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  • Scala 2.8 TreeMap and custom Ordering

    - by Dave
    I'm switching from scala 2.7 and ordered to scala 2.8 and using ordering. It looks quite straight forward but I was wondering could I make it a little less verbose. For example: scala> case class A(i: Int) defined class A scala> object A extends Ordering[A] { def compare(o1: A, o2: A) = o1.i - o2.i} defined module A If I then try to create a TreeMap I get an error scala> new collection.immutable.TreeMap[A, String]() <console>:10: error: could not find implicit value for parameter ordering: Ordering[A] new collection.immutable.TreeMap[A, String]() ^ However if I explicitly specify the object A as the ordering it works fine. scala> new collection.immutable.TreeMap[A, String]()(A) res34: scala.collection.immutable.TreeMap[A,String] = Map() Do I always have to explicitly specify the ordering or is there a shorter format? Thanks

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  • How to get the row and column of button clicked, in the grid event handler?

    - by younevertell
    Once the added button in grid is clicked, how to find which row and column the button is located in the grid event handler, like click event or some other events? Not the button click event handler #region Grid event handler setup myGrid.MouseEnter += new MouseEventHandler(myGrid_MouseEnter); myGrid.MouseLeave += new MouseEventHandler(myGrid_MouseLeave); myGrid.MouseDown += new MouseButtonEventHandler(myGrid_MouseDown); myGrid.MouseUp += new MouseButtonEventHandler(myGrid_MouseUp); #endregion Thanks I notice that Boyan has some solution for the button click event handler case http://stackoverflow.com/questions/363100/in-wpf-how-can-i-determine-what-column-row-in-a-grid-a-control-is In the Click event handler for the button you say: int row; Button btn = sender as Button; if (btn != null) { row = Grid.GetRow(btn); // And you have the row number... } else { // A nasty error occurred... }

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  • AJAX vs AHAH Is there a performance advantage?

    - by LanguaFlash
    My concern is performance, is there a reason to to send the client XML instead of valid HTML? Like most things, I am sure it is application dependent. My specific situation is where there is substantial content being inserted into the web page that has been pulled from a database. What are the advantages of either approach? Is the size of the content even a concern? Or, in the case of using XML, will the time for the Javascript to process the XML into HTML counterbalance the extra time that would have been required to send HTML to start with? Thanks, Jeff

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  • alternatives to System.Diagnostics.Process.Start when command is too long

    - by Frank Schwieterman
    I have some code which is generating a rather long command that is being sent to System.Diagnostics.Process.Start(). The call fails with a Win32Exception, message "The filename or extension is too long". The path to the program itself is not very long, but the parameters passed in are quite long. I am calling the version where an instance of ProcessStartInfo is passed as the parameter, and in this case its the ProcessStartInfo.Arguments .Field that is very long. (other parameters: CreateNoWindow = true, UseShellExecute = false, RedirectStandardError = true). It looks like the exception is coming from a call to win32 function CreateProcess. Does anyone have an idea of another way to start the process?

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  • HTML 5 Canvas - Dynamically include multiple images in canvas

    - by Ron
    I need to include multiple images in a canvas. I want to load them dynamically via a for-loop. I tried a lot but in the best case only the last image is displayed. I check this tread but I still get only the last image. For explanation, here's my latest code(basically the one from the other post): for (var i = 0; i <= max; i++) { thisWidth = 250; thisHeight = 0; imgSrc = "photo_"+i+".jpg"; letterImg = new Image(); letterImg.onload = function() { context.drawImage(letterImg,thisWidth*i,thisHeight); } letterImg.src = imgSrc; } Any ideas?

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  • Specifying location of new inlineshape in Word VBA?

    - by Branan
    I'm working on a document "wizard" for the company that I work for. It's a .dot file with a header consisting of some text and some form fields, and a lot of VBA code. The body of the document is pulled in as an OLE object from a separate .doc file. Currently, this is being done as a Shape, rather than an InlineShape. I did this because I can absolutely position the Shape, whereas the InlineShape always appears at the beginning of the document. The problem with this is that a Shape doesn't move when the size of the header changes. If someone needs to add or remove a line from the header due to a special case, they also need to move the object that defines the body. This is a pain, and I'd like to avoid it if possible. Long story short, how do I position an InlineShape using VBA in Word? Oh, and this is for a 10-year-old system setup, so Office '97.

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  • How to find a word within text using XSLT 2.0 and REGEX (which doesn't have \b word boundary)?

    - by Mads Hansen
    I am attempting to scan a string of words and look for the presence of a particular word(case insensitive) in an XSLT 2.0 stylesheet using REGEX. I have a list of words that I wish to iterate over and determine whether or not they exist within a given string. I want to match on a word anywhere within the given text, but I do not want to match within a word (i.e. A search for foo should not match on "food" and a search for bar should not match on "rebar"). XSLT 2.0 REGEX does not have a word boundary(\b), so I need to replicate it as best I can.

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  • convert string to float without silent NaN/Inf conversion

    - by Peter Hansen
    I'd like convert strings to floats using Python 2.6 and later, but without silently converting things like 'NaN' and 'Inf'. Before 2.6, float("NaN") would raise a ValueError. Now it returns a float for which math.isnan() returns True, which is not useful behaviour for my application. Here's what I've got at the moment: import math def get_floats(source): for text in source.split(): try: val = float(text) if math.isnan(val) or math.isinf(val): raise ValueError yield val except ValueError: pass This is a generator, which I can supply with strings containing whitespace-separated sequences representing real numbers. I'd like it to yield only those fields which are purely numeric representations of floats, as in "1.23" or "-34e6", but not for example "NaN" or "-Inf". Test case: assert list(get_floats('1.23 -34e6 NaN -Inf')) == [1.23, -34000000.0] Please suggest alternatives you consider more elegant, even if they involve "look before you leap" (which is normally considered a lesser approach in Python).

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  • Document Stored in File System Text Searching and Filtering required in ASP .Net Application

    - by Harryboy
    Hello Experts, We are building a jobsite application in which we will store resumes of all the candidates, which is planned to store on file system. Now We need to search inside that file and provide the result to the user, we need to provide that what is the best solution to implement text searching. I have just tried to identify it and got some reference like IFilter (API or interface) and Lucene.Net (open source), but not sure that is it a right solution. In initial phase it is expected to be around 50,000 resumes and it should be scalable enough if number increases. I just want some case study or some analysis or your suggestions that which is the best method to handle this requirement (Technology ASP .Net) Thanks

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  • jQuery UI Datepicker on a qTip

    - by Justin Ethier
    I am trying to display a qTip containing a jQuery UI datepicker control (the version bundled with jQuery UI). However the datepicker's calendar opens behind the qTip. I tried manually setting the calendar's z-order from firebug, which does allow the calendar to open in front of the qTip. However, in this case clicking on the calendar has the effect of closing the qTip as (I assume) it is part of the page's content. I am still working through this but wanted to ask - has anyone run into this problem before? Any possible workarounds to get the datepicker to work?

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  • Laissez les bon temps rouler! (Microsoft BI Conference 2010)

    - by smisner
    Laissez les bons temps rouler" is a Cajun phrase that I heard frequently when I lived in New Orleans in the mid-1990s. It means "Let the good times roll!" and encapsulates a feeling of happy expectation. As I met with many of my peers and new acquaintances at the Microsoft BI Conference last week, this phrase kept running through my mind as people spoke about their plans in their respective businesses, the benefits and opportunities that the recent releases in the BI stack are providing, and their expectations about the future of the BI stack.Notwithstanding some jabs here and there to point out the platform is neither perfect now nor will be anytime soon (along with admissions that the competitors are also not perfect), and notwithstanding several missteps by the event organizers (which I don't care to enumerate), the overarching mood at the conference was positive. It was a refreshing change from the doom and gloom hovering over several conferences that I attended in 2009. Although many people expect economic hardships to continue over the coming year or so, everyone I know in the BI field is busier than ever and expects to stay busy for quite a while.Self-Service BISelf-service was definitely a theme of the BI conference. In the keynote, Ted Kummert opened with a look back to a fairy tale vision of self-service BI that he told in 2008. At that time, the fairy tale future was a time when "every end user was able to use BI technologies within their job in order to move forward more effectively" and transitioned to the present time in which SQL Server 2008 R2, Office 2010, and SharePoint 2010 are available to deliver managed self-service BI.This set of technologies is presumably poised to address the needs of the 80% of users that Kummert said do not use BI today. He proceeded to outline a series of activities that users ought to be able to do themselves--from simple changes to a report like formatting or an addtional data visualization to integration of an additional data source. The keynote then continued with a series of demonstrations of both current and future technology in support of self-service BI. Some highlights that interested me:PowerPivot, of course, is the flagship product for self-service BI in the Microsoft BI stack. In the TechEd keynote, which was open to the BI conference attendees, Amir Netz (twitter) impressed the audience by demonstrating interactivity with a workbook containing 100 million rows. He upped the ante at the BI keynote with his demonstration of a future-state PowerPivot workbook containing over 2 billion records. It's important to note that this volume of data is being processed by a server engine, and not in the PowerPivot client engine. (Yes, I think it's impressive, but none of my clients are typically wrangling with 2 billion records at a time. Maybe they're thinking too small. This ability to work quickly with large data sets has greater implications for BI solutions than for self-service BI, in my opinion.)Amir also demonstrated KPIs for the future PowerPivot, which appeared to be easier to implement than in any other Microsoft product that supports KPIs, apart from simple KPIs in SharePoint. (My initial reaction is that we have one more place to build KPIs. Great. It's confusing enough. I haven't seen how well those KPIs integrate with other BI tools, which will be important for adoption.)One more PowerPivot feature that Amir showed was a graphical display of the lineage for calculations. (This is hugely practical, especially if you build up calculations incrementally. You can more easily follow the logic from calculation to calculation. Furthermore, if you need to make a change to one calculation, you can assess the impact on other calculations.)Another product demonstration will be available within the next 30 days--Pivot for Reporting Services. If you haven't seen this technology yet, check it out at www.getpivot.com. (It definitely has a wow factor, but I'm skeptical about its practicality. However, I'm looking forward to trying it out with data that I understand.)Michael Tejedor (twitter) demonstrated a feature that I think is really interesting and not emphasized nearly enough--overshadowed by PowerPivot, no doubt. That feature is the Microsoft Business Intelligence Indexing Connector, which enables search of the content of Excel workbooks and Reporting Services reports. (This capability existed in MOSS 2007, but was more cumbersome to implement. The search results in SharePoint 2010 are not only cooler, but more useful by describing whether the content is found in a table or a chart, for example.)This may yet be the dawning of the age of self-service BI - a phrase I've heard repeated from time to time over the last decade - but I think BI professionals are likely to stay busy for a long while, and need not start looking for a new line of work. Kummert repeatedly referenced strategic BI solutions in contrast to self-service BI to emphasize that self-service BI is not a replacement for the services that BI professionals provide. After all, self-service BI does not appear magically on user desktops (or whatever device they want to use). A supporting infrastructure is necessary, and grows in complexity in proportion to the need to simplify BI for users.It's one thing to hear the party line touted by Microsoft employees at the BI keynote, but it's another to hear from the people who are responsible for implementing and supporting it within an organization. Rob Collie (blog | twitter), Kasper de Jonge (blog | twitter), Vidas Matelis (site | twitter), and I were invited to join Andrew Brust (blog | twitter) as he led a Birds of a Feather session at TechEd entitled "PowerPivot: Is It the BI Deal-Changer for Developers and IT Pros?" I would single out the prevailing concern in this session as the issue of control. On one side of this issue were those who were concerned that they would lose control once PowerPivot is implemented. On the other side were those who believed that data should be freely accessible to users in PowerPivot, and even acknowledgment that users would get the data they want even if it meant they would have to manually enter into a workbook to have it ready for analysis. For another viewpoint on how PowerPivot played out at the conference, see Rob Collie's observations.Collaborative BII have been intrigued by the notion of collaborative BI for a very long time. Before I discovered BI, I was a Lotus Notes developer and later a manager of developers, working in a software company that enabled collaboration in the legal industry. Not only did I help create collaborative systems for our clients, I created a complete project management from the ground up to collaboratively manage our custom development work. In that case, collaboration involved my team, my client contacts, and me. I was also able to produce my own BI from that system as well, but didn't know that's what I was doing at the time. Only in recent years has SharePoint begun to catch up with the capabilities that I had with Lotus Notes more than a decade ago. Eventually, I had the opportunity at that job to formally investigate BI as another product offering for our software, and the rest - as they say - is history. I built my first data warehouse with Scott Cameron (who has also ventured into the authoring world by writing Analysis Services 2008 Step by Step and was at the BI Conference last week where I got to reminisce with him for a bit) and that began a career that I never imagined at the time.Fast forward to 2010, and I'm still lauding the virtues of collaborative BI, if only the tools will catch up to my vision! Thus, I was anxious to see what Donald Farmer (blog | twitter) and Rita Sallam of Gartner had to say on the subject in their session "Collaborative Decision Making." As I suspected, the tools aren't quite there yet, but the vendors are moving in the right direction. One thing I liked about this session was a non-Microsoft perspective of the state of the industry with regard to collaborative BI. In addition, this session included a better demonstration of SharePoint collaborative BI capabilities than appeared in the BI keynote. Check out the video in the link to the session to see the demonstration. One of the use cases that was demonstrated was linking from information to a person, because, as Donald put it, "People don't trust data, they trust people."The Microsoft BI Stack in GeneralA question I hear all the time from students when I'm teaching is how to know what tools to use when there is overlap between products in the BI stack. I've never taken the time to codify my thoughts on the subject, but saw that my friend Dan Bulos provided good insight on this topic from a variety of perspectives in his session, "So Many BI Tools, So Little Time." I thought one of his best points was that ideally you should be able to design in your tool of choice, and then deploy to your tool of choice. Unfortunately, the ideal is yet to become real across the platform. The closest we come is with the RDL in Reporting Services which can be produced from two different tools (Report Builder or Business Intelligence Development Studio's Report Designer), manually, or by a third-party or custom application. I have touted the idea for years (and publicly said so about 5 years ago) that eventually more products would be RDL producers or consumers, but we aren't there yet. Maybe in another 5 years.Another interesting session that covered the BI stack against a backdrop of competitive products was delivered by Andrew Brust. Andrew did a marvelous job of consolidating a lot of information in a way that clearly communicated how various vendors' offerings compared to the Microsoft BI stack. He also made a particularly compelling argument about how the existence of an ecosystem around the Microsoft BI stack provided innovation and opportunities lacking for other vendors. Check out his presentation, "How Does the Microsoft BI Stack...Stack Up?"Expo HallI had planned to spend more time in the Expo Hall to see who was doing new things with the BI stack, but didn't manage to get very far. Each time I set out on an exploratory mission, I got caught up in some fascinating conversations with one or more of my peers. I find interacting with people that I meet at conferences just as important as attending sessions to learn something new. There were a couple of items that really caught me eye, however, that I'll share here.Pragmatic Works. Whether you develop SSIS packages, build SSAS cubes, or author SSRS reports (or all of the above), you really must take a look at BI Documenter. Brian Knight (twitter) walked me through the key features, and I must say I was impressed. Once you've seen what this product can do, you won't want to document your BI projects any other way. You can download a free single-user database edition, or choose from more feature-rich standard or professional editions.Microsoft Press ebooks. I also stopped by the O'Reilly Media booth to meet some folks that one of my acquisitions editors at Microsoft Press recommended. In case you haven't heard, Microsoft Press has partnered with O'Reilly Media for distribution and publishing. Apart from my interest in learning more about O'Reilly Media as an author, an advertisement in their booth caught me eye which I think is a really great move. When you buy Microsoft Press ebooks through the O'Reilly web site, you can receive it in any (or all) of the following formats where possible: PDF, epub, .mobi for Kindle and .apk for Android. You also have lifetime DRM-free access to the ebooks. As someone who is an avid collector of books, I fnd myself running out of room for storage. In addition, I travel a lot, and it's hard to lug my reference library with me. Today's e-reader options make the move to digital books a more viable way to grow my library. Having a variety of formats means I am not limited to a single device, and lifetime access means I don't have to worry about keeping track of where I've stored my files. Because the e-books are DRM-free, I can copy and paste when I'm compiling notes, and I can print pages when necessary. That's a winning combination in my mind!Overall, I was pleased with the BI conference. There were many more sessions that I couldn't attend, either because the room was full when I got there or there were multiple sessions running concurrently that I wanted to see. Fortunately, many of the sessions are accessible for viewing online at http://www.msteched.com/2010/NorthAmerica along with the TechEd sessions. You can spot the BI sessions by the yellow skyline on the title slide of the presentation as shown below. Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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  • Rx: Piecing together multiple IObservable web requests

    - by McLovin
    Hello, I'm creating multiple asynchronous web requests using IObservables and reactive extensions. So this creates observable for "GET" web request: var tweetObservalue = from request in WebRequestExtensions.CreateWebRequest(outUrl + querystring, method) from response in request.GetResponseAsync() let responseStream = response.GetResponseStream() let reader = new StreamReader(responseStream) select reader.ReadToEnd(); And I can do tweetObservable.Subscribe(response => dosomethingwithresponse(response)); What is the correct way of executing multiple asynchronous web requests with IObservables and LINQ that have to wait until other requests have been finished? For example first I would like to verify user info: create userInfoObservable, then if user info is correct I want to update stats so I get updateStatusObservable then if status is updated I would like create friendshipObservable and so on. Also bonus question, there is a case where I would like to execute web calls simultaneously and when all are finished execute another observable which will until other calls are finished. Thank you.

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  • (partial apply str) and apply-str in clojure's ->

    - by Jason Baker
    If I do the following: user=> (-> ["1" "2"] (partial apply str)) #<core$partial__5034$fn__5040 clojure.core$partial__5034$fn__5040@d4dd758> ...I get a partial function back. However, if I bind it to a variable: user=> (def apply-str (partial apply str)) #'user/apply-str user=> (-> ["1" "2" "3"] apply-str) "123" ...the code works as I intended it. I would assume that they are the same thing, but apparently that isn't the case. Can someone explain why this is to me?

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  • C++0x regex in GCC

    - by rwallace
    The following code: #include <regex> using namespace std; (snippage) regex_search(s, m, re); works in Microsoft C++, but GCC 4.4.3 gives the following error message: /usr/include/c++/4.4/tr1_impl/regex:2255: warning: inline function ‘bool std::regex_search(_Bi_iter, _Bi_iter, std::match_results<_Bi_iter, _Allocator&, const std::basic_regex<_Ch_type, _Rx_traits&, std::regex_constants::match_flag_type) [with _Bi_iter = __gnu_cxx::__normal_iterator, std::allocator , _Allocator = std::allocator, std::allocator , _Ch_type = char, _Rx_traits = std::regex_traits]’ used but never defined Of course it wouldn't surprise me if regex were simply one of the C++0x features still on the to-do list for GCC, but what I'm scratching my head over is, in that case, why does it happily take the include directive, variable declarations etc. and only trip over the function call (which it even seems to understand). Is there something I'm missing?

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  • Neural Network problems

    - by Betamoo
    I am using an external library for Artificial Neural Networks in my project.. While testing the ANN, It gave me output of all NaN (not a number in C#) The ANN has 8 input , 5 hidden , 5 hidden , 2 output, and all activation layers are of Linear type , and it uses back-propagation, with learning rate 0.65 I used one testcase for training { -2.2, 1.3, 0.4, 0.5, 0.1, 5, 3, -5 } ,{ -0.3, 0.2 } for 1000 epoch And I tested it on { 0.2, -0.2, 5.3, 0.4, 0.5, 0, 35, 0.0 } which gave { NaN , NaN} Note: this is one example of many that produces same case... I am trying to discover whether it is a bug in the library, or an illogical configuration.. The reasons I could think of for illogical configuration: All layers should not be linear Can not have descending size layers, i.e 8-5-5-2 is bad.. Only one testcase ? Values must be in range [0,1] or [-1,1] Is any of the above reasons could be the cause of error, or there are some constraints/rules that I do not know in ANN designing..? Note: I am newbie in ANN

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  • Java Meta Search Engine API

    - by Loki
    I'm currently researching Java libraries to help in building a meta type search engine in the sense of being able to replace any given search engine in the back-end of the application or to simultaneously search using multiple search engines. I'm not interested in the GUI part here, just the generalization of search engine APIs and usage. I'd like to know about the common libraries used to achieve this task and if there are any common patterns used in this case. I imagined that this problem is common enough to be able to find plenty of stuff on Google, but it seems like search is a very proprietary domain and not much information is fed back to the community.

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  • How do I integrate SMF into my custom Php member based website?

    - by Ali
    Hi guys, I built a simple social community website for a client - the client would like to add in a forum and he likes Simple Machines Forum. The website I built has its own users management system. The client would like SMF on his website and at the same time when a user is logged into the website they don't need to log into SMF website as well... how can this be done? Or should I just tell the client to consider two separet independant applications in this case i.e forum totally disjoint from the main site?

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  • Success verification of mail() function PHP

    - by Jared
    Hi Is it possible to check if the php can get some kind of a ping/flag back from exchange mail server to say "yes, email has been sent off to the intended recipient"? According to the PHP manual, the return of mail() boolean could mean; "It is important to note that just because the mail was accepted for delivery, it does NOT mean the mail will actually reach the intended destination." Does this mean, PHP can return success but actually there could be a problem on the mail server that php wouldn't know about it? and in this case no email has been sent and the user is none the wiser? TIA Jared

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  • Regular Expression, JEditorPane, Self-closing tags

    - by Stephen Swensen
    I'm am using JEditorPane to render basic HTML. But it renders self-closing tags incorrectly, specifically br tags, e.g. <br /> is bad but <br> is good. I would like to use String.replaceAll(regex, "<br>") to fix the HTML, where regex is a regular expression matching any self-closing br tag with case-insensitivity and zero to infinity number of spaces between the "r" and the "/" (e.g., <br/>, <BR/>, <br />, <Br     />, etc.). Thanks to any regular expression experts who can solve this!

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  • Renaming and Moving Files in Bash

    - by KT
    HI, I'm completely new to Bash and StackOverflow. I need to move a set of files (all contained in the same folder) to a target folder where files with the same name could already exist. In case a specific file exists, I need to rename the file before moving it, by appending for example an incremental integer to the file name. The extensions should be preserved. The file names could contain dots in the middle. Originally, I was thinking about comparing the two folders to have a list of the existing files (I did this with "comm"), but then I got a bit stuck. I think I'm just trying to do things in the most complicated possible way. Any hint to do this in the "bash way"?

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  • COM/DCOM problem when hosting executable is run as a service

    - by Mitch
    I am struggling for days now with the following problem: We have an executable that hosts a COM server, say x.exe. The COM object is instantiated as follows on the calling site: hRes = CoCreateInstance(CLSID_InterceptX, NULL, CLSCTX_SERVER, IID_IInterceptX, (void**)&pInterceptX); It all works fine when x runs as an regular application. We have a tool (I don't know how it works) that encapsulates x.exe so that it runs as a service under Windows (x.exe is a running process). In this case, we never receive a COM call in x.exe (validated by logging). Here is the weird part: From logging the calling site, I can tell that the COM object has been successfully instantiated and also the call to an interface function does not produce an error (SUCEEDED(hres) is true). Any ideas?

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  • How do I set up mod rewrite to do this?

    - by Ali
    Hi guys heres the scene - I'm building a web application which basically creates accounts for all users. Currently its setup like this the file structure: root/index.php root/someotherfile.php root/images/image-sub-folder/image.jpg root/js/somejs.js When users create an account they choose a fixed group name and then users can join that group. Initially I thought of having an extra textbox in the login screen to enter the group the user belongs to login to. BUt I would like instead to have something like virtual folders in this case: root/group-name/index.php I heard it can be done with apache mod rewrite but I'm not sure how to do this - any help here? Basically instead of having something like &group-name=yourGroupName appended to every page I would just like something of the nature above.

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  • Clustering [assessment] algorithm with distance matrix as an input

    - by Max
    Can anyone suggest some clustering algorithm which can work with distance matrix as an input? Or the algorithm which can assess the "goodness" of the clustering also based on the distance matrix? At this moment I'm using a modification of Kruskal's algorithm (http://en.wikipedia.org/wiki/Kruskal%27s_algorithm) to split data into two clusters. It has a problem though. When the data has no distinct clusters the algorithm will still create two clusters with one cluster containing one element and the other containing all the rest. In this case I would rather have one cluster containing all the elements and another one which is empty. Are there any algorithms which are capable of doing this type of clustering? Are there any algorithms which can estimate how well the clustering was done or even better how many clusters are there in the data? The algorithms should work only with distance(similarity) matrices as an input.

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  • Entity Framework 4.3.1 Code based Migrations and Connector/Net 6.6

    - by GABMARTINEZ
     Code-based migrations is a new feature as part of the Connector/Net support for Entity Framework 4.3.1. In this tutorial we'll see how we can use it so we can keep track of the changes done to our database creating a new application using the code first approach. If you don't have a clear idea about how code first works we highly recommend you to check this subject before going further with this tutorial. Creating our Model and Database with Code First  From VS 2010  1. Create a new console application 2.  Add the latest Entity Framework official package using Package Manager Console (Tools Menu, then Library Package Manager -> Package Manager Console). In the Package Manager Console we have to type  Install-Package EntityFramework This will add the latest version of this library.  We will also need to make some changes to your config file. A <configSections> was added which contains the version you have from EntityFramework.  An <entityFramework> section was also added where you can set up some initialization. This section is optional and by default is generated to use SQL Express. Since we don't need it for now (we'll see more about it below) let's leave this section empty as shown below. 3. Create a new Model with a simple entity. 4. Enable Migrations to generate the our Configuration class. In the Package Manager Console we have to type  Enable-Migrations; This will make some changes in our application. It will create a new folder called Migrations where all the migrations representing the changes we do to our model.  It will also create a Configuration class that we'll be using to initialize our SQL Generator and some other values like if we want to enable Automatic Migrations.  You can see that it already has the name of our DbContext. You can also create you Configuration class manually. 5. Specify our Model Provider. We need to specify in our Class Configuration that we'll be using MySQLClient since this is not part of the generated code. Also please make sure you have added the MySql.Data and the MySql.Data.Entity references to your project. using MySql.Data.Entity;   // Add the MySQL.Data.Entity namespace public Configuration() { this.AutomaticMigrationsEnabled = false; SetSqlGenerator("MySql.Data.MySqlClient", new MySql.Data.Entity.MySqlMigrationSqlGenerator());    // This will add our MySQLClient as SQL Generator } 6. Add our Data Provider and set up our connection string <connectionStrings> <add name="PersonalContext" connectionString="server=localhost;User Id=root;database=Personal;" providerName="MySql.Data.MySqlClient" /> </connectionStrings> <system.data> <DbProviderFactories> <remove invariant="MySql.Data.MySqlClient" /> <add name="MySQL Data Provider" invariant="MySql.Data.MySqlClient" description=".Net Framework Data Provider for MySQL" type="MySql.Data.MySqlClient.MySqlClientFactory, MySql.Data, Version=6.6.2.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d" /> </DbProviderFactories> </system.data> * The version recommended to use of Connector/Net is 6.6.2 or earlier. At this point we can create our database and then start working with Migrations. So let's do some data access so our database get's created. You can run your application and you'll get your database Personal as specified in our config file. Add our first migration Migrations are a great resource as we can have a record for all the changes done and will generate the MySQL statements required to apply these changes to the database. Let's add a new property to our Person class public string Email { get; set; } If you try to run your application it will throw an exception saying  The model backing the 'PersonelContext' context has changed since the database was created. Consider using Code First Migrations to update the database (http://go.microsoft.com/fwlink/?LinkId=238269). So as suggested let's add our first migration for this change. In the Package Manager Console let's type Add-Migration AddEmailColumn Now we have the corresponding class which generate the necessary operations to update our database. namespace MigrationsFromScratch.Migrations { using System.Data.Entity.Migrations; public partial class AddEmailColumn : DbMigration { public override void Up(){ AddColumn("People", "Email", c => c.String(unicode: false)); } public override void Down() { DropColumn("People", "Email"); } } } In the Package Manager Console let's type Update-Database Now you can check your database to see all changes were succesfully applied. Now let's add a second change and generate our second migration public class Person   {       [Key]       public int PersonId { get; set;}       public string Name { get; set; }       public string Address {get; set;}       public string Email { get; set; }       public List<Skill> Skills { get; set; }   }   public class Skill   {     [Key]     public int SkillId { get; set; }     public string Description { get; set; }   }   public class PersonelContext : DbContext   {     public DbSet<Person> Persons { get; set; }     public DbSet<Skill> Skills { get; set; }   } If you would like to customize any part of this code you can do that at this step. You can see there is the up method which can update your database and the down that can revert the changes done. If you customize any code you should make sure to customize in both methods. Now let's apply this change. Update-database -verbose I added the verbose flag so you can see all the SQL generated statements to be run. Downgrading changes So far we have always upgraded to the latest migration, but there may be times when you want downgrade to a specific migration. Let's say we want to return to the status we have before our last migration. We can use the -TargetMigration option to specify the migration we'd like to return. Also you can use the -verbose flag. If you like to go  back to the Initial state you can do: Update-Database -TargetMigration:$InitialDatabase  or equivalent: Update-Database -TargetMigration:0  Migrations doesn't allow by default a migration that would ocurr in a data loss. One case when you can got this message is for example in a DropColumn operation. You can override this configuration by setting AutomaticMigrationDataLossAllowed to true in the configuration class. Also you can set your Database Initializer in case you want that these Migrations can be applied automatically and you don't have to go all the way through creating a migration and updating later the changes. Let's see how. Database Initialization by Code We can specify an initialization strategy by using Database.SetInitializer (http://msdn.microsoft.com/en-us/library/gg679461(v=vs.103)). One of the strategies that I found very useful when you are at a development stage (I mean not for production) is the MigrateDatabaseToLatestVersion. This strategy will make all the necessary migrations each time there is a change in our model that needs a database replication, this also implies that we have to enable AutomaticMigrationsEnabled flag in our Configuration class. public Configuration()         {             AutomaticMigrationsEnabled = true;             AutomaticMigrationDataLossAllowed = true;             SetSqlGenerator("MySql.Data.MySqlClient", new MySql.Data.Entity.MySqlMigrationSqlGenerator());    // This will add our MySQLClient as SQL Generator          } In the new EntityFramework section of your Config file we can set this at a context level basis.  The syntax is as follows: <contexts> <context type="Custom DbContext name, Assembly name"> <databaseInitializer type="System.Data.Entity.MigrateDatabaseToLatestVersion`2[[ Custom DbContext name, Assembly name],  [Configuration class name, Assembly name]],  EntityFramework" /> </context> </contexts> In our example this would be: The syntax is kind of odd but very convenient. This way all changes will always be applied when we do any data access in our application. There are a lot of new things to explore in EF 4.3.1 and Migrations so we'll continue writing some more posts about it. Please let us know if you have any questions or comments, also please check our forums here where we keep answering questions in general for the community.  Hope you found this information useful. Happy MySQL/.Net Coding! 

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  • R and SPSS difference

    - by sfactor
    i will be analysing vast amount of network traffic related data shortly. i will pre-process the data in order to analyse it. i have found that R and SPSS are among the most popular tools for statistical analysis. i will also be generating quite a lot of graphs and charts. so i was wondering what is the basic difference between these two softwares. i am not asking which one is better. i just wanted to know what are the difference in terms of workflow between the two besides the fact that SPSS has a GUI. I will be mostly working with scripts in either case anyway so i wanted to know about the other differences.

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