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  • Are protected constructors considered good practice?

    - by Álvaro G. Vicario
    I'm writing some little helper classes to handle trees. Basically, I have a node and a special root node that represents the tree. I want to keep it generic and simple. This is part of the code: <?php class Tree extends TreeNode{ public function addById($node_id, $parent_id, $generic_content){ if( $parent = $this->findNodeById($parent_id) ){ $parent->addChildById($node_id, $generic_content); } } } class TreeNode{ public function __construct($node_id, $parent_id, $generic_content){ // ... } protected function addChildById($node_id, $generic_content){ $this->children[] = new TreeNode($this->node_id, $node_id, $generic_content); } } $Categories = new Tree; $Categories->addById(1, NULL, $foo); $Categories->addById(2, NULL, $bar); $Categories->addById(3, 1, $gee); ?> My questions: Is it sensible to force TreeNode instances to be created through TreeNode::addById()? If it's so, would it be good practise to declare TreeNode::__construct() as private/protected?

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  • Data structure for unrooted trees

    - by Esmond
    I'm having problems figuring out how to build an unrooted tree with weighted edges and what data structure to store such a tree. An example of an unrooted tree would be like the one here: http://www.bio.davidson.edu/courses/GENOMICS/seq/unrooted.gif The problem i am having is the leaves would only have 1 link to the internal nodes and the internal nodes would have 3 links(the internal nodes would have 2 children and a link to another internal node). Do i have to distinguish between the 2 different kinds of nodes or can i have one class having the function of both types of nodes?

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  • Binding in ContentControl Crash

    - by ImJames
    Can anyone tell me why this crashes my app? There seems to be some endless recursion by I can't figure out why. I get this exception Logical tree depth exceeded while traversing the tree. This could indicate a cycle in the tree <ContentControl Content="{Binding}"> <ContentControl.ContentTemplate> <DataTemplate> <Button Content="{Binding MyString}"/> </DataTemplate> </ContentControl.ContentTemplate> </ContentControl> And this is all I have as Source public MainWindow() { InitializeComponent(); MyString = "Test"; this.DataContext = this; } public string MyString { get; set; }

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  • How to ignore viewstate of a previous request for particular control?

    - by AaronLS
    I am dynamically generating controls, and sometimes I want to create a control and have it ignore the viewstate. For example, sometimes the user has clicked a button indicating they want a different form loaded, so the control tree I generate on postback is different from the original control tree. This is fine, except when I call Controls.Add then it tries to load the viewstate form the old controls into the new controls if the control tree structure is similar, and I want them to instead ignore that viewstate(and also ignore the postback values for input controls as well). Can I do something like set the IDs of the controls or something that would allow me to conditionally prevent them from getting the viewstate/postback data of the previous request?

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  • Small questions on data structure

    - by John Graveston
    Hi, I'm trying to search the parent of a node with Kruskal's algorithm. My program works just fine, but I think I have heard of a method to improve the speed of the algorithm by reconstructing the tree while searching for the parent node and connecting it to the parent node. I'm pretty sure that I've heard of this somewhere, maybe in a lecture. Can anyone refresh my memory? And also, given a number of arrays, when searching for the minimum and the maximum value from a certain section of an array, what is the name of the tree that can calculate the minimum/maximum value from the array by making a binary tree that has the minimum/maximum value of each array in O(log N)?

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  • How to make use of Tags property of an xml node to get its information and attributes?

    - by user72731
    How would i make use of tags property of a node so that i can get the attributes of an xml node. I have to display an xml tree in a winform and then when i click on any node, its attributes should get displayed on a list box in same window. I want to make use of tags property, but for that i need to convert that tree node in the winform into an xml node. I wanted to store the tree node in the tag and then typecast that tag to an xml node. I dont know how to do it? I am a newbie at C# so there might be some discrpancy in language...please help

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  • Implementing History Support using jQuery for AJAX websites built on asp.net AJAX

    - by anil.kasalanati
    Problem Statement: Most modern day website use AJAX for page navigation and gone are the days of complete HTTP redirection so it is imperative that we support back and forward buttons on the browser so that end users navigation is not broken. In this article we discuss about solutions which are already available and problems with them. Microsoft History Support: Post .Net 3.5 sp1 Microsoft’s Script manager supports history for websites using Update panels. This is achieved by enabling the ENABLE HISTORY property for the script manager and then the event “Page_Browser_Navigate” needs to be handled. So whenever the browser buttons are clicked the event is fired and the application can write code to do the navigation. The following articles provide good tutorials on how to do that http://www.asp.net/aspnet-in-net-35-sp1/videos/introduction-to-aspnet-ajax-history http://www.codeproject.com/KB/aspnet/ajaxhistorymanagement.aspx And Microsoft api internally creates an IFrame and changes the bookmark of the url. Unfortunately this has a bug and it does not work in Ie6 and 7 which are the major browsers but it works in ie8 and Firefox. And Microsoft has apparently fixed this bug in .Net 4.0. Following is the blog http://weblogs.asp.net/joshclose/archive/2008/11/11/asp-net-ajax-addhistorypoint-bug.aspx For solutions which are still running on .net 3.5 sp1 there is no solution which Microsoft offers so there is  are two way to solve this o   Disable the back button. o   Develop custom solution.   Disable back button Even though this might look like a very simple thing to do there are issues around doing this  because there is no event which can be manipulated from the javascript. The browser does not provide an api to do this. So most of the technical solution on internet offer work arounds like doing a history.forward(1) so that even if the user clicks a back button the destination page redirects the user to the original page. This is not a good customer experience and does not work for asp.net website where there are different views in the same page. There are other ways around detecting the window unload events and writing code there. So there are 2 events onbeforeUnload and onUnload and we can write code to show a confirmation message to the user. If we write code in onUnLoad then we can only show a message but it is too late to stop the navigation. And if we write on onBeforeUnLoad we can stop the navigation if the user clicks cancel but this event would be triggered for all AJAX calls and hyperlinks where the href is anything other than #. We can do this but the website has to be checked properly to ensure there are no links where href is not # otherwise the user would see a popup message saying “you are leaving the website”. Believe me after doing a lot of research on the back button disable I found it easier to support it rather than disabling the button. So I am going to discuss a solution which work  using jQuery with some tweaking. Custom Solution JQuery already provides an api to manage the history of a AJAX website - http://plugins.jquery.com/project/history We need to integrate this with Microsoft Page request manager so that both of them work in tandem. The page state is maintained in the cookie so that it can be passed to the server and I used jQuery cookie plug in for that – http://plugins.jquery.com/node/1386/release Firstly when the page loads there is a need to hook up all the events on the page which needs to cause browser history and following is the code to that. jQuery(document).ready(function() {             // Initialize history plugin.             // The callback is called at once by present location.hash.             jQuery.history.init(pageload);               // set onlick event for buttons             jQuery("a[@rel='history']").click(function() {                 //                 var hash = this.page;                 hash = hash.replace(/^.*#/, '');                 isAsyncPostBack = true;                 // moves to a new page.                 // pageload is called at once.                 jQuery.history.load(hash);                 return true;             });         }); The above scripts basically gets all the DOM objects which have the attribute rel=”history” and add the event. In our test page we have the link button  which has the attribute rel set to history. <asp:LinkButton ID="Previous" rel="history" runat="server" onclick="PreviousOnClick">Previous</asp:LinkButton> <asp:LinkButton ID="AsyncPostBack" rel="history" runat="server" onclick="NextOnClick">Next</asp:LinkButton> <asp:LinkButton ID="HistoryLinkButton" runat="server" style="display:none" onclick="HistoryOnClick"></asp:LinkButton>   And you can see that there is an hidden HistoryLinkButton which used to send a sever side postback in case of browser back or previous buttons. And note that we need to use display:none and not visible= false because asp.net AJAX would disallow any post backs if visible=false. And in general the pageload event get executed on the client side when a back or forward is pressed and the function is shown below function pageload(hash) {                   if (hash) {                         if (!isAsyncPostBack) {                           jQuery.cookie("page", hash);                     __doPostBack("HistoryLinkButton", "");                 }                isAsyncPostBack = false;                             } else {                 // start page             jQuery("#load").empty();             }         }   As you can see in case there is an hash in the url we are basically do an asp.net AJAX post back using the following statement __doPostBack("HistoryLinkButton", ""); So whenever the user clicks back or forward the post back happens using the event statement we provide and Previous event code is invoked in the code behind.  We need to have the code to use the pageId present in the url to change the page content. And there is an important thing to note – because the hash is worked out using the pageId’s there is a need to recalculate the hash after every AJAX post back so following code is plugged in function ReWorkHash() {             jQuery("a[@rel='history']").unbind("click");             jQuery("a[@rel='history']").click(function() {                 //                 var hash = jQuery(this).attr("page");                 hash = hash.replace(/^.*#/, '');                 jQuery.cookie("page", hash);                 isAsyncPostBack = true;                                   // moves to a new page.                 // pageload is called at once.                 jQuery.history.load(hash);                 return true;             });        }   This code is executed from the code behind using ScriptManager RegisterClientScriptBlock as shown below –       ScriptManager.RegisterClientScriptBlock(this, typeof(_Default), "Recalculater", "ReWorkHash();", true);   A sample application is available to be downloaded at the following location – http://techconsulting.vpscustomer.com/Source/HistoryTest.zip And a working sample is available at – http://techconsulting.vpscustomer.com/Samples/Default.aspx

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  • eBooks on iPad vs. Kindle: More Debate than Smackdown

    - by andrewbrust
    When the iPad was presented at its San Francisco launch event on January 28th, Steve Jobs spent a significant amount of time explaining how well the device would serve as an eBook reader. He showed the iBooks reader application and iBookstore and laid down the gauntlet before Amazon and its beloved Kindle device. Almost immediately afterwards, criticism came rushing forth that the iPad could never beat the Kindle for book reading. The curious part of that criticism is that virtually no one offering it had actually used the iPad yet. A few weeks later, on April 3rd, the iPad was released for sale in the United States. I bought one on that day and in the few additional weeks that have elapsed, I’ve given quite a workout to most of its capabilities, including its eBook features. I’ve also spent some time with the Kindle, albeit a first-generation model, to see how it actually compares to the iPad. I had some expectations going in, but I came away with conclusions about each device that were more scenario-based than absolute. I present my findings to you here.   Vital Statistics Let’s start with an inventory of each device’s underlying technology. The iPad has a color, backlit LCD screen and an on-screen keyboard. It has a battery which, on a full charge, lasts anywhere from 6-10 hours. The Kindle offers a monochrome, reflective E Ink display, a physical keyboard and a battery that on my first gen loaner unit can go up to a week between charges (Amazon claims the battery on the Kindle 2 can last up to 2 weeks on a single charge). The Kindle connects to Amazon’s Kindle Store using a 3G modem (the technology and network vary depending on the model) that incurs no airtime service charges whatsoever. The iPad units that are on-sale today work over WiFi only. 3G-equipped models will be on sale shortly and will command a $130 premium over their WiFi-only counterparts. 3G service on the iPad, in the U.S. from AT&T, will be fee-based, with a 250MB plan at $14.99 per month and an unlimited plan at $29.99. No contract is required for 3G service. All these tech specs aside, I think a more useful observation is that the iPad is a multi-purpose Internet-connected entertainment device, while the Kindle is a dedicated reading device. The question is whether those differences in design and intended use create a clear-cut winner for reading electronic publications. Let’s take a look at each device, in isolation, now.   Kindle To me, what’s most innovative about the Kindle is its E Ink display. E Ink really looks like ink on a sheet of paper. It requires no backlight, it’s fully visible in direct sunlight and it causes almost none of the eyestrain that LCD-based computer display technology (like that used on the iPad) does. It’s really versatile in an all-around way. Forgive me if this sounds precious, but reading on it is really a joy. In fact, it’s a genuinely relaxing experience. Through the Kindle Store, Amazon allows users to download books (including audio books), magazines, newspapers and blog feeds. Books and magazines can be purchased either on a single-issue basis or as an annual subscription. Books, of course, are purchased singly. Oddly, blogs are not free, but instead carry a monthly subscription fee, typically $1.99. To me this is ludicrous, but I suppose the free 3G service is partially to blame. Books and magazine issues download quickly. Magazine and blog subscriptions cause new issues or posts to be pushed to your device on an automated basis. Available blogs include 9000-odd feeds that Amazon offers on the Kindle Store; unless I missed something, arbitrary RSS feeds are not supported (though there are third party workarounds to this limitation). The shopping experience is integrated well, has an huge selection, and offers certain graphical perks. For example, magazine and newspaper logos are displayed in menus, and book cover thumbnails appear as well. A simple search mechanism is provided and text entry through the physical keyboard is relatively painless. It’s very easy and straightforward to enter the store, find something you like and start reading it quickly. If you know what you’re looking for, it’s even faster. Given Kindle’s high portability, very reliable battery, instant-on capability and highly integrated content acquisition, it makes reading on whim, and in random spurts of downtime, very attractive. The Kindle’s home screen lists all of your publications, and easily lets you select one, then start reading it. Once opened, publications display in crisp, attractive text that is adjustable in size. “Turning” pages is achieved through buttons dedicated to the task. Notes can be recorded, bookmarks can be saved and pages can be saved as clippings. I am not an avid book reader, and yet I found the Kindle made it really fun, convenient and soothing to read. There’s something about the easy access to the material and the simplicity of the display that makes the Kindle seduce you into chilling out and reading page after page. On the other hand, the Kindle has an awkward navigation interface. While menus are displayed clearly on the screen, the method of selecting menu items is tricky: alongside the right-hand edge of the main display is a thin column that acts as a second display. It has a white background, and a scrollable silver cursor that is moved up or down through the use of the device’s scrollwheel. Picking a menu item on the main display involves scrolling the silver cursor to a position parallel to that menu item and pushing the scrollwheel in. This navigation technique creates a disconnect, literally. You don’t really click on a selection so much as you gesture toward it. I got used to this technique quickly, but I didn’t love it. It definitely created a kind of anxiety in me, making me feel the need to speed through menus and get to my destination document quickly. Once there, I could calm down and relax. Books are great on the Kindle. Magazines and newspapers much less so. I found the rendering of photographs, and even illustrations, to be unacceptably crude. For this reason, I expect that reading textbooks on the Kindle may leave students wanting. I found that the original flow and layout of any publication was sacrificed on the Kindle. In effect, browsing a magazine or newspaper was almost impossible. Reading the text of individual articles was enjoyable, but having to read this way made the whole experience much more “a la carte” than cohesive and thematic between articles. I imagine that for academic journals this is ideal, but for consumer publications it imposes a stripped-down, low-fidelity experience that evokes a sense of deprivation. In general, the Kindle is great for reading text. For just about anything else, especially activity that involves exploratory browsing, meandering and short-attention-span reading, it presents a real barrier to entry and adoption. Avid book readers will enjoy the Kindle (if they’re not already). It’s a great device for losing oneself in a book over long sittings. Multitaskers who are more interested in periodicals, be they online or off, will like it much less, as they will find compromise, and even sacrifice, to be palpable.   iPad The iPad is a very different device from the Kindle. While the Kindle is oriented to pages of text, the iPad orbits around applications and their interfaces. Be it the pinch and zoom experience in the browser, the rich media features that augment content on news and weather sites, or the ability to interact with social networking services like Twitter, the iPad is versatile. While it shares a slate-like form factor with the Kindle, it’s effectively an elegant personal computer. One of its many features is the iBook application and integration of the iBookstore. But it’s a multi-purpose device. That turns out to be good and bad, depending on what you’re reading. The iBookstore is great for browsing. It’s color, rich animation-laden user interface make it possible to shop for books, rather than merely search and acquire them. Unfortunately, its selection is rather sparse at the moment. If you’re looking for a New York Times bestseller, or other popular titles, you should be OK. If you want to read something more specialized, it’s much harder. Unlike the awkward navigation interface of the Kindle, the iPad offers a nearly flawless touch-screen interface that seduces the user into tinkering and kibitzing every bit as much as the Kindle lulls you into a deep, concentrated read. It’s a dynamic and interactive device, whereas the Kindle is static and passive. The iBook reader is slick and fun. Use the iPad in landscape mode and you can read the book in 2-up (left/right 2-page) display; use it in portrait mode and you can read one page at a time. Rather than clicking a hardware button to turn pages, you simply drag and wipe from right-to-left to flip the single or right-hand page. The page actually travels through an animated path as it would in a physical book. The intuitiveness of the interface is uncanny. The reader also accommodates saving of bookmarks, searching of the text, and the ability to highlight a word and look it up in a dictionary. Pages display brightly and clearly. They’re easy to read. But the backlight and the glare made me less comfortable than I was with the Kindle. The knowledge that completely different applications (including the Web and email and Twitter) were just a few taps away made me antsy and very tempted to task-switch. The knowledge that battery life is an issue created subtle discomfort. If the Kindle makes you feel like you’re in a library reading room, then the iPad makes you feel, at best, like you’re under fluorescent lights at a Barnes and Noble or Borders store. If you’re lucky, you’d be on a couch or at a reading table in the store, but you might also be standing up, in the aisles. Clearly, I didn’t find this conducive to focused and sustained reading. But that may have more to do with my own tendency to read periodicals far more than books, and my neurotic . And, truth be known, the book reading experience, when not explicitly compared to Kindle’s, was still pleasant. It is also important to point out that Kindle Store-sourced books can be read on the iPad through a Kindle reader application, from Amazon, specific to the device. This offered a less rich experience than the iBooks reader, but it was completely adequate. Despite the Kindle brand of the reader, however, it offered little in terms of simulating the reading experience on its namesake device. When it comes to periodicals, the iPad wins hands down. Magazines, even if merely scanned images of their print editions, read on the iPad in a way that felt similar to reading hard copy. The full color display, touch navigation and even the ability to render advertisements in their full glory makes the iPad a great way to read through any piece of work that is measured in pages, rather than chapters. There are many ways to get magazines and newspapers onto the iPad, including the Zinio reader, and publication-specific applications like the Wall Street Journal’s and Popular Science’s. The New York Times’ free Editors’ Choice application offers a Times Reader-like interface to a subset of the Gray Lady’s daily content. The completely Web-based but iPad-optimized Times Skimmer site (at www.nytimes.com/timesskimmer) works well too. Even conventional Web sites themselves can be read much like magazines, given the iPad’s ability to zoom in on the text and crop out advertisements on the margins. While the Kindle does have an experimental Web browser, it reminded me a lot of early mobile phone browsers, only in a larger size. For text-heavy sites with simple layout, it works fine. For just about anything else, it becomes more trouble than it’s worth. And given the way magazine articles make me think of things I want to look up online, I think that’s a real liability for the Kindle.   Summing Up What I came to realize is that the Kindle isn’t so much a computer or even an Internet device as it is a printer. While it doesn’t use physical paper, it still renders its content a page at a time, just like a laser printer does, and its output appears strikingly similar. You can read the rendered text, but you can’t interact with it in any way. That’s why the navigation requires a separate cursor display area. And because of the page-oriented rendering behavior, turning pages causes a flash on the display and requires a sometimes long pause before the next page is rendered. The good side of this is that once the page is generated, no battery power is required to display it. That makes for great battery life, optimal viewing under most lighting conditions (as long as there is some light) and low-eyestrain text-centric display of content. The Kindle is highly portable, has an excellent selection in its store and is refreshingly distraction-free. All of this is ideal for reading books. And iPad doesn’t offer any of it. What iPad does offer is versatility, variety, richness and luxury. It’s flush with accoutrements even if it’s low on focused, sustained text display. That makes it inferior to the Kindle for book reading. But that also makes it better than the Kindle for almost everything else. As such, and given that its book reading experience is still decent (even if not superior), I think the iPad will give Kindle a run for its money. True book lovers, and people on a budget, will want the Kindle. People with a robust amount of discretionary income may want both devices. Everyone else who is interested in a slate form factor e-reading device, especially if they also wish to have leisure-friendly Internet access, will likely choose the iPad exclusively. One thing is for sure: iPad has reduced Kindle’s market, and may have shifted its mass market potential to a mere niche play. If Amazon is smart, it will improve its iPad-based Kindle reader app significantly. It can then leverage the iPad channel as a significant market for the Kindle Store. After all, selling the eBooks themselves is what Amazon should care most about.

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  • dynatree: how can i select child node programmatically

    - by Muhammad Adeel Zahid
    hello everyone i m using jquery's dynaTree in my application and i want to select the all the child nodes programmably when a node is selected. the structure of my tree is as follows <div id = "tree"> <ul> <li>package 1 <ul> <li>module 1.1 <ul> <li> document 1.1.1</li> <li> document 1.1.2</li> </ul> </li> <li>module 1.2 <ul> <li>document 1.2.1</li> <li>document 1.2.2</li> </ul> </li> </ul> </li> <li> package 2 <ul> <li> module 2.1 <ul> <li>document 2.1.1</li> <li>document 2.1.1</li> </ul> </li> </ul> </li> </ul> </div> now what i want is that when i click on tree node with title "package 1" all its child nodes i.e (module 1.1, document 1.1.1, document 1.1.2, module 1.2, document 1.2.1, document 1.2.2) should also be selected below is the approach i tried to use $("#tree").dynatree({ onSelect: function(flag, dtnode) { // This will happen each time a check box is selected/deselected var selectedNodes = dtnode.tree.getSelectedNodes(); var selectedKeys = $.map(selectedNodes, function(node) { //alert(node.data.key); return node.data.key; }); // Set the hidden input field's value to the selected items $('#SelectedItems').val(selectedKeys.join(",")); if (flag) { child = dtnode.childList; alert(child.length); for (i = 0; i < child.length; i++) { var x = child[i].select(true); alert(i); } } }, checkbox: true, onActivate: function(dtnode) { //alert("You activated " + dtnode.data.key); } }); in the if(flag) condition i get all the child nodes of element that is selected by user and it gives me the correct value that i can see from alert(child.length) statement. then i run the loop to select all the children but loop never goes beyond the statement var x = child[i].select(true); and i can never see the statement alert(i) being executed. the result of above statement is that if i select package 1, module 1.1 and document 1.1.1 is also selected but never does it execute alert(i) statement neither other children of package 1 are selected. in my view when first time child[i].select(true) statement is executed it also triggers the on select event of its children thus making a recursion kind of thing is my thinking correct? no matter recursion or what why on earth does it not complete the loop and execute very next instruction alert(i). please help me in solving this problem. i m dying to see that alert any suggestion and help is highly appriciated thanks Adeel

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  • Revisiting ANTS Performance Profiler 7.4

    - by James Michael Hare
    Last year, I did a small review on the ANTS Performance Profiler 6.3, now that it’s a year later and a major version number higher, I thought I’d revisit the review and revise my last post. This post will take the same examples as the original post and update them to show what’s new in version 7.4 of the profiler. Background A performance profiler’s main job is to keep track of how much time is typically spent in each unit of code. This helps when we have a program that is not running at the performance we expect, and we want to know where the program is experiencing issues. There are many profilers out there of varying capabilities. Red Gate’s typically seem to be the very easy to “jump in” and get started with very little training required. So let’s dig into the Performance Profiler. I’ve constructed a very crude program with some obvious inefficiencies. It’s a simple program that generates random order numbers (or really could be any unique identifier), adds it to a list, sorts the list, then finds the max and min number in the list. Ignore the fact it’s very contrived and obviously inefficient, we just want to use it as an example to show off the tool: 1: // our test program 2: public static class Program 3: { 4: // the number of iterations to perform 5: private static int _iterations = 1000000; 6: 7: // The main method that controls it all 8: public static void Main() 9: { 10: var list = new List<string>(); 11: 12: for (int i = 0; i < _iterations; i++) 13: { 14: var x = GetNextId(); 15: 16: AddToList(list, x); 17: 18: var highLow = GetHighLow(list); 19: 20: if ((i % 1000) == 0) 21: { 22: Console.WriteLine("{0} - High: {1}, Low: {2}", i, highLow.Item1, highLow.Item2); 23: Console.Out.Flush(); 24: } 25: } 26: } 27: 28: // gets the next order id to process (random for us) 29: public static string GetNextId() 30: { 31: var random = new Random(); 32: var num = random.Next(1000000, 9999999); 33: return num.ToString(); 34: } 35: 36: // add it to our list - very inefficiently! 37: public static void AddToList(List<string> list, string item) 38: { 39: list.Add(item); 40: list.Sort(); 41: } 42: 43: // get high and low of order id range - very inefficiently! 44: public static Tuple<int,int> GetHighLow(List<string> list) 45: { 46: return Tuple.Create(list.Max(s => Convert.ToInt32(s)), list.Min(s => Convert.ToInt32(s))); 47: } 48: } So let’s run it through the profiler and see what happens! Visual Studio Integration First, let’s look at how the ANTS profilers integrate with Visual Studio’s menu system. Once you install the ANTS profilers, you will get an ANTS menu item with several options: Notice that you can either Profile Performance or Launch ANTS Performance Profiler. These sound similar but achieve two slightly different actions: Profile Performance: this immediately launches the profiler with all defaults selected to profile the active project in Visual Studio. Launch ANTS Performance Profiler: this launches the profiler much the same way as starting it from the Start Menu. The profiler will pre-populate the application and path information, but allow you to change the settings before beginning the profile run. So really, the main difference is that Profile Performance immediately begins profiling with the default selections, where Launch ANTS Performance Profiler allows you to change the defaults and attach to an already-running application. Let’s Fire it Up! So when you fire up ANTS either via Start Menu or Launch ANTS Performance Profiler menu in Visual Studio, you are presented with a very simple dialog to get you started: Notice you can choose from many different options for application type. You can profile executables, services, web applications, or just attach to a running process. In fact, in version 7.4 we see two new options added: ASP.NET Web Application (IIS Express) SharePoint web application (IIS) So this gives us an additional way to profile ASP.NET applications and the ability to profile SharePoint applications as well. You can also choose your level of detail in the Profiling Mode drop down. If you choose Line-Level and method-level timings detail, you will get a lot more detail on the method durations, but this will also slow down profiling somewhat. If you really need the profiler to be as unintrusive as possible, you can change it to Sample method-level timings. This is performing very light profiling, where basically the profiler collects timings of a method by examining the call-stack at given intervals. Which method you choose depends a lot on how much detail you need to find the issue and how sensitive your program issues are to timing. So for our example, let’s just go with the line and method timing detail. So, we check that all the options are correct (if you launch from VS2010, the executable and path are filled in already), and fire it up by clicking the [Start Profiling] button. Profiling the Application Once you start profiling the application, you will see a real-time graph of CPU usage that will indicate how much your application is using the CPU(s) on your system. During this time, you can select segments of the graph and bookmark them, giving them mnemonic names. This can be useful if you want to compare performance in one part of the run to another part of the run. Notice that once you select a block, it will give you the call tree breakdown for that selection only, and the relative performance of those calls. Once you feel you have collected enough information, you can click [Stop Profiling] to stop the application run and information collection and begin a more thorough analysis. Analyzing Method Timings So now that we’ve halted the run, we can look around the GUI and see what we can see. By default, the times are shown in terms of percentage of time of the total run of the application, though you can change it in the View menu item to milliseconds, ticks, or seconds as well. This won’t affect the percentages of methods, it only affects what units the times are shown. Notice also that the major hotspot seems to be in a method without source, ANTS Profiler will filter these out by default, but you can right-click on the line and remove the filter to see more detail. This proves especially handy when a bottleneck is due to a method in the BCL. So now that we’ve removed the filter, we see a bit more detail: In addition, ANTS Performance Profiler gives you the ability to decompile the methods without source so that you can dive even deeper, though typically this isn’t necessary for our purposes. When looking at timings, there are generally two types of timings for each method call: Time: This is the time spent ONLY in this method, not including calls this method makes to other methods. Time With Children: This is the total of time spent in both this method AND including calls this method makes to other methods. In other words, the Time tells you how much work is being done exclusively in this method, and the Time With Children tells you how much work is being done inclusively in this method and everything it calls. You can also choose to display the methods in a tree or in a grid. The tree view is the default and it shows the method calls arranged in terms of the tree representing all method calls and the parent method that called them, etc. This is useful for when you find a hot-spot method, you can see who is calling it to determine if the problem is the method itself, or if it is being called too many times. The grid method represents each method only once with its totals and is useful for quickly seeing what method is the trouble spot. In addition, you can choose to display Methods with source which are generally the methods you wrote (as opposed to native or BCL code), or Any Method which shows not only your methods, but also native calls, JIT overhead, synchronization waits, etc. So these are just two ways of viewing the same data, and you’re free to choose the organization that best suits what information you are after. Analyzing Method Source If we look at the timings above, we see that our AddToList() method (and in particular, it’s call to the List<T>.Sort() method in the BCL) is the hot-spot in this analysis. If ANTS sees a method that is consuming the most time, it will flag it as a hot-spot to help call out potential areas of concern. This doesn’t mean the other statistics aren’t meaningful, but that the hot-spot is most likely going to be your biggest bang-for-the-buck to concentrate on. So let’s select the AddToList() method, and see what it shows in the source window below: Notice the source breakout in the bottom pane when you select a method (from either tree or grid view). This shows you the timings in this method per line of code. This gives you a major indicator of where the trouble-spot in this method is. So in this case, we see that performing a Sort() on the List<T> after every Add() is killing our performance! Of course, this was a very contrived, duh moment, but you’d be surprised how many performance issues become duh moments. Note that this one line is taking up 86% of the execution time of this application! If we eliminate this bottleneck, we should see drastic improvement in the performance. So to fix this, if we still wanted to maintain the List<T> we’d have many options, including: delay Sort() until after all Add() methods, using a SortedSet, SortedList, or SortedDictionary depending on which is most appropriate, or forgoing the sorting all together and using a Dictionary. Rinse, Repeat! So let’s just change all instances of List<string> to SortedSet<string> and run this again through the profiler: Now we see the AddToList() method is no longer our hot-spot, but now the Max() and Min() calls are! This is good because we’ve eliminated one hot-spot and now we can try to correct this one as well. As before, we can then optimize this part of the code (possibly by taking advantage of the fact the list is now sorted and returning the first and last elements). We can then rinse and repeat this process until we have eliminated as many bottlenecks as possible. Calls by Web Request Another feature that was added recently is the ability to view .NET methods grouped by the HTTP requests that caused them to run. This can be helpful in determining which pages, web services, etc. are causing hot spots in your web applications. Summary If you like the other ANTS tools, you’ll like the ANTS Performance Profiler as well. It is extremely easy to use with very little product knowledge required to get up and running. There are profilers built into the higher product lines of Visual Studio, of course, which are also powerful and easy to use. But for quickly jumping in and finding hot spots rapidly, Red Gate’s Performance Profiler 7.4 is an excellent choice. Technorati Tags: Influencers,ANTS,Performance Profiler,Profiler

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  • Trace Flag 610 – When should you use it?

    - by simonsabin
    Thanks to Marcel van der Holst for providing this great information on the use of Trace Flag 610. This trace flag can be used to have minimal logging into a b tree (i.e. clustered table or an index on a heap) that already has data. It is a trace flag because in testing they found some scenarios where it didn’t perform as well. Marcel explains why below. “ TF610 can be used to get minimal logging in a non-empty B-Tree. The idea is that when you insert a large amount of data, you don't want to...(read more)

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  • Seam conversation ending suddenly when using Redirect

    - by Markos Fragkakis
    Hi all, Because I get some errors on conversations ending abruptly, I created in my project some test pages that reproduce the issue. The navigation takes place between pageA.xhtml and pageB.xhtml. Please tell me if I am using something in the wrong way. My configuration: Seam 2.2.0.GA WebLogic 10.3.2 (11g) Richfaces 3.3.2 JSF 1.2 Note: the same happens when using annotations to begin / end conversations ======= PAGE A @Name("pageaAction") public class PageaAction { @Out(required = false, scope = ScopeType.CONVERSATION) Person person; public String rule3() { person = new Person(); person.setEmail("[email protected]"); person.setName("markos"); return "rule3"; } } <?xml version="1.0" encoding="UTF-8"?> <page> <navigation> <rule if-outcome="rule3"> <begin-conversation /> <redirect view-id="/pages/seam_sandbox/pageb.xhtml" /> </rule> </navigation> </page> ... <h:commandButton action="#{pageaAction.rule3()}" value="h:commandButton" /><br/> ... ======= PAGE B @Name("pagebAction") public class PagebAction { @In(required = false, scope = ScopeType.CONVERSATION) Person person; public String redirectA() { return "redirectA"; } } <?xml version="1.0" encoding="UTF-8"?> <page> <navigation> <rule if-outcome="redirectA"> <end-conversation before-redirect="true" /> <redirect view-id="/pages/seam_sandbox/pagea.xhtml" /> </rule> </navigation> </page> ... <h:commandButton action="#{pagebAction.redirectA()}" value="h:commandButton" /> ... ========== EXCEPTION: This happens after a random number of redirects. javax.faces.FacesException: {pagebAction.redirectA()}: java.lang.IllegalStateException: No conversation context active at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:118) at javax.faces.component.UICommand.broadcast(UICommand.java:387) at org.ajax4jsf.component.AjaxViewRoot.processEvents(AjaxViewRoot.java:324) at org.ajax4jsf.component.AjaxViewRoot.broadcastEvents(AjaxViewRoot.java:299) at org.ajax4jsf.component.AjaxViewRoot.processPhase(AjaxViewRoot.java:256) at org.ajax4jsf.component.AjaxViewRoot.processApplication(AjaxViewRoot.java:469) at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:82) at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:100) at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118) at javax.faces.webapp.FacesServlet.service(FacesServlet.java:265) at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227) at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125) at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:292) at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:26) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56) at org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:530) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:83) at org.jboss.seam.web.IdentityFilter.doFilter(IdentityFilter.java:40) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.jboss.seam.web.MultipartFilter.doFilter(MultipartFilter.java:90) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.jboss.seam.web.ExceptionFilter.doFilter(ExceptionFilter.java:64) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.jboss.seam.web.RedirectFilter.doFilter(RedirectFilter.java:45) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:178) at org.ajax4jsf.webapp.BaseFilter.handleRequest(BaseFilter.java:290) at org.ajax4jsf.webapp.BaseFilter.processUploadsAndHandleRequest(BaseFilter.java:388) at org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:515) at org.jboss.seam.web.Ajax4jsfFilter.doFilter(Ajax4jsfFilter.java:56) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.jboss.seam.web.LoggingFilter.doFilter(LoggingFilter.java:60) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.jboss.seam.servlet.SeamFilter.doFilter(SeamFilter.java:158) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56) at weblogic.servlet.internal.RequestEventsFilter.doFilter(RequestEventsFilter.java:27) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56) at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3592) at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321) at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:121) at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2202) at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2108) at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1432) at weblogic.work.ExecuteThread.execute(ExecuteThread.java:201) at weblogic.work.ExecuteThread.run(ExecuteThread.java:173) Caused by: javax.faces.el.EvaluationException: java.lang.IllegalStateException: No conversation context active at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:102) at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102) ... 45 more Caused by: java.lang.IllegalStateException: No conversation context active at org.jboss.seam.ScopeType.getContext(ScopeType.java:133) at org.jboss.seam.Component.getValueToInject(Component.java:2325) at org.jboss.seam.Component.injectAttributes(Component.java:1736) at org.jboss.seam.Component.inject(Component.java:1554) at org.jboss.seam.core.BijectionInterceptor.aroundInvoke(BijectionInterceptor.java:61) at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68) at org.jboss.seam.core.ConversationInterceptor.aroundInvoke(ConversationInterceptor.java:65) at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68) at org.jboss.seam.core.MethodContextInterceptor.aroundInvoke(MethodContextInterceptor.java:44) at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68) at org.jboss.seam.intercept.RootInterceptor.invoke(RootInterceptor.java:107) at org.jboss.seam.intercept.JavaBeanInterceptor.interceptInvocation(JavaBeanInterceptor.java:185) at org.jboss.seam.intercept.JavaBeanInterceptor.invoke(JavaBeanInterceptor.java:103) at eu.emea.pim.prs.web.seamsandbox.PagebAction_$$_javassist_seam_8.redirectA(PagebAction_$$_javassist_seam_8.java) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.jboss.el.util.ReflectionUtil.invokeMethod(ReflectionUtil.java:335) at org.jboss.el.util.ReflectionUtil.invokeMethod(ReflectionUtil.java:280) at org.jboss.el.parser.AstMethodSuffix.getValue(AstMethodSuffix.java:59) at org.jboss.el.parser.AstMethodSuffix.invoke(AstMethodSuffix.java:65) at org.jboss.el.parser.AstValue.invoke(AstValue.java:96) at org.jboss.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:276) at com.sun.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:68) at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:88) ... 46 more

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  • How to Search Just the Site You’re Viewing Using Google Search

    - by The Geek
    Have you ever wanted to search the site you’re viewing, but the built-in search box is either hard to find, or doesn’t work very well? Here’s how to add a special keyword bookmark that searches the site you’re viewing using Google’s site: search operator. This technique should work in either Google Chrome or Firefox—in Firefox you’ll want to create a regular bookmark and add the script into the keyword field, and for Google Chrome just follow the steps we’ve provided below Latest Features How-To Geek ETC How to Use the Avira Rescue CD to Clean Your Infected PC The Complete List of iPad Tips, Tricks, and Tutorials Is Your Desktop Printer More Expensive Than Printing Services? 20 OS X Keyboard Shortcuts You Might Not Know HTG Explains: Which Linux File System Should You Choose? HTG Explains: Why Does Photo Paper Improve Print Quality? Simon’s Cat Explores the Christmas Tree! [Video] The Outdoor Lights Scene from National Lampoon’s Christmas Vacation [Video] The Famous Home Alone Pizza Delivery Scene [Classic Video] Chronicles of Narnia: The Voyage of the Dawn Treader Theme for Windows 7 Cardinal and Rabbit Sharing a Tree on a Cold Winter Morning Wallpaper An Alternate Star Wars Christmas Special [Video]

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  • Silverlight Cream for March 06, 2010 -- #808

    - by Dave Campbell
    In this Issue: András Velvárt, felix corke, Colin Eberhardt, Christopher Bennage, Gergely Orosz, Entity Spaces Team Blog, Mike Taulty(-2-), Jit Ghosh, and Jesse Liberty. Shoutouts: Jeremy Likness expands on the Silverlight Team's post Vancouver Olympics - How'd We Do That? Gavin Wignall has a post up Creating a 360 photograph of an object with Silverlight Photosynth From SilverlightCream.com: Transforming an Ugly Duckling into a Graceful Swan With Expression Blend and Silverlight - Part 2 Intro Animation András Velvárt has part 2 of his Transformation series up at SilverlightShow... he's taking the initro animation to a new length, allowing playback even... cool video tutorial! Free Silverlight 4 beta skin! felix corke has a Silerlight 4 theme up for us all to use. If you like a dark theme like Blend, you'll like this... I like it! Linq to Visual Tree Colin Eberhardt has a great tutorial up for using LINQ to query the WPF or Silverlight Visual Tree while retaining the tree structure. He also has links out to other techniques. XAML Attributes on Separate Lines Christopher Bennage has a post up showing how to easily get all your XAML attributes on separate lines using a VS menu option... I didn't know that! Using built-in, embedded and streamed fonts in Silverlight Gergely Orosz has a post up at ScottLogic going over Fonts in Silverlight -- built-in, embedded, or streamed, and examples with code. EntitySpaces 2010 Two Part Series on Silverlight and WCF Entity Spaces Team Blog has a pair of videos up on Entity Spaces 2010, WCF, and Silverlight. Part 1 is the intro and explanation, part 2 is a full-up app demonstrating it. MEF, Silverlight and the DeploymentCatalog In an attempt to respond fully to a query, Mike Taulty literally pushed the record button and took off on what became a tutorial video on building a real Silverlight app utilizing MEF. Silverlight 4, Experiment with Pluggable Navigation and a WCF Data Service Mike Taulty has an experiment detailed on his blog about pluggable navigation and Silverlight 4. He walks through the history of how we got to this point then takes on in an example... good external links too Enhancing Silverlight Video Experiences with Contextual Data This is a post on the MSDN Magazine site where Jit Ghosh has a great long post about not only Smooth Streaming with Silverlight, but also adding context data to your video. When Is It OK To Hack? Read what all Jesse Liberty gets involved in when he's trying to get something out the door and has to work around a problem. Just about as interesting are the comments ... check it out and leave your own! Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    MIX10

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  • How to remove old Linux kernel modules »tp_smapi«?

    - by user43816
    ~$ locate tp_smapi /lib/modules/3.0.0-19-generic/updates/dkms/tp_smapi.ko /lib/modules/3.2.0-26-generic/updates/dkms/tp_smapi.ko /lib/modules/3.2.0-29-generic/updates/dkms/tp_smapi.ko /usr/src/tp-smapi-0.41/tp_smapi.c /var/lib/dkms/tp-smapi/0.41/3.0.0-19-generic/x86_64/module/tp_smapi.ko /var/lib/dkms/tp-smapi/0.41/3.2.0-26-generic/x86_64/module/tp_smapi.ko /var/lib/dkms/tp-smapi/0.41/3.2.0-29-generic/x86_64/module/tp_smapi.ko /var/lib/dkms/tp-smapi/0.41/build/tp_smapi.c' How to remove the 2 old Linux kernel modules from kernels 3.0.0-19 und 3.2.0-26? ~$ man dkms "'dkms remove [module/module-version]' removes a module/version combination from a tree.' What is a "[module/module-version]", please? Please notice: I do not want to remove old Linux kernel modules tp_smapi from a tree but I'd like to remove old Linux kernel modules from my Ubuntu 12.04.1 computer.

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  • How to grant write permissions in Samba?

    - by Eric Fossum
    I'm having trouble with read/write permissions on my Samba server, how do I fix my smb.conf and file permissions to have a more unified access? smb.conf [global] workgroup = workgroup netbios name = LnxNAS server string = %h wins support = no dns proxy = no security = user encrypt passwords = yes panic action = /usr/share/samba/panic-action %d [homes] comment = Home Directories [Video] path = /data/eric/Videos [Music] path = /data/eric/Music [Pictures] path = /data/eric/Pictures [data] path = /data my ls -l of /data/eric/Pictures drwxrwxrwx 2 ericfoss root 4096 2011-03-13 22:09 Android Projs drwxrwxrwx 3 ericfoss root 4096 2011-03-13 22:09 Automotive -rwxrwxrwx 1 ericfoss root 2439 2010-12-17 17:03 BDD reduction.png -rwxrwxrwx 1 ericfoss root 2722 2010-12-17 16:55 BDD Tree.png -rwxrwxrwx 1 ericfoss root 7341 2010-12-17 16:46 BDD Tree.xcf -rwxrwxrwx 1 ericfoss root 72421 2007-11-22 22:59 Bum Ninja.jpg -rwxrwxrwx 1 ericfoss root 32152 2010-12-17 21:25 cell transition.png -rwxrwxrwx 1 ericfoss root 40212 2010-12-17 17:55 control graph.png drwxrwxrwx 2 ericfoss root 4096 2011-03-13 22:09 Crap -rwxrwxrwx 1 ericfoss root 82 2010-09-20 17:18 desktop.ini ericfoss@SERVER:~$ If I try to delete \Server\Pictures\Crap it says permission denied, but \Server\data\eric\Pictures\crap can be deleted... I thought security = user took care of this?

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  • Unable install cmake and ccmake?

    - by user159618
    So the thing is I'm trying to install Cmake and cmake-curses-gui. I have updated the system with apt-get-update. sudo apt-get install cmake Reading package lists... Done Building dependency tree Reading state information... Done Package cmake is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source E: Package 'cmake' has no installation candidate sudo apt-get install cmake-curses-gui Reading package lists... Done Building dependency tree Reading state information... Done E: Unable to locate package cmake-curses-gui That's strange. Can anyone give some pointers? Pastbin sources.list :- http://pastebin.com/DufycYfZ

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  • Data structure: sort and search effectively

    - by Jiten Shah
    I need to have a data structure with say 4 keys . I can sort on any of these keys. What data structure can I opt for? Sorting time should be very little. I thought of a tree, but it will be only help searching on one key. For other keys I'll have to remake the tree on that particular key and then find it. Is there any data structure that can take care of all 4 keys at the same time? these 4 fields are of total 12 bytes and total size for each record - 40 bytes.. have memory constraints too... operations are : insertion, deletion, sorting on different keys.

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  • How to detect two moving shapes overlapped?

    - by user1389813
    Given a list of circles with its coordinates (x and y) that are moving every second in different direction (South-East, South-West, North-East and North-West), and the circle will change direction if it hits the wall sort of like bouncing, so how do we detect if any of them collide or overlap with each other ? I am not sure if we can use some data structures like a Binary Search Tree because since all the coordinates vary every seconds, so the tree will have to re-build accordingly. Or can we use Vertical Sweep Line Algorithm each time ? Any ideas on how to do this in a efficient way ?

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  • Is RTD Stateless or Stateful?

    - by [email protected]
    Yes.   A stateless service is one where each request is an independent transaction that can be processed by any of the servers in a cluster.  A stateful service is one where state is kept in a server's memory from transaction to transaction, thus necessitating the proper routing of requests to the right server. The main advantage of stateless systems is simplicity of design. The main advantage of stateful systems is performance. I'm often asked whether RTD is a stateless or stateful service, so I wanted to clarify this issue in depth so that RTD's architecture will be properly understood. The short answer is: "RTD can be configured as a stateless or stateful service." The performance difference between stateless and stateful systems can be very significant, and while in a call center implementation it may be reasonable to use a pure stateless configuration, a web implementation that produces thousands of requests per second is practically impossible with a stateless configuration. RTD's performance is orders of magnitude better than most competing systems. RTD was architected from the ground up to achieve this performance. Features like automatic and dynamic compression of prediction models, automatic translation of metadata to machine code, lack of interpreted languages, and separation of model building from decisioning contribute to achieving this performance level. Because  of this focus on performance we decided to have RTD's default configuration work in a stateful manner. By being stateful RTD requests are typically handled in a few milliseconds when repeated requests come to the same session. Now, those readers that have participated in implementations of RTD know that RTD's architecture is also focused on reducing Total Cost of Ownership (TCO) with features like automatic model building, automatic time windows, automatic maintenance of database tables, automatic evaluation of data mining models, automatic management of models partitioned by channel, geography, etcetera, and hot swapping of configurations. How do you reconcile the need for a low TCO and the need for performance? How do you get the performance of a stateful system with the simplicity of a stateless system? The answer is that you make the system behave like a stateless system to the exterior, but you let it automatically take advantage of situations where being stateful is better. For example, one of the advantages of stateless systems is that you can route a message to any server in a cluster, without worrying about sending it to the same server that was handling the session in previous messages. With an RTD stateful configuration you can still route the message to any server in the cluster, so from the point of view of the configuration of other systems, it is the same as a stateless service. The difference though comes in performance, because if the message arrives to the right server, RTD can serve it without any external access to the session's state, thus tremendously reducing processing time. In typical implementations it is not rare to have high percentages of messages routed directly to the right server, while those that are not, are easily handled by forwarding the messages to the right server. This architecture usually provides the best of both worlds with performance and simplicity of configuration.   Configuring RTD as a pure stateless service A pure stateless configuration requires session data to be persisted at the end of handling each and every message and reloading that data at the beginning of handling any new message. This is of course, the root of the inefficiency of these configurations. This is also the reason why many "stateless" implementations actually do keep state to take advantage of a request coming back to the same server. Nevertheless, if the implementation requires a pure stateless decision service, this is easy to configure in RTD. The way to do it is: Mark every Integration Point to Close the session at the end of processing the message In the Session entity persist the session data on closing the session In the session entity check if a persisted version exists and load it An excellent solution for persisting the session data is Oracle Coherence, which provides a high performance, distributed cache that minimizes the performance impact of persisting and reloading the session. Alternatively, the session can be persisted to a local database. An interesting feature of the RTD stateless configuration is that it can cope with serializing concurrent requests for the same session. For example, if a web page produces two requests to the decision service, these requests could come concurrently to the decision services and be handled by different servers. Most stateless implementation would have the two requests step onto each other when saving the state, or fail one of the messages. When properly configured, RTD will make one message wait for the other before processing.   A Word on Context Using the context of a customer interaction typically significantly increases lift. For example, offer success in a call center could double if the context of the call is taken into account. For this reason, it is important to utilize the contextual information in decision making. To make the contextual information available throughout a session it needs to be persisted. When there is a well defined owner for the information then there is no problem because in case of a session restart, the information can be easily retrieved. If there is no official owner of the information, then RTD can be configured to persist this information.   Once again, RTD provides flexibility to ensure high performance when it is adequate to allow for some loss of state in the rare cases of server failure. For example, in a heavy use web site that serves 1000 pages per second the navigation history may be stored in the in memory session. In such sites it is typical that there is no OLTP that stores all the navigation events, therefore if an RTD server were to fail, it would be possible for the navigation to that point to be lost (note that a new session would be immediately established in one of the other servers). In most cases the loss of this navigation information would be acceptable as it would happen rarely. If it is desired to save this information, RTD would persist it every time the visitor navigates to a new page. Note that this practice is preferred whether RTD is configured in a stateless or stateful manner.  

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  • Spooling in SQL execution plans

    - by Rob Farley
    Sewing has never been my thing. I barely even know the terminology, and when discussing this with American friends, I even found out that half the words that Americans use are different to the words that English and Australian people use. That said – let’s talk about spools! In particular, the Spool operators that you find in some SQL execution plans. This post is for T-SQL Tuesday, hosted this month by me! I’ve chosen to write about spools because they seem to get a bad rap (even in my song I used the line “There’s spooling from a CTE, they’ve got recursion needlessly”). I figured it was worth covering some of what spools are about, and hopefully explain why they are remarkably necessary, and generally very useful. If you have a look at the Books Online page about Plan Operators, at http://msdn.microsoft.com/en-us/library/ms191158.aspx, and do a search for the word ‘spool’, you’ll notice it says there are 46 matches. 46! Yeah, that’s what I thought too... Spooling is mentioned in several operators: Eager Spool, Lazy Spool, Index Spool (sometimes called a Nonclustered Index Spool), Row Count Spool, Spool, Table Spool, and Window Spool (oh, and Cache, which is a special kind of spool for a single row, but as it isn’t used in SQL 2012, I won’t describe it any further here). Spool, Table Spool, Index Spool, Window Spool and Row Count Spool are all physical operators, whereas Eager Spool and Lazy Spool are logical operators, describing the way that the other spools work. For example, you might see a Table Spool which is either Eager or Lazy. A Window Spool can actually act as both, as I’ll mention in a moment. In sewing, cotton is put onto a spool to make it more useful. You might buy it in bulk on a cone, but if you’re going to be using a sewing machine, then you quite probably want to have it on a spool or bobbin, which allows it to be used in a more effective way. This is the picture that I want you to think about in relation to your data. I’m sure you use spools every time you use your sewing machine. I know I do. I can’t think of a time when I’ve got out my sewing machine to do some sewing and haven’t used a spool. However, I often run SQL queries that don’t use spools. You see, the data that is consumed by my query is typically in a useful state without a spool. It’s like I can just sew with my cotton despite it not being on a spool! Many of my favourite features in T-SQL do like to use spools though. This looks like a very similar query to before, but includes an OVER clause to return a column telling me the number of rows in my data set. I’ll describe what’s going on in a few paragraphs’ time. So what does a Spool operator actually do? The spool operator consumes a set of data, and stores it in a temporary structure, in the tempdb database. This structure is typically either a Table (ie, a heap), or an Index (ie, a b-tree). If no data is actually needed from it, then it could also be a Row Count spool, which only stores the number of rows that the spool operator consumes. A Window Spool is another option if the data being consumed is tightly linked to windows of data, such as when the ROWS/RANGE clause of the OVER clause is being used. You could maybe think about the type of spool being like whether the cotton is going onto a small bobbin to fit in the base of the sewing machine, or whether it’s a larger spool for the top. A Table or Index Spool is either Eager or Lazy in nature. Eager and Lazy are Logical operators, which talk more about the behaviour, rather than the physical operation. If I’m sewing, I can either be all enthusiastic and get all my cotton onto the spool before I start, or I can do it as I need it. “Lazy” might not the be the best word to describe a person – in the SQL world it describes the idea of either fetching all the rows to build up the whole spool when the operator is called (Eager), or populating the spool only as it’s needed (Lazy). Window Spools are both physical and logical. They’re eager on a per-window basis, but lazy between windows. And when is it needed? The way I see it, spools are needed for two reasons. 1 – When data is going to be needed AGAIN. 2 – When data needs to be kept away from the original source. If you’re someone that writes long stored procedures, you are probably quite aware of the second scenario. I see plenty of stored procedures being written this way – where the query writer populates a temporary table, so that they can make updates to it without risking the original table. SQL does this too. Imagine I’m updating my contact list, and some of my changes move data to later in the book. If I’m not careful, I might update the same row a second time (or even enter an infinite loop, updating it over and over). A spool can make sure that I don’t, by using a copy of the data. This problem is known as the Halloween Effect (not because it’s spooky, but because it was discovered in late October one year). As I’m sure you can imagine, the kind of spool you’d need to protect against the Halloween Effect would be eager, because if you’re only handling one row at a time, then you’re not providing the protection... An eager spool will block the flow of data, waiting until it has fetched all the data before serving it up to the operator that called it. In the query below I’m forcing the Query Optimizer to use an index which would be upset if the Name column values got changed, and we see that before any data is fetched, a spool is created to load the data into. This doesn’t stop the index being maintained, but it does mean that the index is protected from the changes that are being done. There are plenty of times, though, when you need data repeatedly. Consider the query I put above. A simple join, but then counting the number of rows that came through. The way that this has executed (be it ideal or not), is to ask that a Table Spool be populated. That’s the Table Spool operator on the top row. That spool can produce the same set of rows repeatedly. This is the behaviour that we see in the bottom half of the plan. In the bottom half of the plan, we see that the a join is being done between the rows that are being sourced from the spool – one being aggregated and one not – producing the columns that we need for the query. Table v Index When considering whether to use a Table Spool or an Index Spool, the question that the Query Optimizer needs to answer is whether there is sufficient benefit to storing the data in a b-tree. The idea of having data in indexes is great, but of course there is a cost to maintaining them. Here we’re creating a temporary structure for data, and there is a cost associated with populating each row into its correct position according to a b-tree, as opposed to simply adding it to the end of the list of rows in a heap. Using a b-tree could even result in page-splits as the b-tree is populated, so there had better be a reason to use that kind of structure. That all depends on how the data is going to be used in other parts of the plan. If you’ve ever thought that you could use a temporary index for a particular query, well this is it – and the Query Optimizer can do that if it thinks it’s worthwhile. It’s worth noting that just because a Spool is populated using an Index Spool, it can still be fetched using a Table Spool. The details about whether or not a Spool used as a source shows as a Table Spool or an Index Spool is more about whether a Seek predicate is used, rather than on the underlying structure. Recursive CTE I’ve already shown you an example of spooling when the OVER clause is used. You might see them being used whenever you have data that is needed multiple times, and CTEs are quite common here. With the definition of a set of data described in a CTE, if the query writer is leveraging this by referring to the CTE multiple times, and there’s no simplification to be leveraged, a spool could theoretically be used to avoid reapplying the CTE’s logic. Annoyingly, this doesn’t happen. Consider this query, which really looks like it’s using the same data twice. I’m creating a set of data (which is completely deterministic, by the way), and then joining it back to itself. There seems to be no reason why it shouldn’t use a spool for the set described by the CTE, but it doesn’t. On the other hand, if we don’t pull as many columns back, we might see a very different plan. You see, CTEs, like all sub-queries, are simplified out to figure out the best way of executing the whole query. My example is somewhat contrived, and although there are plenty of cases when it’s nice to give the Query Optimizer hints about how to execute queries, it usually doesn’t do a bad job, even without spooling (and you can always use a temporary table). When recursion is used, though, spooling should be expected. Consider what we’re asking for in a recursive CTE. We’re telling the system to construct a set of data using an initial query, and then use set as a source for another query, piping this back into the same set and back around. It’s very much a spool. The analogy of cotton is long gone here, as the idea of having a continual loop of cotton feeding onto a spool and off again doesn’t quite fit, but that’s what we have here. Data is being fed onto the spool, and getting pulled out a second time when the spool is used as a source. (This query is running on AdventureWorks, which has a ManagerID column in HumanResources.Employee, not AdventureWorks2012) The Index Spool operator is sucking rows into it – lazily. It has to be lazy, because at the start, there’s only one row to be had. However, as rows get populated onto the spool, the Table Spool operator on the right can return rows when asked, ending up with more rows (potentially) getting back onto the spool, ready for the next round. (The Assert operator is merely checking to see if we’ve reached the MAXRECURSION point – it vanishes if you use OPTION (MAXRECURSION 0), which you can try yourself if you like). Spools are useful. Don’t lose sight of that. Every time you use temporary tables or table variables in a stored procedure, you’re essentially doing the same – don’t get upset at the Query Optimizer for doing so, even if you think the spool looks like an expensive part of the query. I hope you’re enjoying this T-SQL Tuesday. Why not head over to my post that is hosting it this month to read about some other plan operators? At some point I’ll write a summary post – once I have you should find a comment below pointing at it. @rob_farley

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  • OpenGL 2D Depth Perception

    - by Stephen James
    This is the first time i have ever commented on a forum about programming, so sorry if I'm not specific enough. Here's my problem: I have a 2D RPG game written in Java using LWJGL. All works fine, but at the moment I'm having trouble deciding what the best way to do depth perception is. So , for example, if the player goes in front of the tree/enemy (lower than the objects y-coordinate) then show the player in front), if the player goes behind the tree/enemy (higher than the objects specific y-coordinate), then show the player behind the object. I have tried writing a block of code to deal with this, and it works quite well for the trees, but not for the enemies yet. Is there a simpler way of doing this in LWJGL that I'm missing? Thanks :)

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  • OpenGL 2D Depth Perception

    - by Stephen James
    I have a 2D RPG game written in Java using LWJGL. All works fine, but at the moment I'm having trouble deciding what the best way to do depth perception is. So , for example, if the player goes in front of the tree/enemy (lower than the objects y-coordinate) then show the player in front), if the player goes behind the tree/enemy (higher than the objects specific y-coordinate), then show the player behind the object. I have tried writing a block of code to deal with this, and it works quite well for the trees, but not for the enemies yet. Is there a simpler way of doing this in LWJGL that I'm missing?

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  • Trying to install Team viewer on Ubuntu 12.04

    - by Teknikk
    I recently got Ubuntu installed on my server, I wanted to install TeamViewer so i could easy manage the virtual machines, However, I get errors when installing it from App store?, And I also get errors, but more detailed on the terminal. Error output: tek@tek-G53SW:~/Download$ sudo dpkg -i ipts teamviewer_linux_x64.deb dpkg: error processing ipts (--install): cannot access archive: No such file or directory (Reading database ... 142115 files and directories currently installed.) Preparing to replace teamviewer7 7.0.9360 (using teamviewer_linux_x64.deb) ... Unpacking replacement teamviewer7 ... dpkg: dependency problems prevent configuration of teamviewer7: teamviewer7 depends on libc6-i386 (>= 2.7); however: Package libc6-i386 is not installed. teamviewer7 depends on lib32asound2; however: Package lib32asound2 is not installed. teamviewer7 depends on lib32z1; however: Package lib32z1 is not installed. teamviewer7 depends on ia32-libs; however: Package ia32-libs is not installed. dpkg: error processing teamviewer7 (--install): dependency problems - leaving unconfigured Errors were encountered while processing: ipts teamviewer7 I tried to install it manually, but with no luck, I heard some others has this problems. I am running Ubuntu 12.04 x64. Error @ sudo apt-get install libc6-i386 lib32asound2 lib32z1 ia32-libs : tek@tek-G53SW:~/Download$ sudo apt-get install libc6-i386 lib32asound2 lib32z1 ia32-libs Reading package lists... Done Building dependency tree Reading state information... Done You might want to run 'apt-get -f install' to correct these: The following packages have unmet dependencies: ia32-libs : Depends: ia32-libs-multiarch E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution). tek@tek-G53SW:~/Download$ More errors tek@tek-G53SW:~/Download$ sudo apt-get -f install [sudo] password for tek: Reading package lists... Done Building dependency tree Reading state information... Done Correcting dependencies... Done The following packages will be REMOVED: teamviewer7 0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded. 1 not fully installed or removed. After this operation, 81.9 MB disk space will be freed. Do you want to continue [Y/n]? y (Reading database ... 142441 files and directories currently installed.) Removing teamviewer7 ... tek@tek-G53SW:~/Download$ sudo apt-get install libc6-i386 lib32asound2 lib32z1 ia32-libs Reading package lists... Done Building dependency tree Reading state information... Done lib32z1 is already the newest version. libc6-i386 is already the newest version. lib32asound2 is already the newest version. Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation: The following packages have unmet dependencies: ia32-libs : Depends: ia32-libs-multiarch E: Unable to correct problems, you have held broken packages. tek@tek-G53SW:~/Download$ sudo apt-get install ia32-libs-multiarch Reading package lists... Done Building dependency tree Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation: The following packages have unmet dependencies: ia32-libs-multiarch:i386 : Depends: gstreamer0.10-plugins-good:i386 but it is not going to be installed Depends: gtk2-engines:i386 but it is not going to be installed Depends: gtk2-engines-murrine:i386 but it is not going to be installed Depends: gtk2-engines-pixbuf:i386 but it is not going to be installed Depends: gtk2-engines-oxygen:i386 but it is not going to be installed Depends: ibus-gtk:i386 but it is not going to be installed Depends: libcanberra-gtk-module:i386 but it is not going to be installed Depends: libcups2:i386 but it is not going to be installed Depends: libcupsimage2:i386 but it is not going to be installed Depends: libfontconfig1:i386 but it is not going to be installed Depends: libgail-common:i386 but it is not going to be installed Depends: libgphoto2-2:i386 but it is not going to be installed Depends: libgtk2.0-0:i386 but it is not going to be installed Depends: libnss3:i386 but it is not going to be installed Depends: libqt4-opengl:i386 but it is not going to be installed Depends: libqt4-qt3support:i386 but it is not going to be installed Depends: libqt4-scripttools:i386 but it is not going to be installed Depends: libqt4-svg:i386 but it is not going to be installed Depends: libqtgui4:i386 but it is not going to be installed Depends: libqtwebkit4:i386 but it is not going to be installed Depends: librsvg2-common:i386 but it is not going to be installed Depends: libsane:i386 but it is not going to be installed E: Unable to correct problems, you have held broken packages. tek@tek-G53SW:~/Download$

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  • Can't remove the libpcap0.8 package

    - by Yogesh
    I am getting error when running apt-get remove root@System:~/Downloads# sudo apt-get remove The following packages have unmet dependencies: libpcap0.8 : Breaks: libpcap0.8:i386 (!= 1.4.0-2) but 1.5.3-2 is installed libpcap0.8:i386 : Breaks: libpcap0.8 (!= 1.5.3-2) but 1.4.0-2 is installed libpcap0.8-dev : Depends: libpcap0.8 (= 1.5.3-2) but 1.4.0-2 is installed E: Unmet dependencies. Try using -f. and when I ran apt-get remove -f this is what happens: root@System:~/Downloads# sudo apt-get remove -f The following extra packages will be installed: libpcap0.8 The following packages will be upgraded: libpcap0.8 1 upgraded, 0 newly installed, 0 to remove and 365 not upgraded. 2 not fully installed or removed. Need to get 0 B/110 kB of archives. After this operation, 13.3 kB of additional disk space will be used. Do you want to continue? [Y/n] y (Reading database ... 163539 files and directories currently installed.) Preparing to unpack .../libpcap0.8_1.5.3-2_amd64.deb ... Unpacking libpcap0.8:amd64 (1.5.3-2) over (1.4.0-2) ... dpkg: error processing archive /var/cache/apt/archives/libpcap0.8_1.5.3-2_amd64.deb (--unpack): trying to overwrite shared '/usr/share/man/man7/pcap-filter.7.gz', which is different from other instances of package libpcap0.8:amd64 dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Processing triggers for man-db (2.6.7.1-1) ... Errors were encountered while processing: /var/cache/apt/archives/libpcap0.8_1.5.3-2_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1) root@System:~/Downloads# clear root@System:~/Downloads# sudo apt-get remove -f Reading package lists... Done Building dependency tree Reading state information... Done Correcting dependencies... Done The following extra packages will be installed: libpcap0.8 The following packages will be upgraded: libpcap0.8 1 upgraded, 0 newly installed, 0 to remove and 365 not upgraded. 2 not fully installed or removed. Need to get 0 B/110 kB of archives. After this operation, 13.3 kB of additional disk space will be used. Do you want to continue? [Y/n] y (Reading database ... 163539 files and directories currently installed.) Preparing to unpack .../libpcap0.8_1.5.3-2_amd64.deb ... Unpacking libpcap0.8:amd64 (1.5.3-2) over (1.4.0-2) ... dpkg: error processing archive /var/cache/apt/archives/libpcap0.8_1.5.3-2_amd64.deb (--unpack): trying to overwrite shared '/usr/share/man/man7/pcap-filter.7.gz', which is different from other instances of package libpcap0.8:amd64 dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Processing triggers for man-db (2.6.7.1-1) ... Errors were encountered while processing: /var/cache/apt/archives/libpcap0.8_1.5.3-2_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1) root@System:~/Downloads# root@System:~/Downloads# sudo apt-get check Reading package lists... Done Building dependency tree Reading state information... Done You might want to run 'apt-get -f install' to correct these. The following packages have unmet dependencies: libpcap0.8 : Breaks: libpcap0.8:i386 (!= 1.4.0-2) but 1.5.3-2 is installed libpcap0.8:i386 : Breaks: libpcap0.8 (!= 1.5.3-2) but 1.4.0-2 is installed libpcap0.8-dev : Depends: libpcap0.8 (= 1.5.3-2) but 1.4.0-2 is installed E: Unmet dependencies. Try using -f. root@System:~/Downloads# apt-cache policy libpcap0.8:amd64 libpcap0.8 libpcap0.8-dev libpcap0.8: Installed: 1.4.0-2 Candidate: 1.5.3-2 Version table: 1.5.3-2 0 500 http://in.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages *** 1.4.0-2 0 100 /var/lib/dpkg/status libpcap0.8: Installed: 1.4.0-2 Candidate: 1.5.3-2 Version table: 1.5.3-2 0 500 http://in.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages *** 1.4.0-2 0 100 /var/lib/dpkg/status libpcap0.8-dev: Installed: 1.5.3-2 Candidate: 1.5.3-2 Version table: *** 1.5.3-2 0 500 http://in.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages 100 /var/lib/dpkg/status root@System:~/Downloads# root@System:~/Downloads# sudo apt-get -f remove libpcap0.8 libpcap0.8-dev libpcap0.8-dev:i386 libpcap0.8:i386 Reading package lists... Done Building dependency tree Reading state information... Done Package 'libpcap0.8-dev:i386' is not installed, so not removed. Did you mean 'libpcap0.8-dev'? You might want to run 'apt-get -f install' to correct these: The following packages have unmet dependencies: libpcap-dev : Depends: libpcap0.8-dev but it is not going to be installed E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution). root@System:~/Downloads# sudo apt-get -f install Reading package lists... Done Building dependency tree Reading state information... Done Correcting dependencies... Done The following extra packages will be installed: libpcap0.8 The following packages will be upgraded: libpcap0.8 1 upgraded, 0 newly installed, 0 to remove and 365 not upgraded. 2 not fully installed or removed. Need to get 0 B/110 kB of archives. After this operation, 13.3 kB of additional disk space will be used. Do you want to continue? [Y/n] y (Reading database ... 163539 files and directories currently installed.) Preparing to unpack .../libpcap0.8_1.5.3-2_amd64.deb ... Unpacking libpcap0.8:amd64 (1.5.3-2) over (1.4.0-2) ... dpkg: error processing archive /var/cache/apt/archives/libpcap0.8_1.5.3-2_amd64.deb (--unpack): trying to overwrite shared '/usr/share/man/man7/pcap-filter.7.gz', which is different from other instances of package libpcap0.8:amd64 dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Processing triggers for man-db (2.6.7.1-1) ... Errors were encountered while processing: /var/cache/apt/archives/libpcap0.8_1.5.3-2_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1) root@System:~/Downloads#

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