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  • OpenGL particle system

    - by allan
    I'm really new with OpenGL, so bear with me. I'm trying to simulate a particle system using OpenGl but I can't get it to work, this is what I have so far: #include <GL/glut.h> int main (int argc, char **argv){ // data allocation, various non opengl stuff ............ glutInit(&argc, argv); glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE ); glutInitWindowPosition(100,100); glutInitWindowSize(size, size); glPointSize (4); glutCreateWindow("test gl"); ............ // initial state, not opengl ............ glViewport(0,0,size,size); glutDisplayFunc(display); glutIdleFunc(compute); glutMainLoop(); } void compute (void) { // change state not opengl glutPostRedisplay(); } void display (void) { glClear(GL_COLOR_BUFFER_BIT); glBegin(GL_POINTS); for(i = 0; i<nparticles; i++) { // two types of particles if (TYPE(particle[i]) == 1) glColor3f(1,0,0); else glColor3f(0,0,1); glVertex2f(X(particle[i]),Y(particle[i])); } glEnd(); glFlush(); glutSwapBuffers(); } I get a black window after a couple of seconds (the window has just the title bar before that). Where do I go wrong? Any help would be very much appreciated. Thanks. LE: the x and y coordinates of each particle are within the interval (0,size)

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  • Reasons for & against a Database

    - by dbemerlin
    Hi, i had a discussion with a coworker about the architecture of a program i'm writing and i'd like some more opinions. The Situation: The Program should update at near-realtime (+/- 1 Minute). It involves the movement of objects on a coordinate system. There are some events that occur at regular intervals (i.e. creation of the objects). Movements can change at any time through user input. My solution was: Build a server that runs continously and stores the data internally. The server dumps a state-of-the-program at regular intervals to protect against powerfailures and/or crashes. He argued that the program requires a Database and i should use cronjobs to update the data. I can store movement information by storing startpoint, endpoint and speed and update the position in the cronjob (and calculate collisions with other objects there) by calculating direction and speed. His reasons: Requires more CPU & Memory because it runs constantly. Powerfailures/Crashes might destroy data. Databases are faster. My reasons against this are mostly: Not very precise as events can only occur at full minutes (wouldn't be that bad though). Requires (possibly costly) transformation of data on every run from relational data to objects. RDBMS are a general solution for a specialized problem so a specialized solution should be more efficient. Powerfailures (or other crashes) can leave the Data in an undefined state with only partially updated data unless (possibly costly) precautions (like transactions) are taken. What are your opinions about that? Which arguments can you add for any side?

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  • Session Variable Not Being Updated? ASP.NET

    - by davemackey
    I have a three step wizard. On the first step I use a repeater to create a series of buttons that an individual can select from. When the user selects one of the buttons the value of the button is saved to session state. They are taken to the next step and shown a similar list of buttons that are based on what they previously selected. Thus, if you choose "Hamburger" you might receive the options of "onion", "lettuce", "tomato" while if you choose "Hot Dog" you might receive "sauerkraut" and "ketchup". Lets say an individual chooses Hamburger. This is saved into session state like so: Public Sub Button_ItemCommand(ByVal Sender As Object, ByVal e As RepeaterCommandEventArgs) ' ******** Lets pass on the results of our query in LinqDataSource1_Selecting. Session("food_select") = RTrim(e.CommandName) Wizard1.ActiveStepIndex = 1 End Sub Now, this works fine and dandy. But lets say I select hamburger and then realize I'm really hankering for a hot dog. I go back to the first wizard step and click on the hot dog button - but when the wizard progresses to the next step I still see the options for hamburgers! The session variable has not been updated. Why? Thanks!

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  • php - replace array elements with another array's elements?

    - by Simpson88Keys
    Not sure how to go about this... But, I have two arrays, one with updated information, another with outdated information... There are a lot more elements in the second array, but I'm looking to "update" the outdated one with the updated information. Here's what the arrays look like: //Outdated Array ( [0] => Array ( [anum] => 3236468462 [cid] => 4899097762 [mid] => 1104881401 [na_title] => [na_fname] => JOHN [m_initial] => [na_lname] => DOE [na_suffix] => [na_addr1] => 1234 SAMPLE AVENUE [na_addr2] => [na_city] => NORWALK [state] => OH [zip] => [zip_plus_4] => [route] => R002 [dma_code] => 510334 ) ) //Updated Array ( [1] => Array ( [0] => YUD990 [1] => 98 [2] => 1234 Sample Avenue [3] => [4] => Norwalk [5] => OH [6] => 44857-9215 [7] => 3236468462 ) ) To clarify, I want to: (1) Match up the value for [7] from the updated array with the value for [anum] in the outdated array, and then update [na_addr1], [na_addr2], [na_city], [state], [zip], [zip_plus_4] in the outdated array with the values for [2],[3],[4],[5],[6] (I know I'll need to split the updated [6] in order to get it to map corrected to the outdated) Feel like I'm making this very confusing... sorry about that...

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  • Rendering Swing Components to an Offscreen buffer

    - by Nick C
    I have a Java (Swing) application, running on a 32-bit Windows 2008 Server, which needs to render it's output to an off-screen image (which is then picked up by another C++ application for rendering elsewhere). Most of the components render correctly, except in the odd case where a component which has just lost focus is occluded by another component, for example where there are two JComboBoxes close to each other, if the user interacts with the lower one, then clicks on the upper one so it's pull-down overlaps the other box. In this situation, the component which has lost focus is rendered after the one occluding it, and so appears on top in the output. It renders correctly in the normal Java display (running full-screen on the primary display), and attempting to change the layers of the components in question does not help. I am using a custom RepaintManager to paint the components to the offscreen image, and I assume the problem lies with the order in which addDirtyRegion() is called for each of the components in question, but I can't think of a good way of identifying when this particular state occurs in order to prevent it. Hacking it so that the object which has just lost focus is not repainted stops the problem, but obviously causes the bigger problem that it is not repainted in all other, normal, circumstances. Is there any way of programmatically identifying this state, or of reordering things so that it does not occur? Many thanks, Nick

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  • Table cell in a split-view controller - selected cell becomes deselected when called by reloadData

    - by bpapa
    I'm working on a universal app that uses a SplitViewController to present a master-detail view. In the iPad HIG on Split Views, Apple states: In general, indicate the current selection in the left pane in a persistent way. This behavior helps people understand the relationship between the item in the left pane and the contents of the right pane. This is important because the contents of the right pane can change, but they should always remain related to the item selected in the left pane. So I'm trying to maintain selection state on the left. Easy enough when the user taps, I just remove the deselectRowAtIndexPath:animated: message from tableView:didSelectRowAtIndexPath: implementation. But, I also want the selection state to show up by default (without a user tap). I wound up putting this in my tableView:cellForRowAtIndexPath: implementation: if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) { if (cellShouldBeSelected) cell.selected = YES; else cell.selected = NO; } The behavior I'm seeing, is that when the cells finall appear, for a fraction of a section the cell is indeed selected, but then the selection disappears without any user interaction. Any ideas? I set the new clearsSelectionOnViewWillAppear property to NO, but that doesn't seem to fix it, and it shouldn't really matter because I'm marking the cell as selected long after viewWillAppear is called - I'm actually doing it after some network activity and then sending the table view a reloadData message.

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  • Hadoop Map/Reduce - simple use example to do the following...

    - by alexeypro
    I have MySQL database, where I store the following BLOB (which contains JSON object) and ID (for this JSON object). JSON object contains a lot of different information. Say, "city:Los Angeles" and "state:California". There are about 500k of such records for now, but they are growing. And each JSON object is quite big. My goal is to do searches (real-time) in MySQL database. Say, I want to search for all JSON objects which have "state" to "California" and "city" to "San Francisco". I want to utilize Hadoop for the task. My idea is that there will be "job", which takes chunks of, say, 100 records (rows) from MySQL, verifies them according to the given search criteria, returns those (ID's) which qualify. Pros/cons? I understand that one might think that I should utilize simple SQL power for that, but the thing is that JSON object structure is pretty "heavy", if I put it as SQL schemas, there will be at least 3-5 tables joins, which (I tried, really) creates quite a headache, and building all the right indexes eats RAM faster than I one can think. ;-) And even then, every SQL query has to be analyzed to be utilizing the indexes, otherwise with full scan it literally is a pain. And with such structure we have the only way "up" is just with vertical scaling. But I am not sure it's the best option for me, as I see how JSON objects will grow (the data structure), and I see that the number of them will grow too. :-) Help? Can somebody point me to simple examples of how this can be done? Does it make sense at all? Am I missing something important? Thank you.

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  • Using Rails, problem testing has_many relationship

    - by east
    The summary is that I've code that works when manually testing, but isn't doing what I would think it should when trying to build an automated test. Here are the details: I've two models: Payment and PaymentTranscation. class Payment ... has_many :transactions, :class_name => 'PaymentTransaction' class PaymentTranscation ... belongs_to payment The PaymentTransaction is only created in a Payment model method, like so: def pay_up ... transactions.create!(params...) ... end I've manually tested this code, inspected the database, and everything works well. The failing automated test looks like this: def test_pay_up purchase = Payment.new(...) assert purchase.save assert_equal purchase.state, :initialized.to_s assert purchase.pay_up # this should create a new PaymentTransaction... assert_equal purchase.state, :succeeded.to_s assert_equal purchase.transactions.count, 1 # FAILS HERE; transactions is an empty array end If I step through the code, it's clear that the PaymentTransaction is getting created correctly (though I can't see it in the database because everything is in a testing transaction). What I can't figure out is why transactions is returning an empty array in the test when I know a valid PaymentTransaction is getting created. Anybody have some suggestions? Thanks in advance, east

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  • Ignore case in Python strings

    - by Paul Oyster
    What is the easiest way to compare strings in Python, ignoring case? Of course one can do (str1.lower() <= str2.lower()), etc., but this created two additional temporary strings (with the obvious alloc/g-c overheads). I guess I'm looking for an equivalent to C's stricmp(). [Some more context requested, so I'll demonstrate with a trivial example:] Suppose you want to sort a looong list of strings. You simply do theList.sort(). This is O(n * log(n)) string comparisons and no memory management (since all strings and list elements are some sort of smart pointers). You are happy. Now, you want to do the same, but ignore the case (let's simplify and say all strings are ascii, so locale issues can be ignored). You can do theList.sort(key=lambda s: s.lower()), but then you cause two new allocations per comparison, plus burden the garbage-collector with the duplicated (lowered) strings. Each such memory-management noise is orders-of-magnitude slower than simple string comparison. Now, with an in-place stricmp()-like function, you do: theList.sort(cmp=stricmp) and it is as fast and as memory-friendly as theList.sort(). You are happy again. The problem is any Python-based case-insensitive comparison involves implicit string duplications, so I was expecting to find a C-based comparisons (maybe in module string). Could not find anything like that, hence the question here. (Hope this clarifies the question).

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  • Does Java 6 open a default port for JMX remote connections?

    - by Bob Cross
    My specific question has to do with JMX as used in JDK 1.6: if I am running a Java process using JRE 1.6 with com.sun.management.jmxremote in the command line, does Java pick a default port for remote JMX connections? Backstory: I am currently trying to develop a procedure to give to a customer that will enable them to connect to one of our processes via JMX from a remote machine. The goal is to facillitate their remote debugging of a situation occurring on a real-time display console. Because of their service level agreement, they are strongly motivated to capture as much data as possible and, if the situation looks too complicated to fix quickly, to restart the display console and allow it to reconnect to the server-side. I am aware the I could run jconsole on JDK 1.6 processes and jvisualvm on post-JDK 1.6.7 processes given physical access to the console. However, because of the operational requirements and people problems involved, we are strongly motivated to grab the data that we need remotely and get them up and running again. EDIT: I am aware of the command line port property com.sun.management.jmxremote.port=portNum The question that I am trying to answer is, if you do not set that property at the command line, does Java pick another port for remote monitoring? If so, how could you determine what it might be?

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  • Error while updating Database record with Entity Framework on ASP.NET MVC Page

    - by Rupa
    Hi I have an ASP.NET Page that updates registered User Address Details for a selected record. Below is the Update method that i am calling from Controller. When i am calling ApplyPropertyChanges method, I am getting the below error. Did anyone run into the same error while updating the record with Entity Framework. Appreciate your responses. Error Message: The existing object in the ObjectContext is in the Added state. Changes can only be applied when the existing object is in an unchanged or modified state. My Update Method Code: [HttpPost] public bool UpdateAddressDetail([Bind(Prefix = "RegUser")] AddressDetail regUserAddress, FormCollection formData) { regUserAddress.AD_Id = 3; regUserAddress.LastUpdated = HttpContext.User.Identity.Name; regUserAddress.UpdatedOn = DateTime.Now; regUserAddress.AddressType = ((AddressDetail)Session["CurrentAddress"]).AddressType ?? "Primary"; regUserAddress.Phone = ((AddressDetail)Session["CurrentAddress"]).Phone; regUserAddress.Country = ((AddressDetail)Session["CurrentAddress"]).AddressType ?? "USA"; miEntity.ApplyPropertyChanges(regUserAddress.EntityKey.EntitySetName, regUserAddress); miEntity.SaveChanges(); return true; }

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  • How can I apply a style to existing tikz node on specific slides

    - by Eugene Pimenov
    This is what I'm trying to do \begin{tikzpicture} [node distance = 1cm, auto,font=\footnotesize, % STYLES every node/.style={node distance=1.3cm}, comment/.style={rectangle, inner sep= 5pt, text width=4cm, node distance=0.25cm, font=}, module/.style={rectangle, drop shadow, draw, fill=black!10, inner sep=5pt, text width=3cm, text badly centered, minimum height=0.8cm, font=\bfseries\footnotesize\sffamily,rounded corners}, selected/.style={fill=red!40}] \node [module] (nodeA) {node A}; \node [module, below of=nodeA] (nodeA) {node B}; \only<1>{ \node [comment, text width=6cm, right=0.25 of nodeA] {short description of Node A}; \node [comment, text width=6cm, right=0.25 of nodeB] {short description of Node B}; } \only<2>{ \node [selected] (nodeA) {}; \node [comment, text width=6cm, right=0.25 of nodeA] {long description of node A}; } \only<3>{ \node [selected] (nodeB) {}; \node [comment, text width=6cm, right=0.25 of nodeA] {long description of node B}; } \end{tikzpicture} The problem is \node [selected] (nodeB) {}; creates a new node, but I want it to apply the style for the existing node. Is there any way to do so? Of course I could have copies of every node in selected state and not-selected state, but I really want to have a normal solution.

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  • Beginner: Restore previously serialized JFrame-object, how?

    - by elementz
    Hi all. I have managed to serialize my very basic GUI-object containing a JTextArea and a few buttons to a file 'test.ser'. Now, I would like to completely restore the previously saved state from 'test.ser', but seem to have a misconception of how to properly deserialize an objects state. The class MyFrame creates the JFrame and serializes it. Now I tried to deserialize like so: public class Deserialize { static Deserialize ds; MyFrame frame; public static void main(String[] args) { try { ds.deserialize(); } catch (ClassNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } } public void deserialize() throws ClassNotFoundException { try { ObjectInputStream ois = new ObjectInputStream(new FileInputStream("test.ser")); frame = (MyFrame) ois.readObject(); ois.close(); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } Maybe somebody could point me into the direction where my misconception is? Thx in advance!

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  • How to select the first property with unknown name and first item from array in JSON

    - by Oscar Godson
    I actually have two questions, both are probably simple, but for some odd reason I cant figure it out... I've worked with JSON 100s of times before too! but here is the JSON in question: {"69256":{ "streaminfo":{ "stream_ID":"1025", "sourceowner_ID":"2", "sourceowner_avatar":"http:\/\/content.nozzlmedia.com\/images\/sourceowner_avatar2.jpg", "sourceownertype_ID":"1", "stream_name":"Twitter", "streamtype":"Social media" "appsarray":[] }, "item":{ "headline":"Charboy", "main_image":"http:\/\/content.nozzlmedia.com\/images\/author_avatar173212.jpg", "summary":"ate a tomato and avocado for dinner...", "nozzl_captured":"2010-05-12 23:02:12", "geoarray":[{ "state":"OR", "county":"Multnomah", "city":"Portland", "neighborhood":"Downtown", "zip":"97205", "street":"462 SW 11th Ave", "latitude":"45.5219", "longitude":"-122.682" }], "full_content":"ate a tomato and avocado for dinner tonight. such tasty foods. just enjoyable.", "body_text":"ate a tomato and avocado for dinner tonight. such tasty foods. just enjoyable.", "author_name":"Charboy", "author_avatar":"http:\/\/content.nozzlmedia.com\/images\/author_avatar173212.jpg", "fulltext_url":"http:\/\/twitter.com\/charboy\/statuses\/13889868936", "leftovers":{ "twitter_id":"tag:search.twitter.com,2005:13889868936", "date":"2010-05-13T02:59:59Z", "location":"iPhone: 45.521866,-122.682262" }, "wordarray":{ "0":"ate", "1":"tomato", "2":"avocado", "3":"dinner", "4":"tonight", "5":"tasty", "6":"foods", "7":"just", "8":"enjoyable", "9":"Charboy", "11":"Twitter", "13":"state:OR", "14":"county:Multnomah, OR", "15":"city:Portland, OR", "16":"neighborhood:Downtown", "17":"zip:97205" } } } } Question 1: How do I loop through each item (69256) when the number is random? e.g. item 1 is 123, item2 is 646? Like, for example, a normal JSON feed would have something like: {'item':{'blah':'lorem'},'item':{'blah':'ipsum'}} the JS would be like console.log(item.blah) to return lorem then ipsum in a loop How do I do it when i dont know the first item of the object? Question 2: How do I select items from the geoarray object? I tried: json.test.item.geoarray.latitude and json.test.item.geoarray['latitude']

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  • What happens to my PriorityQueue if my Comparator throws an exception while it's busy bubbling up or

    - by nieldw
    Hi, I'm trying order pairs of integers ascendantly where a pair is considered less than another pair if both its entries are strictly less than those of the other pair, and larger than the other pair if both its entries are strictly larger than those of the other pair. All other cases are considered incomparable. They way I want to solve this is by defining a Comparator that implements the above, but will throw an exception for incomparable cases, and provide that to a PriorityQueue. Of course, while inserting a pair the priority queue does several comparisons while bubbling the new entry up to its correct position in the heap, and many of these will be comparable. But it may happen during the bubbling process that a pair is encountered with which this new pair is incomparable, and an exception will be thrown. If this happens, what will be the state of the PriorityQueue? Will the pair I was trying to insert sit in the heap at the last position it was in before the exception was thrown? If I use the PriorityQueue's remove(Object o) method, will the PriorityQueue be restored to a consistent state? Thanks

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  • Unit testing opaque structure based C API

    - by Nicolas Goy
    I have a library I wrote with API based on opaque structures. Using opaque structures has a lot of benefits and I am very happy with it. Now that my API are stable in term of specifications, I'd like to write a complete battery of unit test to ensure a solid base before releasing it. My concern is simple, how do you unit test API based on opaque structures where the main goal is to hide the internal logic? For example, let's take a very simple object, an array with a very simple test: WSArray a = WSArrayCreate(); int foo = 5; WSArrayAppendValue(a, &foo); int *bar = WSArrayGetValueAtIndex(a, 0); if(&foo != bar) printf("Eroneous value returned\n"); else printf("Good value returned\n"); WSRelease(a); Of course, this tests some facts, like the array actually acts as wanted with 1 value, but when I write unit tests, at least in C, I usualy compare the memory footprint of my datastructures with a known state. In my example, I don't know if some internal state of the array is broken. How would you handle that? I'd really like to avoid adding codes in the implementation files only for unit testings, I really emphasis loose coupling of modules, and injecting unit tests into the implementation would seem rather invasive to me. My first thought was to include the implementation file into my unit test, linking my unit test statically to my library. For example: #include <WS/WS.h> #include <WS/Collection/Array.c> static void TestArray(void) { WSArray a = WSArrayCreate(); /* Structure members are available because we included Array.c */ printf("%d\n", a->count); } Is that a good idea? Of course, the unit tests won't benefit from encapsulation, but they are here to ensure it's actually working.

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  • Updating a specific key/value inside of an array field with MongoDB

    - by Jesta
    As a preface, I've been working with MongoDB for about a week now, so this may turn out to be a pretty simple answer. I have data already stored in my collection, we will call this collection content, as it contains articles, news, etc. Each of these articles contains another array called author which has all of the author's information (Address, Phone, Title, etc). The Goal - I am trying to create a query that will update the author's address on every article that the specific author exists in, and only the specified author block (not others that exist within the array). Sort of a "Global Update" to a specific article that affects his/her information on every piece of content that exists. Here is an example of what the content with the author looks like. { "_id" : ObjectId("4c1a5a948ead0e4d09010000"), "authors" : [ { "user_id" : null, "slug" : "joe-somebody", "display_name" : "Joe Somebody", "display_title" : "Contributing Writer", "display_company_name" : null, "email" : null, "phone" : null, "fax" : null, "address" : null, "address2" : null, "city" : null, "state" : null, "zip" : null, "country" : null, "image" : null, "url" : null, "blurb" : null }, { "user_id" : null, "slug" : "jane-somebody", "display_name" : "Jane Somebody", "display_title" : "Editor", "display_company_name" : null, "email" : null, "phone" : null, "fax" : null, "address" : null, "address2" : null, "city" : null, "state" : null, "zip" : null, "country" : null, "image" : null, "url" : null, "blurb" : null }, ], "tags" : [ "tag1", "tag2", "tag3" ], "title" : "Title of the Article" } I can find every article that this author has created by running the following command: db.content.find({authors: {$elemMatch: {slug: 'joe-somebody'}}}); So theoretically I should be able to update the authors record for the slug joe-somebody but not jane-somebody (the 2nd author), I am just unsure exactly how you reach in and update every record for that author. I thought I was on the right track, and here's what I've tried. b.content.update( {authors: {$elemMatch: {slug: 'joe-somebody'} } }, {$set: {address: '1234 Avenue Rd.'} }, false, true ); I just believe there's something I am missing in the $set statement to specify the correct author and point inside of the correct array. Any ideas? **Update** I've also tried this now: b.content.update( {authors: {$elemMatch: {slug: 'joe-somebody'} } }, {$set: {'authors.$.address': '1234 Avenue Rd.'} }, false, true );

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  • SQL Server Database In Single User Mode after Failover

    - by jlichauc
    Here is a weird situation we experienced with a SQL Server 2008 Database Mirroring Failover. We have a pair of mirrored databases running in high-availability mode and both the principal and mirror showed as synchronized. As part of some maintenance I triggered a manual failover of the principal to the mirror. However after the failover the principal was now in single-user mode instead of the expected "Principal/Synchronized" state we usually get. The database had been in multi-user mode on the previous principal before this had happened. We ended up stopping all applications, restarting the SQL Server instances, and executing "ALTER DATABASE ... SET MULTI_USER" to bring the database back to the expected "Principal/Synchronized" state in a multi-user mode. Question. Does anyone know where SQL Server stores information about whether a database should be in single-user mode or not? I'm wondering if there is some system database or table that has this setting recorded somewhere. In particular we had an incident once with the database on the original principal (the one I was failing over to) where when trying to detach the database it was put into single-user mode. I'm wondering if that setting is cached somewhere and is the reason that SQL Server put it back into single-user mode after a failover.

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  • Can parser combinators be made efficient?

    - by Jon Harrop
    Around 6 years ago, I benchmarked my own parser combinators in OCaml and found that they were ~5× slower than the parser generators on offer at the time. I recently revisited this subject and benchmarked Haskell's Parsec vs a simple hand-rolled precedence climbing parser written in F# and was surprised to find the F# to be 25× faster than the Haskell. Here's the Haskell code I used to read a large mathematical expression from file, parse and evaluate it: import Control.Applicative import Text.Parsec hiding ((<|>)) expr = chainl1 term ((+) <$ char '+' <|> (-) <$ char '-') term = chainl1 fact ((*) <$ char '*' <|> div <$ char '/') fact = read <$> many1 digit <|> char '(' *> expr <* char ')' eval :: String -> Int eval = either (error . show) id . parse expr "" . filter (/= ' ') main :: IO () main = do file <- readFile "expr" putStr $ show $ eval file putStr "\n" and here's my self-contained precedence climbing parser in F#: let rec (|Expr|) (P(f, xs)) = Expr(loop (' ', f, xs)) and loop = function | ' ' as oop, f, ('+' | '-' as op)::P(g, xs) | (' ' | '+' | '-' as oop), f, ('*' | '/' as op)::P(g, xs) -> let h, xs = loop (op, g, xs) let op = match op with | '+' -> (+) | '-' -> (-) | '*' -> (*) | '/' -> (/) loop (oop, op f h, xs) | _, f, xs -> f, xs and (|P|) = function | '('::Expr(f, ')'::xs) -> P(f, xs) | c::xs when '0' <= c && c <= '9' -> P(int(string c), xs) My impression is that even state-of-the-art parser combinators waste a lot of time back tracking. Is that correct? If so, is it possible to write parser combinators that generate state machines to obtain competitive performance or is it necessary to use code generation?

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  • Trying to compile a linux-based app on Mac OS X

    - by Scott
    I'm just trying to compile the linux-based FCEUX (NES emulator) on my mac, OS X 10.5 Leopard. I got all the dependencies (SDL, GTK+ 2) going and everything but of all things this is now my problem: Undefined symbols: "_compress", referenced from: SaveSnapshot() in video.o "_gzclose", referenced from: FCEU_fopen(char const*, char const*, char*, char*, int, char const**)in file.o "_crc32", referenced from: CalcCRC32(unsigned int, unsigned char*, unsigned int)in crc32.o _unzReadCurrentFile in unzip.o _unzReadCurrentFile in unzip.o "_uncompress", referenced from: NetplayUpdate(unsigned char*)in netplay.o FCEUSS_LoadFP(EMUFILE*, ENUM_SSLOADPARAMS) in state.o "_compress2", referenced from: FCEUNET_SendFile(unsigned char, char*)in netplay.o FCEUSS_SaveMS(EMUFILE*, int) in state.o "_inflateEnd", referenced from: _unzCloseCurrentFile in unzip.o "_inflate", referenced from: _unzReadCurrentFile in unzip.o "inflateInit2", referenced from: _unzOpenCurrentFile in unzip.o "_gzgetc", referenced from: FCEU_fopen(char const*, char const*, char*, char*, int, char const**)in file.o "_gzopen", referenced from: FCEU_fopen(char const*, char const*, char*, char*, int, char const**)in file.o "_gzread", referenced from: FCEU_fopen(char const*, char const*, char*, char*, int, char const**)in file.o "_gzseek", referenced from: FCEU_fopen(char const*, char const*, char*, char*, int, char const*)in file.o ld: symbol(s) not found collect2: ld returned 1 exit status scons: ** [src/fceux] Error 1 scons: building terminated because of errors. Those are zlib functions. It seems like it is loading the zlib.h ok, but the symbols aren't being linked in? Just to make sure I downloaded the latest zlib and did a make install, no help. I have no clue what's going on here, it seems like it should be pretty basic, that library is nothing special. Help would be appreciated. Thanks.

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  • How can I execute a .sql from C#?

    - by J. Pablo Fernández
    For some integration tests I want to connect to the database and run a .sql file that has the schema needed for the tests to actually run, including GO statements. How can I execute the .sql file? (or is this totally the wrong way to go?) I've found a post in the MSDN forum showing this code: using System.Data.SqlClient; using System.IO; using Microsoft.SqlServer.Management.Common; using Microsoft.SqlServer.Management.Smo; namespace ConsoleApplication1 { class Program { static void Main(string[] args) { string sqlConnectionString = "Data Source=(local);Initial Catalog=AdventureWorks;Integrated Security=True"; FileInfo file = new FileInfo("C:\\myscript.sql"); string script = file.OpenText().ReadToEnd(); SqlConnection conn = new SqlConnection(sqlConnectionString); Server server = new Server(new ServerConnection(conn)); server.ConnectionContext.ExecuteNonQuery(script); } } } but on the last line I'm getting this error: System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. --- System.TypeInitializationException: The type initializer for '' threw an exception. --- .ModuleLoadException: The C++ module failed to load during appdomain initialization. --- System.DllNotFoundException: Unable to load DLL 'MSVCR80.dll': The specified module could not be found. (Exception from HRESULT: 0x8007007E). I was told to go and download that DLL from somewhere, but that sounds very hacky. Is there a cleaner way to? Is there another way to do it? What am I doing wrong? I'm doing this with Visual Studio 2008, SQL Server 2008, .Net 3.5SP1 and C# 3.0.

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  • App will not launch from drawer after phone is removed from car dock

    - by BigFwoosh
    I am creating a replacement Car Home app for Android 2.0+ devices. The app needs to launch when the phone is inserted into the car dock, as well as terminate when it is removed from the dock. It also needs to be able to be launched from the app drawer. I'm having a problem right now where once the phone is inserted and removed from the dock, I can no longer launch the app from the app drawer because every time I launch the app my BroadcastReceiver picks up a DOCK_EVENT action for some reason. I created a test project that only registers my BroadcastReceiver, and the same thing happens. Here's the code for the BroadcastReceiver: public class CarDockBroadcastReceiver extends BroadcastReceiver { /** * @see android.content.BroadcastReceiver#onReceive(Context,Intent) */ @Override public void onReceive(Context context, Intent intent) { // TODO Put your code here if(intent.getExtras().containsKey("android.intent.extra.DOCK_STATE")){ int state = intent.getExtras().getInt("android.intent.extra.DOCK_STATE",1); if(state == 0){ Log.i("Dock", "Removed from dock!"); ((Activity)context).finish(); } } } } My main Activity is as follows: public class MainActivity extends Activity { /** Called when the activity is first created. */ CarDockBroadcastReceiver receiver; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); IntentFilter filter = new IntentFilter("android.intent.action.DOCK_EVENT"); receiver = new CarDockBroadcastReceiver(); registerReceiver(receiver, filter); } @Override protected void onDestroy() { // TODO Auto-generated method stub unregisterReceiver(receiver); super.onDestroy(); } } The main Activity has an intent filter for action.MAIN, category.LAUNCHER, category.DEFAULT, and category.CAR_DOCK. Any ideas on why this is happening?

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  • Advice on a DB that can be uploaded to a website by a smart client for collecting survey feedback

    - by absfabs
    Hello, I'm hoping you can help. I'm looking for a zero config multi-user datbase that my winforms application can easily upload to a webserver folder (together with 1 or 2 classic asp pages) and am looking for some suggestions/recommendations. The idea is that the database will be used to collect feedback entered by people filling in the asp pages. The pages will write to the database using javascript. The database will subsequently be downloaded again for processing once the responses are in. In Summary: It will mostly run in MS Windows environments. I have a modest budget for this and do not mind paying for such a database. No runtime licensing costs. Should be xcopy - Once uploaded to a website folder it should be operational. It should not have a dotnet CLR dependency. It should support a resonable level of concurrent access. Average respondent count would be around 20-30 but one never knows. Should be a reasonable size so that uploads/downloads to and from the site will be reasonably fast. Would appreciate your suggestions/comments Many thanks Abz To clarify - this is a desktop commercial application for feedback management in a vertical market. It uses SQL Server as the backing store. The application currently provides feedback management from email and paper feedback. I now want to add web feedback capability. Getting users to to make their SQL servers accessible to a website is not at option at this time as I am want to make getting up and running as painless as possible. I intend to release a web based implementation of the software in the near future but for now am looking at the above as a pragmatic way to provide web based feedback collection.

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  • How to search cvs comment history

    - by Chris Noe
    I am aware of this command: cvs log -N -w<userid> -d"1 day ago" Unfortunately this generates a formatted report with lots of newlines in it, such that the file-path, the file-version, and the comment-text are all on separate lines. Therefore it is difficult to scan it for all occurrences of comment text, (eg, grep), and correlate the matches to file/version. (Note that the log output would be perfectly acceptable, if only cvs could perform the filtering natively.) EDIT: Sample output. A block of text like this is reported for each repository file: RCS file: /data/cvs/dps/build.xml,v Working file: build.xml head: 1.49 branch: locks: strict access list: keyword substitution: kv total revisions: 57; selected revisions: 1 description: ---------------------------- revision 1.48 date: 2008/07/09 17:17:32; author: noec; state: Exp; lines: +2 -2 Fixed src.jar references ---------------------------- revision 1.47 date: 2008/07/03 13:13:14; author: noec; state: Exp; lines: +1 -1 Fixed common-src.jar reference. =============================================================================

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  • image not displaying in midlet

    - by user316843
    Hello all,am new here. i have a slight problem; PLease look at the following code and tell me if am doing something wrong because the image is not displaying. i have made it really small so it should fit but its not displaying. i have images displaying in other screens but this main midlet would not. Here is the code: import java.io.IOException; import javax.microedition.midlet.*; import javax.microedition.lcdui.*; /** * @author jay */ public class WShop extends MIDlet implements CommandListener { /* Declare display variables*/ private Form mainForm; private Display display; private Command OK,Exit,wView, mView, myView; /* */ Categories categories = new Categories(this); Image image; public WShop() { /* initialize Screen and Command buttons that will be used when the application starts in the class constructor*/ mainForm = new Form("Wind Shopper"); OK = new Command("OK", Command.OK, 2); Exit = new Command("Exit", Command.EXIT, 0); wview= new Command("wview", Command.OK, 0); mview= new Command("mview", Command.OK, 0); try { /* retrieving the main image of the application*/ image = Image.createImage("/main.png"); } catch (IOException ex) { ex.printStackTrace(); } mainForm.addCommand(OK); mainForm.addCommand(Exit); mainForm.addCommand(wView); mainForm.addCommand(mView); mainForm.setCommandListener(this); } public void startApp() { /* checks to see if the display is currently empty and then sets it to the current screen */ if (display == null) { display = Display.getDisplay(this); } display.setCurrent(mainForm); } /* paused state of the application*/ public void pauseApp() { } /* Destroy Midlet state*/ public void destroyApp(boolean unconditional) { } Thanks in advance.

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