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  • How to convert X/Y position to Canvas Left/Top properties when using ItemsControl

    - by kshahar
    I am trying to use a Canvas to display objects that have "world" location (rather than "screen" location). The canvas is defined like this: <Canvas Background="AliceBlue"> <ItemsControl Name="myItemsControl" ItemsSource="{Binding MyItems}"> <ItemsControl.ItemTemplate> <DataTemplate> <Canvas> <TextBlock Canvas.Left="{Binding WorldX}" Canvas.Top="{Binding WorldY}" Text="{Binding Text}" Width="Auto" Height="Auto" Foreground="Red" /> </Canvas> </DataTemplate> </ItemsControl.ItemTemplate> </ItemsControl> </Canvas> MyItem is defined like this: public class MyItem { public MyItem(double worldX, double worldY, string text) { WorldX = worldX; WorldY = worldY; Text = text; } public double WorldX { get; set; } public double WorldY { get; set; } public string Text { get; set; } } In addition, I have a method to convert between world and screen coordinates: Point worldToScreen(double worldX, double worldY) { // return screen coordinates using the canvas properties and an internal MapData object } With the current implementation, the items are positioned in the wrong location, because their location is not converted to screen coordinates. How can I apply the worldToScreen method on the MyItem objects before they are added to the canvas?

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  • Loop through a set of HTML files and append text at top and bottom of each file

    - by NJTechGuy
    For instance, I have an HTML file like this : a.htm <body> Hello world! </body> I want : a.htm <html> <LINK href='style.css' rel=stylesheet type='text/css'> <body> Hello world! </body> </html> The code I have so far is : #!/bin/sh for i in `ls *.htm` do @echo off echo ***New top line*** > temp.txt type i >> temp.txt echo ***New bottom line*** >> temp.txt move /y temp.txt i done Errors : abc@bunny:~/fileAppendText$ ./loopAllFilesTest.sh ./loopAllFilesTest.sh: line 5: @echo: command not found ./loopAllFilesTest.sh: line 7: type: i: not found ./loopAllFilesTest.sh: line 9: move: command not found ./loopAllFilesTest.sh: line 5: @echo: command not found ./loopAllFilesTest.sh: line 7: type: i: not found ./loopAllFilesTest.sh: line 9: move: command not found ./loopAllFilesTest.sh: line 5: @echo: command not found ./loopAllFilesTest.sh: line 7: type: i: not found ./loopAllFilesTest.sh: line 9: move: command not found Please help. Thanks!

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  • Pass Arguments to Included Module in Ruby?

    - by viatropos
    I'm hoping to implement something like all of the great plugins out there for ruby, so that you can do this: acts_as_commentable has_attached_file :avatar But I have one constraint: That helper method can only include a module; it can't define any variables or methods. The reason for this is because, I want the options hash to define something like type, and that could be converted into one of say 20 different 'workhorse' modules, all of which I could sum up in a line like this: def dynamic_method(options = {}) include ("My::Helpers::#{options[:type].to_s.camelize}").constantize(options) end Then those 'workhorses' would handle the options, doing things like: has_many "#{options[:something]}" Here's what the structure looks like, and I'm wondering if you know the missing piece in the puzzle: # 1 - The workhorse, encapsuling all dynamic variables module My::Module def self.included(base) base.extend ClassMethods base.class_eval do include InstanceMethods end end module InstanceMethods self.instance_eval %Q? def #{options[:my_method]} "world!" end ? end module ClassMethods end end # 2 - all this does is define that helper method module HelperModule def self.included(base) base.extend(ClassMethods) end module ClassMethods def dynamic_method(options = {}) # don't know how to get options through! include My::Module(options) end end end # 3 - send it to active_record ActiveRecord::Base.send(:include, HelperModule) # 4 - what it looks like class TestClass < ActiveRecord::Base dynamic_method :my_method => "hello" end puts TestClass.new.hello #=> "world!" That %Q? I'm not totally sure how to use, but I'm basically just wanting to somehow be able to pass the options hash from that helper method into the workhorse module. Is that possible? That way, the workhorse module could define all sorts of functionality, but I could name the variables whatever I wanted at runtime.

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  • Flash browser game - HTTP + PHP vs Socket + Something else

    - by Maurycy Zarzycki
    I am developing a non-real time browser RPG game (think Kingdom of Loathing) which would be played from within a Flash app. At first I just wanted to make the communication with server using simply URLLoader to tell PHP what I am doing, and using $_SESSION to store data needed in-between request. I wonder if it wouldn't be better to base it on a socket connection, an app residing on a server written in Java or Python. The problem is I have never ever written such an app so I have no idea how much I'd have to "shift" my thoughts from simple responding do request (like PHP) to continuously working application. I won't hide I am also concerned about the memory and CPU usage of such Server app, when for example there would be hundreds of users connected. I've done some research. I have tried to do some research, but thanks to my nil knowledge on the sockets subject I haven't found anything helpful. So, considering the fact I don't need real time data exchange, will it be wise to develop the server side part as socket server, not in plain ol' PHP?

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  • Stop Rewrite htaccess create random pages

    - by Vistol
    Recently I saw in my Webmaster tools that some random sites are linking to my site. Actually this is not an big issue. The issue comes when the pages that are linked are not real pages because of my httaccess file. This is the htaccess code that Im running: <pre> #Options +FollowSymLinks RewriteEngine on RewriteRule ^([^/\.]+)/?$ index.php?id=$1 [L] RewriteRule ^([0-9]+)/(.*)$ index.php?id=$1 [L] </pre> So the real URLs would be: mysite.com/folder/999/TITLE-OR-NAME But cecause I only check the 1st folder ($1) which is an I numberD, this htaccess file is allowing hackers linking to my site with random URLs like: mysite.com/folder/999/TITLE-OR-NAME1 mysite.com/folder/999/TITLE-OR-NAME2 mysite.com/folder/999/TITLE-OR-NAME3 mysite.com/folder/999/TITLE-OR-NAME4 mysite.com/folder/999/TITLE-OR-NAME5 The worst part comes when google tells me that I am duplicating content!!! Actually I am not duplicating content, the htaccess is duplicating it for me. And yes I know, Im a bad newbie programmer but Id really appreciate your help with this cause Im struggling to find a solution but it never. Thank you very much for all your support to this newbie :)

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  • how to create a https proxy?

    - by davidshen84
    hi, i want to implement a simple ssl web proxy. i do not want to work with the network connection problems. so i think i can utilize a web server (like apache) to help me establish the connection, and my program works like a cgi app on the web server to redirect the web browser request. below is how i want to implement it: client make http/https requests to the target web site, and setting to use my http/https proxy; apache get the request, and use a rewrite rule to redirect the to my cgi app; my app parse the request and make request to the real web site; my app get the response from the real web site, then send the response back to the client; currently, http requests seem to work. but https requests do not work at all. i tried to use curl to make a request to a https web site through my proxy, and the result is CONNECTION FAILED. my question is, will my idea work? if yes, how to make the https requests work.

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  • Choosing approach for an IM client-server app

    - by John
    Update: totally re-wrote this to be more succint. I'm looking at a new application, one part of which will be very similar to standard IM clients, i.e text chat, ability to send attachments, maybe some real-time interaction like a multi-user whiteboard. It will be client-server, i.e all traffic goes through my central server. That means if I want to support cross-communication with other IM systems, I am still free to pick any protocol for my own client<--server communication - my server can use XMPP or whatever to talk to other systems. Clients are expected to include desktop apps, but probably also browser-based as well either through Flex/Silverlight or HTML/AJAX. I see 3 options for my own client-server communication layer: XMPP. The benefits are clients already exist as do open-source servers. However it requires the most up-front research/learning and also appears like it might raise legal issues due to GPL. Custom sockets. A server app makes connections with the clients, allowing any text/binary data to be sent very fast. However this approach requires building said server from scratch, and also makes a JS client tricky Servlets (or similar web server). Using tried and tested Java web-stack, clients send HTTP requests similar to AJAX-based websites. The benefit is the server is easy to write using well-established technologies, and easy to talk to. But what restrictions would this bring? Is it appropriate technology for real-time communication? Advice and suggests are welcome, especially what pros and cons surround using a web-server approach as compared to a socket-based approach.

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  • Java JRE vs GCJ

    - by Martijn Courteaux
    Hi, I have this results from a speed test I wrote in Java: Java real 0m20.626s user 0m20.257s sys 0m0.244s GCJ real 3m10.567s user 3m5.168s sys 0m0.676s So, what is the but of GCJ then? With this results I'm sure I'm not going to compile it with GCJ! I tested this on Linux, are the results in Windows maybe better than that? This was the code from the application: public static void main(String[] args) { String str = ""; System.out.println("Start!!!"); for (long i = 0; i < 5000000L; i++) { Math.sqrt((double) i); Math.pow((double) i, 2.56); long j = i * 745L; String string = new String(String.valueOf(i)); string = string.concat(" kaka pipi"); // "Kaka pipi" is a kind of childly call in Dutch. string = new String(string.toUpperCase()); if (i % 300 == 0) { str = ""; } else { str += Long.toHexString(i); } } System.out.println("Stop!!!"); }

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  • Are reads and (transactional) writes faster for entities of the same group than otherwise?

    - by indiehacker
    What advantage is there to designing child-parent relationships, which allow us to do writes in transactions, when there is never a real concern for consistency and contention and those sort of more complex issues? Does it make writes and reads faster? Consider my situation where there are many .png images that are referenced to one mosaic layer, and these .png images are written just once by a single user. The user can design many mosaic layers and her mosaic layers and referenced image entities are never changed/updated, they are just deleted some time in the future. Other users can come to the web project site and interactively view the mosaic layer as different layouts/configurations of the images as they play (query) with different criteria. So reads should be very fast. So there is no real worry of contention, or users conflicting with one another with writing new image entities. And because of that I am assuming there is no "requirement" for the .png image entities to be grouped by their same mosaic layer in child-parent relationship. However, perhaps, since the documentation says they are stored close to one another, if the many image entities were grouped as children to a single mosaic layer parent than this has the advantage that the writing (in transaction) and reading will happen much faster?

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  • Why use shorter VARCHAR(n) fields?

    - by chryss
    It is frequently advised to choose database field sizes to be as narrow as possible. I am wondering to what degree this applies to SQL Server 2005 VARCHAR columns: Storing 10-letter English words in a VARCHAR(255) field will not take up more storage than in a VARCHAR(10) field. Are there other reasons to restrict the size of VARCHAR fields to stick as closely as possible to the size of the data? I'm thinking of Performance: Is there an advantage to using a smaller n when selecting, filtering and sorting on the data? Memory, including on the application side (C++)? Style/validation: How important do you consider restricting colunm size to force non-sensical data imports to fail (such as 200-character surnames)? Anything else? Background: I help data integrators with the design of data flows into a database-backed system. They have to use an API that restricts their choice of data types. For character data, only VARCHAR(n) with n <= 255 is available; CHAR, NCHAR, NVARCHAR and TEXT are not. We're trying to lay down some "good practices" rules, and the question has come up if there is a real detriment to using VARCHAR(255) even for data where real maximum sizes will never exceed 30 bytes or so. Typical data volumes for one table are 1-10 Mio records with up to 150 attributes. Query performance (SELECT, with frequently extensive WHERE clauses) and application-side retrieval performance are paramount.

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  • What is the strangest programming language you have used?

    - by Anders Sandvig
    For me I think it has to be the scripting language of an old proprietary telephony platform I used in the early 2000s. The language itself was not so bad, but the fact that it was meant to be edited with a drag-and-drop GUI, which did not expose all the functionality I needed, was quite frustrating. I also remember having to manually implement many common functions, such as calculating the length of a string. Whenever I wanted to use "custom" or "advanced" functions, I had to edit the script files in a text editor, but as soon as I opened the files in the GUI again they were reformatted and restructured, which usually resulted in broken code. And, of course, this was an interpreted language, so I would not know it was broken until I actually ran it—oh, and did I mention that it did not run the same in the simulator as in the live environment? So, what is the strangest programming language or environment you have used, and why did you use it? Note that I'm interested in languages and environments that you have actually used for "real-world" situations, so Whitespace, Brainf***k and friends are not valid—unless you have used them for something "real", of course.

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  • simple wordpress plugin with some html and javascript

    - by h_a86
    I have an html page which i have to convert to wordpress plugin. my code is simple html and javascript <html> <head> <title>Calculate</title> <script language="javascript"> function addNumbers() { var val1 = parseInt(document.getElementById("value1").value); var val2 = parseInt(document.getElementById("value2").value); var ansD = document.getElementById("answer"); ansD.value = val1 + val2; } </script> </head> <body> <input type="text" id="value1" name="value1" value="1"/> <input type="text" id="value2" name="value2" value="2"/> <input type="button" name="Sumbit" value="Click here" onclick="javascript:addNumbers()"/> <input type="text" id="answer" name="answer" value=""/> </body> </html> I know basic plugin writing skills such as <?php /* Plugin Name: Coding friends hello world Plugin URI: http://www.codingfriends.com/ Description: Outputs hello world Version: 0.1 Author: Genux Author URI: http://www.codingfriends.com License: GPL2 */ function codingfriends_helloworld() { //put you form here and javascript here } add_action('get_header', 'codingfriends_helloworld'); ?> Thanks in advance

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  • Python - Access a class from a list using a key

    - by Fake Name
    Is there any way to make a list of classes behave like a set in python? Basically, I'm working on a piece of software that does some involved string comparison, and I have a custom class for handling the strings. Therefore, there is an instance of the class for each string. As a result, I have a large list containing all these classes. I would like to be able to access them like list[key], where in this case, the key is a string the class is based off of. It seems to me that I sould be able to do this somewhat easily, by adding something like __cmp__ to the class, but either I'm being obtuse (likely), or Im missing someting in the docs. Basically, I want to be able to do something like this (Python prompt example): >>class a: ... def __init__(self, x): ... self.var = x ... >>> from test import a >>> cl = set([a("Hello"), a("World"), a("Pie")]) >>> print cl set([<test.a instance at 0x00C866C0>, <test.a instance at 0x00C866E8>, <test.a instance at 0x00C86710>]) >>> cl["World"] <test.a instance at 0x00C866E8> Thanks!

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  • cocos2d - how to draw a bottle sprite with dynamically changing water level

    - by Oliver
    I am trying to draw a (2d) sprite in cocos2d showing a bottle. The bottle shall be able to have a dynamic water level (i.e. the amount of water in the bottle can change over the lifetime of the sprite). I am wondering how to do this. I currently have a PNG file of the empty bottle. I adjusted the alpha channel of that PNG so when rendering the sprite I can draw a blue rectangle and render the bottle texture over it. That will give the impression of the water being inside the bottle. However, the bottle's shape is not a rectangle itself of course, so the water can be seen out of the bounds of the bottle. I can change the bottle image in a way that only the bottle itself is transparent and set the "outside world" to an opaque color & alpha channel value, but that again prevents the "world background" to be visible in that area. I simply don't have a clue how to realize this in a sane manner. Do I really have to read every pixel of the bottle image, identify which pixel is "inside" of the bottle and then draw the water pixel by pixel? There must be an easier way, right? ;) Any best practices for these kinds of tasks? edit: see picture below, to make somewhat clearer, what I am talking about ;) http://i47.tinypic.com/10rqww0.png

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  • Context path routing in Tomcat ( service swapping )

    - by jojovilco
    Here is what I would like to achieve: I have a web service A which I want to be able to deploy side by side with other web services of type A - different version(s). For now I assume 2 instances side by side. I need it because the service has a warm up stage, which takes some time to build up stuff from DB and only after it is ready it can start serving requests ... I was thinking to deploy to Tomcat context paths like: "/ServiceA-1.0", "/ServiceA-2.0" and then have a "virtual" context like "/ServiceA" which will point to the desired physical service e.g. "/ServiceA-1.0". So external world will know about ServiceA, but internally, my ServiceA related stack would know about versioned ServiceA url ( there are more components involved but only ServiceA is serving outer world ). When new service is ready, I would just reconfigure the "virtual" context to point to a new service. So far, I was not able to find out how to do this with Tomcat and starting to tkink it is not possible. I found suggestions to place Apache Server in front of Tomcat and do the routing there, but I do not want to enroll another piece of software unless necessary. My questions are: - is this kind of a "virtual" context and routing possible to do with Tomcat? - any other options, wisdom and lessons learned how to achieve this kind of service swapping scenario? Best, Jozef

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  • c++ simple conditional logging

    - by Sunny
    Disclaimer: I'm not a c++ developer, I can only do basic things. (I understand pointers, just my knowledge is so rusty, I haven't touch c/c++ for about 20 years :) ) The setup: I have an Outlook addin, written in C#/.Net 1.1. It uses a c++ shim to load. Usually, this works pretty well, and I use in my c# code nlog for logging purposes. But sometimes, the addin fails to load, i.t. it does not hit the managed code at all for me to be able to investigate the problem from the log files. So, I need to hook some basic logging into the c++ shim - just writing in a file. I need to make it as simple as possible for our users to enable. Actually I would prefer not to ship it by default. I was thinking about something, which will check if a specific dll is present (the logging dll), and if so, to use it. Otherwise, it will just not log anything. That way, when I have a user with such a problems, I can send him only the logging dll, the user will save it in the runtime directory, and I'll have the file. I guess this have to be done with some form a factory solution, which returns either a dummy logger, or if the dll is found, a real one. Another option would be to make some simple logger, and rebuild the shim with or w/o using it, based on directives. This is not the desirable approach, because the shim needs to be signed, and I have to instruct the user to make a backup copy of the "real" one, then restore when done, etc., instead of just saving and deleting a dll. I'd appreciate any good suggestion how to approach it, together with links or sample code how to go after this. Cheers

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  • Call 32-bit or 64-bit program from bootloader

    - by user1002358
    There seems to be quite a lot of identical information on the Internet about writing the following 3 bootloaders: Infinite loop jmp $ Print a single character Print "Hello World". This is fantastic, and I've gone through these 3 variations with very little trouble. I'd like to write some 32- or 64-bit code in C and compile it, and call that code from the bootloader... basically a bootloader that, for example, sets the computer up to run some simple numerical simulation. I'll start by listing primes, for example, and then maybe some input/output from the user to maybe compute a Fourier transform. I don't know. I haven't found any information on how to do this, but I can already foresee some problems before I even begin. First of all, compiling a C program compiles it into one of several different files, depending on the target. For Windows, it's a PE file. For Linux, it's a .out file. These files are both quite different. In my instance, the target isn't Windows or Linux, it's just whatever I have written in the bootloader. Secondly, where would the actual code reside? The bootloader is exactly 512 bytes, but the program I write in C will certainly compile to something much larger. It will need to sit on my (virtual) hard disk, probably in some sort of file system (which I haven't even defined!) and I will need to load the information from this file into memory before I can even think about executing it. But from my understanding, all this is many, many orders of magnitude more complex than a 12-line "Hello World" bootloader. So my question is: How do I call a large 32- or 64-bit program (written in C/C++) from my 16-bit bootloader.

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  • Set the background color for a fixed range of cells

    - by Count Boxer
    I have VBA code in an Excel spreadsheet. It is used to set the font and background color of a cell based on the value in that cell. I am doing it in VBA instead of "Conditional Formatting" because I have more than 3 conditions. The code is: Private Sub Worksheet_Change(ByVal Target As Range) Dim c As Range, d As Range, fc As Long, bc As Long, bf As Boolean Set d = Intersect(Range("A:K"), Target) If d Is Nothing Then Exit Sub For Each c In d If c >= Date And c <= Date + 5 Then fc = 2: fb = True: bc = 3 Else Select Case c Case "ABC" fc = 2: fb = True: bc = 5 Case 1, 3, 5, 7 fc = 2: fb = True: bc = 1 Case "D", "E", "F" fc = 2: fb = True: bc = 10 Case "1/1/2009" fc = 2: fb = True: bc = 45 Case "Long string" fc = 3: fb = True: bc = 1 Case Else fc = 1: fb = False: bc = xlNone End Select End If c.Font.ColorIndex = fc c.Font.Bold = fb c.Interior.ColorIndex = bc c.Range("A1:D1").Interior.ColorIndex = bc Next End Sub The problem is in the "c.Range" line. It always uses the current cell as "A" and then goes four cells to the right. I want it to start in the "real" cell "A" of the current row and go to the "real" cell "D" of the current row. Basically, I want a fixed range and not a dynamic one.

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  • Binding Javascript Event Handlers to a an Ajax HTML Response?

    - by John
    Let's say I have the following HTML code <div id="outer"> <div id="inner">Hello World</div> </div> At the end of my HTML page, I use javascript to attach event handlers like so, document.getElementById('inner').onclick = function() {alert(this.innerHTML);} document.getElementById('outer').onclick = function() { /* An Ajax Call where the response, which will be a string of HTML content, then goes into document.getElementById('outer').innerHTML */ document.getElementById('inner').onclick = function() {alert(this.innerHTML);} } In the above code, I am expecting <div id="inner">Hello World 2</div> to come back which requires me to re-attach the onclick event handler. This makes sense because the new response coming back is just a string, and I have to tell the browser that after converting to DOM, i also need some event handlers So my question is, is there a better way to manage event handlers on AJAX response that contains HTML content? I could use inline javascript within the html response, but then it prevents me from achieving non-intrusive javascript. So is there a way to achieve non-intrusive javascript and an efficient way to "maintain" event handlers of ajax html responses?

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  • Python "callable" attribute (pseudo-property)

    - by mgilson
    In python, I can alter the state of an instance by directly assigning to attributes, or by making method calls which alter the state of the attributes: foo.thing = 'baz' or: foo.thing('baz') Is there a nice way to create a class which would accept both of the above forms which scales to large numbers of attributes that behave this way? (Shortly, I'll show an example of an implementation that I don't particularly like.) If you're thinking that this is a stupid API, let me know, but perhaps a more concrete example is in order. Say I have a Document class. Document could have an attribute title. However, title may want to have some state as well (font,fontsize,justification,...), but the average user might be happy enough just setting the title to a string and being done with it ... One way to accomplish this would be to: class Title(object): def __init__(self,text,font='times',size=12): self.text = text self.font = font self.size = size def __call__(self,*text,**kwargs): if(text): self.text = text[0] for k,v in kwargs.items(): setattr(self,k,v) def __str__(self): return '<title font={font}, size={size}>{text}</title>'.format(text=self.text,size=self.size,font=self.font) class Document(object): _special_attr = set(['title']) def __setattr__(self,k,v): if k in self._special_attr and hasattr(self,k): getattr(self,k)(v) else: object.__setattr__(self,k,v) def __init__(self,text="",title=""): self.title = Title(title) self.text = text def __str__(self): return str(self.title)+'<body>'+self.text+'</body>' Now I can use this as follows: doc = Document() doc.title = "Hello World" print (str(doc)) doc.title("Goodbye World",font="Helvetica") print (str(doc)) This implementation seems a little messy though (with __special_attr). Maybe that's because this is a messed up API. I'm not sure. Is there a better way to do this? Or did I leave the beaten path a little too far on this one? I realize I could use @property for this as well, but that wouldn't scale well at all if I had more than just one attribute which is to behave this way -- I'd need to write a getter and setter for each, yuck.

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  • Embedded Development Board

    - by ALF3130
    I'm new to the embedded development world and am looking to get my very first board. After some research, I realize that there aren't many choices with FPUs. This is important in my project as I'm going to be doing quite a bit of floating point computations. I found the Mini2440 which seems to run on the ARM920T core. This particular unit is perfect for my needs (decent price, all the right I/O ports, and a touch screen to boot) but it seems that it doesn't have an FPU. I don't know how big of a penalty I'd be paying for FP emulation, so I'm unsure of whether to pull the trigger on this one. That said: Can someone please confirm whether this product (Mini2440) has an FPU or not? My project will do image capture and analysis. Does anyone have any experience with running things like OpenMP on such platforms? Please suggest any other similar boards in the = $200 price range that have an FPU. This world is new to me. Any other advice or things I should be aware of is much appreciated.

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  • overload == (and != , of course) operator, can I bypass == to determine whether the object is null

    - by LLS
    Hello, when I try to overload operator == and != in C#, and override Equal as recommended, I found I have no way to distinguish a normal object and null. For example, I defined a class Complex. public static bool operator ==(Complex lhs, Complex rhs) { return lhs.Equals(rhs); } public static bool operator !=(Complex lhs, Complex rhs) { return !lhs.Equals(rhs); } public override bool Equals(object obj) { if (obj is Complex) { return (((Complex)obj).Real == this.Real && ((Complex)obj).Imaginary == this.Imaginary); } else { return false; } } But when I want to use if (temp == null) When temp is really null, some exception happens. And I can't use == to determine whether the lhs is null, which will cause infinite loop. What should I do in this situation. One way I can think of is to us some thing like Class.Equal(object, object) (if it exists) to bypass the == when I do the check. What is the normal way to solve the problem?

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  • Cannot see echo message but my localhost works

    - by Sean
    This is my very first php code and I can't seem to get it to work. (I'm using Eclipse) <html> <body> <?php echo 'Hello World!'; $txt = "I <3 you!"; $num = 19; ?> </html> </body> When I run it (http://localhost/Assignment3.0/index.php), I get: Not Found The requested URL /Assignment3.0/index.php was not found on this server. Apache/2.2.22 (Ubuntu) Server at localhost Port 80 But when I run this (http://localhost/), I get: It works! This is the default web page for this server. The web server software is running but no content has been added, yet. So what could be the problem? Where's my "Hello World!"? Also, for Stackoverflow formatting, how do I start a new line w/o adding a blank line in between?

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  • QLearning and never-ending episodes

    - by devoured elysium
    Let's imagine we have an (x,y) plane where a robot can move. Now we define the middle of our world as the goal state, which means that we are going to give a reward of 100 to our robot once it reaches that state. Now, let's say that there are 4 states(which I will call A,B,C,D) that can lead to the goal state. The first time we are in A and go to the goal state, we will update our QValues table as following: Q(state = A, action = going to goal state) = 100 + 0 One of 2 things can happen. I can end the episode here, and start a different one where the robot has to find again the goal state, or I can continue exploring the world even after I found the goal state. If I try to do this, I see a problem though. If I am in the goal state and go back to state A, it's Qvalue will be the following: Q(state = goalState, action = going to A) = 0 + gamma * 100 Now, if I try to go again to the goal state from A: Q(state = A, action = going to goal state) = 100 + gamma * (gamma * 100) Which means that if I keep doing this, as 0 <= gamma <= 0, both qValues are going to rise forever. Is this the expected behavior of QLearning? Am I doing something wrong? If this is the expected behavior, can't this lead to problems? I know that probabilistically, all the 4 states(A,B,C and D), will grow at the same rate, but even so it kinda bugs me having them growing forever. The ideia of allowing the agent to continue exploring even after finding the goal has to do with that the nearer he is from the goal state, the more likely it is to being in states that can be updated at the moment.

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  • SQL Server: Why use shorter VARCHAR(n) fields?

    - by chryss
    It is frequently advised to choose database field sizes to be as narrow as possible. I am wondering to what degree this applies to SQL Server 2005 VARCHAR columns: Storing 10-letter English words in a VARCHAR(255) field will not take up more storage than in a VARCHAR(10) field. Are there other reasons to restrict the size of VARCHAR fields to stick as closely as possible to the size of the data? I'm thinking of Performance: Is there an advantage to using a smaller n when selecting, filtering and sorting on the data? Memory, including on the application side (C++)? Style/validation: How important do you consider restricting colunm size to force non-sensical data imports to fail (such as 200-character surnames)? Anything else? Background: I help data integrators with the design of data flows into a database-backed system. They have to use an API that restricts their choice of data types. For character data, only VARCHAR(n) with n <= 255 is available; CHAR, NCHAR, NVARCHAR and TEXT are not. We're trying to lay down some "good practices" rules, and the question has come up if there is a real detriment to using VARCHAR(255) even for data where real maximum sizes will never exceed 30 bytes or so. Typical data volumes for one table are 1-10 Mio records with up to 150 attributes. Query performance (SELECT, with frequently extensive WHERE clauses) and application-side retrieval performance are paramount.

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