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  • using CSS to center FLOATED input elements wrapped in a DIV

    - by Tim
    There's no shortage of questions and answers about centering but I've not been able to get it to work given my specific circumstances, which involve floating. I want to center a container DIV that contains three floated input elements (split-button, text, checkbox), so that when my page is resized wider, they go from this: ||.....[ ][v] [ ] [ ] label .....|| to this ||......................[ ][v] [ ] [ ] label.......................|| They float fine, but when the page is made wider, they stay to the left: ||.....[ ][v] [ ] [ ] label .......................................|| If I remove the float so that the input elements are stacked rather than side-by-side: [ ][v] [ ] [ ] label then they DO center correctly when the page is resized. SO it is the float being applied to the elements of the DIV#hbox inside the container that is messing up the centering. Is what I want to do impossible because of the way float is designed to work? Here is my DOCTYPE, and the markup does validate at w3c: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> Here is my markup: <div id="term1-container"> <div class="hbox"> <div> <button id="operator1" class="operator-split-button">equals</button> <button id="operator1drop">show all operators</button> </div> <div><input type="text" id="term1"></input></div> <div><input type="checkbox" id="meta2"></input><label for="meta2" class="tinylabel">meta</label></div> </div> </div> And here's the (not-working) CSS: #term1-container {text-align: center} .hbox {margin: 0 auto;} .hbox div {float:left; } I have also tried applying display: inline-block to the floated button, text-input, and checkbox; and even though I think it applies only to text, I've also tried applying white-space: nowrap to the #term1-container DIV, based on posts I've seen here on SO. And just to be a little more complete, here's the jQuery that creates the split-button: $(".operator-split-button").button().click( function() { alert( "foo" ); }).next().button( { text: false, icons: { primary: "ui-icon-triangle-1-s" } }).click( function(){positionOperatorsMenu();} ) })

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  • Estimating the boundary of arbitrarily distributed data

    - by Dave
    I have two dimensional discrete spatial data. I would like to make an approximation of the spatial boundaries of this data so that I can produce a plot with another dataset on top of it. Ideally, this would be an ordered set of (x,y) points that matplotlib can plot with the plt.Polygon() patch. My initial attempt is very inelegant: I place a fine grid over the data, and where data is found in a cell, a square matplotlib patch is created of that cell. The resolution of the boundary thus depends on the sampling frequency of the grid. Here is an example, where the grey region are the cells containing data, black where no data exists. OK, problem solved - why am I still here? Well.... I'd like a more "elegant" solution, or at least one that is faster (ie. I don't want to get on with "real" work, I'd like to have some fun with this!). The best way I can think of is a ray-tracing approach - eg: from xmin to xmax, at y=ymin, check if data boundary crossed in intervals dx y=ymin+dy, do 1 do 1-2, but now sample in y An alternative is defining a centre, and sampling in r-theta space - ie radial spokes in dtheta increments. Both would produce a set of (x,y) points, but then how do I order/link neighbouring points them to create the boundary? A nearest neighbour approach is not appropriate as, for example (to borrow from Geography), an isthmus (think of Panama connecting N&S America) could then close off and isolate regions. This also might not deal very well with the holes seen in the data, which I would like to represent as a different plt.Polygon. The solution perhaps comes from solving an area maximisation problem. For a set of points defining the data limits, what is the maximum contiguous area contained within those points To form the enclosed area, what are the neighbouring points for the nth point? How will the holes be treated in this scheme - is this erring into topology now? Apologies, much of this is me thinking out loud. I'd be grateful for some hints, suggestions or solutions. I suspect this is an oft-studied problem with many solution techniques, but I'm looking for something simple to code and quick to run... I guess everyone is, really! Cheers, David

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  • How to properly preload images, js and css files?

    - by Kenny Bones
    Hi, I'm creating a website from scratch and I was really into this in the late 90's but the web has changed alot since then! And I'm more of a designer so when I started putting this site together, I basically did a system of php includes to make the site more "dynamic" When you first visit the site, you'll be presented to a logon screen, if you're not already logged on (cookies). If you're not logged on, a page called access.php is introdused. I thought I'd preload the most heavy images at this point. So that when the user is done logging on, the images are already cached. And this is working as I want. But I still notice that the biggest image still isn't rendered immediatly anyway. So it's seems kinda pointless. All of this has made me rethink how the site is structured and how scripts and css files are loaded. Using FireBug and YSlow with Firefox I see a few pointers like expires headers and reducing the size of each script. But is this really the culprit? For example, would this be really really stupid in the main index.php? The entire site is basically structured like this <?php require("dbconnect.php"); ?> <?php include ("head.php"); ?> And below this is basically just the body and the content of the site. Head.php however consists of the doctype, head portions, linking of two css style sheets, jQuery library, jQuery validation engine, Cufon and Cufon font file, and then the small Cufon.Replace snippet. The rest of the body comes with the index.php file, but at the bottom of this again is an include of a file called "footer.php" which basically consists of loading of a couple of jsLoader scripts and a slidepanel and then a js function. All of this makes the end page source look like a typical complete webpage, but I'm wondering if any of you can see immediatly that "this is really really stupid" and "don't do that, do this instead" etc. :) Are includes a bad way to go? This site is also pretty image intensive and I can probably do a little more optimization. But I don't think that's its the primary culprit. YSlow gives me a report of what takes up the most space: doc(1) - 5.8K js(5) - 198.7K css(2) - 5.6K cssimage(8) - 634.7K image(6) - 110.8K I know it looks like it's cssimage(8) that weighs the most, but I've already preloaded these images from before and it doesn't really affect the rendering.

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  • how to develop a program to minimize errors in human transcription of hand written surveys

    - by Alex. S.
    I need to develop custom software to do surveys. Questions may be of multiple choice, or free text in a very few cases. I was asked to design a subsystem to check if there is any error in the manual data entry for the multiple choices part. We're trying to speed up the user data entry process and to minimize human input differences between digital forms and the original questionnaires. The surveys are filled with handwritten marks and text by human interviewers, so it's possible to find hard to read marks, or also the user could accidentally select a different value in some question, and we would like to avoid that. The software must include some automatic control to detect possible typing differences. Each answer of the multiple choice questions has the same probability of being selected. This question has two parts: The GUI. The most simple thing I have in mind is to implement the most usable design of the questions display: use of large and readable fonts and space generously the choices. Is there something else? For faster input, I would like to use drop down lists (favoring keyboard over mouse). Given the questions are grouped in sections, I would like to show the answers selected for the questions of that section, but this could slow down the process. Any other ideas? The error checking subsystem. What else can I do to minimize or to check human typos in the multiple choice questions? Is this a solvable problem? is there some statistical methodology to check values that were entered by the users are the same from the hand filled forms? For example, let's suppose the survey has 5 questions, and each has 4 options. Let's say I have n survey forms filled in paper by interviewers, and they're ready to be entered in the software, then how to minimize the accidental differences that can have the manual transcription of the n surveys, without having to double check everything in the 5 questions of the n surveys? My first suggestion is that at the end of the processing of all the hand filled forms, the software could choose some forms randomly to make a double check of the responses in a few instances, but on what criteria can I make this selection? This validation would be enough to cover everything in a significant way? The actual survey is nation level and it has 56 pages with over 200 questions in total, so it will be a lot of hand written pages by many people, and the intention is to reduce the likelihood of errors and to optimize speed in the data entry process. The surveys must filled in paper first, given the complications of taking laptops or handhelds with the interviewers.

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  • c++ class member functions instatiated by traits

    - by Jive Dadson
    I am reluctant to say I can't figure this out, but I can't figure this out. I've googled and searched stackoverflow, and come up empty. The abstract, and possibly overly vague form of the question is, how can I use the traits-pattern to instantiate non-virtual member functions? The question came up while modernizing a set of multivariate function optimizers that I wrote more than 10 years ago. The optimizers all operate by selecting a straight-line path through the parameter space away from the current best point (the "update"), then finding a better point on that line (the "line search"), then testing for the "done" condition, and if not done, iterating. There are different methods for doing the update, the line-search, and conceivably for the done test, and other things. Mix and match. Different update formulae require different state-variable data. For example, the LMQN update requires a vector, and the BFGS update requires a matrix. If evaluating gradients is cheap, the line-search should do so. If not, it should use function evaluations only. Some methods require more accurate line-searches than others. Those are just some examples. The original version instantiates several of the combinations by means of virtual functions. Some traits are selected by setting mode bits that are tested at runtime. Yuck. It would be trivial to define the traits with #define's and the member functions with #ifdef's and macros. But that's so twenty years ago. It bugs me that I cannot figure out a whiz-bang modern way. If there were only one trait that varied, I could use the curiously recurring template pattern. But I see no way to extend that to arbitrary combinations of traits. I tried doing it using boost::enable_if, etc.. The specialized state info was easy. I managed to get the functions done, but only by resorting to non-friend external functions that have the this-pointer as a parameter. I never even figured out how to make the functions friends, much less member functions. The compiler (vc++ 2008) always complained that things didn't match. I would yell, "SFINAE, you moron!" but the moron is probably me. Perhaps tag-dispatch is the key. I haven't gotten very deeply into that. Surely it's possible, right? If so, what is best practice?

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  • How to implement a tagging plugin for jQuery

    - by anxiety
    Goal: To implement a jQuery plugin for my rails app (or write one myself, if necessary) that creates a "box" around text after a delimiter is typed. Example: With tagging on SO, the user begins typing a tag, then selects one from the drop-down list provided. The input field recognizes that a tag has been selected, puts a space and then is ready for the next tag. Similarly, I am attempting to use this plugin to put a box around the previously entered tag before moving to to accept the next tag/input. The instructions in the README.txt seem simple enough, however I have been receiving a $(".tagbox").tagbox is not a function error when debugging my app with firebug. Here is what I have in my application.js: $(document).ready( function(){ $('.tagbox').tagbox({ separator: /\[,]/, // specifying comma separation for <code>tags</code> }); }); And here is my _form.html.erb: <% form_for @tag do |f| %> <%= f.error_messages %> <p> <%= f.label :name %><br /> <%= text_field :tag, :name, { :method => :get, :class => "tagbox" } %> </p> <p><%= f.submit "Submit" %></p> <% end %> I have omitted some other code (namely the implementation of an autocomplete plugin) existing within my _form.html.erb and application.js for sake of readability. The inclusion or exclusion of this omitted code does not affect the performance of this plugin. I have included all of the necessary files for the tagbox plugin (as well as application.js after all other included JS files) within the javascript_include_tag in my application.html.erb file. I'm pretty much confused as to why I'd be getting this "not a function" error when jquery.tagbox.js clearly defines the function and is included in the head of my html page in question. I've been struggling with this plugin for longer than I'd like to admit, so any help would really be appreciated. And, of course, I'm open to any other plugins or from-scratch suggestions you may have in mind.. This tagbox plugin does not seem to have a wealth of documentation or any currently working examples. Also to note, I'm trying to avoid using jrails. Thanks for your time

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  • How to measure a canvas that has auto height and width

    - by Wymmeroo
    Hi Folks, I'm a beginner in silverlight so i hope i can get an answer that brings me some more light in the measure process of silverlight. I found an interessting flap out control from silverlight slide control and now I try to use it in my project. So that the slide out is working proper, I have to place the user control on a canvas. The user control then uses for itself the height of its content. I just wanna change that behavior so that the height is set to the available space from the parent canvas. You see the uxBorder where the height is set. How can I measure the actual height and set it to the border? I tried it with Height={Binding ElementName=notificationCanvas, Path=ActualHeight} but this dependency property has no callback, so the actualHeight is never set. What I want to achieve is a usercontrol like the tweetboard per example on Jesse Liberty's blog Sorry for my English writing, I hope you understand my question. <Canvas x:Name="notificationCanvas" Background="Red"> <SlideEffectEx:SimpleSlideControl GripWidth="20" GripTitle="Task" GripHeight="100"> <Border x:Name="uxBorder" BorderThickness="2" CornerRadius="5" BorderBrush="DarkGray" Background="DarkGray" Padding="5" Width="300" Height="700" > <StackPanel> <TextBlock Text="Tasks"></TextBlock> <Button x:Name="btn1" Margin="5" Content="{Binding ElementName=MainBorder, Path=Height}"></Button> <Button x:Name="btn2" Margin="5" Content="Second Button"></Button> <Button x:Name="btn3" Margin="5" Content="Third Button"></Button> <Button x:Name="btn1_Copy" Margin="5" Content="First Button"/> <Button x:Name="btn1_Copy1" Margin="5" Content="First Button"/> <Button x:Name="btn1_Copy2" Margin="5" Content="First Button"/> <Button x:Name="btn1_Copy3" Margin="5" Content="First Button"/> <Button x:Name="btn1_Copy4" Margin="5" Content="First Button"/> <Button x:Name="btn1_Copy5" Margin="5" Content="First Button"/> <Button x:Name="btn1_Copy6" Margin="5" Content="First Button"/> </StackPanel> </Border> </SlideEffectEx:SimpleSlideControl>

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  • Safari Frames Invisible Scrollbar

    - by mobiuschic42
    I'm working on a website that uses not just frames, but frames within frames (ew, I know, but I don't get to choose). It actually works OK most of the time, but I'm running into a problem with some of the frames within frames in Safari (only). Some of the two-deep frames render in Safari with a small space on the right-hand side of the frame - I think it's just the ones with scroll set to "no", but fiddling with the scroll settings hasn't fixed it yet. It basically looks like there should be a scroll bar there, but there isn't. I've been working on this awhile and tried a lot of things: changing the heights of the rows, changing the scroll settings, adding a colls='100%' tag, changing the heights of the contents of the frames, as well as checking to make sure widths are set to 100% throughout. Nothing's fixed it so far. Does any one know what's happening here? Here's the basic gist of the code and some screenshots - please forgive the lack of proper quotes; it still renders and fixing them all in this codebase would be a losing battle: <html> <frameset id=fset frameborder=0 border=0 framespacing=0 onbeforeunload="onAppClosing()" onload="onAppInit()" rows="125px,*,0"> <frame src="navFrame.html" name=ControlPanel marginwidth=0 marginheight=0 frameborder=0 scrolling=no noresize> <frame src="contentFrame.html" name=C marginwidth=0 marginheight=0 frameborder=0 scrolling=no> <frame src="invisiFrame.html" name=PING marginwidth=0 marginheight=0 frameborder=0 noresize> <noframes><body>Tough luck.</center></body></noframes> </frameset></html> Inside that second frame (named "C" and with src of "contentFrame") is this: <HTML> <HEAD><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=utf-8"></head> <frameset rows="48px,*,28px" border=0 frameborder=0 framespacing=0> <frame src="pageTitle.html" name=Title marginwidth=0 marginheight=0 noresize scrolling=no frameborder=0> <frame src="content.html" name=ScreenBody marginwidth=0 marginheight=0 frameborder=0> <frame src="submitBar.html" name=ContextPanel marginwidth=0 marginheight=0 frameborder=0 scrolling=no noresize> </FRAMESET> </HTML> The frames that are troublesome are the first frame (named "Title" with src of "pageTitle.html") and the last frame (named "ContextPanel" with src of "submitBar.html") both have their widths set to 100% and heights are either 100%, not set, or a value less than or equal to their row height. Here is an image of the problem:

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  • How do I get the current time in a Windows 7 gadget?

    - by norlando02
    For my first windows gadget I'm trying to make one that displays the current time and date. The code below is what I have, but I can't figure out why the javascript is not running. Any ideas? <html> <head> http-equiv="Content-Type" content="text/html; charset=Unicode" /> <title>Clock</title> <style type="text/css"> body { width: 130px; height: 60px; margin: 1 1 1 2; } body { font-family: Segoe UI, Arial; font-size: 11px; font-weight: bold; white-space: nowrap; } </style> <script type="text/javascript"> var background; var interval; var connection_id; var timeZone; var now; function load() { try { interval = 1000; connection_id = 0; timeZone = System.Time.currentTimeZone; update(); } catch(e){} } function update() { try { now = new Date(Date.parse(System.Time.getLocalTime(timeZone))); curDate.innerHTML = now.format('M jS, Y'); curTime.innerHTML = now.format('h:i:s A'); clearTimeout(connection_id); connection_id = setTimeout("update()", interval); } catch(e) {} </script> </head> <body onload="load()"> <div id="curDate"> </div> <div id="curTime"> </div> </body> </html>

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  • How do I make a full screen scrolling messagebox or window?

    - by chobo2
    Hi First let me start of saying I know absolutely nothing about c++ and I am really just more interested in getting this to work then learning c++(I got enough on my plate to learn). So basically I am trying to make a terms of service for my windows mobile 6 professional application but it seems I need to use c++ to do it. After hours of searching I found a solution but it developed for windows mobile standard. So they somehow used c++ to make a message box and on standard devices(ie non touch screen phones) the message box can have like scrolling. For some reason this is not the case with professional devices(touch screen devices). So my message box goes off the page and you can never accept or decline the terms. So your stuck and on the screen forever till you do some sort of soft restart. http://www.mobilepractices.com/2008/10/setupdll-sample-and-walkthrough-terms.html The above link is the tutorial but here is the actual file that seems to display the message. #include "stdafx.h" #include "ce_setup.h" // This is a variable containing the text to be displayed // in the Terms & Conditions dialog TCHAR Message[] = _T("TERMS & CONDITIONS\r\n ") _T("Selecting YES you're accepting our terms & conditions.\r\n") _T("This is just a sample application.\r\n") _T("From http://www.mobilepractices.com\r\n") _T("You can replace this text with your own.\r\n") _T("We're using a setup.dll to show this dialog.\r\n") _T("Extra line to force vertical scrollbar.\r\n") _T("Extra line to force vertical scrollbar.\r\n") _T("Extra line to force vertical scrollbar.\r\n") _T("Extra line to force vertical scrollbar.\r\n") _T("Extra line to force vertical scrollbar.\r\n") _T("Extra line to force vertical scrollbar.\r\n") _T("Last line.\r\n") ; // This function will be called when the user // tries to install the cab. According to its return // value the installation continues or is cancelled. // As this could be called more than once // (i.e. if there is not enough space on the target) // we should take care about fFirstCall parameter // to show the dialog only once. codeINSTALL_INIT Install_Init( HWND hwndParent, BOOL fFirstCall, BOOL fPreviouslyInstalled, LPCTSTR pszInstallDir ) { if (!fFirstCall || ::MessageBoxW(0, Message, _T("SplashScreenSample") , MB_YESNO) == IDYES) return codeINSTALL_INIT_CONTINUE; else return codeINSTALL_INIT_CANCEL; } So I want to change this to something that can scroll. Can I use like a panel control since I know what has scroll or something else? Thanks

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  • how do I make my submenu position dynamic based on the distance to the edge of the window?

    - by Mario Antoci
    I'm trying to write a jQuery script that will find the distance to the right edge of the browser window from my css class element and then position the child submenu dropdowns to the right or left depending on the available space to the right. Also it needs to revert to the default settings on hoverout. Here is what I have so far but it's not calculating properly. $(document).ready(function(){ $('#dnnMenu .subLevel').hover(function(){ if ($(window).width() - $('#dnnMenu .subLevel').offset().left - '540' >= '270') { $('#dnnMenu .subLevelRight').css('left', '270px');} else {$('#dnnMenu .subLevelRight').css('left', '-270px');} }); $(document).ready(function () { function HoverOver() { $(this).addClass('hover'); } function HoverOut() { $(this).removeClass('hover'); } var config = { sensitivity: 2, interval: 100, over: HoverOver, timeout: 100, out: HoverOut }; $("#dnnMenu .topLevel > li.haschild").hoverIntent(config); $(".subLevel li.haschild").hover(HoverOver, HoverOut); }); Basically I tried to take the width of the current window, minus the distance to the left edge of the browser of the first level submenu, minus the width of both elements together which would equal 540px, to calculate the distance to the right edge of the window when the first level submenu is hovered over. if the distance to the right of my first level submenu element is less than 540px then the second level sub menu css property is changed to position to the left instead of right. I also know that it needs to revert back to default after hover out so it can recalculate the distance from other positions within the menu structure and still have those second level submenus with enough room to still display on the right of the first level. here is css for the elements in question. #dnnMenu .subLevel{ display: none; position: absolute; margin: 0; z-index: 1210; background: #639ec8; text-transform: none;} #dnnMenu .subLevelRight{ position: absolute; display: none; left: 270px; top: 0px;} The site's not live yet and I tried to create a jsfiddle but it doesn't look right. Any help would be greatly appreciated! Best Regards, Mario

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  • div "top" bug IE and everything else. Big problem

    - by Victor
    Hi everyone. I am new in CSS so please help me in this problem. I hope to describe it wright. I am making div named content where my site content is. I made it with z-index:-1; so an image to be over this div. But in Chrome, FF and safari, content became inactive. I cant select text , click on link and write in the forms. So I tried with positive states in the z-index but IE don't know what this means. Damn. So I decided to make conditional div. Here is the code: .content { background:#FFF; width:990px; position:relative; float:left; top:50px; } .content_IE { background:#FFF; width:990px; position:relative; float:left; top: 50px; z-index:-1; } and here is the HTML: <!--[if IE 7]> <div class="content_IE" style="height:750px;"> <![endif]--> <div class="content" style="height:550px;"> Everything is fine with the z-index but the problem is that if there is no top in .content class everything looks fine in IE but there is no space in the other browsers. If i put back the top:50px; there onother 50px like padding in the .content_IE class. I mean that the page looks like I've put top:50px; and padding-top=50px;. I've try everything like margin-top:-50px; padding-top:-50px; and stuff like this but I am still in the circle. It look fine only if there is no top option in .content class. Please help.

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  • Calling a function that resides in the main page from a plugin?

    - by Justin Lee
    I want to call a function from within plugin, but the function is on the main page and not the plugin's .js file. EDIT I have jQuery parsing a very large XML file and building, subsequently, a large list (1.1 MB HTML file when dynamic content is copied, pasted, then saved) that has expand/collapse functionality through a plugin. The overall performance on IE is super slow and doggy, assuming since the page/DOM is so big. I am currently trying to save the collapsed content in the event.data when it is collapsed and remove it from the DOM, then bring it back when it is told to expand... the issue that I am having is that when I bring the content back, obviously the "click" and "hover" events are gone. I'm trying to re-assign them, currently doing so inside the plugin after the plugin expands the content. The issue then though is that is says the function that I declare within the .click() is not defined. Also the hover event doesn't seem to be re-assigning either.... if ($(event.data.trigger).attr('class').indexOf('collapsed') != -1 ) { // if expanding // console.log(event.data.targetContent); $(event.data.trigger).after(event.data.targetContent); $(event.data.target).hide(); /* This Line --->*/ $(event.data.target + 'a.addButton').click(addResourceToList); $(event.data.target + 'li.resource') .hover( function() { if (!($(this).attr("disabled"))) { $(this).addClass("over"); $(this).find("a").css({'display':'block'}); } }, function () { if (!($(this).attr("disabled"))) { $(this).removeClass("over"); $(this).children("a").css({'display':'none'}); } } ); $(event.data.target).css({ "height": "0px", "padding-top": "0px", "padding-bottom": "0px", "margin-top": "0px", "margin-bottom": "0px"}); $(event.data.target).show(); $(event.data.target).animate({ height: event.data.heightVal + "px", paddingTop: event.data.topPaddingVal + "px", paddingBottom: event.data.bottomPaddingVal + "px", marginTop: event.data.topMarginVal + "px", marginBottom: event.data.bottomMarginVal + "px"}, "normal");//, function(){$(this).hide();}); $(event.data.trigger).removeClass("collapsed"); $.cookies.set('jcollapserSub_' + event.data.target, 'expanded', {hoursToLive: 24 * 365}); } else if ($(event.data.trigger).attr('class').indexOf('collapsed') == -1 ) { // if collapsing $(event.data.target).animate({ height: "0px", paddingTop: "0px", paddingBottom: "0px", marginTop: "0px", marginBottom: "0px"}, "normal", function(){$(this).hide();$(this).remove();}); $(event.data.trigger).addClass("collapsed"); $.cookies.set('jcollapserSub_' + event.data.target, 'collapsed', {hoursToLive: 24 * 365}); } EDIT So, having new eyes truly makes a difference. As I was reviewing the code in this post this morning after being away over the weekend, I found where I had err'd. This: $(event.data.target + 'a.addButton').click(addResourceToList); Should be this (notice the space before a.addbutton): $(event.data.target + ' a.addButton').click(addResourceToList); Same issue with the "li.resource". So it was never pointing to the right elements... Thank you, Rene, for your help!!

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  • Having trouble wrapping functions in the linux kernel

    - by Corey Henderson
    I've written a LKM that implements Trusted Path Execution (TPE) into your kernel: https://github.com/cormander/tpe-lkm I run into an occasional kernel OOPS (describe at the end of this question) when I define WRAP_SYSCALLS to 1, and am at my wit's end trying to track it down. A little background: Since the LSM framework doesn't export its symbols, I had to get creative with how I insert the TPE checking into the running kernel. I wrote a find_symbol_address() function that gives me the address of any function I need, and it works very well. I can call functions like this: int (*my_printk)(const char *fmt, ...); my_printk = find_symbol_address("printk"); (*my_printk)("Hello, world!\n"); And it works fine. I use this method to locate the security_file_mmap, security_file_mprotect, and security_bprm_check functions. I then overwrite those functions with an asm jump to my function to do the TPE check. The problem is, the currently loaded LSM will no longer execute the code for it's hook to that function, because it's been totally hijacked. Here is an example of what I do: int tpe_security_bprm_check(struct linux_binprm *bprm) { int ret = 0; if (bprm->file) { ret = tpe_allow_file(bprm->file); if (IS_ERR(ret)) goto out; } #if WRAP_SYSCALLS stop_my_code(&cs_security_bprm_check); ret = cs_security_bprm_check.ptr(bprm); start_my_code(&cs_security_bprm_check); #endif out: return ret; } Notice the section between the #if WRAP_SYSCALLS section (it's defined as 0 by default). If set to 1, the LSM's hook is called because I write the original code back over the asm jump and call that function, but I run into an occasional kernel OOPS with an "invalid opcode": invalid opcode: 0000 [#1] SMP RIP: 0010:[<ffffffff8117b006>] [<ffffffff8117b006>] security_bprm_check+0x6/0x310 I don't know what the issue is. I've tried several different types of locking methods (see the inside of start/stop_my_code for details) to no avail. To trigger the kernel OOPS, write a simple bash while loop that endlessly starts a backgrounded "ls" command. After a minute or so, it'll happen. I'm testing this on a RHEL6 kernel, also works on Ubuntu 10.04 LTS (2.6.32 x86_64). While this method has been the most successful so far, I have tried another method of simply copying the kernel function to a pointer I created with kmalloc but when I try to execute it, I get: kernel tried to execute NX-protected page - exploit attempt? (uid: 0). If anyone can tell me how to kmalloc space and have it marked as executable, that would also help me solve the above problem. Any help is appreciated!

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  • Stored procedure performance randomly plummets; trivial ALTER fixes it. Why?

    - by gWiz
    I have a couple of stored procedures on SQL Server 2005 that I've noticed will suddenly take a significantly long time to complete when invoked from my ASP.NET MVC app running in an IIS6 web farm of four servers. Normal, expected completion time is less than a second; unexpected anomalous completion time is 25-45 seconds. The problem doesn't seem to ever correct itself. However, if I ALTER the stored procedure (even if I don't change anything in the procedure, except to perhaps add a space to the script created by SSMS Modify command), the completion time reverts to expected completion time. IIS and SQL Server are running on separate boxes, both running Windows Server 2003 R2 Enterprise Edition. SQL Server is Standard Edition. All machines have dual Xeon E5450 3GHz CPUs and 4GB RAM. SQL Server is accessed using its TCP/IP protocol over gigabit ethernet (not sure what physical medium). The problem is present from all web servers in the web farm. When I invoke the procedure from a query window in SSMS on my development machine, the procedure completes in normal time. This is strange because I was under the impression that SSMS used the same SqlClient driver as in .NET. When I point my development instance of the web app to the production database, I again get the anomalous long completion time. If my SqlCommand Timeout is too short, I get System.Data.SqlClient.SqlException: Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding. Question: Why would performing ALTER on the stored procedure, without actually changing anything in it, restore the completion time to less than a second, as expected? Edit: To clarify, when the procedure is running slow for the app, it simultaneously runs fine in SSMS with the same parameters. The only difference I can discern is login credentials (next time I notice the behavior, I'll be checking from SSMS with the same creds). The ultimate goal is to get the procs to sustainably run with expected speed without requiring occasional intervention. Resolution: I wanted to to update this question in case others are experiencing this issue. Following the leads of the answers below, I was able to consistently reproduce this behavior. In order to test, I utilize sp_recompile and pass it one of the susceptible sprocs. I then initiate a website request from my browser that will invoke the sproc with atypical parameters. Lastly, I initiate a website request to a page that invokes the sproc with typical parameters, and observe that the request does not complete because of a SQL timeout on the sproc invocation. To resolve this on SQL Server 2005, I've added OPTIMIZE FOR hints to my SELECT. The sprocs that were vulnerable all have the "all-in-one" pattern described in this article. This pattern is certainly not ideal but was a necessary trade-off given the timeframe for the project.

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  • Image animation problem in silverlight

    - by Jak
    Hi followed " http://www.switchonthecode.com/tutorials/silverlight-3-tutorial-planeprojection-and-perspective-3d#comment-4688 ".. the animation is working fine. I am new to silver light. when i use dynamic image from xml instead of static image as in tutorial,.. it is not working fine, please help me on this. i used list box.. for this animation effect do i need to change listbox to some other arrangement ? if your answer yes means, pls give me some sample code. Thanks in advance. Xaml code: <ListBox Name="listBox1"> <ListBox.ItemTemplate> <DataTemplate> <StackPanel> <Image Source="{Binding imgurl}" HorizontalAlignment="Left" Name="image1" Stretch="Fill" VerticalAlignment="Top" MouseLeftButtonUp="FlipImage" /> </StackPanel> </DataTemplate> </ListBox.ItemTemplate> </ListBox> My C# code: //getting image URL from xml XElement xmlads = XElement.Parse(e.Result); //i bind the url in to listBox listBox1.ItemsSource = from ads in xmlads.Descendants("ad") select new zestItem { imgurl = ads.Element("picture").Value }; public class zestItem { public string imgurl { get; set; } } private int _zIndex = 10; private void FlipImage(object sender, MouseButtonEventArgs e) { Image image = sender as Image; // Make sure the image is on top of all other images. image.SetValue(Canvas.ZIndexProperty, _zIndex++); // Create the storyboard. Storyboard flip = new Storyboard(); // Create animation and set the duration to 1 second. DoubleAnimation animation = new DoubleAnimation() { Duration = new TimeSpan(0, 0, 1) }; // Add the animation to the storyboard. flip.Children.Add(animation); // Create a projection for the image if it doesn't have one. if (image.Projection == null) { // Set the center of rotation to -0.01, which will put a little space // between the images when they're flipped. image.Projection = new PlaneProjection() { CenterOfRotationX = -0.01 }; } PlaneProjection projection = image.Projection as PlaneProjection; // Set the from and to properties based on the current flip direction of // the image. if (projection.RotationY == 0) { animation.To = 180; } else { animation.From = 180; animation.To = 0; } // Tell the animation to animation the image's PlaneProjection object. Storyboard.SetTarget(animation, projection); // Tell the animation to animation the RotationYProperty. Storyboard.SetTargetProperty(animation, new PropertyPath(PlaneProjection.RotationYProperty)); flip.Begin(); }

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  • Is there a reason why a base class decorated with XmlInclude would still throw a type unknown exception when serialized?

    - by Tedford
    I will simplify the code to save space but what is presented does illustrate the core problem. I have a class which has a property that is a base type. There exist 3 dervived classes which could be assigned to that property. If I assign any of the derived classes to the container then the XmlSerializer throws dreaded "The type xxx was not expected. Use the XmlInclude or SoapInclude attribute to specify types that are not known statically." exception when attempting to seralize the container. However my base class is already decorated with that attribute so I figure there must be an additional "hidden" requirement. The really odd part is that the default WCF serializer has no issues with this class hierarchy. The Container class [DataContract] [XmlRoot(ElementName = "TRANSACTION", Namespace = Constants.Namespace)] public class PaymentSummaryRequest : CommandRequest { /// <summary> /// Gets or sets the summary. /// </summary> /// <value>The summary.</value> /// <remarks></remarks> [DataMember] public PaymentSummary Summary { get; set; } /// <summary> /// Initializes a new instance of the <see cref="PaymentSummaryRequest"/> class. /// </summary> public PaymentSummaryRequest() { Mechanism = CommandMechanism.PaymentSummary; } } The base class [DataContract] [XmlInclude(typeof(xxxPaymentSummary))] [XmlInclude(typeof(yyyPaymentSummary))] [XmlInclude(typeof(zzzPaymentSummary))] [KnownType(typeof(xxxPaymentSummary))] [KnownType(typeof(xxxPaymentSummary))] [KnownType(typeof(zzzPaymentSummary))] public abstract class PaymentSummary { } One of the derived classes [DataContract] public class xxxPaymentSummary : PaymentSummary { } The serialization code var serializer = new XmlSerializer(typeof(PaymentSummaryRequest)); serializer.Serialize(Console.Out,new PaymentSummaryRequest{Summary = new xxxPaymentSummary{}}); The Exception System.InvalidOperationException: There was an error generating the XML document. --- System.InvalidOperationException: The type xxxPaymentSummary was not expected. Use the XmlInclude or SoapInclude attribute to specify types that are not known statically. at Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationWriterPaymentSummaryRequest.Write13_PaymentSummary(String n, String ns, PaymentSummary o, Boolean isNullable, Boolean needType) at Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationWriterPaymentSummaryRequest.Write14_PaymentSummaryRequest(String n, String ns, PaymentSummaryRequest o, Boolean isNullable, Boolean needType) at Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationWriterPaymentSummaryRequest.Write15_TRANSACTION(Object o) --- End of inner exception stack trace --- at System.Xml.Serialization.XmlSerializer.Serialize(XmlWriter xmlWriter, Object o, XmlSerializerNamespaces namespaces, String encodingStyle, String id) at System.Xml.Serialization.XmlSerializer.Serialize(TextWriter textWriter, Object o, XmlSerializerNamespaces namespaces) at UserQuery.RunUserAuthoredQuery() in c:\Users\Tedford\AppData\Local\Temp\uqacncyo.0.cs:line 47

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  • Combining FileStream and MemoryStream to avoid disk accesses/paging while receiving gigabytes of data?

    - by w128
    I'm receiving a file as a stream of byte[] data packets (total size isn't known in advance) that I need to store somewhere before processing it immediately after it's been received (I can't do the processing on the fly). Total received file size can vary from as small as 10 KB to over 4 GB. One option for storing the received data is to use a MemoryStream, i.e. a sequence of MemoryStream.Write(bufferReceived, 0, count) calls to store the received packets. This is very simple, but obviously will result in out of memory exception for large files. An alternative option is to use a FileStream, i.e. FileStream.Write(bufferReceived, 0, count). This way, no out of memory exceptions will occur, but what I'm unsure about is bad performance due to disk writes (which I don't want to occur as long as plenty of memory is still available) - I'd like to avoid disk access as much as possible, but I don't know of a way to control this. I did some testing and most of the time, there seems to be little performance difference between say 10 000 consecutive calls of MemoryStream.Write() vs FileStream.Write(), but a lot seems to depend on buffer size and the total amount of data in question (i.e the number of writes). Obviously, MemoryStream size reallocation is also a factor. Does it make sense to use a combination of MemoryStream and FileStream, i.e. write to memory stream by default, but once the total amount of data received is over e.g. 500 MB, write it to FileStream; then, read in chunks from both streams for processing the received data (first process 500 MB from the MemoryStream, dispose it, then read from FileStream)? Another solution is to use a custom memory stream implementation that doesn't require continuous address space for internal array allocation (i.e. a linked list of memory streams); this way, at least on 64-bit environments, out of memory exceptions should no longer be an issue. Con: extra work, more room for mistakes. So how do FileStream vs MemoryStream read/writes behave in terms of disk access and memory caching, i.e. data size/performance balance. I would expect that as long as enough RAM is available, FileStream would internally read/write from memory (cache) anyway, and virtual memory would take care of the rest. But I don't know how often FileStream will explicitly access a disk when being written to. Any help would be appreciated.

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  • Can I make a LaTeX macro 'return' a filename?

    - by drfrogsplat
    I'm writing my thesis/dissertation and since its an on-going work I don't always have the actual images ready for the figures I put into my document, but for various reasons want to automatically have it substitute a dummy figure in place when the included graphics file doesn't exist. E.g. I can do something like \includegraphics[width=8cm]{\chapdir/figures/fluxcapacitor} (where \chapdir is a macro for my 'current' chapter directory, e.g. \def\chapdir{./ch_timetravel} and if there's no ./ch_timetravel/figures/fluxcapacitor.jpg it'll insert ./commands/dummy.jpg instead. I've structured my macros (perhaps naïvely?) so that I have a macro (\figFileOrDummy) that determines the appropriate file to include by checking if the argument provided to it exists, so that I can call \includegraphics[properties]{\figFileOrDummy{\chapdir/figures/fluxcapacitor}}. Except I'm getting various errors depending on how I try to call this, which seem to suggest that I'm approaching the problem in a fundamentally flawed way as far as 'good LaTeX programming' goes. Here's the macro to check if the file exists (and 'return' either filename or the dummy filename): \newcommand{\figFileOrDummy}[1]{% % Figure base name (no extension) to be used if the file exists \def\fodname{#1}% \def\dummyfig{commands/dummy}% % Check if output is PS (.EPS) or PDF (.JPG/.PDF/.PNG/...) figures \ifx\pdfoutput\undefined% % EPS figures only \IfFileExists{\fodname.eps}{}{\def\fodname{\dummyfig}}% \else% % Check existence of various extensions: PDF, TIF, TIFF, JPG, JPEG, PNG, MPS \def\figtest{0}% flag below compared to this value \IfFileExists{\fodname.pdf}{\def\figfilenamefound{1}}{\def\figfilenamefound{0}}% \IfFileExists{\fodname.jpg}{\def\figfilenamefound{1}}{}% \IfFileExists{\fodname.png}{\def\figfilenamefound{1}}{}% % and so on... % If no files found matching the filename (flag is 0) then use the dummy figure \ifx\figfilenamefound\figtest% \def\fodname{\dummyfig}% \fi% \fi% % 'return' the filename \fodname% }% Alternatively, here's a much simpler version which seems to have similar problems: \newcommand{\figFileOrDummy}[1]{% \def\dummyfig{commands/dummy}% \dummyfig% } The \def commands seems to be processed after the expansion of the macro they're trying to define, so it ends up being \def {commands/dummy}... (note the space after \def) and obviously complains. Also it seems to treat the literal contents of the macro as the filename for \includegraphics, rather than resolving/expanding it first, so complains that the file '\def {commands/dummy}... .png' doesn't exist.. I've tried also doing something like \edef\figfilename{\figFileOrDummy{\chapdir/figures/fluxcapacitor}} to try to force it to make \figfilename hold just the value rather than the full macro, but I get an Undefined control sequence error complaining the variables I'm trying to \def in the \figFileOrDummy macro are undefined. So my question is either How do I make this macro expand properly?; or If this is the wrong way of structuring my macros, how should I actually structure such a macro, in order to be able to insert dummy/real figures automatically?; or Is there a package that already handles this type of thing nicely that I've overlooked? I feel like I'm missing something pretty fundamental here...

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  • Safely escaping and reading back a file path in ruby

    - by user336851
    I need to save a few informations about some files. Nothing too fancy so I thought I would go with a simple one line per item text file. Something like this : # write io.print "%i %s %s\n" % [File.mtime(fname), fname, Digest::SHA1.file(fname).hexdigest] # read io.each do |line| mtime, name, hash = line.scanf "%i %s %s" end Of course this doesn't work because a file name can contain spaces (breaking scanf) and line breaks (breaking IO#each). The line break problem can be avoided by dropping the use of each and going with a bunch of gets(' ') while not io.eof? mtime = Time.at(io.gets(" ").to_i) name = io.gets " " hash = io.gets "\n" end Dealing with spaces in the names is another matter. Now we need to do some escaping. note : I like space as a record delimiter but I'd have no issue changing it for one easier to use. In the case of filenames though, the only one that could help is ascii nul "\0" but a nul delimited file isn't really a text file anymore... I initially had a wall of text detailing the iterations of my struggle to make a correct escaping function and its reciprocal but it was just boring and not really useful. I'll just give you the final result: def write_name(io, val) io << val.gsub(/([\\ ])/, "\\\\\\1") # yes that' 6 backslashes ! end def read_name(io) name, continued = "", true while continued continued = false name += io.gets(' ').gsub(/\\(.)/) do |c| if c=="\\\\" "\\" elsif c=="\\ " continued=true " " else raise "unexpected backslash escape : %p (%s %i)" % [c, io.path, io.pos] end end end return name.chomp(' ') end I'm not happy at all with read_name. Way too long and akward, I feel it shouldn't be that hard. While trying to make this work I tried to come up with other ways : the bittorrent encoded / php serialize way : prefix the file name with the length of the name then just io.read(name_len.to_i). It works but it's a real pita to edit the file by hand. At this point we're halfway to a binary format. String#inspect : This one looks expressly made for that purpose ! Except it seems like the only way to get the value back is through eval. I hate the idea of eval-ing a string I didn't generate from trusted data. So. Opinions ? Isn't there some lib which can do all this ? Am I missing something obvious ? How would you do that ?

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  • go programming POST FormValue can't be printed

    - by poor_programmer
    Before I being a bit of background, I am very new to go programming language. I am running go on Win 7, latest go package installer for windows. I'm not good at coding but I do like some challenge of learning a new language. I wanted to start learn Erlang but found go very interesting based on the GO I/O videos in youtube. I'm having problem with capturing POST form values in GO. I spend three hours yesterday to get go to print a POST form value in the browser and failed miserably. I don't know what I'm doing wrong, can anyone point me to the right direction? I can easily do this in another language like C#, PHP, VB, ASP, Rails etc. I have search the entire interweb and haven't found a working sample. Below is my sample code. Here is Index.html page {{ define "title" }}Homepage{{ end }} {{ define "content" }} <h1>My Homepage</h1> <p>Hello, and welcome to my homepage!</p> <form method="POST" action="/"> <p> Enter your name : <input type="text" name="username"> </P> <p> <button>Go</button> </form> <br /><br /> {{ end }} Here is the base page <!DOCTYPE html> <html lang="en"> <head> <title>{{ template "title" . }}</title> </head> <body> <section id="contents"> {{ template "content" . }} </section> <footer id="footer"> My homepage 2012 copy </footer> </body> </html> now some go code package main import ( "fmt" "http" "strings" "html/template" ) var index = template.Must(template.ParseFiles( "templates/_base.html", "templates/index.html", )) func GeneralHandler(w http.ResponseWriter, r *http.Request) { index.Execute(w, nil) if r.Method == "POST" { a := r.FormValue("username") fmt.Fprintf(w, "hi %s!",a); //<-- this variable does not rendered in the browser!!! } } func helloHandler(w http.ResponseWriter, r *http.Request) { remPartOfURL := r.URL.Path[len("/hello/"):] fmt.Fprintf(w, "Hello %s!", remPartOfURL) } func main() { http.HandleFunc("/", GeneralHandler) http.HandleFunc("/hello/", helloHandler) http.ListenAndServe("localhost:81", nil) } Thanks! PS: Very tedious to add four space before every line of code in stackoverflow especially when you are copy pasting. Didn't find it very user friendly or is there an easier way?

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  • Calculating the Angle Between Two vectors Using Dot Product

    - by P. Avery
    I'm trying to calculate the angle between two vectors so that I can rotate a character in the direction of an object in 3D space. I have two vectors( character & object), loc_look, and modelPos respectively. For simplicity's sake I am only trying to rotate along the up axis...yaw. loc_look = D3DXVECTOR3 (0, 0, 1), modelPos = D3DXVECTOR3 (0, 0, 15); I have written this code which seems to be the correct calculations. My problem arises, seemingly, because the rotation I apply to the character's look vector(loc_look) exceeds the value of the object's position (modelPos). Here is my code: BOOL CEntity::TARGET() { if(graphics.m_model->m_enemy) { D3DXVECTOR3 modelPos = graphics.m_model->position; D3DXVec3Normalize(&modelPos, &modelPos); //D3DXVec3Normalize(&loc_look, &loc_look); float dot = D3DXVec3Dot(&loc_look, &modelPos); float yaw = acos(dot); BOOL neg = (loc_look.x > modelPos.x) ? true : false; switch ( neg ) { case false: Yaw(yaw); return true; case true: Yaw(-yaw); return true; } } else return false; } I rotate the character's orientation matrix with the following code: void CEntity::CalculateOrientationMatrix(D3DXMATRIX *orientationMatrix) { D3DXMatrixRotationAxis(&rotY, &loc_up, loc_yaw); D3DXVec3TransformCoord(&loc_look, &loc_look, &rotY); D3DXVec3TransformCoord(&loc_right, &loc_right, &rotY); D3DXMatrixRotationAxis(&rotX, &loc_right, loc_pitch); D3DXVec3TransformCoord(&loc_look, &loc_look, &rotX); D3DXVec3TransformCoord(&loc_up, &loc_up, &rotX); D3DXMatrixRotationAxis(&rotZ, &loc_look, loc_roll); D3DXVec3TransformCoord(&loc_up, &loc_up, &rotZ); D3DXVec3TransformCoord(&loc_right, &loc_right, &rotZ); *orientationMatrix *= rotX * rotY * rotZ; orientationMatrix->_41 = loc_position.x; orientationMatrix->_42 = loc_position.y; orientationMatrix->_43 = loc_position.z; //D3DXVec3Normalize(&loc_look, &loc_look); SetYawPitchRoll(0,0,0); // Reset Yaw, Pitch, & Roll Amounts } Also to note, the modelPos.x increases by 0.1 each iteration so the character will face the object as it moves along the x-axis... Now, when I run program, in the first iteration everything is fine(I haven't rotated the character yet). On the second iteration, the loc_look.x value is greater than the modelPos.x value(I rotated the character too much using the angle specified with the dot product calculations in the TARGET function). Therefore on the second iteration my code will rotate the character left to adjust for the difference in the vectors' x values... How can I tighten up the measurements so that I do not rotate my character's look vector by too great a value?

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  • C++ class member functions instantiated by traits

    - by Jive Dadson
    I am reluctant to say I can't figure this out, but I can't figure this out. I've googled and searched Stack Overflow, and come up empty. The abstract, and possibly overly vague form of the question is, how can I use the traits-pattern to instantiate non-virtual member functions? The question came up while modernizing a set of multivariate function optimizers that I wrote more than 10 years ago. The optimizers all operate by selecting a straight-line path through the parameter space away from the current best point (the "update"), then finding a better point on that line (the "line search"), then testing for the "done" condition, and if not done, iterating. There are different methods for doing the update, the line-search, and conceivably for the done test, and other things. Mix and match. Different update formulae require different state-variable data. For example, the LMQN update requires a vector, and the BFGS update requires a matrix. If evaluating gradients is cheap, the line-search should do so. If not, it should use function evaluations only. Some methods require more accurate line-searches than others. Those are just some examples. The original version instantiates several of the combinations by means of virtual functions. Some traits are selected by setting mode bits that are tested at runtime. Yuck. It would be trivial to define the traits with #define's and the member functions with #ifdef's and macros. But that's so twenty years ago. It bugs me that I cannot figure out a whiz-bang modern way. If there were only one trait that varied, I could use the curiously recurring template pattern. But I see no way to extend that to arbitrary combinations of traits. I tried doing it using boost::enable_if, etc.. The specialized state information was easy. I managed to get the functions done, but only by resorting to non-friend external functions that have the this-pointer as a parameter. I never even figured out how to make the functions friends, much less member functions. The compiler (VC++ 2008) always complained that things didn't match. I would yell, "SFINAE, you moron!" but the moron is probably me. Perhaps tag-dispatch is the key. I haven't gotten very deeply into that. Surely it's possible, right? If so, what is best practice?

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  • Akka framework support for finding duplicate messages

    - by scala_is_awesome
    I'm trying to build a high-performance distributed system with Akka and Scala. If a message requesting an expensive (and side-effect-free) computation arrives, and the exact same computation has already been requested before, I want to avoid computing the result again. If the computation requested previously has already completed and the result is available, I can cache it and re-use it. However, the time window in which duplicate computation can be requested may be arbitrarily small. e.g. I could get a thousand or a million messages requesting the same expensive computation at the same instant for all practical purposes. There is a commercial product called Gigaspaces that supposedly handles this situation. However there seems to be no framework support for dealing with duplicate work requests in Akka at the moment. Given that the Akka framework already has access to all the messages being routed through the framework, it seems that a framework solution could make a lot of sense here. Here is what I am proposing for the Akka framework to do: 1. Create a trait to indicate a type of messages (say, "ExpensiveComputation" or something similar) that are to be subject to the following caching approach. 2. Smartly (hashing etc.) identify identical messages received by (the same or different) actors within a user-configurable time window. Other options: select a maximum buffer size of memory to be used for this purpose, subject to (say LRU) replacement etc. Akka can also choose to cache only the results of messages that were expensive to process; the messages that took very little time to process can be re-processed again if needed; no need to waste precious buffer space caching them and their results. 3. When identical messages (received within that time window, possibly "at the same time instant") are identified, avoid unnecessary duplicate computations. The framework would do this automatically, and essentially, the duplicate messages would never get received by a new actor for processing; they would silently vanish and the result from processing it once (whether that computation was already done in the past, or ongoing right then) would get sent to all appropriate recipients (immediately if already available, and upon completion of the computation if not). Note that messages should be considered identical even if the "reply" fields are different, as long as the semantics/computations they represent are identical in every other respect. Also note that the computation should be purely functional, i.e. free from side-effects, for the caching optimization suggested to work and not change the program semantics at all. If what I am suggesting is not compatible with the Akka way of doing things, and/or if you see some strong reasons why this is a very bad idea, please let me know. Thanks, Is Awesome, Scala

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  • I have a problem with a TextBox in an application... A window has a Grid with two columns. The left

    - by haagel
    I have a problem with a TextBox in an application... A window has a Grid with two columns. The left column contains a control with a constant width but with a height that adapts. The right column contains a TextBox that takes up all remaining space in the Grid (and thereby in the Window). The Grid is given a minimal width and height and is wrapped within a ScrollViewer. If the user resizes the window to be smaller than the minimal widht/height of the Grid, scrollbars are displayed. This is exactly how I want it to be. However, a problem occurs when the user starts typing text. If the text is to long to fit in one line in the TextBox, I want the text to wrap. Therefore I set TextWrapping="Wrap" on the TextBox. But since the TextBox has an automatic width and is wrapped in a ScrollViewer (its actually the whole Grid that is wrapped), the TextBox just keeps expanding to the right. I do want the TextBox to expand if the window is expanded, but I don't want the TextBox to expand by the text. Rather the text should wrap inside the available TextBox. If the text don't fit within the TextBox height, a scrollbar should be displayed within the TextBox. Is there a way to accomplish this? Below is some code that shows my problem. <Window x:Class="AdaptingTextBoxes.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="MainWindow" Height="300" Width="400" Background="DarkCyan"> <Grid Margin="10" Name="LayoutRoot"> <ScrollViewer HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Auto"> <Grid MinWidth="300" MinHeight="200"> <Grid.ColumnDefinitions> <ColumnDefinition Width="auto" /> <ColumnDefinition Width="*" /> </Grid.ColumnDefinitions> <Button Grid.Column="0" Margin="0,0,10,0" Content="Button" Width="100" /> <TextBox Grid.Column="1" AcceptsReturn="True" TextWrapping="Wrap" ScrollViewer.HorizontalScrollBarVisibility="Disabled" ScrollViewer.VerticalScrollBarVisibility="Auto" /> </Grid> </ScrollViewer> </Grid> </Window>

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