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  • Putting WPF Control (ComboBox) into canvas with Visuals

    - by Mikhail
    I am writing a WPF chart and use Visuals for performance. The code looks like: public class DrawingCanvas2 : Canvas { private List<Visual> _visuals = new List<Visual>(); protected override Visual GetVisualChild( int index ) { return _visuals[index]; } protected override int VisualChildrenCount { get { return _visuals.Count; } } public void AddVisual( Visual visual ) { _visuals.Add( visual ); base.AddVisualChild( visual ); base.AddLogicalChild( visual ); } } Beside DrawingVisual elements (line, text) I need a ComboBox in the chart. So I tried this: public DrawingCanvas2() { ComboBox box = new ComboBox(); AddVisual( box ); box.Width = 100; box.Height = 30; Canvas.SetLeft( box, 10 ); Canvas.SetTop( box, 10 ); } but it does not work, there is no ComboBox displayed. What I am missing?

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  • Branchless memory manager?

    - by Richard Fabian
    Anyone thought about how to write a memory manager (in C++) that is completely branch free? I've written a pool, a stack, a queue, and a linked list (allocating from the pool), but I am wondering how plausible it is to write a branch free general memory manager. This is all to help make a really reusable framework for doing solid concurrent, in-order CPU, and cache friendly development. Edit: by branchless I mean without doing direct or indirect function calls, and without using ifs. I've been thinking that I can probably implement something that first changes the requested size to zero for false calls, but haven't really got much more than that. I feel that it's not impossible, but the other aspect of this exercise is then profiling it on said "unfriendly" processors to see if it's worth trying as hard as this to avoid branching.

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  • Is there a DRMAA Java library that works with Torque/PBS?

    - by dondondon
    Does anybody know a Java implementation of the DRMAA-API that is known to work with PBS/Torque cluster software? The background behind this: I would like to submit jobs to a newly set-up linux cluster from java using a DRMAA compliant API. The cluster is managed by PBS/Torque. Torque includes PBS DRMAA 1.0 library for Torque/PBS that contains a DRMA-C binding and provides in libdrmaa.so and .a binaries. I know that Sun grid engine includes a drmaa.jar providing a Java-DRMAA API. In fact I opted to use SGE but it was decided to try PBS first. The theory behind that decision was: 'DRMAA is a standard and therefore a Java API needs only a standards compliant drmaa-c binding.' However, I couldn't find such 'general DRMAA-C-java API' and now assume that this assumption is wrong and that the Java libraries are engine specific. Are we stuck here? Any comments appreciated.

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  • Smoothing Small Data Set With Second Order Quadratic Curve

    - by Rev316
    I'm doing some specific signal analysis, and I am in need of a method that would smooth out a given bell-shaped distribution curve. A running average approach isn't producing the results I desire. I want to keep the min/max, and general shape of my fitted curve intact, but resolve the inconsistencies in sampling. In short: if given a set of data that models a simple quadratic curve, what statistical smoothing method would you recommend? If possible, please reference an implementation, library, or framework. Thanks SO!

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  • Windows Mobile Development on MacBook Pro?

    - by Ted Nichols
    I am a frequent Windows Mobile application developer in need of a new development laptop. I am considering a MacBook or Macbook Pro running either Fusion from VMWare or Parallels Desktop. This will give me the option to port my applications to the iPhone depending on what MS does with WM 6.5 and 7. Has anybody tried doing Windows Mobile development using Microsoft Windows Mobile Device Center (or ActiveSync) and VS2008 on the MacBook Pro using one of these virtual machines? Does the device emulator work properly? What about debugging a Windows Mobile device over a USB cable? In general, do most USB drivers (non HID) designed for Windows work under these virtual machines? Thanks.

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  • Does JavaME and/or Proguard reorder assignments?

    - by chrisdew
    This is a simplified example - I have two threads: Can JavaME and/Proguard ever reorder the obX = ... statements, such that thread_B will have a null pointer exception at ob2.someMethod? thread_A: Object ob1 = null; Object ob2 = null; ... ob1 = something1; ob2 = something2; thread_B: if (ob2 != null) { ob1.someMethod(); ... } P.S. I do realise that synchronising these will avoid the issue. Synchronisation has both a performance overhead, and more importantly, a chance to introduce deadlock.

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  • Difference between 'scope' and 'namespace'?

    - by katriel
    What is the difference, in general, between the concepts of namespaces and scope? To my understanding, both describe the parts of a program in which a variable/object/method/function will be accessible. I understand that 'scope' tends to be a property of the variable (e.g., "This variable has global scope"), while a 'namespace' is a property of the program (e.g., "A Python function creates a local namespace"). Are there other differences? Global scope vs global namespace addresses a slightly narrower question: global namespaces in C++. http://www.alan-g.me.uk/tutor/tutname.htm states, There are a few very subtle differences between the terms but only a Computer Scientist pedant would argue with you, and for our purposes namespace and scope are identical. What are those subtle differences? Under what circumstances or with which kinds of languages do people use each concept?

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  • Does a .NET 4.0 website load faster for a reason?

    - by Clarence Klopfstein
    I have been using DotNetBlogEngine for many years, and today my host (JodoHost.com) officially turned on support for .NET 4.0. What I've noticed immediately is that the website loads tremendously faster on the first load, subsequent loads are only slightly faster. The website is compiled as a .NET 2.0 web application. Is there a known reason for this performance increase? Was there a change in the .NET 4.0 framework that improved the initial load time of websites into an application pool? This is hosted on a 2003 server. Here is the site for reference: http://www.ocdprogrammer.com

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  • Variable alpha blending in pylab

    - by Hooked
    How does one control the transparency over a 2D image in pylab? I'd like to give two sets of values (X,Y,Z,T) where X,Y are arrays of positions, Z is the color value, and T is the transparency to a function like imshow but it seems that the function only takes alpha as a scalar. As a concrete example, consider the code below that attempts to display two Gaussians. The closer the value is to zero, the more transparent I'd like the plot to be. from pylab import * side = linspace(-1,1,100) X,Y = meshgrid(side,side) extent = (-1,1,-1,1) Z1 = exp(-((X+.5)**2+Y**2)) Z2 = exp(-((X-.5)**2+(Y+.2)**2)) imshow(Z1, cmap=cm.hsv, alpha=.6, extent=extent) imshow(Z2, cmap=cm.hsv, alpha=.6, extent=extent) show() Note: I am not looking for a plot of Z1+Z2 (that would be trivial) but for a general way to specify the alpha blending across an image.

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  • Allow single-line accessor (getter/setter) syntax with Checkstyle

    - by Sam3
    We'd like to have trivial Java property accessors using a single line syntax, so they take up much much less space, and are more readable (in terms of 'seeing' the set of accessors quickly). But we do want to enforce multi-line method syntax for everything else in our checkstyle configuration. But I'm not sure how to make this exception for accessors in Checkstyle config and suspect it may not be possible. So we'd like our accessors to look something like this: public String getFoo() { return foo; } public void setFoo(String foo) { this.foo = foo; } [In fact we'd rather not have trivial accessors at all and instead just annotate the private member variables with @Property or something and have the accessors generated for us, since writing endless get and set code delivers no real benefit, but that's a general Java frustration and an aside as far as this question goes.]

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  • Any exprience with Castle ActiveRecord?

    - by afsharm
    Hi all, I was searching for a light data access framework based on NHibernate. I needed simple CRUD and some simple HQL or LINQ-to-NHhibernate queries. Performance was not an important issue and applications which I'm working on have simple table structure but many tables. This data access framework is going to be used in a ASP.NET Webform application. Once a time I found S#harp architecture, but it was developed for ASP.NET MVC. Just today I found Castle ActiveRecord. But I'm wondering: If any one has any experience with it? Is it suitable for me? Should I consider any specific matter? What about its future? Is Castle ActiveRecord supposed to be developed and be active in coming years? Thanks in Advance

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  • Understanding OpenGL Matrices

    - by Omega
    I'm starting to learn about 3D rendering and I've been making good progress. I've picked up a lot regarding matrices and the general operations that can be performed on them. One thing I'm still not quite following is OpenGL's use of matrices. I see this (and things like it) quite a lot: x y z n ------- 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 So my best understanding, is that it is a normalized (no magnitude) 4 dimensional, column-major matrix. Also that this matrix in particular is called the "identity matrix". Some questions: What is the "nth" dimension? How and when are these applied? My biggest confusion arises from how OpenGL makes use of this kind of data.

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  • Reading data from a socket, considerations for robustness and security

    - by w.brian
    I am writing a socket server that will implement small portions of the HTTP and the WebSocket protocol, and I'm wondering what I need to take into consideration in order to make it robust/secure. This is my first time writing a socket-based application so please excuse me if any of my questions are particularly naive. Here goes: Is it wrong to assume that you've received an entire HTTP request (WebSocket request, etc) if you've read all data available from the socket? Likewise, is it wrong to assume you've only received one request? Is TCP responsible for making sure I'm getting the "message" all at once as sent by the client? Or do I have to manually detect the beginning and end of each "message" for whatever protocol I'm implementing? Regarding security: What, in general, should I be aware of? Are there any common pitfalls when implementing something like this? As always, any feedback is greatly appreciated.

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  • Parametrize the WHERE clause?

    - by ControlFlow
    Hi, stackoverflow! I'm need to write an stored procedure for SQL Server 2008 for performing some huge select query and I need filter it results with specifying filtering type via procedure's parameters (parameterize where clause). I found some solutions like this: create table Foo( id bigint, code char, name nvarchar(max)) go insert into Foo values (1,'a','aaa'), (2,'b','bbb'), (3,'c','ccc') go create procedure Bar @FilterType nvarchar(max), @FilterValue nvarchar(max) as begin select * from Foo as f where case @FilterType when 'by_id' then f.id when 'by_code' then f.code when 'by_name' then f.name end = case @FilterType when 'by_id' then cast(@FilterValue as bigint) when 'by_code' then cast(@FilterValue as char) when 'by_name' then @FilterValue end end go exec Bar 'by_id', '1'; exec Bar 'by_code', 'b'; exec Bar 'by_name', 'ccc'; But it doesn't work when the columns has different data types... It's possible to cast all the columns to nvarchar(max) and compare they as strings, but I think it will cause a performance degradation... Is it possible to parameterize where clause in stored procedure without using things like EXEC sp_executesql (dynamic SQL and etc.)?

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  • setting up/installing/configuring nginx LEMP stack on fresh VPS server

    - by grant tailor
    I need some help in settingup/installing and configuring nginx LEMP stack on a fresh new VPS i have. The specs of the CentOS 5.7 VPS are 2GB DDR3 ECC RAM(4GB burst), 1 core 1.5Ghz(3Ghz burst) and 100GB RAID 10 storage, unmetered bandwidth @ 100Mpbs all for a whopping $25/month(unbeatable, yeah i know :) Anyways i have followed this LEMP(will also need MySQL and PHP) stack guide on linode http://library.linode.com/lemp-guides/centos-5 but basically what i want is to be able to host multiple website on this webserver after everything is setup. I am used to using DirectAdmin control panel on other server and want to have things setup so i can host multiple websites...mostly wordpress and drupal themes. Lets say 10 websites on this nginx web server. So can someone please help me on what i need to do to take "full" advantage of nginx power and performance, while been able to easily manage these multiple websites (wordpress and drupal themes)? Thanks.

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  • Using Parallel Extensions In Web Applications

    - by Greg
    I'd like to hear some opinions as to what role, if any, parallel computing approaches, including the potential use of the parallel extensions (June CTP for example), have a in web applications. What scenarios does this approach fit and/or not fit for? My understanding of how exactly IIS and web browsers thread tasks is fairly limited. I would appreciate some insight on that if someone out there has a good understanding. I'm more curious to know if the way that IIS and web browsers work limits the ROI of creating threaded and/or asynchronous tasks in web applications in general. Thanks in advance.

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  • Returning several COUNT results from one ASP SQL statement

    - by user89691
    Say I have a table like this: Field1 Field2 Field3 Field4 fred tom fred harry tom tom dick harry harry and I want to determine what proportion of it has been completed for each field. I can execute: SELECT COUNT (Field1) WHERE (Field1 <> '') AS Field1Count SELECT COUNT (Field2) WHERE (Field2 <> '') AS Field2Count SELECT COUNT (Field3) WHERE (Field3 <> '') AS Field3Count SELECT COUNT (Field4) WHERE (Field4 <> '') AS Field4Count Is it possible to roll up these separate SQL statements into one that will return the 4 results in one hit? Is there any performance advantage to doing so (given that the number of columns and rows may be quite large in practice)?

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  • extracting secrets from an embedded chip

    - by Will
    I am looking at an embedded system where secrets are stored in flash that is internal to the chip package, and there is no physical interface to get that information out - all access to this flash is policed by program code. All DMA attacks and JTAG and such are disabled. This seems to be a common locked-down configuration for system-on-a-chip. How might an attacker recover the secrets in that Flash? I understand they can fuzz for vulnerabilities in the app code and exploit it, that there could be some indistinct general side channel attack or something. But how would an attacker really go about trying to recover those keys? Are there viable approaches for a determined attacker to somehow shave-down the chip or some kind of microscope attack?

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  • Exclude category from custom taxonomy output

    - by Nordin
    Hello, I'm using the query below to output all links from a custom taxonomy. It outputs all posts that are tagged 'http' from the taxonomy 'words'. I would like to exclude some general categories from the output. So, fe. it only outputs links in the media and news categories. What would be the best way to achieve this. $wp_query->request = " SELECT DISTINCT * FROM $wpdb->posts LEFT JOIN $wpdb->term_relationships ON($wpdb->posts.ID = $wpdb->term_relationships.object_id) LEFT JOIN $wpdb->term_taxonomy ON($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id) LEFT JOIN $wpdb->terms ON($wpdb->term_taxonomy.term_id = $wpdb->terms.term_id) WHERE $wpdb->posts.post_type = 'post' AND $wpdb->posts.post_status = 'publish' AND $wpdb->term_taxonomy.taxonomy = 'words' AND $wpdb->terms.slug = 'http' ORDER BY $wpdb->posts.post_date DESC LIMIT $ppp OFFSET $offset"; $pagelinkposts = $wpdb->get_results($wp_query->request, OBJECT);

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  • Why dont Android applications provide an "Exit" option?

    - by Howiecamp
    Is there something in the Android developer guidelines that disuadea developers from providing the option to "exit" (stop running) an application from within the application itself? I love multitasking and all but it's not clear to me why: the vast majority of apps don't have their own Exit functions and hence just keep running forever don't give you a choice about running when you turn on the phone - they just do by default Both of these things lead to memory usage constantly increasing and your device running with this performance burden all of the time despite the fact that you may only want certain apps to run some of the time. Am I missing something?

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  • How to generate pdf files _with_ utf-8 multibyte characters using Zend Framework

    - by Sejanus
    Hello, I've got a "little" problem with Zend Framework Zend_Pdf class. Multibyte characters are stripped from generated pdf files. E.g. when I write aabccdee it becomes abcd with lithuanian letters stripped. I'm not sure if it's particularly Zend_Pdf problem or php in general. Source text is encoded in utf-8, as well as the php source file which does the job. Thank you in advance for your help ;) P.S. I run Zend Framework v. 1.6 and I use FONT_TIMES_BOLD font. FONT_TIMES_ROMAN does work

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  • send form data as web service in symfony

    - by Lars
    I am making a restrictive portal to a WiFi network using symfony, and I want to send a form as web service to other sites that want to use this portal. How should I solve this? I realize I could go the SOAP/WSDL route, but since symfony is already RESTful, it seems to me I could go the RESTful route with considerably less pain and loss of performance. Right now, I have a working form, but I've only made a casual attempt to bring the form to a remote site by using cURL. The form does not work remotely since the routing is not set up correctly (I think). Can someone help me with this? Thanks.

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  • I don't understand Application Domains

    - by Jeremy Edwards
    .NET has this concept of Application Domains which from what I understand can be used to load an assembly into memory. I've done some research on Application Domains as well as go to my local book store for some additional knowledge on this subject matter but it seems very scarce. All I know that I can do with Application Domains is to load assemblies in memory and I can unload them when I want. What are the capabilities other that I have mentioned of Application Domains? Do Threads respect Application Domains boundaries? Are there any drawbacks from loading Assemblies in different Application Domains other than the main Application Domains beyond performance of communication? Links to resources that discuss Application Domains would be nice as well. I've already checked out MSDN which doesn't have that much information about them.

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  • Help need to with MySQL query to join data spanning multiple tables and use data as column names

    - by gurun8
    I need a little help putting together a SQL query that will give me the following resultsets: and The data model looks like this: The tricky part for me is that the columns to the right of the "Product" in the resultset aren't really columns in the database but rather key/value pairs spanned across the data model. Table data is as follows: My apologies in advance for the image heavy question and the image quality. This just seemed like the easiest way to convey the information. It'll probably take someone less time to write the query statement to achieve the results than it did for me to assemble this question. By the way, the "product_option" table image is truncated but it illustrated the general idea of the data structure. The MySQL server version is 5.1.45.

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  • Help with these warnings. [inheritance].

    - by sil3nt
    Hello there. I have a set of code, which mimics a basic library cataloging system. There is a base class named items, in which the the general id,title and year variables are defined and 3 other derived classes (DVD,Book and CD). Base [Items] Derived [DVD,Book,CD]. The programs runs, however I get the following warnings, I'm not sure how to fix these. "C:\Program Files\gcc\bin/g++" -Os -mconsole -g -Wall -Wshadow -fno-common mainA4.cpp -o mainA4.exe In file included from mainA4.cpp:5: a4.h: In constructor `DVD::DVD(int, std::string, int, std::string)': a4.h:28: warning: `DVD::director' will be initialized after a4.h:32: warning: base `Items' a4.h:32: warning: when initialized here a4.h: In constructor `Book::Book(int, std::string, int, std::string, int)': a4.h:48: warning: `Book::numPages' will be initialized after a4.h:52: warning: base `Items' a4.h:52: warning: when initialized here a4.h: In constructor `CD::CD(int, std::string, int, std::string, int)': a4.h:66: warning: `CD::numSongs' will be initialized after a4.h:70: warning: base `Items' a4.h:70: warning: when initialized here Exit code: 0

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