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  • IoC & Interfaces Best Practices

    - by n8wrl
    I'm experimenting with IoC on my way to TDD by fiddling with an existing project. In a nutshell, my question is this: what are the best practices around IoC when public and non-public methods are of interest? There are two classes: public abstract class ThisThingBase { public virtual void Method1() {} public virtual void Method2() {} public ThatThing GetThat() { return new ThatThing(this); } internal virtual void Method3() {} internal virtual void Method4() {} } public class Thathing { public ThatThing(ThisThingBase thing) { m_thing = thing; } ... } ThatThing does some stuff using its ThisThingBase reference to call methods that are often overloaded by descendents of ThisThingBase. Method1 and Method2 are public. Method3 and Method4 are internal and only used by ThatThings. I would like to test ThatThing without ThisThing and vice-versa. Studying up on IoC my first thought was that I should define an IThing interface, implement it by ThisThingBase and pass it to the ThatThing constructor. IThing would be the public interface clients could call but it doesn't include Method3 or Method4 that ThatThing also needs. Should I define a 2nd interface - IThingInternal maybe - for those two methods and pass BOTH interfaces to ThatThing?

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  • DataGridComboBoxColumn was not found

    - by Budda
    The System.Windows.Controls.Data.DataGrid is used in my Silverlight application, but on attempt to add 'DataGridComboBoxColumn' column to the grid the following error messages are obtained: Error 1 The tag 'DataGridComboBoxColumn' does not exist in XML namespace 'clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data'. C:\Project\Budda\VFMElita\VfmElitaView\Pages\SquadView.xaml 140 22 VfmElitaView Error 2 The type 'data:DataGridComboBoxColumn' was not found. Verify that you are not missing an assembly reference and that all referenced assemblies have been built. C:\Project\Budda\VFMElita\VfmElitaView\Pages\SquadView.xaml 142 22 VfmElitaView Here is my "header" of the xaml-file: Here is grid: <StackPanel Grid.Row="1" Grid.Column="0" Grid.RowSpan="2"> <TextBlock Text="????"/> <data:DataGrid AutoGenerateColumns="False" ItemsSource="{Binding FieldPlayers}"> <data:DataGrid.Columns> <!--<data:DataGridTemplateColumn Header="#"> <data:DataGridTemplateColumn.CellTemplate> <DataTemplate> <TextBlock Margin="4" Loaded="TextBlock_Loaded"/> </DataTemplate> </data:DataGridTemplateColumn.CellTemplate> </data:DataGridTemplateColumn>--> <data:DataGridTextColumn Header="?" Binding="{Binding Number}"/> <data:DataGridComboBoxColumn> - that doesn't work </data:DataGridComboBoxColumn> </data:DataGrid.Columns> </data:DataGrid> </StackPanel> What is required to get 'DataGridComboBoxColumn' workable? Any help is welcome. Thanks.

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  • Practical size limitations for RDBMS

    - by grenade
    I am working on a project that must store very large datasets and associated reference data. I have never come across a project that required tables quite this large. I have proved that at least one development environment cannot cope at the database tier with the processing required by the complex queries against views that the application layer generates (views with multiple inner and outer joins, grouping, summing and averaging against tables with 90 million rows). The RDBMS that I have tested against is DB2 on AIX. The dev environment that failed was loaded with 1/20th of the volume that will be processed in production. I am assured that the production hardware is superior to the dev and staging hardware but I just don't believe that it will cope with the sheer volume of data and complexity of queries. Before the dev environment failed, it was taking in excess of 5 minutes to return a small dataset (several hundred rows) that was produced by a complex query (many joins, lots of grouping, summing and averaging) against the large tables. My gut feeling is that the db architecture must change so that the aggregations currently provided by the views are performed as part of an off-peak batch process. Now for my question. I am assured by people who claim to have experience of this sort of thing (which I do not) that my fears are unfounded. Are they? Can a modern RDBMS (SQL Server 2008, Oracle, DB2) cope with the volume and complexity I have described (given an appropriate amount of hardware) or are we in the realm of technologies like Google's BigTable? I'm hoping for answers from folks who have actually had to work with this sort of volume at a non-theoretical level.

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  • When and how should independent hierarchies be used in clojure?

    - by Rob Lachlan
    Clojure's system for creating an ad hoc hierarchy of keywords is familiar to most people who have spent a bit of time with the language. For example, most demos and presentations of the language include examples such as (derive ::child ::parent) and they go on to show how this can be used for multi-method dispatch. In all of the slides and presentations that I've seen, they use the global hierarchy. But it is possible to put keyword relationships in independent hierarchies, by using (derive h ::child ::parent), where h is created by (make-hierarchy). Some questions, therefore: Are there any guidelines on when this is useful or necessary? Are there any functions for manipulating hierarchies? Merging is particularly useful, so I do this: (defn merge-h [& hierarchies] (apply merge-with (cons #(merge-with clojure.set/union %1 %2) hierarchies)) But I was wondering if such functions already exist somewhere. EDIT: Changed "custom" hierarchy to "independent" hierarchy, since that term better describes this animal. Also, I've done some research and included my own answer below. Further comments are welcome.

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  • Getting minimum - Min() - for DateTime column in a DataTable using LINQ to DataSets?

    - by Jay Stevens
    I need to get the minimum DateTime value of a column in a DataTable. The DataTable is generated dynamically from a CSV file, therefore I don't know the name of that column until runtime. Here is code I've got that doesn't work... private DateTime GetStartDateFromCSV(string inputFile, string date_attr) { EnumerableRowCollection<DataRow> table = CsvStreamReader.GetDataTableFromCSV(inputFile, "input", true).AsEnumerable(); DateTime dt = table.Select(record => record.Field<DateTime>(date_attr)).Min(); return dt; } The variable table is broken out just for clarity. I basically need to find the minimum value as a DateTime for one of the columns (to be chosen at runtime and represented by date_attr). I have tried several solutions from SO (most deal with known columns and/or non-DateTime fields). What I've got throws an error at runtime telling me that it can't do the DateTime conversion (that seems to be a problem with Linq?) I've confirmed that the data for the column name that is in the string date_attr is a date value.

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  • FtpWebRequest Download File

    - by pm_2
    The following code is intended to retrieve a file via FTP. However, I'm getting an error with it. serverPath = "ftp://x.x.x.x/tmp/myfile.txt"; FtpWebRequest request = (FtpWebRequest)WebRequest.Create(serverPath); request.KeepAlive = true; request.UsePassive = true; request.UseBinary = true; request.Method = WebRequestMethods.Ftp.DownloadFile; request.Credentials = new NetworkCredential(username, password); // Read the file from the server & write to destination using (FtpWebResponse response = (FtpWebResponse)request.GetResponse()) // Error here using (Stream responseStream = response.GetResponseStream()) using (StreamReader reader = new StreamReader(responseStream)) using (StreamWriter destination = new StreamWriter(destinationFile)) { destination.Write(reader.ReadToEnd()); destination.Flush(); } The error is: The remote server returned an error: (550) File unavailable (e.g., file not found, no access) The file definately does exist on the remote machine and I am able to perform this ftp manually (i.e. I have permissions). Can anyone tell me why I might be getting this error?

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  • After Navigate2 Method returns S_OK Stuck at READYSTATE of READYSTATE_LOADING

    - by Stone Free
    I am working on a MFC Document View architecture application which has multiple documents and views and a tabbed window interface. I have been tasked with making an automatic switch to another tab on the press of the OK button in one of the other tabs. When the other tab is clicked on it uses a C++ wrapper over IWebBrowser2 to navigate to a specific web page. When this is done manually by clicking on the tab everything is fine and the webpage within the view loads successfully. In my first attempt at doing this the tab successfully switched in response to a call to AfxGetMainWnd()->SendMessageToDescendants(SOME_MESSAGE, ...); however by sending this windows message at the wrong point the application would crash once control returned because the chain of events caused the (modeless) dialog (*) that sent the message, to no longer exist. I then found the correct place to make the call, but now when the other tab is activated, it no longer displays the webpage as it should. To debug this problem I added code to check the READYSTATE in both the situation where it works and the situation where it does not. When the page fails to load (despite the call to Navigate2 returning S_OK), the READYSTATE just stays at READYSTATE_LOADING. Unfortunately now I am to many edits away from when I had it partially working. I have added TRACE statements to the most obvious events such as OnSetFocus, CView::OnActivateView but all traces come out in the same order despite the behaviour being different * hosted in the view

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  • How to delete duplicate records in MySQL by retaining those fields with data in the duplicate item b

    - by NJTechGuy
    I have few thousands of records with few 100 fields in a MySQL Table. Some records are duplicates and are marked as such. Now while I can simply delete the dupes, I want to retain any other possible valuable non-null data which is not present in the original version of the record. Hope I made sense. For instance : a b c d e f key dupe -------------------- 1 d c f k l 1 x 2 g h j 1 3 i h u u 2 4 u r t 2 x From the above sample table, the desired output is : a b c d e f key dupe -------------------- 2 g c h k j 1 3 i r h u u 2 If you look at it closely, the duplicate is determined by using the key (it is the same for 2 records, so the one that has an 'x' for dupe field is the one to be deleted by retaining some of the fields from the dupe (like c, e values for key 1). Please let me know if you need more info about this puzzling problem. Thanks a tonne! p.s : If it is not possible using MySQL, a PERL/Python script sample would be awesome! Thanks!

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  • Circular Dependencies in XML file

    - by user3006081
    my android xml layout file keeps on Exception raised during rendering: Circular dependencies cannot exist in RelativeLayout Exception details are logged in Window Show View Error Log I cant figure out why? here is my code <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.amandhapola.ribbit.LoginActivity" android:background="@drawable/background_fill" > <ImageView android:id="@+id/backgroundImage" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_alignParentLeft="true" android:layout_alignParentTop="true" android:scaleType="fitStart" android:src="@drawable/background" android:contentDescription="@string/content_desc_background"/> <TextView android:id="@+id/title" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentTop="true" android:layout_above="@+id/subtitle" android:layout_centerHorizontal="true" android:textSize="60sp" android:layout_marginTop="32dp" android:textColor="@android:color/white" android:textStyle="bold" android:text="@string/app_name" /> <TextView android:id="@+id/subtitle" android:layout_centerHorizontal="true" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/title" android:layout_above="@+id/usernameField" android:textSize="13sp" android:textColor="@android:color/white" android:textStyle="bold" android:text="@string/subtitle"/> <EditText android:id="@+id/usernameField" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_above="@+id/passwordField" android:layout_below="@+id/subtitle" android:layout_alignParentLeft="true" android:ems="10" android:hint="@string/username_hint" /> <EditText android:id="@+id/passwordField" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/usernameField" android:layout_above="@+id/loginButton" android:layout_alignParentLeft="true" android:layout_marginBottom="43dp" android:ems="10" android:hint="@string/password_hint" android:inputType="textPassword" /> <Button android:id="@+id/loginButton" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/passwordField" android:layout_above="@+id/signUpText" android:layout_alignParentLeft="true" android:text="@string/login_button_label" /> <TextView android:id="@+id/signUpText" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="12dp" android:layout_centerHorizontal="true" android:textColor="@android:color/white" android:layout_below="@+id/loginButton" android:text="@string/sign_up_text" /> </RelativeLayout>

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  • Replacing/Extending Visual Studio's Generate Stub in Visual Studio 2010

    - by devoured elysium
    When we write the name of a method that doesn't exist, Visual Studio 2010 asks us if we'd like to generate a method stub with that name. What I'd like to know if is it possible to replace that same code stub generating command with one made by myself. I never did any kind of extensibility programming for Visual Studio so I have a couple of questions: How hard is it? Is it something I can learn in a couple of nights, or is it something that'll make me "lose" a lot of time? It seems to me that there isn't a lot of support for that kind of programming, as generally people are not that interested in developing solutions that extend the Visual Studio IDE. I searched on SO and it doesn't appear to have many threads about extending Visual Studio. I don't know how the generate method stub thing works in Visual Studio, but I just wanted to turn it into something a bit more flexible and useful. Has anyone dealt with these kind of things before, that can give me a pointer to where to start? I know of MS VSX site but that has a lot of resources and can be overwhelming for someone new to the subject as I am. What technology will I need to use? T4? Maybe I'll need to know a lot about the code, like Visual Studio does, so I can know other method's type arguments, names, etc. Is that what T4 is for? Thanks

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  • Error doing an MSBuild on a CLR Storedprocedure project on Build Server

    - by CraftyFella
    Hi, When building a CLR Storedprocedure Project using MSBuild on our build server (Team City) we're getting the following error: error MSB4019: The imported project "C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\SqlServer.targets" was not found. Confirm that the path in the declaration is correct, and that the file exists on disk I've checked to see if the file exists on disk and sure enough it doesn't. I've checked on my own machine and it does exist. I don't really want to start copying over files manually to the build server. Here's the line from the csproj file which is being imported to the proj file: <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" /> <Import Project="$(MSBuildToolsPath)\SqlServer.targets" /> Here's the line from the proj file which is begin run by our Team City Server: <Import Project="..\$(ProjectName).csproj"/> My question is really: Where does this file comes from? Is it part of the Visual Studio install for example.. Or is there some re-distribution package somewhere to allow me to compile this project on our build server? Thanks BTW.. if i just copy the file onto the Build server it does actually work. Dave

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  • F# Active Pattern List.filter or equivalent

    - by akaphenom
    I have a records of types type tradeLeg = { id : int ; tradeId : int ; legActivity : LegActivityType ; actedOn : DateTime ; estimates : legComponents ; entryType : ShareOrDollarBased ; confirmedPrice: DollarsPerShare option; actuals : legComponents option ; type trade = { id : int ; securityId : int ; ricCode : string ; tradeActivity : TradeType ; enteredOn : DateTime ; closedOn : DateTime ; tradeLegs : tradeLeg list ; } Obviously the tradeLegs are a type off of a trade. A leg may be settled or unsettled (or unsettled but price confirmed) - thus I have defined the active pattern: let (|LegIsSettled|LegIsConfirmed|LegIsUnsettled|) (l: tradeLeg) = if Helper.exists l.actuals then LegIsSettled elif Helper.exists l.confirmedPrice then LegIsConfirmed else LegIsUnsettled and then to determine if a trade is settled (based on all legs matching LegIsSettled pattern: let (|TradeIsSettled|TradeIsUnsettled|) (t: trade) = if List.exists ( fun l -> match l with | LegIsSettled -> false | _ -> true) t.tradeLegs then TradeIsSettled else TradeIsUnsettled I can see some advantages of this use of active patterns, however i would think there is a more efficient way to see if any item of a list either matches (or doesn't) an actie pattern without having to write a lambda expression specifically for it, and using List.exist. Question is two fold: is there a more concise way to express this? is there a way to abstract the functionality / expression (fun l - match l with | LegIsSettled - false | _ - true) Such that let itemMatchesPattern pattern item = match item with | pattern -> true | _ -> false such I could write (as I am reusing this design-pattern): let curriedItemMatchesPattern = itemMatchesPattern LegIsSettled if List.exists curriedItemMatchesPattern t.tradeLegs then TradeIsSettled else TradeIsUnsettled Thoughts?

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  • html5 vs flash - full comparison chart anywhere?

    - by iddqd
    So since Steve Jobs said Flash sucks and implied that HTML5 can do everything Flash can without the need for a Plugin, I keep hearing those exact words from a lot of People. I would really like to have a Chart somewhere (similar to http://en.wikipedia.org/wiki/Comparison_of_layout_engines_%28HTML5%29#Form_elements_and_attributes ) that I can just show to those people. Showing all the little things that Flash can do right now, that HTML5/Ajax/CSS is not yet even thinking about. But of course also the things that HTML5 does better. I would like to see details compared like audio playback, realtime audio processing, byte level access, bitmap data manipulation, webcam access, binary sockets, stuff in the works such as P2P technology (adobe stratus) and all the stuff I don't know about myself. Ideally with examples of what can be accomplished with, lets say Binary Sockets (such as a POP3 client) because otherwise it won't mean a lot to non-programmers since they will just say "well we can do without Binary Sockets". And ideally with some current benchmarks and some examples of websites that use this technology. I've searched the web and am surprised not to find anything. So is there such a comparison somewhere? Or does anybody want to create this and post it to Wikipedia? ;-)

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  • Handling one-to-many relationship with ZF partialLoop

    - by snaken
    Lets say i'm listing musical artists, each artist has basic information like Name, Age etc. stored in an artist table. They also have entries in an Albums table (album name/album cover etc), referencing the artist table using the artist id as a foreign key. I have the Model_Artist (Artist.php) file: class Model_Artist extends Zend_Db_Table_Abstract { protected $_name = 'artist'; protected $_dependentTables = array('Model_ArtistAlbums'); public function fetchArtistss() { $select = $this->select(); return $this->fetchAll($select); } } and to the Model_ArtistAlbums (ArtistAlbums.php) file class Model_ArtistAlbums extends Zend_Db_Table_Abstract { protected $_name = 'albums'; protected $_referenceMap = array( 'Artists' => array( 'columns' => 'alb_art_id', 'refTableClass' => 'Model_Artist', 'refColumns' => 'art_id' ) ); // etc } in my controller: public function indexAction() { /* THIS WORKS $art = new Model_Artist(); $artRowset = $art->find(1); $art1 = $artRowset->current(); $artalbums = $art1->findDependentRowset('Model_ArtistAlbums'); foreach($artalbums as $album){ echo $album->alb_title."<br>"; } */ $arts = new Model_Artist(); $this->view->artists = $arts->fetchArtists(); } in the view file: $this->partial()->setObjectKey('artist'); echo $this->partialLoop('admin/list-artists.phtml', $this->artists); but with this code in artists/list-artists.phtml: foreach($this->artist->findDependentRowset('albums') as $album): // other stuff endforeach; i get this error: Fatal error: Call to a member function findDependentRowset() on a non-object A var_dump of $this->artist = NULL.

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  • IDN aware tools to encode/decode human readable IRI to/from valid URI

    - by Denis Otkidach
    Let's assume a user enter address of some resource and we need to translate it to: <a href="valid URI here">human readable form</a> HTML4 specification refers to RFC 3986 which allows only ASCII alphanumeric characters and dash in host part and all non-ASCII character in other parts should be percent-encoded. That's what I want to put in href attribute to make link working properly in all browsers. IDN should be encoded with Punycode. HTML5 draft refers to RFC 3987 which also allows percent-encoded unicode characters in host part and a large subset of unicode in both host and other parts without encoding them. User may enter address in any of these forms. To provide human readable form of it I need to decode all printable characters. Note that some parts of address might not correspond to valid UTF-8 sequences, usually when target site uses some other character encoding. An example of what I'd like to get: <a href="http://xn--80aswg.xn--p1ai/%D0%BF%D1%83%D1%82%D1%8C?%D0%B7%D0%B0%D0%BF%D1%80%D0%BE%D1%81"> http://????.??/???????????</a> Are there any tools to solve these tasks? I'm especially interested in libraries for Python and JavaScript.

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  • Losing 'post' requests sent to Pylons paster server

    - by Philip McDermott
    I'm sending post requests to a Pylons server (served by paster serve), and if I send them with any frequency many don't arrive at the server. One at a time is ok, but if I fire off a few (or more) within seconds, only a small number get dealt with. If I send with no post data, or with get, it works fine, but putting just one character of data in the post fields causes massive losses. For example, sending 200, 2 will come back. Sending 100 more slowly, 10 will come back. I'm making the requests form inside a Qt application. Tis will work ok (no data): QString postFields = "" QNetworkRequest request(QUrl("http://server.com/endpoint")); QNetworkReply *reply = networkAccessManager-post(request, postFields.toAscii()); And this will result in only a fraction of the requests being dealt with: QString postFields = "" QNetworkRequest request(QUrl("http://server.com/endpoint")); QNetworkReply *reply = networkAccessManager-post(request, postFields.toAscii()); I've played around with turning on use_threadpool, and other options (threadpool_workers, threadpool_max_requests = 300), of which some combinations can alter the results slightly (best case 10 responses in 200). If I send similar requests to other (non paster) servers, the replies come back ok, so I'm almost certain its'a paster serve config issue. Any help or advice greatly appreciated. Thanks Philip

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  • PHP: Array of objects is empty when I come to retrieve one from the array

    - by Tom
    Good morning, I am trying to load rows from a database and then create objects from them and add these objects to a private array. Here are my classes: <?php include("databaseconnect.php"); class stationItem { private $code = ''; private $description = ''; public function setCode($code ){ $this->code = $code; } public function getCode(){ return $this->code; } public function setDescription($description){ $this->description = $description; } public function getDescription(){ return $this->description; } } class stationList { private $stationListing; function __construct() { connect(); $stationListing = array(); $result = mysql_query('SELECT * FROM stations'); while ($row = mysql_fetch_assoc($result)) { $station = new stationItem(); $station->setCode($row['code']); $station->setDescription($row['description']); array_push($stationListing, $station); } mysql_free_result($result); } public function getStation($index){ return $stationListing[$index]; } } ?> As you can see I am creating a stationItem object per database row (which for now has a code and description) and I then push these on to the end of my array which is held as a private variable in stationList. This is code which creates this classes and attempts to access the properties on them: $stations = new stationList(); $station = $stations->getStation(0); echo $station->getCode(); I am finding that the sizeof($stationList) at the end of the constructor is 1 but then it is zero when we come to try to get an object from the array using the index. Therefore the error that I get is: Fatal error: Call to a member function getCode() on a non-object Please can someone explain to me why this is happening? I guess I am misunderstanding how object references work in PHP5.

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  • What are the most interesting equivalences arising from the Curry-Howard Isomorphism?

    - by Tom
    I came upon the Curry-Howard Isomorphism relatively late in my programming life, and perhaps this contributes to my being utterly fascinated by it. It implies that for every programming concept there exists a precise analogue in formal logic, and vice versa. Here's an "obvious" list of such analogies, off the top of my head: program/definition | proof type/declaration | proposition inhabited type | theorem function | implication function argument | hypothesis/antecedent function result | conclusion/consequent function application | modus ponens recursion | induction identity function | tautology non-terminating function | absurdity tuple | conjunction (and) disjoint union | exclusive disjunction (xor) parametric polymorphism | universal quantification So, to my question: what are some of the more interesting/obscure implications of this isomorphism? I'm no logician so I'm sure I've only scratched the surface with this list. For example, here are some programming notions for which I'm unaware of pithy names in logic: currying | "((a & b) => c) iff (a => (b => c))" scope | "known theory + hypotheses" And here are some logical concepts which I haven't quite pinned down in programming terms: primitive type? | axiom set of valid programs? | theory ? | disjunction (or)

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  • New Perl user: using a hash of arrays

    - by Zach H
    I'm doing a little datamining project where a perl script grabs info from a SQL database and parses it. The data consists of several timestamps. I want to find how many of a particular type of timestamp exist on any particular day. Unfortunately, this is my first perl script, and the nature of perl when it comes to hashes and arrays is confusing me quite a bit. Code segment: my %values=();#A hash of the total values of each type of data of each day. #The key is the day, and each key stores an array of each of the values I need. my @proposal; #[drafted timestamp(0), submitted timestamp(1), attny approved timestamp(2),Organiziation approved timestamp(3), Other approval timestamp(4), Approved Timestamp(5)] while(@proposal=$sqlresults->fetchrow_array()){ #TODO: check to make sure proposal is valid #Increment the number of timestamps of each type on each particular date my $i; for($i=0;$i<=5;$i++) $values{$proposal[$i]}[$i]++; #Update rolling average of daily #TODO: To check total load, increment total load on all dates between attourney approve date and accepted date for($i=$proposal[1];$i<=$proposal[2];$i++) $values{$i}[6]++; } I keep getting syntax errors inside the for loops incrementing values. Also, considering that I'm using strict and warnings, will Perl auto-create arrays of the right values when I'm accessing them inside the hash, or will I get out-of bounds errors everywhere? Thanks for any help, Zach

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  • How to implement Excel Solver functionality in C#?

    - by Vic
    Hi, I have an application in C#, I need to do some optimization calculations, like Excel Solver Add-in does, one option is certainly to write my own solver implementation, but I'm kind of short of time, so I'm looking into libraries that already exist that can help me with this. I've been trying the Microsoft Solver Foundation, which seems pretty neat and cool, the problem is that it doesn't seem to work with the kind of calculations that I need to do. At the end of this question I'm adding the information about the calculations I need to perform and optimize. So basically my question is if any of you know of any other library that I can use for this purpose, or any tutorial that can help to do my own solver, or any idea that gives me a lead to solve this issue. Thanks. Additional Info: This is the data I need to calculate: I have 7 variables, lets call them var1, var2,...,var7 The constraints for these variables are: All of them need to be 0 <= varn <= 0.5 (where n is the number of the variable) The sum of all the variables should be equal to 1 The objective is to maximize the target formula, which in Excel looks like this: (MMULT(TRANSPOSE(L26:L32),M14:M20)) / (SQRT(MMULT(MMULT(TRANSPOSE(L26:L32),M4:S10),L26:L32))) The range that you see in this formula, L26:L32, is actually the range with the variables from above, var1, var2,..., varn. M14:M20 and M4:S10 are ranges with data that I get from different sources, there are more likely decimal values. As I said before, I was using Microsoft Solver Foundation, I modeled pretty much everything with it, I created functions that handle the operations of the target formula, but when I tried to solve the model it always fail, I think it is because of the complexity of the operations. In any case, I just wanted to show these data so you can have an idea about the kind of calculations that I need to implement.

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  • Can a GeneralPath be modified?

    - by Dov
    java2d is fairly expressive, but requires constructing lots of objects. In contrast, the older API would let you call methods to draw various shapes, but lacks all the new features like transparency, stroke, etc. Java has fairly high costs associated with object creation. For speed, I would like to create a GeneralPath whose structure does not change, but go in and change the x,y points inside. path = new GeneralPath(GeneralPath.WIND_EVEN_ODD, 10); path.moveTo(x,y); path.lineTo(x2, y2); double len = Math.sqrt((x2-x)*(x2-x) + (y2-y)*(y2-y)); double dx = (x-x2) * headLen / len; double dy = (y-y2) * headLen / len; double dx2 = -dy * (headWidth/headLen); double dy2 = dx * (headWidth/headLen); path.lineTo(x2 + dx + dx2, y2 + dy + dy2); path.moveTo(x2 + dx - dx2, y2 + dy - dy2); path.lineTo(x2,y2); This one isn't even that long. Imagine a much longer sequence of commands, and only the ones on the end are changing. I just want to be able to overwrite commands, to have an iterator effectively. Does that exist?

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  • Vim with Powershell

    - by Kevin Berridge
    I'm using gvim on Windows. In my _vimrc I've added: set shell=powershell.exe set shellcmdflag=-c set shellpipe=> set shellredir=> function! Test() echo system("dir -name") endfunction command! -nargs=0 Test :call Test() If I execute this function (:Test) I see nonsense characters (non number/letter ASCII characters). If I use cmd as the shell, it works (without the -name), so the problem seems to be with getting output from powershell into vim. Interestingly, this works great: :!dir -name As does this: :r !dir -name UPDATE: confirming behavior mentioned by David If you execute the set commands mentioned above in the _vimrc, :Test outputs nonsense. However, if you execute them directly in vim instead of in the _vimrc, :Test works as expected. Also, I've tried using iconv in case it was an encoding problem: :echo iconv( system("dir -name"), "unicode", &enc ) But this didn't make any difference. I could be using the wrong encoding types though. Anyone know how to make this work?

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  • Delivery of JMS message before the transaction is committed

    - by ewernli
    Hi, I have a very simple scenario involving a database and a JMS in an application server (Glassfish). The scenario is dead simple: 1. an EJB inserts a row in the database and sends a message. 2. when the message is delivered with an MDB, the row is read and updated. The problem is that sometimes the message is delivered before the insert has been committed in the database. This is actually understandable if we consider the 2 phase commit protocol: 1. prepare JMS 2. prepare database 3. commit JMS 4. ( tiny little gap where message can be delivered before insert has been committed) 5. commit database I've discussed this problem with others, but the answer was always: "Strange, it should work out of the box". My questions are then: How could it work out-of-the box? My scenario sounds fairly simple, why isn't there more people with similar troubles? Am I doing something wrong? Is there a way to solve this issue correctly? Here are a bit more details about my understanding of the problem: This timing issue exist only if the participant are treated in this order. If the 2PC treats the participants in the reverse order (database first then message broker) that should be fine. The problem was randomly happening but completely reproducible. I found no way to control the order of the participants in the distributed transactions in the JTA, JCA and JPA specifications neither in the Glassfish documentation. We could assume they will be enlisted in the distributed transaction according to the order when they are used, but with an ORM such as JPA, it's difficult to know when the data are flushed and when the database connection is really used. Any idea?

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  • When does it makes sense to use a map?

    - by kiwicptn
    I am trying to round up cases when it makes sense to use a map (set of key-value entries). So far I have five categories (see below). Assuming more exist, what are they? Please limit each answer to one unique category, put up an example, and vote up the fascinating ones. Property values (like a bean) age -> 30 sex -> male loc -> calgary Histograms peter -> 1 john -> 7 paul -> 5 Presence, with O(1) performance peter -> 1 john -> 1 paul -> 1 Functions peter -> treatPeter() john -> dealWithJohn() paul -> managePaul() Conversion peter -> pierre john -> jean paul -> paul

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  • Academic question: typename

    - by Arman
    Hi, recently I accounted with a "simple problem" of porting code from VC++ to gcc/intel. The code is compiles w/o error on VC++: #include <vector> using std::vector; template <class T> void test_vec( std::vector<T> &vec) { typedef std::vector<T> M; /*==> add here typename*/ M::iterator ib=vec.begin(),ie=vec.end(); }; int main() { vector<double> x(100, 10); test_vec<double>(x); return 0; } then with g++ we have some unclear errors: g++ t.cpp t.cpp: In function 'void test_vec(std::vector<T, std::allocator<_CharT> >&)': t.cpp:13: error: expected `;' before 'ie' t.cpp: In function 'void test_vec(std::vector<T, std::allocator<_CharT> >&) [with T = double]': t.cpp:18: instantiated from here t.cpp:12: error: dependent-name 'std::M::iterator' is parsed as a non-type, but instantiation yields a type t.cpp:12: note: say 'typename std::M::iterator' if a type is meant If we add typename before iterator the code will compile w/o pb. If it is possible to make a compiler which can understand the code written in the more "natural way", then for me is unclear why we should add typename? Which rules of "C++ standards"(if there are some) will be broken if we allow all compilers to use without "typename"? kind regards Arman.

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