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  • Synergy - easy share of keyboard and mouse between multiple computers

    Did you ever have the urge to share one set of keyboard and mouse between multiple machines? If so, please read on... Using multiple machines Honestly, as a software craftsman it is my daily business to run multiple machines - either physical or virtual - to be able to solve my customers' requirements. Recent hardware equipment allows this very easily. For laptops it's a no-brainer to attach a second or even a third screen in order to extend your native display. This works quite handy and in my case I used to attached two additional screens - one via HD15 connector, the other via HDMI. But... as it's a laptop and therefore a mobile unit there are slight restrictions. Detaching and re-attaching all cables when changing locations is one of them but hardware limitations, too. After all, it's a laptop and not a workstation. I guess, that anyone working in IT (or ICT) has more than one machine at their workplace or their home office and at least I find it quite annoying to have multiple sets of keyboard and mouse conquering my remaining space on my desk. Despite the ugly looks of all those cables and whatsoever 'chaos of distraction' I prefer a more clean solution and working environment. This allows me to actually focus on my work and tasks to do rather than to worry about choosing the right combination of keyboard/mouse. My current workplace is a patch work of various pieces of hardware (approx. 2-3 years): DIY desktop on Ubuntu 12.04 64-bit, Core2 Duo (E7400, 2.8GHz), 4GB RAM, 2x 250GB HDD, nVidia GPU 512MB Dell Inspiron 1525 on Windows 8 64-bit, 4GB RAM, 200GB HDD HP Compaq 6720s on Windows Vista 32-bit, Core2 Duo (T5670, 1.8GHz), 2GB RAM, 160GB HDD Mac mini on Mac OS X 10.7, Core i5 (2.3 GHz), 2GB RAM, 500GB HDD I know... Not the latest and greatest but a decent combination to work with. New system(s) is/are already on the shopping list but I live in the 'wrong' country to buy computer hardware. So, the next trip abroad will provide me with some new stuff. Using multiple operating systems The list of hardware above already names different operating systems, and actually I have only one preference: Linux. But still my job as a software craftsman for Visual FoxPro and .NET development requires other OSes, too. Not a big deal, it's just like this. Additionally to those physical machines, there are a bunch of virtual machines around. Most of them running either Windows XP or Windows 7. Since years I have the practice that each development for one customer is isolated into its own virtual machine and environment. This keeps it clean and version-safe. But as you can easily imagine with that setup there are a couple of constraints referring to keyboard and mouse. Usually, those systems require their own pieces of hardware attached. As stated, I don't like clutter on my desk's surface, so a cross-platform solution has to come in here. In the past, I tried it with various applications, hardware or network protocols like X11, RDP, NX, TeamViewer, RAdmin, KVM switch, etc. but the problem in this case is that they either allow you to remotely connect to the other system or exclusively 'bind' your peripherals to the active system. Not optimal after all. Synergy to the rescue Quote from their website: "Synergy lets you easily share your mouse and keyboard between multiple computers on your desk, and it's Free and Open Source. Just move your mouse off the edge of one computer's screen on to another. You can even share all of your clipboards. All you need is a network connection. Synergy is cross-platform (works on Windows, Mac OS X and Linux)." Yep, that's it! All I need for my setup here... Actually, I couldn't believe it myself that I didn't stumble over synergy earlier but 'Get over it' and there we go. And despite the fact that it is Open Source, no, it's also for free. Donations for the developers are very welcome and recently they introduced Synergy Premium. A possibility to buy so-called premium votes that can be used to put more weight / importance on specific issues or bugs that you would like the developers to look into. Installation and configuration Simply download the installation packages for your systems of choice, run the installer and enter some minor information about your network setup. I chose my desktop machine for the role of the Synergy server and configured my screen setup as follows: The screen setup allows you currently to build or connect up to 15 machines. The number of screens can be higher as those machine might have multiple screens physically attached. Synergy takes this into the overall calculations and simply works as expected. I tried it for fun with a second monitor each connected to both laptops to have a total number of 6 active screens. No flaws after all - stunning! All the other machines are configured as clients like so: Side note: The screenshot was taken on Windows 8 and pasted via clipboard into Gimp running on Ubuntu. Resume Synergy is now definitely in my box of tools for my daily work, and amongst the first pieces of software I install after the operating system. It just simplifies my life and cleans my desk. Never again without Synergy!Now, only waiting for an Android version to integrate my Galaxy Tab 10.1, too. ;-) Please, check out that superb product and enjoy sharing one keyboard, one mouse and one clipboard between your various machines and operating systems.

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  • What's New in SGD 5.1?

    - by Fat Bloke
    Oracle announced the latest version of Secure Global Desktop (SGD) this week with 3 major themes: Support for Android devices; Support for Desktop Chrome clients;  Support for Oracle Unified Directory. I'll talk about the new features in a moment, but a bit of context first: Oracle SGD - what, how and why?  Oracle Secure Global Desktop is Oracle's secure remote access product which allows users on almost any device, to access almost any type application which  is hosted in the data center, from almost any location. And it does this by sitting on the edge of the datacenter, between the user and the applications: This is actually a really smart environment for an increasing number of use cases where: Users need mobility of location AND device (i.e. work from anywhere); IT needs to ensure security of applications and data (of course!) The application requires an end-user environment which can't be guaranteed and IT may not own the client platform (e.g. BYOD, working from home, partners or contractors). Oracle has a a specific interest in this of course. As the leading supplier of enterprise applications, many of Oracle's customers, and indeed Oracle itself, fit these criteria. So, as an IT guy rolling out an application to your employees, if one of your apps absolutely needs, say,  IE10 with Java 6 update 32, how can you be sure that the user population has this, especially when they're using their own devices? In the SGD model you, the IT guy, can set up, say, a Windows Server running the exact environment required, and then use SGD to publish this app, without needing to worry any further about the device the end user is using. What's new?  So back to SGD 5.1 and what is new there: Android devices Since we introduced our support for iPad tablets in SGD 5.0 we've had a big demand from customers to extend this to Android tablets too, and so we're pleased to announce that 5.1 supports Android 4.x tablets such as Nexus 7 and 10, and the Galaxy Tab. Here's how it works, with screenshots from my Nexus 7: Simply point your browser to the SGD server URL and login; The workspace is the list of apps that the admin has deemed ok for you to run. You click on an application to run it (here's Excel and Oracle E-Business Suite): There's an extended on-screen keyboard (extended because desktop apps need keys that don't appear on a tablet keyboard such as ctrl, WIndow key, etc) and touch gestures can be mapped to desktop events (such as tap and hold to right click) All in all a pretty nice implementation for Android tablet users. Desktop Chrome Browsers SGD has always been designed around using a browser to access your applications. But traditionally, this has involved using Java to deliver the SGD client component. With HTML5 and Javascript engines becoming so powerful, we thought we'd see how well a pure web client could perform with desktop apps. And the answer was, surprisingly well. So with this release we now offer this additional way of working, which can be enabled by a simple bit of configuration. Here's a Linux desktop running in a tab in Chrome. And if you resize the browser window, the Linux desktop is resized by SGD too. Very cool! Oracle Unified Directory As I mentioned above, a lot of Oracle users already benefit from SGD. And a lot of Oracle customers use Oracle Unified Directory as their Enterprise and Carrier grade user directory. So it makes a lot of sense that SGD now supports this LDAP directory for both Authentication and as a means to determine which users get which applications, e.g. publish the engineering app to the guys in the Development group, but give everyone E-Business Suite to let them do their expenses. Summary With new devices, and faster 4G networking becoming more prevalent, the pressure for businesses to move to a increasingly mobile enterprise is stronger than ever. SGD is good for users, and even better for IT. By offering the user the ability to work from anywhere, and IT the control and security they need, everyone wins with SGD. To try this for yourself, download SGD 5.1 (look under Desktop Virtualization Products) from the Oracle Software Delivery Cloud or if you're an existing customer, get it from My Oracle Support.  -FB 

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  • Android: OutofMemoryError: bitmap size exceeds VM budget with no reason I can see.

    - by Meymann
    Hi. I am having an OutOfMemory exception with a gallery over 600x800 pixels JPEG's. The environment I've been using Gallery with JPG images around 600x800 pixels. Since my content may be a bit more complex than just images, I have set each view to be a RelativeLayout that wraps ImageView with the JPG. In order to "speed up" the user experience I have a simple cache of 4 slots that prefetches (in a looper) about 1 image left and 1 image right to the displayed image and keeps them in a 4 slot HashMap. The platform I am using AVD of 256 RAM and 128 Heap Size, with a 600x800 screen. It also happens on an Entourage Edge target, except that with the device it's harder to debug. The problem I have been getting an exception: OutofMemoryError: bitmap size exceeds VM budget And it happens when fetching the fifth image. I have tried to change the size of my image cache, and it is still the same. The strange thing: There should not be a memory problem In order to make sure the heap limit is very far away from what I need, I have defined a dummy 8MB array in the beginning, and left it unreferenced so it's immediately dispatched. It is a member of the activity thread and is defined as following static { @SuppressWarnings("unused") byte dummy[] = new byte[ 8*1024*1024 ]; } The result is that the heap size is nearly 11MB and it's all free. Note I have added that trick after it began to crash. It makes OutOfMemory less frequent. Now, I am using DDMS. Just before the crash (does not change much after the crash), DDMS shows: ID Heap Size Allocated Free %Used #Objects 1 11.195 MB 2.428 MB 8.767 MB 21.69% 47,156 And in the detail table it shows: Type Count Total Size Smallest Largest Median Average free 1,536 8.739MB 16B 7.750MB 24B 5.825KB The largest block is 7.7MB. And yet the LogCat says: ERROR/dalvikvm-heap(1923): 925200-byte external allocation too large for this process. If you mind the relation of the median and the average, it is plausible to assume that most of the available blocks are very small. However, there is a block large enough for the bitmap, it's 7.7M. How come it is still not enough? Note: I recorded a heap trace. When looking at the amount of data allocated, it does not feel like more than 2M is allocated. It does match the free memory report by DDMS. Could it be that I experience some problem like heap-fragmentation? How do I solve/workaround the problem? Is the heap shared to all threads? Could it be that I interpret the DDMS readout in a wrong way, and there is really no 900K block to allocate? If so, can anybody please tell me where I can see that? Thanks a lot Meymann

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  • Revisiting .NET, but what should I focus on?

    - by Wayne M
    After about a two-year hiatus, I'm brushing up on my .NET skills to find a .NET job (my previous two positions have very little development, or development using legacy technologies, so apart from a few very minor apps I have not touched .NET in close to two years). I'm aware of things like ASP.NET MVC, and I have previously read on things like NHibernate and DI/IOC, albeit I have yet to use them apart from very trivial "Hello World" type applications. I have a subscription to Rob Conery's Tekpub website and occasionally watch these videos when I have free time. My concern is this: I don't live in a very technical area. I would be surprised if any but the most tech-savvy companies have heard of, let alone use, ASP.NET MVC, NHibernate (or even LINQ/EF), or know about IoC. I would be willing to bet a large sum of money that 95% of the possible jobs I could obtain will use the following: Visual Source Safe, if any VCS at all ASP.NET 2.0 Webforms (3.5 if lucky) Raw ADO.NET on top of a very thin implementation of the Gateway pattern Stored Procedures in the database for most CRUD operations Gratuitous use of code-behind, with a Service layer if I'm lucky If I were extremely lucky, I might find a shop that has heard of ORMs and either uses one, or has wrote their own data abstraction. Also if I were lucky, the company would be using Model-View-Presenter. In light of this I'm not sure what I should focus on learning. Personally, I would prefer to be using the latest stuff - ASP.NET MVC, NHibernate, jQuery, WCF etc. Reality says I should go back to the basics, since it looks like most potential opportunities aren't going to be anywhere near the cutting edge, or anywhere close to it. And, as much as I would like to find a position and start to show the other developers the benefits, in my past experience this has usually resulted in my being fired for "not being a team player" and doing things the bad old way. So, I am curious how you would approach a situation like this? What should I focus on, in order to A) Reaquaint myself with .NET, and B) Prepare myself to obtain a .NET job again that is more than likely going to use techniques that I and most other knowledgeable developers will scoff at?

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  • How can I define a clojure type that implements the servlet interface?

    - by Rob Lachlan
    I'm attempting to use deftype (from the bleeding-edge clojure 1.2 branch) to create a java class that implements the java Servlet interface. I would expect the code below to compile (even though it's not very useful). (ns foo [:import [javax.servlet Servlet ServletRequest ServletResponse]]) (deftype servlet [] javax.servlet.Servlet (service [this #^javax.servlet.ServletRequest request #^javax.servlet.ServletResponse response] nil)) But it doesn't compile. The compiler produces the message: Mismatched return type: service, expected: void, had: java.lang.Object [Thrown class java.lang.IllegalArgumentException] Which doesn't make sense to me, because I'm returning nil. So the fact that the return type of the method is void shouldn't be a problem. For instance, for the java.util.Set interface: (deftype bar [#^Number n] java.util.Set (clear [this] nil)) compiles without issue. So what am I doing wrong with the Servlet interface? To be clear: I know that the typical case is to subclass one of the servlet abstract classes rather than implement this interface directly, but it should still be possible to do this. Stack Trace: The stack trace for the (deftype servlet... is: Mismatched return type: service, expected: void, had: java.lang.Object [Thrown class java.lang.IllegalArgumentException] Restarts: 0: [ABORT] Return to SLIME's top level. Backtrace: 0: clojure.lang.Compiler$NewInstanceMethod.parse(Compiler.java:6461) 1: clojure.lang.Compiler$NewInstanceExpr.build(Compiler.java:6119) 2: clojure.lang.Compiler$NewInstanceExpr$DeftypeParser.parse(Compiler.java:6003) 3: clojure.lang.Compiler.analyzeSeq(Compiler.java:5289) 4: clojure.lang.Compiler.analyze(Compiler.java:5110) 5: clojure.lang.Compiler.analyze(Compiler.java:5071) 6: clojure.lang.Compiler.eval(Compiler.java:5347) 7: clojure.lang.Compiler.eval(Compiler.java:5334) 8: clojure.lang.Compiler.eval(Compiler.java:5311) 9: clojure.core$eval__4350.invoke(core.clj:2364) 10: swank.commands.basic$eval_region__673.invoke(basic.clj:40) 11: swank.commands.basic$eval_region__673.invoke(basic.clj:31) 12: swank.commands.basic$eval__686$listener_eval__687.invoke(basic.clj:54) 13: clojure.lang.Var.invoke(Var.java:365) 14: foo$eval__2285.invoke(NO_SOURCE_FILE) 15: clojure.lang.Compiler.eval(Compiler.java:5343) 16: clojure.lang.Compiler.eval(Compiler.java:5311) 17: clojure.core$eval__4350.invoke(core.clj:2364) 18: swank.core$eval_in_emacs_package__320.invoke(core.clj:59) 19: swank.core$eval_for_emacs__383.invoke(core.clj:128) 20: clojure.lang.Var.invoke(Var.java:373) 21: clojure.lang.AFn.applyToHelper(AFn.java:169) 22: clojure.lang.Var.applyTo(Var.java:482) 23: clojure.core$apply__3776.invoke(core.clj:535) 24: swank.core$eval_from_control__322.invoke(core.clj:66) 25: swank.core$eval_loop__324.invoke(core.clj:71) 26: swank.core$spawn_repl_thread__434$fn__464$fn__465.invoke(core.clj:183) 27: clojure.lang.AFn.applyToHelper(AFn.java:159) 28: clojure.lang.AFn.applyTo(AFn.java:151) 29: clojure.core$apply__3776.invoke(core.clj:535) 30: swank.core$spawn_repl_thread__434$fn__464.doInvoke(core.clj:180) 31: clojure.lang.RestFn.invoke(RestFn.java:398) 32: clojure.lang.AFn.run(AFn.java:24) 33: java.lang.Thread.run(Thread.java:637)

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  • Python performance: iteration and operations on nested lists

    - by J.J.
    Problem Hey folks. I'm looking for some advice on python performance. Some background on my problem: Given: A mesh of nodes of size (x,y) each with a value (0...255) starting at 0 A list of N input coordinates each at a specified location within the range (0...x, 0...y) Increment the value of the node at the input coordinate and the node's neighbors within range Z up to a maximum of 255. Neighbors beyond the mesh edge are ignored. (No wrapping) BASE CASE: A mesh of size 1024x1024 nodes, with 400 input coordinates and a range Z of 75 nodes. Processing should be O(x*y*Z*N). I expect x, y and Z to remain roughly around the values in the base case, but the number of input coordinates N could increase up to 100,000. My goal is to minimize processing time. Current results I have 2 current implementations: f1, f2 Running speed on my 2.26 GHz Intel Core 2 Duo with Python 2.6.1: f1: 2.9s f2: 1.8s f1 is the initial naive implementation: three nested for loops. f2 is replaces the inner for loop with a list comprehension. Code is included below for your perusal. Question How can I further reduce the processing time? I'd prefer sub-1.0s for the test parameters. Please, keep the recommendations to native Python. I know I can move to a third-party package such as numpy, but I'm trying to avoid any third party packages. Also, I've generated random input coordinates, and simplified the definition of the node value updates to keep our discussion simple. The specifics have to change slightly and are outside the scope of my question. thanks much! f1 is the initial naive implementation: three nested for loops. 2.9s def f1(x,y,n,z): rows = [] for i in range(x): rows.append([0 for i in xrange(y)]) for i in range(n): inputX, inputY = (int(x*random.random()), int(y*random.random())) topleft = (inputX - z, inputY - z) for i in xrange(max(0, topleft[0]), min(topleft[0]+(z*2), x)): for j in xrange(max(0, topleft[1]), min(topleft[1]+(z*2), y)): if rows[i][j] <= 255: rows[i][j] += 1 f2 is replaces the inner for loop with a list comprehension. 1.8s def f2(x,y,n,z): rows = [] for i in range(x): rows.append([0 for i in xrange(y)]) for i in range(n): inputX, inputY = (int(x*random.random()), int(y*random.random())) topleft = (inputX - z, inputY - z) for i in xrange(max(0, topleft[0]), min(topleft[0]+(z*2), x)): l = max(0, topleft[1]) r = min(topleft[1]+(z*2), y) rows[i][l:r] = [j+1 for j in rows[i][l:r] if j < 255]

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  • Nested attributes in the index view?

    - by user283179
    I seem to be getting error: uninitialized constant Style::Pic when I'm trying to render a nested object in to the index view the show view is fine. class Style < ActiveRecord::Base #belongs_to :users has_many :style_images, :dependent => :destroy accepts_nested_attributes_for :style_images, :reject_if => proc { |a| a.all? { |k, v| v.blank?} } #found this here http://ryandaigle.com/articles/2009/2/1/what-s-new-in-edge-rails-nested-attributes has_one :cover, :class_name => "Pic", :order => "updated_at DESC" accepts_nested_attributes_for :cover end class StyleImage < ActiveRecord::Base belongs_to :style #belongs_to :style_as_cover, :class_name => "Style", :foreign_key => "style_id" has_attached_file :pic, :styles => { :small => "200x0>", :normal => "600x> " } validates_attachment_presence :pic #validates_attachment_size :pic, :less_than => 5.megabytes end <% for style_image in @style.style_images %> <li><%= style_image.caption %></li> <div id="show_photo"> <%= image_tag style_image.pic.url(:normal) %></div> <% end %> As you can see from the above The main model style has many style_images, all these style_images are displayed in the show view but, in the the index view I wish to show one image which has been name and will act as a cover that is displayed for each style. in the index controller I have tried the following: class StylesController < ApplicationController layout "mini" def index @styles = Style.find(:all, :inculde => [:cover,]).reverse respond_to do |format| format.html # index.html.erb format.xml { render :xml => @styles } end end and the index <% @styles.each do |style| %> <%=image_tag style.cover.pic.url(:small) %> <% end %> class StyleImage < ActiveRecord::Base belongs_to :style #belongs_to :style_as_cover, :class_name => "Style", :foreign_key => "style_id" has_attached_file :pic, :styles => { :small => "200x0>", :normal => "600x> " } validates_attachment_presence :pic #validates_attachment_size :pic, :less_than => 5.megabytes end In the style_images table there is an cover_id also. From the about you can see that I have included the cover in the controller and the model. I have know idea where I'm going wrong here! If any one can help please do!

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  • doofus ASP.Net master page scrollbar question

    - by Stephen Falken
    Like happens to all of us sometimes, I inherited some crappy code I have to fix. We need to center our pages on widescreen machines, so we have a master page layout div like so: .MasterLayout { width:1100px; height: 100%; position:absolute; left:50%; margin-left:-550px; vertical-align:top; } I removed most of the detailed attributes for readability here, but here's how the table for the master page is laid out: <table border="0" cellpadding="0" cellspacing="0" style="width: 100%;"> <tr> <td style="width: 100%" align="center" colspan="2"> </td> </tr> <tr> <td colspan="2" style="height: 20px; background-color: #333;"> <asp:SiteMapPath/> </td> </tr> <tr> <td style="width: 86px; height: 650px; background-color: #B5C7DE; margin: 6px;" valign="top"> <asp:Menu /> <asp:SiteMapDataSource /> </td> <td style="background-color:#ffffff; margin:5px; width:1000px;" valign="top"> <asp:contentplaceholder id="ContentPlaceHolder1" runat="server"/> </td> </tr> </table> When resizing the browser window, the horizontal scrollbar only reaches as far as the left edge of the <asp:contentplaceholder/> control, and the <asp:menu/> that's in the 86px wide <td> is hidden. How can I fix this problem? THANKS IN ADVANCE

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  • ASP.Net master page scrollbar question

    - by Stephen Falken
    Like happens to all of us sometimes, I inherited some crappy code I have to fix. We need to center our pages on widescreen machines, so we have a master page layout div like so: .MasterLayout { width:1100px; height: 100%; position:absolute; left:50%; margin-left:-550px; vertical-align:top; } I removed most of the detailed attributes for readability here, but here's how the table for the master page is laid out: <table border="0" cellpadding="0" cellspacing="0" style="width: 100%;"> <tr> <td style="width: 100%" align="center" colspan="2"> </td> </tr> <tr> <td colspan="2" style="height: 20px; background-color: #333;"> <asp:SiteMapPath/> </td> </tr> <tr> <td style="width: 86px; height: 650px; background-color: #B5C7DE; margin: 6px;" valign="top"> <asp:Menu /> <asp:SiteMapDataSource /> </td> <td style="background-color:#ffffff; margin:5px; width:1000px;" valign="top"> <asp:contentplaceholder id="ContentPlaceHolder1" runat="server"/> </td> </tr> </table> When resizing the browser window, the horizontal scrollbar only reaches as far as the left edge of the <asp:contentplaceholder/> control, and the <asp:menu/> that's in the 86px wide <td> is hidden. How can I fix this problem? THANKS IN ADVANCE

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  • PHP-based LaTeX parser -- where to begin?

    - by Alex Basson
    The project: I want to build a LaTeX-to-MathML translator in PHP. Why? Because I'm a mathematician, and I want to publish math on my Drupal site. It doesn't have to translate all of LaTeX, since the basic document-level stuff is ably handled by the CMS and wouldn't be written in LaTeX to begin with; it just has to translate math written in LaTeX into math written in MathML. Although I feel as though I've done my due diligence, this doesn't seem to exist already. Maybe I'm wrong---if you know of something that would serve this purpose, by all means let me know, and thank you in advance. But assuming it doesn't exist, I guess I have to go write it myself. Here's the thing, though: I've never done anything this ambitious. I don't really know where to begin. I've used PHP for years, but just to do the standard "build a CMS with PHP and MySQL"-type of stuff. I've never attempted anything as seemingly sophisticated as translation from one language to another. I'm just dumb enough to consider doing it with regex---after all, LaTeX is a much more formal language, and it doesn't allow for nearly the kinds of pathological edge-cases, as say, HTML. But on the other hand, I'm just smart enough to realize this is probably a terrible idea: now I have two problems, and I sure don't want to end up like this guy. So if that's not the way to go (right?), what is? How should I start thinking about this problem? Am I essentially writing a LaTeX compiler in PHP, and if so, what do I need to know to do that (like, should I just go read the Purple Dragon book first?)? I'm both really excited and pretty intimidated by the prospect of this project, but hey, this is how we all learn to be programmers, right? If something we need doesn't exist, we go and build it, necessity is the mother of... you get the point. Tremendous thanks to everyone in advance for any and all guidance you can offer.

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  • Annoying Captcha >> How to programm a form that can SMELL difference between human and robot?

    - by Sam
    Hi folks. On the comment of my old form needing a CAPTHA, I felt I share my problem, perhaps you recognize it and find its time we had better solutions: FACTUAL PROBLEM I know most of my clients (typical age= 40~60) hate CAPTCHA things. Now, I myself always feel like a robot, when I have to sueeze my eyes and fill in the strange letters from the Capcha... Sometimes I fail! Go back etc. Turnoff. I mean comon its 2011, shouldnt the forms have better A.I. by now? MY NEW IDEA (please dont laugh) Ive thought about it and this is my idea's to tell difference between human and robot: My idea is to give credibility points. 100 points = human 0% = robot. require real human mouse movements require mousemovements that dont follow any mathematical pattern require non-instantaneous reading delays, between load and first input in form when typing in form, delays are measured between letters and words approve as human when typical human behaviour measured (deleting, rephrasing etc) dont allow instant pasting or all fields give points for real keyboard pressures retract points for credibility when hyperlinks in form Test wether fake email field (invisible by human) is populated (suggested by Tomalak) when more than 75% human cretibility, allow to be sent without captcha when less than 25% human crecibility, force captcha puzzle to be sure Could we write a A.I. PHP that replaces the human-annoying capthas, meanwhile stopping most spamservers filing in the data? Not only for the fun of it, but also actually to provide a 99% better alternative than CAPTHCA's. Imagine the userfriendlyness of your forms! Your site distinguishing itself from others, showing your audience your sites KNOWS the difference between a robot and a human. Imagine the advangage. I am trying to capture the essense of that distinguishing edge. PROGRAMMING QUESTION: 1) Are such things possible to programm? 2) If so how would you start such programm? 3) Are there already very good working solutions available elsewhere? 4) If it isn't so hard, your are welcome to share your answer/solutions below. 5) upon completion of hints and new ideas, could this page be the start of a new AI captcha, OR should I forget about it and just go with the flow, forget about the whole AI dream, and use captcha like everyone else.

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  • Browser displays page without styles for a short moment (visual glitch)

    - by Pierre
    I have observed that, very infrequently, Internet Explorer (7 or 8, it does not matter) displays our web pages (www.epsitec.ch) a short time without applying the CSS. The layout appears completely broken, with everything displayed sequentially from top to bottom. When the page has finished loading, everything finally gets displayed properly. Our web pages do not use any fancy scripting, just two javascript inclusions for QuantCast and Google Analytics, done at the end of the page. By the way, we already had the issue before adding the QuantCast script. The CSS gets linked in the <head> section: <head> <title>Crésus Comptabilité</title> <link rel="icon" href="/favicon.ico" type="image/x-icon" /> <link rel="shortcut icon" href="http://www.epsitec.ch/favicon.ico" /> <link href="../../style.css" rel="stylesheet" type="text/css" /> ... </head> and then follows static HTML up to the final chunk which includes the JavaScript: ... <div id="account"> <a class="deselect" href="/account/login">Identifiez-vous</a> <script type="text/javascript"> _qoptions={qacct:"..."}; </script> <script type="text/javascript" src="http://edge.quantserve.com/quant.js"> </script> <noscript> <img src="..." style="display: none;" border="0" height="1" width="1"/> </noscript> </div> <div id="contact"> <a href="/support/contact">Contactez-nous</a> </div> <div id="ending"><!-- --></div> </div> <script type="text/javascript"> ... </script> <script type="text/javascript"> var pageTracker = _gat._getTracker("..."); pageTracker._initData(); pageTracker._trackPageview(); </script> </body> As this is a very short visual glitch, I have no idea what provokes it. Worse, I cannot reproduce it and it appears only on seldom occasions. How can I further investigate the cause of the glitch? Are there any best practices I should be aware of?

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  • usercontrol hosted in IE renders as a textbox

    - by coxymla
    On my ongoing saga to mirror the hosting of a legacy app on a clean box, I've hit my next snag. One page relies on a big .NET UserControl that on the new machine renders only as a big, greyed out textarea (greyed out vertical scrollbar on the right hand edge. Inspecting the source shows the expected object tag.) This is particularly tricky because nobody seems to know much about hosted UserControls and all the discussions data back to 2002-2004. The page is quite simple: <%@ Page language="c#" Codebehind="DataExport.aspx.cs" AutoEventWireup="false" Inherits="yyyyy.Web.DataExport" %> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" > <html> <head> <title>DataExport</title> <link rel="Configuration" href="/xxxxx/yyyyy/DataExport.config"> </head> <body style="margin:0px;padding:0px;overflow:hidden"> <OBJECT id="DataExport" style="WIDTH: 100%; HEIGHT: 100%; position:absolute; left: 0px; top:0px" classid="yyyyy.Common.dll#yyyyy.Controls.DataExport" VIEWASTEXT> </OBJECT> </body> </html> The config file referenced: <?xml version="1.0" encoding="utf-8" ?> <configuration> <configSections> <sectionGroup name="yyyyy"> <section name="dataExport" type="yyyyy.Controls.DataExportSectionHandler,yyyyy.Common" /> </sectionGroup> </configSections> <yyyyy> <dataExport> <layoutFile>http://vm2/xxxxx/yyyyy/layout.xml</layoutFile> <webServiceUrl>http://vm2/xxxxx/yyyyy/services/yyyyy.asmx</webServiceUrl> </dataExport> </yyyyy> </configuration> What I've checked: Security permissions should be OK, the site is trusted and adding a URL exception to grant FullTrust doesn't change anything. Config file is acessible over the web, layout.xml is accessible, ASMX shows the expected command list Machine.config grants GET permission for the usercontrol.config file. What perhaps looks fishy to me: The DataExport UserControl references Aspose.Excel to generate the spreadsheets it exports. When I navigate to the page and get a blank textbox, then run gacutil /ldl, nothing is in the local download cache. On the working machine, running the same command after viewing the page shows a laundry list of DLLs including the control DLL and the Aspose DLL.

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  • train wreck. Rails requires RubyGems >= 1.3.2

    - by JZ
    I recently upgraded ruby to ruby 1.8.7 (2009-06-12 patchlevel 174) [i686-darwin10] and I think I broke rails. When I attempt to load rails. I get an odd message. Please help! $ ruby script/server Rails requires RubyGems = 1.3.2. Please install RubyGems and try again: http://rubygems.rubyforge.org $ rails -v Rails 3.0.0.beta $ gem -v 1.3.6 $ which gem /usr/bin/gem $ whereis gem /usr/bin/gem $ which rails /usr/bin/rails $ whereis rails /usr/bin/rails $ /usr/bin/gem -v 1.3.6 $ /usr/bin/rails -v Rails 3.0.0.beta $ ruby script/console Rails requires RubyGems >= 1.3.2. Please install RubyGems and try again: http://rubygems.rubyforge.org $ gem list rails *** LOCAL GEMS *** rails (3.0.0.beta, 2.3.5, 2.2.2, 1.2.6) $ gem list *** LOCAL GEMS *** abstract (1.0.0) actionmailer (3.0.0.beta, 2.3.5, 2.2.2, 1.3.6) actionpack (3.0.0.beta, 2.3.5, 2.2.2, 1.13.6) actionwebservice (1.2.6) activemerchant (1.4.1) activemodel (3.0.0.beta) activerecord (3.0.0.beta, 2.3.5, 2.2.2, 1.15.6) activerecord-tableless (0.1.0) activeresource (3.0.0.beta, 2.3.5, 2.2.2) activesupport (3.0.0.beta, 2.3.5, 2.2.2, 1.4.4) acts_as_ferret (0.4.3) arel (0.2.pre) authlogic (2.1.3) builder (2.1.2) bundler (0.9.3) calendar_date_select (1.15) capistrano (2.5.2) cgi_multipart_eof_fix (2.5.0) chronic (0.2.3) columnize (0.3.1) compass (0.8.17) daemons (1.0.10) dnssd (0.6.0) erubis (2.6.5) fastercsv (1.5.0) fastthread (1.0.1) fcgi (0.8.7) ferret (0.11.6) flay (1.4.0) flog (2.4.0) gbarcode (0.98.16) gem_plugin (0.2.3) git (1.2.5) haml (2.2.15) haml-edge (2.3.100) highline (1.5.0) hoe (2.4.0) hpricot (0.6.164) i18n (0.3.3) javan-whenever (0.3.7) jeweler (1.4.0) jscruggs-metric_fu (1.1.5) json_pure (1.2.0) libxml-ruby (1.1.2) linecache (0.43) mail (2.1.2) mechanize (0.9.3) memcache-client (1.7.8) mime-types (1.16) mislav-will_paginate (2.3.11) mocha (0.9.7) mojombo-chronic (0.3.0) mongrel (1.1.5) needle (1.3.0) net-scp (1.0.1) net-sftp (2.0.1, 1.1.1) net-ssh (2.0.4, 1.1.4) net-ssh-gateway (1.0.0) nifty-generators (0.3.0) nokogiri (1.4.0) openrain-action_mailer_tls (1.1.3) passenger (2.2.5) polyglot (0.2.9) prawn (0.6.3) prawn-core (0.6.3) prawn-format (0.2.3) prawn-layout (0.3.2) prawn-security (0.1.1) rack (1.1.0, 1.0.1) rack-mount (0.4.5) rack-test (0.5.3) rails (3.0.0.beta, 2.3.5, 2.2.2, 1.2.6) railties (3.0.0.beta) rake (0.8.7, 0.8.3) rake-compiler (0.6.0) RedCloth (4.1.1) reek (1.2.6) relevance-rcov (0.9.2.1) rmagick (2.12.2) roodi (2.1.0) rsl-stringex (1.0.3) rspec (1.2.9) rspec-rails (1.2.9) ruby-debug (0.10.3) ruby-debug-base (0.10.3) ruby-openid (2.1.2) ruby-yadis (0.3.4) ruby2ruby (1.2.4) ruby_parser (2.0.4) rubyforge (2.0.3) rubygems-update (1.3.6, 1.3.5) rubynode (0.1.5) searchlogic (2.3.9) sexp_processor (3.0.3) spree (0.9.4) sqlite3-ruby (1.2.5, 1.2.4) termios (0.9.4) test-unit (2.0.5) text-format (1.0.0) text-hyphen (1.0.0) thor (0.13.0) tlsmail (0.0.1) topfunky-gruff (0.3.5) treetop (1.4.3) tzinfo (0.3.16) xmpp4r (0.4)

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  • change attributes of SVG graph without refresh

    - by Mike Hudak
    Hello, I have a simple SVG graph generated by GraphViz: <?xml version="1.0" encoding="UTF-8" standalone="no"?> <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd"> <!-- Generated by graphviz version 2.26.3 (20100126.1600) --> <!-- Title: G Pages: 1 --> <svg width="138pt" height="168pt" viewBox="0.00 0.00 138.00 168.00" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <g id="graph1" class="graph" transform="scale(1 1) rotate(0) translate(4 164)"> <title>G</title> <polygon fill="white" stroke="white" points="-4,5 -4,-164 135,-164 135,5 -4,5"/> <!-- Node1 --> <g id="node1" class="node"><title>Node1</title> <a xlink:href="http://localhost/viz/applet.php" xlink:title="Internet"> <image xlink:href="images/cloud.png" width="130px" height="77px" preserveAspectRatio="xMinYMin meet" x="0" y="-159.5"/> <text text-anchor="middle" x="65" y="-116.4" font-family="Times New Roman,serif" font-size="14.00">&#39;.$Internet.&#39;</text> </a> </g> <!-- Node2 --> <g id="node2" class="node"><title>Node2</title> <a xlink:href="http://localhost/viz/applet.php"> <image xlink:href="images/file server.png" width="44px" height="45px" preserveAspectRatio="xMinYMin meet" x="43" y="-45.5"/> </a> </g> <!-- Node1&#45;&gt;Node2 --> <g id="edge2" class="edge"><title>Node1&#45;&gt;Node2</title> <a xlink:title="Bandwidth: 1544kbps&#10;Using link: 12%&#10;VOIP calls: 4&#10;Packet rate: 10000&#10;Packet loss: 2"> <path fill="none" stroke="black" d="M65,-82.2678C65,-73.5404 65,-64.358 65,-55.8964"/> <polygon fill="black" stroke="black" points="68.5001,-55.6524 65,-45.6524 61.5001,-55.6525 68.5001,-55.6524"/> </a> </g> </g> </svg> I want to change some atributes: for example " VOIP calls: 4 " -changing "4" to value from Database(LDAP) without refreshing whole SVG graph <a xlink:title="Bandwidth: 1544kbps&#10;Using link: 12%&#10;VOIP calls: 4&#10;Packet rate: 10000&#10;Packet loss: 2"> Thank you for your answers

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  • Looking for Reachability (2.0) Use Case Validation

    - by user350243
    There is so much info out there on using Apple's Reachability example, and so much is conflicting. I'm trying to find out of I'm using it (Reachability 2.0) correctly below. My App use case is this: If an internet connection is available through any means (wifi, LAN, Edge, 3G, etc.) a UIButton ("See More") is visible on various views. If no connection, the button is not visible. The "See More" part is NOT critical in any way to the app, it's just an add-on feature. "See More" could be visible or not anytime during the application lifecycle as connection is established or lost. Here's how I did it - Is this correct and/or is there a better way? Any help is Greatly Appreciated! lq // AppDelegate.h #import "RootViewController.h" @class Reachability; @interface AppDelegate : NSObject <UIApplicationDelegate> { UIWindow *window; UINavigationController *navigationController; RootViewController *rootViewController; Reachability* hostReach; // NOT USED: Reachability* internetReach; // NOT USED: Reachability* wifiReach; } @property (nonatomic, retain) IBOutlet UIWindow *window; @property (nonatomic, retain) IBOutlet UINavigationController *navigationController; @property (nonatomic, retain) IBOutlet RootViewController *rootViewController; @end // AppDelegate.m #import "AppDelegate.h" #import "Reachability.h" #define kHostName @"www.somewebsite.com" @implementation AppDelegate @synthesize window; @synthesize navigationController; @synthesize rootViewController; - (void) updateInterfaceWithReachability: (Reachability*) curReach { if(curReach == hostReach) { NetworkStatus netStatus = [curReach currentReachabilityStatus]; BOOL connectionRequired = [curReach connectionRequired]; // Set a Reachability BOOL value flag in rootViewController // to be referenced when opening various views if ((netStatus != ReachableViaWiFi) && (netStatus != ReachableViaWWAN)) { rootViewController.bConnection = (BOOL *)0; } else { rootViewController.bConnection = (BOOL *)1; } } } - (void) reachabilityChanged: (NSNotification* )note { Reachability* curReach = [note object]; NSParameterAssert([curReach isKindOfClass: [Reachability class]]); [self updateInterfaceWithReachability: curReach]; } - (void)applicationDidFinishLaunching:(UIApplication *)application { // NOTE: #DEFINE in Reachability.h: // #define kReachabilityChangedNotification @"kNetworkReachabilityChangedNotification" [[NSNotificationCenter defaultCenter] addObserver: self selector: @selector(reachabilityChanged:) name: kReachabilityChangedNotification object: nil]; hostReach = [[Reachability reachabilityWithHostName: kHostName] retain]; [hostReach startNotifer]; [self updateInterfaceWithReachability: hostReach]; [window addSubview:[navigationController view]]; [window makeKeyAndVisible]; } - (void)dealloc { [navigationController release]; [rootViewController release]; [window release]; [super dealloc]; } @end

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  • .NET: Is there a way to finagle a default namespace in an XPath 1.0 query?

    - by Cheeso
    I'm building a tool that performs xpath 1.0 queries on XHTML documents. The requirement to use a namespace prefix in the query is killing me. The query looks like this: html/body/div[@class='contents']/div[@class='body']/ div[@class='pgdbbyauthor']/h2[a[@name][starts-with(.,'Quick')]]/ following-sibling::ul[1]/li/a (all on one line) ...which is bad enough, except because it's xpath 1.0, I need to use an explicit namespace prefix on each QName, so it looks like this: ns1:html/ns1:body/ns1:div[@class='contents']/ns1:div[@class='body']/ ns1:div[@class='pgdbbyauthor']/ns1:h2[ns1:a[@name][starts-with(.,'Quick')]]/ following-sibling::ns1:ul[1]/ns1:li/ns1:a To set up the query, I do something like this: var xpathDoc = new XPathDocument(new StringReader(theText)); var nav = xpathDoc.CreateNavigator(); var xmlns = new XmlNamespaceManager(nav.NameTable); foreach (string prefix in xmlNamespaces.Keys) xmlns.AddNamespace(prefix, xmlNamespaces[prefix]); XPathNodeIterator selection = nav.Select(xpathExpression, xmlns); But what I want is for the xpathExpression to use the implicit default namespace. Is there a way for me to transform the unadorned xpath expression, after it's been written, to inject a namespace prefix for each element name in the query? I'm thinking, anything between two slashes, I could inject a prefix there. Excepting of course axis names like "parent::" and "preceding-sibling::" . And wildcards. That's what I mean by "finagle a default namespace". Is this hack gonna work? Addendum Here's what I mean. suppose I have an xpath expression, and before passing it to nav.Select(), I transform it. Something like this: string FixupWithDefaultNamespace(string expr) { string s = expr; s = Regex.Replace(s, "^(?!::)([^/:]+)(?=/)", "ns1:$1"); // beginning s = Regex.Replace(s, "/([^/:]+)(?=/)", "/ns1:$1"); // stanza s = Regex.Replace(s, "::([A-Za-z][^/:*]*)(?=/)", "::ns1:$1"); // axis specifier s = Regex.Replace(s, "\\[([A-Za-z][^/:*\\(]*)(?=[\\[\\]])", "[ns1:$1"); // predicate s = Regex.Replace(s, "/([A-Za-z][^/:]*)(?!<::)$", "/ns1:$1"); // end s = Regex.Replace(s, "^([A-Za-z][^/:]*)$", "ns1:$1"); // edge case s = Regex.Replace(s, "([-A-Za-z]+)\\(([^/:\\.,\\)]+)(?=[,\\)])", "$1(ns1:$2"); // xpath functions return s; } This actually works for simple cases I tried. To use the example from above - if the input is the first xpath expression, the output I get is the 2nd one, with all the ns1 prefixes. The real question is, is it hopeless to expect this Regex.Replace approach to work, as the xpath expressions get more complicated?

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  • Finding contained bordered regions from Excel imports.

    - by dmaruca
    I am importing massive amounts of data from Excel that have various table layouts. I have good enough table detection routines and merge cell handling, but I am running into a problem when it comes to dealing with borders. Namely performance. The bordered regions in some of these files have meaning. Data Setup: I am importing directly from Office Open XML using VB6 and MSXML. The data is parsed from the XML into a dictionary of cell data. This wonks wonderfully and is just as fast as using docmd.transferspreadsheet in Access, but returns much better results. Each cell contains a pointer to a style element which contains a pointer to a border element that defines the visibility and weight of each border (this is how the data is structured inside OpenXML, also). Challenge: What I'm trying to do is find every region that is enclosed inside borders, and create a list of cells that are inside that region. What I have done: I initially created a BFS(breadth first search) fill routine to find these areas. This works wonderfully and fast for "normal" sized spreadsheets, but gets way too slow for imports into the thousands of rows. One problem is that a border in Excel could be stored in the cell you are checking or the opposing border in the adjacent cell. That's ok, I can consolidate that data on import to reduce the number of checks needed. One thing I thought about doing is to create a separate graph that outlines the cells using the borders as my edges and using a graph algorithm to find regions that way, but I'm having trouble figuring out how to implement the algorithm. I've used Dijkstra in the past and thought I could do similar with this. So I can span out using no endpoint to search the entire graph, and if I encounter a closed node I know that I just found an enclosed region, but how can I know if the route I've found is the optimal one? I guess I could flag that to run a separate check for the found closed node to the previous node ignoring that one edge. This could work, but wouldn't be much better performance wise on dense graphs. Can anyone else suggest a better method? Thanks for taking the time to read this.

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  • What to Expect in Rails 4

    - by mikhailov
    Rails 4 is nearly there, we should be ready before it released. Most developers are trying hard to keep their application on the edge. Must see resources: 1) @sikachu talk: What to Expect in Rails 4.0 - YouTube 2) Rails Guides release notes: http://edgeguides.rubyonrails.org/4_0_release_notes.html There is a mix of all major changes down here: ActionMailer changes excerpt: Asynchronously send messages via the Rails Raise an ActionView::MissingTemplate exception when no implicit template could be found ActionPack changes excerpt Added controller-level etag additions that will be part of the action etag computation Add automatic template digests to all CacheHelper#cache calls (originally spiked in the cache_digests plugin) Add Routing Concerns to declare common routes that can be reused inside others resources and routes Added ActionController::Live. Mix it in to your controller and you can stream data to the client live truncate now always returns an escaped HTML-safe string. The option :escape can be used as false to not escape the result Added ActionDispatch::SSL middleware that when included force all the requests to be under HTTPS protocol ActiveModel changes excerpt AM::Validation#validates ability to pass custom exception to :strict option Changed `AM::Serializers::JSON.include_root_in_json' default value to false. Now, AM Serializers and AR objects have the same default behaviour Added ActiveModel::Model, a mixin to make Ruby objects work with AP out of box Trim down Active Model API by removing valid? and errors.full_messages ActiveRecord changes excerpt Use native mysqldump command instead of structure_dump method when dumping the database structure to a sql file. Attribute predicate methods, such as article.title?, will now raise ActiveModel::MissingAttributeError if the attribute being queried for truthiness was not read from the database, instead of just returning false ActiveRecord::SessionStore has been extracted from Active Record as activerecord-session_store gem. Please read the README.md file on the gem for the usage Fix reset_counters when there are multiple belongs_to association with the same foreign key and one of them have a counter cache Raise ArgumentError if list of attributes to change is empty in update_all Add Relation#load. This method explicitly loads the records and then returns self Deprecated most of the 'dynamic finder' methods. All dynamic methods except for find_by_... and find_by_...! are deprecated Added ability to ActiveRecord::Relation#from to accept other ActiveRecord::Relation objects Remove IdentityMap ActiveSupport changes excerpt ERB::Util.html_escape now escapes single quotes ActiveSupport::Callbacks: deprecate monkey patch of object callbacks Replace deprecated memcache-client gem with dalli in ActiveSupport::Cache::MemCacheStore Object#try will now return nil instead of raise a NoMethodError if the receiving object does not implement the method, but you can still get the old behavior by using the new Object#try! Object#try can't call private methods Add ActiveSupport::Deprecations.behavior = :silence to completely ignore Rails runtime deprecations What are the most important changes for you?

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  • circles and triangles problem

    - by Faken
    Hello everyone, I have an interesting problem here I've been trying to solve for the last little while: I have 3 circles on a 2D xy plane, each with the same known radius. I know the coordinates of each of the three centers (they are arbitrary and can be anywhere). What is the largest triangle that can be drawn such that each vertice of the triangle sits on a separate circle, what are the coordinates of those verticies? I've been looking at this problem for hours and asked a bunch of people but so far only one person has been able to suggest a plausible solution (though i have no way of proving it). The solution that we have come up with involves first creating a triangle about the three circle centers. Next we look at each circle individually and calculate the equation of a line that passes through the circle's center and is perpendicular to the opposite edge. We then calculate two intersection points of the circle. This is then done for the next two circles with a result of 6 points. We iterate over the 8 possible 3 point triangles that these 6 points create (the restriction is that each point of the big triangle must be on a separate circle) and find the maximum size. The results look reasonable (at least when drawn out on paper) and it passes the special case of when the centers of the circles all fall on a straight line (gives a known largest triangle). Unfortunate i have no way of proving this is correct or not. I'm wondering if anyone has encountered a problem similar to this and if so, how did you solve it? Note: I understand that this is mostly a math question and not programming, however it is going to be implemented in code and it must be optimized to run very fast and efficient. In fact, I already have the above solution in code and tested to be working, if you would like to take a look, please let me know, i chose not to post it because its all in vector form and pretty much impossible to figure out exactly what is going on (because it's been condensed to be more efficient). Lastly, yes this is for school work, though it is NOT a homework question/assignment/project. It's part of my graduate thesis (abet a very very small part, but still technically is part of it). Thanks for your help.

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  • Technical non-terminating condition in a loop

    - by Snarfblam
    Most of us know that a loop should not have a non-terminating condition. For example, this C# loop has a non-terminating condition: any even value of i. This is an obvious logic error. void CountByTwosStartingAt(byte i) { // If i is even, it never exceeds 254 for(; i < 255; i += 2) { Console.WriteLine(i); } } Sometimes there are edge cases that are extremely unlikeley, but technically constitute non-exiting conditions (stack overflows and out-of-memory errors aside). Suppose you have a function that counts the number of sequential zeros in a stream: int CountZeros(Stream s) { int total = 0; while(s.ReadByte() == 0) total++; return total; } Now, suppose you feed it this thing: class InfiniteEmptyStream:Stream { // ... Other members ... public override int Read(byte[] buffer, int offset, int count) { Array.Clear(buffer, offset, count); // Output zeros return count; // Never returns -1 (end of stream) } } Or more realistically, maybe a stream that returns data from external hardware, which in certain cases might return lots of zeros (such as a game controller sitting on your desk). Either way we have an infinite loop. This particular non-terminating condition stands out, but sometimes they don't. A completely real-world example as in an app I'm writing. An endless stream of zeros will be deserialized into infinite "empty" objects (until the collection class or GC throws an exception because I've exceeded two billion items). But this would be a completely unexpected circumstance (considering my data source). How important is it to have absolutely no non-terminating conditions? How much does this affect "robustness?" Does it matter if they are only "theoretically" non-terminating (is it okay if an exception represents an implicit terminating condition)? Does it matter whether the app is commercial? If it is publicly distributed? Does it matter if the problematic code is in no way accessible through a public interface/API? Edit: One of the primary concerns I have is unforseen logic errors that can create the non-terminating condition. If, as a rule, you ensure there are no non-terminating conditions, you can identify or handle these logic errors more gracefully, but is it worth it? And when? This is a concern orthogonal to trust.

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  • Getting up to speed on modern architecture

    - by Matt Thrower
    Hi, I don't have any formal qualifications in computer science, rather I taught myself classic ASP back in the days of the dotcom boom and managed to get myself a job and my career developed from there. I was a confident and, I think, pretty good programmer in ASP 3 but as others have observed one of the problems with classic ASP was that it did a very good job of hiding the nitty-gritty of http so you could become quite competent as a programmer on the basis of relatively poor understanding of the technology you were working with. When I changed on to .NET at first I treated it like classic ASP, developing stand-alone applications as individual websites simply because I didn't know any better at the time. I moved jobs at this point and spent the next several years working on a single site whose architecture relied heavily on custom objects: in other words I gained a lot of experience working with .NET as a middle-tier development tool using a quite old-fashioned approach to OO design along the lines of the classic "car" class example that's so often used to teach OO. Breaking down programs into blocks of functionality and basing your classes and methods around that. Although we worked under an Agile approach to manage the work the whole setup was classic client/server stuff. That suited me and I gradually got to grips with .NET and started using it far more in the manner that it should be, and I began to see the power inherent in the technology and precisely why it was so much better than good old ASP 3. In my latest job I have found myself suddenly dropped in at the deep end with two quite young, skilled and very cutting-edge programmers. They've built a site architecture which is modelling along a lot of stuff which is new to me and which, in truth I'm having a lot of trouble understanding. The application is built on a cloud computing model with multi-tenancy and the architecture is all loosely coupled using a lot of interfaces, factories and the like. They use nHibernate a lot too. Shortly after I joined, both these guys left and I'm now supposedly the senior developer on a system whose technology and architecture I don't really understand and I have no-one to ask questions of. Except you, the internet. Frankly I feel like I've been pitched in at the deep end and I'm sinking. I'm not sure if this is because I lack the educational background to understand this stuff, if I'm simply not mathematically minded enough for modern computing (my maths was never great - my approach to design is often to simply debug until it works, then refactor until it looks neat), or whether I've simply been presented with too much of too radical a nature at once. But the only way to find out which it is is to try and learn it. So can anyone suggest some good places to start? Good books, tutorials or blogs? I've found a lot of internet material simply presupposes a level of understanding that I just don't have. Your advice is much appreciated. Help a middle-aged, stuck in the mud developer get enthusastic again! Please!

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  • XSL transformation of SVG adds namespace attribute to new tag

    - by Steve
    I have a SVG file that I want to extend by adding onclick handlers to edges and nodes. I also want to add a script tag referring to a JavaScript. The problem is that the script tag gets an empty namespace attribute added to it. I haven't found any information regarding this that I understand. Why does XSLT add an empty namespace? XSL file: <?xml version="1.0"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:svg="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <xsl:output method="xml" encoding="utf-8" /> <xsl:template match="/svg:svg"> <xsl:copy> <script type="text/ecmascript" xlink:href="base.js" /> <!-- this tag gets a namespace attr --> <xsl:apply-templates /> </xsl:copy> </xsl:template> <!-- Identity transform http://www.w3.org/TR/xslt#copying --> <xsl:template match="@*|node()"> <xsl:copy> <xsl:apply-templates select="@*|node()"/> </xsl:copy> </xsl:template> <!-- Check groups and add functions --> <xsl:template match="svg:g"> <xsl:copy> <xsl:if test="@class = 'node'"> <xsl:attribute name="onclick">node_clicked()</xsl:attribute> </xsl:if> <xsl:if test="@class = 'edge'"> <xsl:attribute name="onclick">edge_clicked()</xsl:attribute> </xsl:if> <xsl:apply-templates select="@*|node()" /> </xsl:copy> </xsl:template> </xsl:stylesheet>

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  • Finding good heuristic for A* search

    - by Martin
    I'm trying to find the optimal solution for a little puzzle game called Twiddle (an applet with the game can be found here). The game has a 3x3 matrix with the number from 1 to 9. The goal is to bring the numbers in the correct order using the minimum amount of moves. In each move you can rotate a 2x2 square either clockwise or counterclockwise. I.e. if you have this state 6 3 9 8 7 5 1 2 4 and you rotate the upper left 2x2 square clockwise you get 8 6 9 7 3 5 1 2 4 I'm using a A* search to find the optimal solution. My f() is simply the number of rotations need. My heuristic function already leads to the optimal solution but I don't think it's the best one you can find. My current heuristic takes each corner, looks at the number at the corner and calculates the manhatten distance to the position this number will have in the solved state (which gives me the number of rotation needed to bring the number to this postion) and sums all these values. I.e. You take the above example: 6 3 9 8 7 5 1 2 4 and this end state 1 2 3 4 5 6 7 8 9 then the heuristic does the following 6 is currently at index 0 and should by at index 5: 3 rotations needed 9 is currently at index 2 and should by at index 8: 2 rotations needed 1 is currently at index 6 and should by at index 0: 2 rotations needed 4 is currently at index 8 and should by at index 3: 3 rotations needed h = 3 + 2 + 2 + 3 = 10 But there is the problem, that you rotate 4 elements at once. So there a rare cases where you can do two (ore more) of theses estimated rotations in one move. This means theses heuristic overestimates the distance to the solution. My current workaround is, to simply excluded one of the corners from the calculation which solves this problem at least for my test-cases. I've done no research if really solves the problem or if this heuristic still overestimates in same edge-cases. So my question is: What is the best heuristic you can come up with? (Disclaimer: This is for a university project, so this is a bit of homework. But I'm free to use any resource if can come up with, so it's okay to ask you guys. Also I will credit Stackoverflow for helping me ;) )

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  • jQuery animate slidding background image using mouse position wont stop... just keeps going

    - by simian
    I have a neat little jQuery script I am working on. Goal: parent div with overflow hidden holds a larger div with image. When I move the mouse to the left or right of the parent div, the div with image changes margin-left to move left or right. Problem is... if I move the mouse out of the parent div (left or right), the image keeps going. I need the image to stop when the mouse is not on the inside left or right edge of the parent div. Any ideas? <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <script type="text/javascript" src="http://code.jquery.com/jquery-latest.js"></script> <script type="text/javascript"> //<![CDATA[ jQuery.noConflict (); jQuery(document).ready(function(){ jQuery('#container').mousemove(function(e){ var parentWidth = jQuery('#container').width(); var parentWidthLeft = Math.round(.1 * jQuery('#container').width()); var parentWidthRight = Math.round(jQuery('#container').width() - parentWidthLeft); var parentHeight = jQuery('#container').height(); var parentOffset = jQuery('#container').offset(); var X = Math.round(e.pageX - parentOffset.left); var Y = Math.round(e.pageY - parentOffset.top); if (X<parentWidthLeft) { jQuery('#image').animate({'left': '-' + parentWidth }, 5000); } if (X>parentWidthRight) { jQuery('#image').animate({'left': parentWidth }, 5000); } if (X<=parentWidthRight && X>=parentWidthLeft) { jQuery('#image').stop(); } if (X<1) { jQuery('#image').stop(); } }); jQuery('#container').mouseleave(function(){ jQuery('#image').stop(); }); }); // ]]> </script> </head> <body> <div id="container" style="width: 500px; height: 500px; overflow: hidden; border: 10px solid #000; position: relative; margin: auto auto;"> <div id="image" style="position: absolute; left: 0; top: 0;"><img src="http://dump4free.com/imgdump/1/Carmen-Electra_1wallpaper1024x768.jpg" alt="" /></div> </div> </body> </html>

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