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  • Doctesting functions that receive and display user input - Python (tearing my hair out)

    - by GlenCrawford
    Howdy! I am currently writing a small application with Python (3.1), and like a good little boy, I am doctesting as I go. However, I've come across a method that I can't seem to doctest. It contains an input(), an because of that, I'm not entirely sure what to place in the "expecting" portion of the doctest. Example code to illustrate my problem follows: """ >>> getFiveNums() Howdy. Please enter five numbers, hit <enter> after each one Please type in a number: Please type in a number: Please type in a number: Please type in a number: Please type in a number: """ import doctest numbers = list() # stores 5 user-entered numbers (strings, for now) in a list def getFiveNums(): print("Howdy. Please enter five numbers, hit <enter> after each one") for i in range(5): newNum = input("Please type in a number:") numbers.append(newNum) print("Here are your numbers: ", numbers) if __name__ == "__main__": doctest.testmod(verbose=True) When running the doctests, the program stops executing immediately after printing the "Expecting" section, waits for me to enter five numbers one after another (without prompts), and then continues. As shown below: I don't know what, if anything, I can place in the Expecting section of my doctest to be able to test a method that receives and then displays user input. So my question (finally) is, is this function doctestable?

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  • SendMessage to window created by AllocateHWND cause deadlock

    - by user2704265
    In my Delphi project, I derive a thread class TMyThread, and follow the advice from forums to use AllocateHWnd to create a window handle. In TMyThread object, I call SendMessage to send message to the window handle. When the messages sent are in small volume, then the application works well. However, when the messages are in large volume, the application will deadlock and lose responses. I think may be the message queue is full as in LogWndProc, there are only codes to process the message, but no codes to remove the messages from the queue, that may cause all the processed messages still exist in the queue and the queue becomes full. Is that correct? The codes are attached below: var hLogWnd: HWND = 0; procedure TForm1.FormCreate(Sender: TObject); begin hLogWnd := AllocateHWnd(LogWndProc); end; procedure TForm1.FormDestroy(Sender: TObject); begin if hLogWnd <> 0 then DeallocateHWnd(hLogWnd); end; procedure TForm1.LogWndProc(var Message: TMessage); var S: PString; begin if Message.Msg = WM_UPDATEDATA then begin S := PString(msg.LParam); try List1.Items.Add(S^); finally Dispose(S); end; end else Message.Result := DefWindowProc(hLogWnd, Message.Msg, Message.WParam, Message.LParam); end; procedure TMyThread.SendLog(I: Integer); var Log: PString; begin New(Log); Log^ := 'Log: current stag is ' + IntToStr(I); SendMessage(hLogWnd, WM_UPDATEDATA, 0, LPARAM(Log)); Dispose(Log); end;

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  • Setting up a multi-site CMS, collecting thoughts about the DB schema

    - by Ben Fransen
    Hello all, I'm collecting some thoughts about creating a multisite CMS. In my opinion there are two major approaches. All data is stored into 1 database, giving me the advantage of single point of updates; Seperated databases, so each client has its own database. Giving me the advantage to measure bandwith. Option 1 gives me the disadvantage of measuring bandwith while option is giving me the disadvantage of a single point of update structure. Are there any generic approaches for creating a sort of update system? So my clients can download a small package (maybe a zip with a conf file to tell the updatescript where to put all the files and how to extend the database??) Do you guys have some thougths about the best solution for a situation like this? I have my own webserver, full access to all resources and I'm developing in PHP with MySQL as DBMS. I hope to hear from you and I surely appreciate any effort you make to help me further! Greets from Holland, Ben Fransen

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  • (solved) jQuery click and drag/scroll window: jagged movement

    - by Josh
    Edit: derp, using pageX/Y instead of clientX/Y -- apparently scrollBy expects input with that offset rather than the other. Jaggy movement gone. I am getting jagged movement when doing small scroll increments using the following bindings. Can anyone point me in the right direction for how to smooth this out? FYI, its intermittent. It seems like, if I click and hold for a second, then drag at a decent speed there are no problems. Edit: What the hell? I get this output on debug... obvious jog backwards and forwards. This will happen in succession and seems to have no correlation with the mouse, other than the mouse is moving. x 398 : 403 y 374 : 377 x 403 : 399 y 377 : 374 x 399 : 404 y 374 : 377 Josh sococo.client.panMap = function(e){ e.preventDefault(); var movex = sococo.client.currX - e.pageX ; var movey = sococo.client.currY - e.pageY; console.log( sococo.client.currX +" : " + e.pageX ); window.scrollBy(movex,movey); sococo.client.currY = e.pageY; sococo.client.currX = e.pageX; } $(document).mousedown( function(e){ e.preventDefault(); sococo.client.currX = e.pageX; sococo.client.currY = e.pageY; $(document).bind( "mousemove", sococo.client.panMap ); }); $(document).mouseup( function(e){ e.preventDefault(); $(document).unbind( "mousemove", sococo.client.panMap ); });

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  • Help with Cygwin bash file

    - by Mestika
    Hi, I have a bash file, which I’m trying to run in Cygwin on a Windows 7 platform, but I gives me some odd errors when doing so. The bash file works on my Linux system. The bach file looks like this: for ((r=0; r <10; r++)) netcat localhost 4444 < myfile.file & done wait but I’m getting an error for my for-loop. More precise it writes: ./tuning_test.bsh: line 1: syntax error near unexpected token `(' '/tuning_test.bsh: line 1: `?for ((r=0; r <10; r++)) I do not understand it because I was sure that I’ve a working bash file on my Linux. I even tried to find a for-loop example from a Linux-bash site and run it but with same error. I’m brand new to Cygwin and doesn’t know if it has some small quirks or some other thing I have to be aware of and I’ve tried to look through the documentation and FAQ on their homepage. Sincere Mestika

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  • Google Code Jam 2010 Large DataSets Take Too Long to Submit

    - by Travis
    Hey Guys, I'm participating in the 2010 code jam and I solved two of the problems for the small data sets, but I'm not even close to solving the large data sets in the 8 minute time frame. I'm wondering if anyone out there has solved the large data set: What hardware were you running on? What language were you running on? What performance tuning techniques did you do on your code to run as fast as possible? I'm writing the solutions in Ruby, which is not my day to day language, and executing them on my Macbook Pro. My solutions for problem A and problem C are on github at http://github.com/tjboudreaux/codejam2010. I'd appreciate any suggestions that you may have. FWIW, I have alot of experience in C++ from college, my primary language is PHP, and my "sandbox" language is Ruby. Was I just a bit ambitious by taking a shot at this in Ruby, not knowing where the language struggles for performance, or does anyone see anything that's a redflag as to why I can't complete the large dataset in time to submit.

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  • Can the Flash CS4 [embed] tag be made to export assets to frame 2 rather than frame 1?

    - by Tim Knauf
    We're working on a Flash CS4 project where the main .fla file has ballooned in size and 'Publish' is taking forever. I suspect a large amount of the size (and at least some of the compile time) is due to the quantity of audio symbols in the library. I would love to remove this unnecessary bloat from the .fla file. I've experimented with removing an audio symbol from the library and using the [embed] metadata tag instead, like so: [Embed(source="audio/music/EndOfLevelDitty.mp3")] public var EndOfLevelDitty:Class The resulting published file works perfectly, but there is a problem. Our game uses a preloader on the first frame of the timeline, so all other classes need to be exported in frame 2 (as set in Publish Settings ActionScript 3.0 Settings). So a size report normally begins like this: Frame # Frame Bytes Total Bytes Scene ------- ----------- ----------- ---------------- 1 284515 284515 Scene 1 2 5485305 5769820 (AS 3.0 Classes Export Frame) However, if I use an [embed] tag on a small sound, my size report is now: Frame # Frame Bytes Total Bytes Scene ------- ----------- ----------- ---------------- 1 363320 363320 Scene 1 2 5407240 5770560 (AS 3.0 Classes Export Frame) As you can see, the embedded sound has been exported into frame 1 rather than frame 2. If I were to embed all sounds in this manner, the size of frame 1 would grow to be huge, and users would be looking at a white screen for ages before the preloader frame even loaded. So my question is this: can I use an [embed] tag but have the embedded asset export in frame 2 instead of frame 1? Project constraints: Our team composition means we can't change to pure Flex at this stage. The compiled .swf needs to be 'all in one', so we can't split the preloader into a separate file, and we can't access external resources. Edit: I'd also settle for having the audio in an embedded library SWC, but there seems to be no way to make that embed in frame 2 either; it always ends up in frame 1.

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  • how to implement login and service features as in skype or msn chat in a wpf application

    - by black sensei
    Hello Good people! I'm building an WPF application that connect to web services for its operations.Things that i needed to be working are so far fine.Now i'll like to improve use experience by adding features like username editable combobox, sign me in when skype start and start when computer start. I have a fair idea about each feature but very small knowledge about their implementation. Question 1 username combobox : i use a combobox with isEditable set to true but i think it doesnt have the previous username, would that mean that i have to store every successful login username in a sqlite for example? Question 2 sign me in when skype start : i think about using sqlite after all to store the credentials and store the value (as in true or false) if autologin has to be performed. Question 3 start when computer start : i know it's about having is as service.but the process of using it as a service and removing its service when checkbox is checked or unckecked is a bit confusing to me. Question 4 Please wait(signing in) of skype if i want to do things like please wait at login(login is over webservice) in a WPF application should i use a animated gif in a grid that i can show when hiding the login combobox and passwordbox grid or i should use an animated object(for which i have no knowledge about for now) ? This post in mainly for you experts to either point me to the right resource and tell me what is done as best practice. things like dos and dons.Thanks for reading this and please let me have a clair idea about how to start implementing those features. thanks again

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  • How to write C++ audio processing applications?

    - by cesko82
    Hi everyone, I'm an Electronics and Telecommunications student, next to my graduation. I'm gonna work on a project that involves my knowledge about DSP, music and audio in general. I allready know all the basic mathematic instruments and all the stuff I need to manage it, such as FFT, circular convolution ecc ecc. I want to learn C++ programming basically for one reason: it's very important in the professional world!!! And I think it's one of the most used to write applications working with audio, especially when it's about real time processing. Ok, after this small introduction I would like to know first, which are the most used libraries to work with audio processing in c++?? I was longer looking on the web but i couldn't find a lo of working stuff. (I work under linux with eclipse CDT enviroment). Then I would like to know if there are good sources to learn how to write some working code, such as for example how to write a simple low pass filter. Basically now i will not write real time applications, I would like to start from the processing of a WAV file, or even better an MP3 file, so basically on vectors of samples. Let's say that basically for now I would like to extract the waveform from an audio file, and save it to a thumbnail or to a PNG image. Ok, for now I think it's all I would need. Any ideas, advices, libraries, books, interesting sources about that? Thanks a lot in advance for any kind of answer. Giovanni.

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  • create board for game with events support

    - by netmajor
    How can I create board for simple game, looks like for chess,but user could dynamically change number of column and rows? In cells I could insert symbol of pawn, like small image or just ellipse or rectangle with fill. This board should have possibility add and remove pawn from cells and move pown from one cell to another. My first idea was Grid. I do it in code behind, but it's hurt to implement events or everything in runtime create board :/ int size = 12; Grid board = new Grid(); board.ShowGridLines = true; for (int i = 0; i < size;i++ ) { board.ColumnDefinitions.Add(new ColumnDefinition()); board.RowDefinitions.Add(new RowDefinition()); } //komputer Rectangle ai = new Rectangle(); ai.Height = 20; ai.Width = 20; ai.AllowDrop = true; ai.Fill = Brushes.Orange; Grid.SetRow(ai, 0); Grid.SetColumn(ai,0); //czlowiek Rectangle hum = new Rectangle(); hum.Height = 20; hum.Width = 20; hum.AllowDrop = true; hum.Fill = Brushes.Green; Grid.SetRow(hum,size); Grid.SetColumn(hum,size); board.Children.Add(ai); board.Children.Add(hum); this.Content = board; It's a way to do this dynamically col and row change in XAML ? It's better way to implement that board create and implement events on move pawn from one cell to another ?

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  • Decoding tcp packets using python

    - by mikip
    Hello I am trying to decode data received over a tcp connection. The packets are small, no more than 100 bytes. However when there is a lot of them I receive some of the the packets joined together. Is there a way to prevent this. I am using python I have tried to separate the packets, my source is below. The packets start with STX byte and end with ETX bytes, the byte following the STX is the packet length, (packet lengths less than 5 are invalid) the checksum is the last bytes before the ETX def decode(data): while True: start = data.find(STX) if start == -1: #no stx in message pkt = '' data = '' break #stx found , next byte is the length pktlen = ord(data[1]) #check message ends in ETX (pktken -1) or checksum invalid if pktlen < 5 or data[pktlen-1] != ETX or checksum_valid(data[start:pktlen]) == False: print "Invalid Pkt" data = data[start+1:] continue else: pkt = data[start:pktlen] data = data[pktlen:] break return data , pkt I use it like this #process reports try: data = sock.recv(256) except: continue else: while data: data, pkt = decode(data) if pkt: process(pkt) Also if there are multiple packets in the data stream, is it best to return the packets as a collection of lists or just return the first packet I am not that familiar with python, only C, is this method OK. Any advice would be most appreciated. Thanks in advance Thanks

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  • Troubles with PyDev and external libraries in OS X

    - by Davide Gualano
    I've successfully installed the latest version of PyDev in my Eclipse (3.5.1) under OS X 10.6.3, with python 2.6.1 I have troubles in making the libraries I have installed work. For example, I'm trying to use the cx_Oracle library, which is perfectly working if called from the python interpeter of from simple scripts made with some text editor. But I cant make it work inside Eclipse: I have this small piece of code: import cx_Oracle conn = cx_Oracle.connect(CONN_STRING) sql = "select field from mytable" cursor = conn.cursor() cursor.execute(sql) for row in cursor: field = row[0] print field If I execute it from Eclipse, I get the following error: import cx_Oracle File "build/bdist.macosx-10.6-universal/egg/cx_Oracle.py", line 7, in <module> File "build/bdist.macosx-10.6-universal/egg/cx_Oracle.py", line 6, in __bootstrap__ ImportError: dlopen(/Users/dave/.python-eggs/cx_Oracle-5.0.3-py2.6-macosx-10.6-universal.egg-tmp/cx_Oracle.so, 2): Library not loaded: /b/227/rdbms/lib/libclntsh.dylib.10.1 Referenced from: /Users/dave/.python-eggs/cx_Oracle-5.0.3-py2.6-macosx-10.6-universal.egg-tmp/cx_Oracle.so Reason: no suitable image found. Did find: /Users/dave/lib/libclntsh.dylib.10.1: mach-o, but wrong architecture Same snippet works perfectly from the python shell I have configured the interpeter in Eclipse in preferences - PyDev -- Interpreter - Python, using the Auto Config option and selecting all the libs found. What am I doing wrong here? Edit: launching file /Users/dave/.python-eggs/cx_Oracle-5.0.3-py2.6-macosx-10.6-universal.egg-tmp/cx_Oracle.so from the command line tells this: /Users/dave/.python-eggs/cx_Oracle-5.0.3-py2.6-macosx-10.6-universal.egg-tmp/cx_Oracle.so: Mach-O universal binary with 3 architectures /Users/dave/.python-eggs/cx_Oracle-5.0.3-py2.6-macosx-10.6-universal.egg-tmp/cx_Oracle.so (for architecture i386): Mach-O bundle i386 /Users/dave/.python-eggs/cx_Oracle-5.0.3-py2.6-macosx-10.6-universal.egg-tmp/cx_Oracle.so (for architecture ppc7400): Mach-O bundle ppc /Users/dave/.python-eggs/cx_Oracle-5.0.3-py2.6-macosx-10.6-universal.egg-tmp/cx_Oracle.so (for architecture x86_64): Mach-O 64-bit bundle x86_64

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  • Fast JSON serialization (and comparison with Pickle) for cluster computing in Python?

    - by user248237
    I have a set of data points, each described by a dictionary. The processing of each data point is independent and I submit each one as a separate job to a cluster. Each data point has a unique name, and my cluster submission wrapper simply calls a script that takes a data point's name and a file describing all the data points. That script then accesses the data point from the file and performs the computation. Since each job has to load the set of all points only to retrieve the point to be run, I wanted to optimize this step by serializing the file describing the set of points into an easily retrievable format. I tried using JSONpickle, using the following method, to serialize a dictionary describing all the data points to file: def json_serialize(obj, filename, use_jsonpickle=True): f = open(filename, 'w') if use_jsonpickle: import jsonpickle json_obj = jsonpickle.encode(obj) f.write(json_obj) else: simplejson.dump(obj, f, indent=1) f.close() The dictionary contains very simple objects (lists, strings, floats, etc.) and has a total of 54,000 keys. The json file is ~20 Megabytes in size. It takes ~20 seconds to load this file into memory, which seems very slow to me. I switched to using pickle with the same exact object, and found that it generates a file that's about 7.8 megabytes in size, and can be loaded in ~1-2 seconds. This is a significant improvement, but it still seems like loading of a small object (less than 100,000 entries) should be faster. Aside from that, pickle is not human readable, which was the big advantage of JSON for me. Is there a way to use JSON to get similar or better speed ups? If not, do you have other ideas on structuring this? (Is the right solution to simply "slice" the file describing each event into a separate file and pass that on to the script that runs a data point in a cluster job? It seems like that could lead to a proliferation of files). thanks.

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  • Android - Linear Layout arrangement, not positioning as expected

    - by Arun
    The following is my code. I want an interface where I have a single line textbox, a multiline textbox with 2 buttons below. I want the multiline textbox to occupy all the space available after rendering the buttons and textbox. For this I created two LinearLayouts inside the main layout. The first one has vertical orientation with layout_width set to fill_parent. The second one is horizontal with fill_parent again. The first one has a textbox for which I have set the layout_height to fill parent. The second one has two textboxes OK and Cancel. When I run this application I get the UI, but the Buttons are very small (about 5px in height). I have to set the button height manually. What am I doing wrong here. I don't want to hard code the button height. <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent"> <LinearLayout android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1"> <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="Name"></TextView> <EditText android:layout_width="fill_parent" android:layout_height="wrap_content"></EditText> <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="Contents"></TextView> <EditText android:layout_width="fill_parent" android:layout_height="fill_parent" android:gravity="top" /> </LinearLayout> <LinearLayout android:orientation="horizontal" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_weight="1"> <Button android:id="@+id/okbutt" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="OK" android:layout_weight="1" /> <Button android:layout_width="fill_parent" android:layout_height="fill_parent" android:text="Cancel" android:layout_weight="1" /> </LinearLayout> Thanks, Arun

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  • How best to use XPath with very large XML files in .NET?

    - by glenatron
    I need to do some processing on fairly large XML files ( large here being potentially upwards of a gigabyte ) in C# including performing some complex xpath queries. The problem I have is that the standard way I would normally do this through the System.XML libraries likes to load the whole file into memory before it does anything with it, which can cause memory problems with files of this size. I don't need to be updating the files at all just reading them and querying the data contained in them. Some of the XPath queries are quite involved and go across several levels of parent-child type relationship - I'm not sure whether this will affect the ability to use a stream reader rather than loading the data into memory as a block. One way I can see of making it work is to perform the simple analysis using a stream-based approach and perhaps wrapping the XPath statements into XSLT transformations that I could run across the files afterward, although it seems a little convoluted. Alternately I know that there are some elements that the XPath queries will not run across, so I guess I could break the document up into a series of smaller fragments based on it's original tree structure, which could perhaps be small enough to process in memory without causing too much havoc. I've tried to explain my objective here so if I'm barking up totally the wrong tree in terms of general approach I'm sure you folks can set me right...

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  • CSS layout - Aligning two divs side by side

    - by Ronnie
    Hello, I have a small problem. I am trying to align two divs side by side using CSS, however, I would like the center div to be positioned horizontally central in the page, I achieved this by using: #page-wrap { margin 0 auto; } Thats worked fine. The second div I would like positioned to the left side of the central page wrap but I can't manage to do this using floats although I'm sure it is possible. Maybe its best to show the example of what I am describing: I would like to push the red div up alongside the white div. Here is my current CSS concerning these two divs, sidebar being the red div and page-wrap being the white div: #sidebar { width: 200px; height: 400px; background: red; float: left; } #page-wrap { margin: 0 auto; width: 600px; background: #ffffff; height: 400px; } Any help would be appreciated.

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  • phpmyadmin shows numbers or blob for mysql's utf8_bin callation columns?

    - by marc40000
    Hi ! I have a table with a varchar column. Its collation is set to utf8_bin. My software using this table and column works perfectly. But when I look at the content in phpmyadmin, I only see some hex values or [Blob xB]. Can I make phpmyadmin show the content correctly? Besides, when I set the collation to utf8_general_ci or utf8_unicode_ci, the phpmyadmin shows the content correctly. Thx Marc [edit]Hah, I found out, there is a small "+Options" link above every table in phpmyadmin. It opens several options including "Show BLOB contents" - which makes the [blob] to readable text when enabled and "Show binary contents as HEX" which shows the hex codes as text when disabled. No idea why there are two options though and why sometimes there is a [Blob] and sometimes hex values. Well. Now I'm still wondering: Setting these options get lost when I go to another table. I have to set them every time I go there. Is there a way to save those options? [/edit]

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  • Efficient cron job utilizing Zend_Mail_Storage_Imap.

    - by fireeyedboy
    I'm new to the IMAP protocol and Zend_Mail_Storage and I'm writing a small php script for a cron job that should regularly poll an IMAP account and check for new messages, and send an e-mail if new messages have arrived. As you can imagine, I want to only poll the IMAP account for relevant messages, and I only want to send a new e-mail if new messages have arrived since the last polled new message. So I thought of keeping track of the last message I polled with some unique identifier for a message. But I'm a bit uncertain about whether the methods I want to utilize for this do what I expect them to do though. So my questions are: Does the iterator position of Zend_Mail_Storage_Imap actually resemble some IMAP unique identifier for messages, or is it simply only and internal position of Zend_Mail_Storage_Abstract? For instance, if I tell it to seek() to message 5 (which I stored from an earlier session) will it indeed seek to the appropriate message on the IMAP server, even if for instance messages have been deleted since last session? Would keeping track of this latest polled message id in a file suffice for a cron job that, say, polls the account every 5 or 10 minutes? Or is this too naive, and should I be using a database for instance. Or is there maybe a much easier way to keep track of such state with Zend_Mail_Storage_Abstract? Also, do I need to poll every IMAP folder? Or is everything accumulated when I poll INBOX? If you could shed some light on any of these matters, I'ld appreciate it. Thanks in advance.

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  • Collaborative filtering in MySQL ?

    - by user281434
    Hi I'm trying to develop a site that recommends items(fx. books) to users based on their preferences. So far, I've read O'Reilly's "Collective Intelligence" and numerous other online articles. They all, however, seem to deal with single instances of recommendation, for example if you like book A then you might like book B. What I'm trying to do is to create a set of 'preference-nodes' for each user on my site. Let's say a user likes book A,B and C. Then, when they add book D, I don't want the system to recommend other books based solely other users experience with book D. I wan't the system to look up similar 'preference-nodes' and recommend books based on that. Here's an example of 4 nodes: User1: 'book A'->'book B'->'book C' User2: 'book A'->'book B'->'book C'->'book D' user3: 'book X'->'book Y'->'book C'->'book Z' user4: 'book W'->'book Q'->'book C'->'book Z' So a recommendation system, as described in the material I've read, would recommend book Z to User 1, because there are two people who recommends Z in conjuction with liking C (ie. Z weighs more than D), even though a user with a similar 'preference-node', User2, would be more qualified to recommend book D because he has a more similar interest-pattern. So does any of you have any experience with this sort of thing? Is there some things I should try to read or does there exist any open source systems for this? Thanks for your time! Small edit: I think last.fm's algorithm is doing exactly what I my system to do. Using the preference-trees of people to recommmend music more personally to people. Instead of just saying "you might like B because you liked A"

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  • Implementing parts of rfc4226 (HOTP) in mysql

    - by Moose Morals
    Like the title says, I'm trying to implement the programmatic parts of RFC4226 "HOTP: An HMAC-Based One-Time Password Algorithm" in SQL. I think I've got a version that works (in that for a small test sample, it produces the same result as the Java version in the code), but it contains a nested pair of hex(unhex()) calls, which I feel can be done better. I am constrained by a) needing to do this algorithm, and b) needing to do it in mysql, otherwise I'm happy to look at other ways of doing this. What I've got so far: -- From the inside out... -- Concatinate the users secret, and the number of time its been used -- find the SHA1 hash of that string -- Turn a 40 byte hex encoding into a 20 byte binary string -- keep the first 4 bytes -- turn those back into a hex represnetation -- convert that into an integer -- Throw away the most-significant bit (solves signed/unsigned problems) -- Truncate to 6 digits -- store into otp -- from the otpsecrets table select (conv(hex(substr(unhex(sha1(concat(secret, uses))), 1, 4)), 16, 10) & 0x7fffffff) % 1000000 into otp from otpsecrets; Is there a better (more efficient) way of doing this?

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  • priority queue with limited space: looking for a good algorithm

    - by SigTerm
    This is not a homework. I'm using a small "priority queue" (implemented as array at the moment) for storing last N items with smallest value. This is a bit slow - O(N) item insertion time. Current implementation keeps track of largest item in array and discards any items that wouldn't fit into array, but I still would like to reduce number of operations further. looking for a priority queue algorithm that matches following requirements: queue can be implemented as array, which has fixed size and _cannot_ grow. Dynamic memory allocation during any queue operation is strictly forbidden. Anything that doesn't fit into array is discarded, but queue keeps all smallest elements ever encountered. O(log(N)) insertion time (i.e. adding element into queue should take up to O(log(N))). (optional) O(1) access for *largest* item in queue (queue stores *smallest* items, so the largest item will be discarded first and I'll need them to reduce number of operations) Easy to implement/understand. Ideally - something similar to binary search - once you understand it, you remember it forever. Elements need not to be sorted in any way. I just need to keep N smallest value ever encountered. When I'll need them, I'll access all of them at once. So technically it doesn't have to be a queue, I just need N last smallest values to be stored. I initially thought about using binary heaps (they can be easily implemented via arrays), but apparently they don't behave well when array can't grow anymore. Linked lists and arrays will require extra time for moving things around. stl priority queue grows and uses dynamic allocation (I may be wrong about it, though). So, any other ideas?

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  • MS SQL datetime precision problem

    - by Nailuj
    I have a situation where two persons might work on the same order (stored in an MS SQL database) from two different computers. To prevent data loss in the case where one would save his copy of the order first, and then a little later the second would save his copy and overwrite the first, I've added a check against the lastSaved field (datetime) before saving. The code looks roughly like this: private bool orderIsChangedByOtherUser(Order localOrderCopy) { // Look up fresh version of the order from the DB Order databaseOrder = orderService.GetByOrderId(localOrderCopy.Id); if (databaseOrder != null && databaseOrder.LastSaved > localOrderCopy.LastSaved) { return true; } else { return false; } } This works for most of the time, but I have found one small bug. If orderIsChangedByOtherUser returns false, the local copy will have its lastSaved updated to the current time and then be persisted to the database. The value of lastSaved in the local copy and the DB should now be the same. However, if orderIsChangedByOtherUser is run again, it sometimes returns true even though no other user has made changes to the DB. When debugging in Visual Studio, databaseOrder.LastSaved and localOrderCopy.LastSaved appear to have the same value, but when looking closer they some times differ by a few milliseconds. I found this article with a short notice on the millisecond precision for datetime in SQL: Another problem is that SQL Server stores DATETIME with a precision of 3.33 milliseconds (0. 00333 seconds). The solution I could think of for this problem, is to compare the two datetimes and consider them equal if they differ by less than say 10 milliseconds. My question to you is then: are there any better/safer ways to compare two datetime values in MS SQL to see if they are exactly the same?

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  • Should I move big data blobs in JSON or in separate binary connection?

    - by Amagrammer
    QUESTION: Is it better to send large data blobs in JSON for simplicity, or send them as binary data over a separate connection? If the former, can you offer tips on how to optimize the JSON to minimize size? If the latter, is it worth it to logically connect the JSON data to the binary data using an identifier that appears in both, e.g., as "data" : "< unique identifier " in the JSON and with the first bytes of the data blob being < unique identifier ? CONTEXT: My iPhone application needs to receive JSON data over the 3G network. This means that I need to think seriously about efficiency of data transfer, as well as the load on the CPU. Most of the data transfers will be relatively small packets of text data for which JSON is a natural format and for which there is no point in worrying much about efficiency. However, some of the most critical transfers will be big blobs of binary data -- definitely at least 100 kilobytes of data, and possibly closer to 1 megabyte as customers accumulate a longer history with the product. (Note: I will be caching what I can on the iPhone itself, but the data still has to be transferred at least once.) It is NOT streaming data. I will probably use a third-party JSON SDK -- the one I am using during development is here. Thanks

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  • Apply a recursive CTE on grouped table rows (SQL server 2005).

    - by Evan V.
    Hi all, I have a table (ROOMUSAGE) containing the times people check in and out of rooms grouped by PERSONKEY and ROOMKEY. It looks like this: PERSONKEY | ROOMKEY | CHECKIN | CHECKOUT | ROW ---------------------------------------------------------------- 1 | 8 | 13-4-2010 10:00 | 13-4-2010 11:00 | 1 1 | 8 | 13-4-2010 08:00 | 13-4-2010 09:00 | 2 1 | 1 | 13-4-2010 15:00 | 13-4-2010 16:00 | 1 1 | 1 | 13-4-2010 14:00 | 13-4-2010 15:00 | 2 1 | 1 | 13-4-2010 13:00 | 13-4-2010 14:00 | 3 13 | 2 | 13-4-2010 15:00 | 13-4-2010 16:00 | 1 13 | 2 | 13-4-2010 15:00 | 13-4-2010 16:00 | 2 I want to select just the consecutive rows for each PERSONKEY, ROOMKEY grouping. So the desired resulting table is: PERSONKEY | ROOMKEY | CHECKIN | CHECKOUT | ROW ---------------------------------------------------------------- 1 | 8 | 13-4-2010 10:00 | 13-4-2010 11:00 | 1 1 | 1 | 13-4-2010 15:00 | 13-4-2010 16:00 | 1 1 | 1 | 13-4-2010 14:00 | 13-4-2010 15:00 | 2 1 | 1 | 13-4-2010 13:00 | 13-4-2010 14:00 | 3 13 | 2 | 13-4-2010 15:00 | 13-4-2010 16:00 | 1 I want to avoid using cursors so I thought I would use a recursive CTE. Here is what I came up with: ;with CTE (PERSONKEY, ROOMKEY, CHECKIN, CHECKOUT, ROW) as (select RU.PERSONKEY, RU.ROOMKEY, RU.CHECKIN, RU.CHECKOUT, RU.ROW from ROOMUSAGE RU where RU.ROW = 1 union all select RU.PERSONKEY, RU.ROOMKEY, RU.CHECKIN, RU.CHECKOUT, RU.ROW from ROOMUSAGE RU inner join CTE on RU.ROWNUM = CTE.ROWNUM + 1 where CTE.CHECKIN = RU.CHECKOUT and CTE.PERSONKEY = RU.PERSONKEY and CTE.ROOMKEY = RU.ROOMKEY) This worked OK for very small datasets (under 100 records) but it's unusable on large datasets. I'm thinking that I should somehow apply the cte recursevely on each PERSONKEY, ROOMKEY grouping on my ROOMUSAGE table but I am not sure how to do that. Any help would be much appreciated, Cheers!

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  • What's the best way to develop a debugging window for an ajax ASP.Net MVC application

    - by KallDrexx
    While developing my ASP.NET MVC, I have started to see the need for a debugging console window to assist in figuring out what is going right and wrong in my code. I read the last few chapters of the Pro Asp.net MVC book, and the author details how to use http modules to show page load/creation times and linq to sql query logs, both of which I definitely want to be able to see. However, since I am loading a lot of small sections of my page individually with ajax I don't want the debug information right there in the middle of my screen. So the idea I came up with was to have a separate browser window (open-able by a link or some javascript) with a console log, that can contain logged entries both from javascript and from the asp.net mvc run. The former should be relatively easy, but I'm having trouble coming up with a way to log the asp.net information in ajax requests. The direction I have been thinking of going is to create an httpmodule (like the Pro MVC book does), and have that module contain some that append the javascript's log to console calls with the messages. The issue I see with this is finding a way to get the log messages from the controller's action methods to the httpmodule's methods. The only way I see to do this is with a singleton, but I'm not sure if singletons are bad practice for a stateless web application. Furthermore, it seems like if I return json with my ajax calls (instead of pure html) then that won't work at all anyways and unless there is a way to add data to an existing json structure inside the httpmodule. How does everyone else handle this type of debugging in heavily ajax applications? For reference, the javascript library I am using is jquery.

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