) and the other is running the latest Ubuntu 12.04 LTS with kernel 3.2.0-23 (the slow context switch box). Have there been any changes in the kernel that could account for this ridiculous slow down in how long it takes for a thread to be scheduled to run?

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  • GLSL custom interpolation filter

    - by Cyan
    I'm currently building a fragment shader which is using several textures to render the final pixel color. The textures are not really textures, they are in fact "input data" to be used in the formula to generate the final color. The problem I've got is that the texture are getting bi-linear-filtered, and therefore the input data as well. This results in many unwanted side-effects, especially when final rendered texture is "zoomed" compared to original resolution. Removing the side effect is a complex task, and only result in "average" rendering. I was thinking : well, all my problems seems to come from the "default" bi-linear filtering on these input data. I can't move to GL_NEAREST either, since it would create "blocky" rendering. So i guess the better way to proceed is to be fully in charge of the interpolation. For this to work, i would need the input data at their "natural" resolution (so that means 4 samples), and a relative position between the sampled points. Is that possible, and if yes, how ? [EDIT] Since i started this question, i found this internet entry, which seems to (mostly) answer my needs. http://www.gamerendering.com/2008/10/05/bilinear-interpolation/ One aspect of the solution worry me though : the dimensions of the texture must be provided in an argument. It seems there is no way to "find this information transparently". Adding an argument into the rendering pipeline is unwelcomed though, since it's not under my responsibility, and translates into adding complexity for others.

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  • How do 2D physics engines solve the problem of resolving collisions along tiled walls/floors in non-grid-based worlds?

    - by ssb
    I've been working on implementing my SAT algorithm which has been coming along well, but I've found that I'm at a wall when it comes to its actual use. There are plenty of questions regarding this issue on this site, but most of them either have no clear, good answer or have a solution based on checking grid positions. To restate the problem that I and many others are having, if you have a tiled surface, like a wall or a floor, consisting of several smaller component rectangles, and you traverse along them with another rectangle with force being applied into that structure, there are cases where the object gets caught on a false collision on an edge that faces the inside of the shape. I have spent a lot of time thinking about how I could possibly solve this without having to resort to a grid-based system, and I realized that physics engines do this properly. What I want to know is how they do this. What do physics engines do beyond basic SAT that allows this kind of proper collision resolution in complex environments? I've been looking through the source code to Box2D trying to find out how they do it but it's not quite as easy as looking at a Collision() method. I think I'm not good enough at physics to know what they're doing mathematically and not good enough at programming to know what they're doing programmatically. This is what I aim to fix.

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  • Artists and music - Need Help Deciding on a CMS

    - by infty
    A friend has asked me to build a site with the following options: staff members must be able to add new music and artists to the page a gallery must be provided - it is also good if each artist has the ability to have his/her own smaller gallery users must be able to vote for artists users must be able to alter in discussions (forums or comments sections) staff members must be able to blog staff members must be able to write articles I did a small project where i actually implemented all of these features, but I want to use an existing content management system for all of these features so that future developers can, hopefully, more easy extend the website. And also, so that I don't have to provide too much documentation. I have never developed a website using an external CMS like Drupal or Wordpress and after seeing hours of tutorial videos of both systems, I still can't make up my mind on whether i should : a) use Drupal 7 b) use Wordpress 3 c) create my own cms I can imagine that staff members would also want to create content using iPhone or android based mobile devices, but this is not a required feature. Can someone, with experience, please tell me about their experiences with larger projects like this? The site will have approximately 400 000 - 500 000 visitors (not daily visitors, based on numbers from last year in a period of 4 months)

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  • Working with volonteers

    - by JavaCecilia
    I've been engaged as a scout leader in the Scout movement since 1993, working on a local and national level, leading both kids and other scout leaders.Last year, the Swedish Scout Association invited 40000 scouts aged 14-17 years old from 150 countries around the world to go camping for 10 days. I was on the planning team with a couple of hundreds of my closest scout friends and during a couple of years we spent our spare time planning logistics, food, program, etc to give these youths an experience of a life time. It was a big and complex project; different languages, religion (Ramadan was celebrated during the camp) and the Swedish weather were some of the factors we had to take into account. The camp was a huge success, the daily wow factor was measured and people truly had fun and got to know each other. I learnt a lot and got friends around the globe - looking back at the pictures it feels unreal that we managed it.The Java platform as OpenJDK and its' future is a similar project in my mind. With 9 million developers and being installed on 3 bn devices, the platform touches a lot of users and businesses. There's a strong community taking Java into the future, making sure it stays relevant. Finding ways to collaborate in a scalable way is the key to success here. We have the bylaws directing how decisions are made, roles are appointed and how to "level" within the community. Using these, we can then make contributions according to our competence and interest and innovate taking our platform into the future.If you find a way to organize volunteers towards a common goal, solving conflicts, making decisions, dividing the work into manageable chunks and having fun while doing it - there's no end to what you can achieve.

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