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  • Printing Arrays from Structs

    - by Carlll
    I've been stumped for a few hours on an exercise where I must use functions to build up an array inside a struct and print it. In my current program, it compiles but crashes upon running. #define LIM 10 typedef char letters[LIM]; typedef struct { int counter; letters words[LIM]; } foo; int main(int argc, char **argv){ foo apara; structtest(apara, LIM); print_struct(apara); } int structtest(foo *p, int limit){ p->counter = 0; int i =0; for(i; i< limit ;i++){ strcpy(p->words[p->counter], "x"); //only filling arrays with 'x' as an example p->counter ++; } return; I do believe it's due to my incorrect usage/combination of pointers. I've tried adjusting them, but either an 'incompatible types' error is produced, or the array is seemingly blank } void print_struct(foo p){ printf(p.words); } I haven't made it successfully up to the print_struct stage, but I'm unsure whether p.words is the correct item to be calling. In the output, I would expect the function to return an array of x's. I apologize in advance if I've made some sort of grievous "I should already know this" C mistake. Thanks for your help.

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  • shell scripting: search/replace & check file exist

    - by johndashen
    I have a perl script (or any executable) E which will take a file foo.xml and write a file foo.txt. I use a Beowulf cluster to run E for a large number of XML files, but I'd like to write a simple job server script in shell (bash) which doesn't overwrite existing txt files. I'm currently doing something like #!/bin/sh PATTERN="[A-Z]*0[1-2][a-j]"; # this matches foo in all cases todo=`ls *.xml | grep $PATTERN -o`; isdone=`ls *.txt | grep $PATTERN -o`; whatsleft=todo - isdone; # what's the unix magic? #tack on the .xml prefix with sed or something #and then call the job server; jobserve E "$whatsleft"; and then I don't know how to get the difference between $todo and $isdone. I'd prefer using sort/uniq to something like a for loop with grep inside, but I'm not sure how to do it (pipes? temporary files?) As a bonus question, is there a way to do lookahead search in bash grep? To clarify: so the simplest way to do what i'm asking is (in pseudocode) for i in `/bin/ls *.xml` do replace xml suffix with txt if [that file exists] add to whatsleft list end done

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  • Does overloading Grails static 'mapping' property to bolt on database objects violate DRY?

    - by mikesalera
    Does Grails static 'mapping' property in Domain classes violate DRY? Let's take a look at the canonical domain class: class Book {      Long id      String title      String isbn      Date published      Author author      static mapping = {             id generator:'hilo', params:[table:'hi_value',column:'next_value',max_lo:100]      } } or: class Book { ...         static mapping = {             id( generator:'sequence', params:[sequence_name: "book_seq"] )     } } And let us say, continuing this thought, that I have my Grails application working with HSQLDB or MySQL, but the IT department says I must use a commercial software package (written by a large corp in Redwood Shores, Calif.). Does this change make my web application nobbled in development and test environments? MySQL supports autoincrement on a primary key column but does support sequence objects, for example. Is there a cleaner way to implement this sort of 'only when in production mode' without loading up the domain class?

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  • Top 10 collection completion - a monster in-query formula in MySQL?

    - by Andrew Heath
    I've got the following tables: User Basic Data (unique) [userid] [name] [etc] User Collection (one to one) [userid] [game] User Recorded Plays (many to many) [userid] [game] [scenario] [etc] Game Basic Data (unique) [game] [total_scenarios] I would like to output a table that shows the collection play completion percentage for the Top 10 users in descending order of %: Output Table [userid] [collection_completion] 3 95% 1 81% 24 68% etc etc In my mind, the calculation sequence for ONE USER is: grab user's total owned scenarios from User Collection joined with Game Basic Data and COUNT(gbd.total_scenarios) grab all recorded plays by COUNT(DISTINCT scenario) for that user Divide all recorded plays by total owned scenarios So that's 2 queries and a little PHP massage at the end. For a list of users sorted by completion percentage things get a little more complicated. I figure I could grab all users' collection totals in one query, and all users recorded plays in another, and then do the calcs and sort the final array in PHP, but it seems like overkill to potentially be doing all that for 1000+ users when I only ever want the Top 10. Is there a wicked monster query in MySQL that could do all that and LIMIT 10? Or is sticking with PHP handling the bulk of the work the way to go in this case?

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  • Why do people say that Ruby is slow?

    - by stephen murdoch
    I like Ruby on Rails and I use it for all my web development projects. A few years ago there was a lot of talk about Rails being a memory hog and about how it didn't scale very well but these suggestions were put to bed by Gregg Pollack here. Lately though, I've been hearing people saying that Ruby itself is slow. Why is Ruby considered slow? I do not find Ruby to be slow but then again, I'm just using it to make simple CRUD apps and company blogs. What sort of projects would I need to be doing before I find Ruby becoming slow? Or is this slowness just something that affects all programming languages? What are your options as a Ruby programmer if you want to deal with this "slowness"? Which version of Ruby would best suit an application like Stack Overflow where speed is critical and traffic is intense? The questions are subjective, and I realise that architectural setup (EC2 vs standalone servers etc) makes a big difference but I'd like to hear what people think about Ruby being slow. Finally, I can't find much news on Ruby 2.0 - I take it we're a good few years away from that then?

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  • HELP!!! Upgrading to windows 2008 R2 server has caused major issue with screen scraping remote serve

    - by bobsov534
    I have three servers. One is Windows 2003(A) and another is Windows 2008(B) and third one is also Windows 2008 (C). All of them are web servers. A and B contains classic asp pages and they are 32 bit servers and C contains asp.net pages and is 64 bit server. The asp pages of A and B use the screen scraping technology to render the asp.net pages from C. When A is ran, the asp.net page is rendered fine, meaning there are no broken images or file not found error. When B is ran, the images appears to be broken because its looking for those images in Server B instead of Server C itself. I believe this issue is caused by IIS 7 or 7.5 since IIS 6 has no problem scraping the remote server pages. Can you please help me with solution to this problem? This is sort of urgent since upgrading to windows server 2008 R2 now has been a major show stopper for us at the moment. Thanks in advance.

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  • ISP Config 3 - squirrel login error & how to add an smtp server for sending mails

    - by A Prasetyo
    Hi, Case #1: I have ISPConfig3 running, sending email through telnet server.mydomain.com 25 are possible. Receiving email also possible. BUT!! problem occurs when I try to login to squirrel... I've been awaken for 2 days now and still couldn't figured out why logging in into squirrel always having an error: ERROR: Connection dropped by IMAP server. here is the /var/log/mail.log: Jun 3 00:23:27 server-01 imapd: Connection, ip=[::ffff:127.0.0.1] Jun 3 00:23:27 server-01 imapd: chdir /var/vmail/mydomain.com/info: Permission denied Jun 3 00:23:27 server-01 imapd: [email protected]: Permission denied I did chmod 777 & still doesn't work, only another message appeared Jun 3 00:24:28 server-01 imapd: Connection, ip=[::ffff:127.0.0.1] Jun 3 00:24:28 server-01 imapd: [email protected]: Account's mailbox directory is not owned by the correct uid or gid Try to do telnet to IMAP port telnet mydomain.com 143 Trying 63.105.102.48... Connected to mydomain.com. Escape character is '^]'. OK [CAPABILITY IMAP4rev1 UIDPLUS CHILDREN NAMESPACE THREAD=ORDEREDSUBJECT THREAD=REFERENCES SORT QUOTA IDLE ACL ACL2=UNION STARTTLS] Courier-IMAP ready. Copyright 1998-2008 Double Precision, Inc. See COPYING for distribution information. login [email protected] mypassword login NO Error in IMAP command received by server. and give no result... -_- I checked mysql.sock, I checked username and password in mysql db, everything is correct.. anyone can help? PLEASE?! Case #2: Does anyone know how to set or to view SMTP settings in ISPConfig 3? thank you..

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  • Python script, runs well, but not perfectly, debugging help.

    - by S1syphus
    What it does (sort of)... or is meant to, the script reads from a csv file that contains information on sound files and create a play list exactly 60 minutes long. An example csv, contains: their title, duration (in seconds), minium total time to be played (in minutes) An example is: Soundfoo,120,10 Soundbar,30,6 Sounddev,60,20 Soundrandom,15,8 The script works out the minimum instances of plays, take 'Soundfoo' for example, the length of each sample is 120 seconds and the minimum time to be played is 10 minutes, so basic maths 10*60/120 gives the number of instances the song is to be played, in this case 5. It is meant to take minimum number of instances and spread out equally from each other; so there will never be a period where for example Soundbar is played twice in a row. Then if the minium instances of each song has been used, and there is still time with in the 60 min, how is it possible to tell it to go back and fill the time by selecting each sound and including it till the 60 min is filled while remaining sparsely populated. Heres the issue(s)! The script fails to calculate the actual time require to play all the sounds in a file and the total time of the playlist, the thing is tho it doesn't get it wrong all the time maybe 3/5 times, even if I run it on the same csv file it will give me different answers. Here is the file I shall run the script on e for sake of ease to see the issue: Sound1,60,10 Sound2,60,10 Sound3,60,10 Sound4,60,10 Sound5,60,10 Sound6,60,10 I'll do it three times and post the results: 1 Required playtime in minutes: 60 Actual time in minutes to play all required ads: 62 Total playtime in minutes: 62.0 2 Required playtime in minutes: 60 Actual time in minutes to play all required ads: 71 Total playtime in minutes: 71.0 3 Required playtime in minutes: 60 Actual time in minutes to play all required ads: 60 Total playtime in minutes: 60.0 Relevant Code: pastebin.com/demkBXk6 And finally... in context: http://pastebin.com/demkBXk6 If you made it down to here, thanks for staying and reading, kudos.

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  • what data structure should I use for hash lookup as well as binary search?

    - by zebraman
    I am working on a school homework. I have a list of names. I want to be able to perform binary search on these names (find all names between a lower and upper bound) for first name as well as last name, and perform keyword searches as well (this will be accomplished using hashing. For example, if I have the names Garfield Cat Snoopy Dog Captain Crunch Fat Cat then a binary search of first names (C,H) will return Captain Crunch, Fat Cat, and Garfield Cat. A binary search of last names (Cr,D) will return Captain Crunch. A keyword search of 'cat' will return Fat Cat and Garfield Cat. I understand binary search will only work on a sorted list, but since I am planning on searching two different criteria, I will have to sort the list by last name or first name depending on what I'm searching for. I feel like it will be too inefficient to have to resort the list each time I want to perform a new binary search. Would it just be better for me to set up and maintain two sorted lists (one for sorted by first name, one for sorted by last name)? Also, for hashing, will I have to set up a different table of names for that as well? I understand each keyword will hash to some value determined by a hash function, and this value (or key) is a table address where the corresponding names are stored. So I just want to know what would be the best way to solve this problem? Maintaining separate structures, or is there a way to efficiently do everything I want with just one data structure?

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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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  • Why does the Combo.SelectedValue get lost after some time

    - by tzup
    So I have this asp:DropDownList on a page. It renders like this (in IE7): <select name="ctl00$cphFilter$cbLista" onchange="javascript:setTimeout('__doPostBack(\'ctl00$cphFilter$cbLista\',\'\')', 0)" id="ctl00_cphFilter_cbLista" class="agsSelect"> <option selected="selected" value="4350">A</option> <option value="4352">B</option> <option value="4349">C</option> <option value="4348">D</option> And then I have a grid and a button on the same page. When the user clicks the button the selected item of the dropdown is read (well a datasource object reads it) and the grid does a databind after a trip to a DB where it gets some data based on that selected value. This works fine most of the time. However sometimes, the selection in the dropdownlist seems to get lost even though the rendered page says the A is the selected item. The datasource object is defined like this: <asp:ObjectDataSource ID="dsVM" runat="server" EnablePaging="False" SelectMethod="Select" SortParameterName="sort" TypeName="X.Business.Entities.LPVM.BE"> <SelectParameters> <asp:ControlParameter Name="listaId" Type="Int32" ControlID="cphFilter$cbLista" PropertyName="SelectedValue" /> </SelectParameters> </asp:ObjectDataSource> Any ideas why the grid would reload its data with a select parameter that is 0 instead of the selected value of the dropdownlist? EDIT Suppose the dropdownlist is bound, the user selected B and the grid is bound as well and shows the right data. Now, I wait 2 minutes and I click the Refresh button. Surprisingly, at this particular moment the dropdownlist.SelectedValue (which I already know it was 4352 before I clicked because that's how it looks in the rendered page) is actually an empty string. Where did the value go?

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  • What's the best practice to setup testing for ASP.Net MVC? What to use/process/etc?

    - by melaos
    hi there, i'm trying to learn how to properly setup testing for an ASP.Net MVC. and from what i've been reading here and there thus far, the definition of legacy code kind of piques my interests, where it mentions that legacy codes are any codes without unit tests. so i did my project in a hurry not having the time to properly setup unit tests for the app and i'm still learning how to properly do TDD and unit testing at the same time. then i came upon selenium IDE/RC and was using it to test on the browser end. it was during that time too that i came upon the concept of integration testing, so from my understanding it seems that unit testing should be done to define the test and basic assumptions of each function, and if the function is dependent on something else, that something else needs to be mocked so that the tests is always singular and can be run fast. Questions: so am i right to say that the project should have started with unit test with proper mocks using something like rhino mocks. then anything else which requires 3rd party dll, database data access etc to be done via integration testing using selenium? because i have a function which calls a third party dll, i'm not sure whether to write a unit test in nunit to just instantiate the object and pass it some dummy data which breaks the mocking part to test it or just cover that part in my selenium integration testing when i submit my forms and call the dll. and for user acceptance tests, is it safe to say we can just use selenium again? Am i missing something or is there a better way/framework? i'm trying to put in more tests for regression testing, and to ensure that nothing breaks when we put in new features. i also like the idea of TDD because it helps to better define the function, sort of like a meta documentation. thanks!! hope this question isn't too subjective because i need it for my case.

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  • Manually Writing the HTML in TWebBrowser Pt. 2

    - by nomad311
    As the name suggests this is a continuation (sort of) of http://stackoverflow.com/questions/2784679/manually-writing-the-html-in-twebbrowser This time around I'm trying to add some auto-refresh logic to the HTML I get. I have pieced together an approach from several sources (see below). In short, I am trying to locate the title node and add a meta node after it (in the HTML head node). But, I get an access violation. Here is the source: iHtmlDoc := IHTMLDocument3(WebBrowser1.Document); iHtmlEleTitle := IHTMLElement2(iHtmlDoc.getElementsByName('title').item(0, 0)); iHtmlEle := IHTMLElement2(IHTMLDocument2(iHtmlDoc).createElement(Format('<meta http-equiv="refresh" content="%d">', [1]))); iHtmlEleTitle.insertAdjacentElement('afterEnd', IHTMLElement(iHtmlEle)); And A (technically not functionally) different way of doing it ...casting is slightly different here: IHTMLElement2(IHtmlDocument3(WebBrowser1.Document).getElementsByName('title').item(0, 0)).insertAdjacentElement('afterEnd', IHTMLDocument2(WebBrowser1.Document).createElement(Format('<meta http-equiv="refresh" content="%d">', [VPI_ISSUANCE_AUTO_RELOAD]))); Again all I get from Delphi is a access exception, and I fished through MSDN documentation on it, but now I'm hoping someone out there has gone through the same and has some insight. Any help? Sources (I think this is all of them): http://webdesign.about.com/od/metataglibraries/a/aa080300a.htm (auto-reload) http://delphi.about.com/od/adptips2005/qt/webbrowserhtml.htm (web browser document as an HTML document) http://msdn.microsoft.com/en-us/library/system.windows.forms.htmlelement.insertadjacentelement(VS.80).aspx (GetElementsByName) http://www.experts-exchange.com/Web_Development/Components/ActiveX/Q_26131034.html (insertAdjacentElement) http://www.experts-exchange.com/Programming/Languages/Pascal/Delphi/Q_23407977.html (GetElementsByName)

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  • Tailing 'Jobs' with Perl under mod_perl

    - by Matthew
    Hi everyone, I've got this project running under mod_perl shows some information on a host. On this page is a text box with a dropdown that allows users to ping/nslookup/traceroute the host. The output is shown in the text box like a tail -f. It works great under CGI. When the user requests a ping it would make an AJAX call to the server, where it essentially starts the ping with the output going to a temp file. Then subsequent ajax calls would 'tail' the file so that the output was updated until the ping finished. Once the job finished, the temp file would be removed. However, under mod_perl no matter what I do I can's stop it from creating zombie processes. I've tried everything, double forking, using IPC::Run etc. In the end, system calls are not encouraged under mod_perl. So my question is, maybe there's a better way to do this? Is there a CPAN module available for creating command line jobs and tailing output that will work under mod_perl? I'm just looking for some suggestions. I know I could probably create some sort of 'job' daemon that I signal with details and get updates from. It would run the commands and keep track of their status etc. But is there a simpler way? Thanks in advance.

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  • 3 Servers, is this is a cluster?

    - by Andy Barlow
    Hello, At the moment I have one Ubuntu server, 9.10, running with a simple Samba share, a mail server, DNS server and DHCP server. Mostly its just there for file sharing and email server. I also have 2 other servers that are exactly the same hardware and spec as the first, which have an rsync set up to retrieve the shared folders and backs them up. However, if the first server goes down, all of our shares disappear along with our mail and the system must be rebuilt. Also I tend to find if people are downloading a large amount from the file server, no-one can access there emails - especially in the morning when everyone is signing in at once. Would it be more beneficial for me to have all 3 servers, all running the same services, doing the same thing with some sort of cluster with load balancing? I'm not really sure where to begin looking, or how to go about such a setup where 3 servers are all identical, but perhaps one acts as the main load balancer?? If someone can point me in the right direction, or if this simply sounds like one of those Enterprise Cloud's that is now a default setup in Ubuntu Server 9.10+, then I'll go down that route. Cheers in advance. Andy

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  • Setting database-agnostic default column timestamp using Hibernate

    - by unsquared
    I'm working on a java project full of Hibernate (3.3.1) mapping files that have the following sort of declaration for most domain objects. <property name="dateCreated" generated="insert"> <column name="date_created" default="getdate()" /> </property> The problem here is that getdate() is an MSSQL specific function, and when I'm using something like H2 to test subsections of the project, H2 screams that getdate() isn't a recognized function. It's own timestamping function is current_timestamp(). I'd like to be able to keep working with H2 for testing, and wanted to know whether there was a way of telling Hibernate "use this database's own mechanism for retrieving the current timestamp". With H2, I've come up with the following solution. CREATE ALIAS getdate AS $$ java.util.Date now() { return new java.util.Date(); } $$; CALL getdate(); It works, but is obviously H2 specific. I've tried extending H2Dialect and registering the function getdate(), but that doesn't seem to be invoked when Hibernate is creating tables. Is it possible to abstract the idea of a default timestamp away from the specific database engine?

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  • Should this even be a has_many :through association?

    - by GoodGets
    A Post belongs_to a User, and a User has_many Posts. A Post also belongs_to a Topic, and a Topic has_many Posts. class User < ActiveRecord::Base has_many :posts end class Topic < ActiveRecord::Base has_many :posts end class Post < ActiveRecord::Base belongs_to :user belongs_to :topic end Well, that's pretty simple and very easy to set up, but when I display a Topic, I not only want all of the Posts for that Topic, but also the user_name and the user_photo of the User that made that Post. However, those attributes are stored in the User model and not tied to the Topic. So how would I go about setting that up? Maybe it can already be called since the Post model has two foreign keys, one for the User and one for the Topic? Or, maybe this is some sort of "one-way" has_many through assiociation. Like the Post would be the join model, and a Topic would has_many :users, :through = :posts. But the reverse of this is not true. Like a User does NOT has_many :topics. So would this even need to be has_many :though association? I guess I'm just a little confused on what the controller would look like to call both the Post and the User of that Post for a give Topic. Edit: Seriously, thank you to all that weighed in. I chose tal's answer because I used his code for my controller; however, I could have just as easily chosen either j.'s or tim's instead. Thank you both as well. This was so damn simple to implement, and I think today marks the day that I'm beginning to fall in love with rails.

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  • Java Swing Table questions

    - by Dalton Conley
    Hey guys, working on an event calendar. I'm having some trouble getting my column heads to display.. here is the code private JTable calendarTable; private DefaultTableModel calendarTableModel; final private String [] days = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"}; ////////////////////////////////////////////////////////////////////// /* Setup the actual calendar table */ calendarTableModel = new DefaultTableModel() { public boolean isCellEditable(int row, int col){ return false; } }; // setup columns for(int i = 0; i < 7; i++) calendarTableModel.addColumn(days[i]); calendarTable = new JTable(calendarTableModel); calendarTable.getTableHeader().setResizingAllowed(false); calendarTable.getTableHeader().setReorderingAllowed(false); calendarTable.setColumnSelectionAllowed(true); calendarTable.setRowSelectionAllowed(true); calendarTable.setSelectionMode(ListSelectionModel.SINGLE_SELECTION); calendarTable.setRowHeight(105); calendarTableModel.setColumnCount(7); calendarTableModel.setRowCount(6); Also, Im sort of new with tables.. how can I make the rowHeight split between the max size of the table?

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  • XSLT Global count of grouped items

    - by Chris
    Hi there, I have a set of items which i am grouping using the muenchian method using keys. This is working great however when i try to do things with the first x number of items it is doing it on the x number of items in each group rather than across the whole set of results. How would i get the individual position of each item accross the whole collection? <xsl:key name="pictures-by-productid" match="/dsQueryResponse/Rows/Row" use="@ProductId" /> <xsl:template match="/"> <div style="border:1px solid red; float:left;"> <xsl:apply-templates select="/" mode="sub"> </xsl:apply-templates> </div> </xsl:template> and the second template <xsl:template match="/" mode="sub"> <xsl:for-each select="/dsQueryResponse/Rows/Row[count(. | key('pictures-by-productid', @ProductId)[1]) = 1]"> <xsl:for-each select="key('pictures-by-productid', @ProductId)"> <xsl:sort select="@PictureType" /> <div style="float:left; margin:2px;"> <img src="{@ThumbNailUrl}" width="58" /> <br /> Download <xsl:number value="position()" format="1. " /> <xsl:value-of select="." /> </div> </xsl:for-each> </xsl:for-each> </xsl:template> Thanks Chris

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  • Comparing two collections for equality

    - by Crossbrowser
    I would like to compare two collections (in C#), but I'm not sure of the best way to implement this efficiently. I've read the other thread about Enumerable.SequenceEqual, but it's not exactly what I'm looking for. In my case, two collections would be equal if they both contain the same items (no matter the order). Example: collection1 = {1, 2, 3, 4}; collection2 = {2, 4, 1, 3}; collection1 == collection2; // true What I usually do is to loop through each item of one collection and see if it exists in the other collection, then loop through each item of the other collection and see if it exists in the first collection. (I start by comparing the lengths). if (collection1.Count != collection2.Count) return false; // the collections are not equal foreach (Item item in collection1) { if (!collection2.Contains(item)) return false; // the collections are not equal } foreach (Item item in collection2) { if (!collection1.Contains(item)) return false; // the collections are not equal } return true; // the collections are equal However, this is not entirely correct, and it's probably not the most efficient way to do compare two collections for equality. An example I can think of that would be wrong is: collection1 = {1, 2, 3, 3, 4} collection2 = {1, 2, 2, 3, 4} Which would be equal with my implementation. Should I just count the number of times each item is found and make sure the counts are equal in both collections? The examples are in some sort of C# (let's call it pseudo-C#), but give your answer in whatever language you wish, it does not matter. Note: I used integers in the examples for simplicity, but I want to be able to use reference-type objects too (they do not behave correctly as keys because only the reference of the object is compared, not the content).

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  • Lazy non-modifiable list in Google Collections

    - by mindas
    I was looking for a decent implementation of a generic lazy non-modifiable list implementation to wrap my search result entries. The unmodifiable part of the task is easy as it can be achieved by Collections.unmodifiableList() so I only need to sort out the the lazy part. Surprisingly, google-collections doesn't have anything to offer; while LazyList from Apache Commons Collections does not support generics. I have found an attempt to build something on top of google-collections but it seems to be incomplete (e.g. does not support size()), outdated (does not compile with 1.0 final) and requiring some external classes, but could be used as a good starting point to build my own class. Is anybody aware of any good implementation of a LazyList? If not, which option do you think is better: write my own implementation, based on google-collections ForwardingList, similar to what Peter Maas did; write my own wrapper around Commons Collections LazyList (the wrapper would only add generics so I don't have to cast everywhere but only in the wrapper itself); just write something on top of java.util.AbstractList; Any other suggestions are welcome.

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  • weighted matching algorithm in Perl

    - by srk
    Problem : We have equal number of men and women.each men has a preference score toward each woman. So do the woman for each man. each of the men and women have certain interests. Based on the interest we calculate the preference scores. So initially we have an input in a file having x columns. First column is the person(men/woman) id. id are nothing but 0.. n numbers.(first half are men and next half woman) the remaining x-1 columns will have the interests. these are integers too. now using this n by x-1 matrix... we have come up with a n by n/2 matrix. the new matrix has all men and woman as their rows and scores for opposite sex in columns. We have to sort the scores in descending order, also we need to know the id of person related to the scores after sorting. So here i wanted to use hash table. once we get the scores we need to make up pairs.. for which we need to follow some rules. My trouble is with the second matrix of n by n/2 that needs to give information of which man/woman has how much preference on a woman/man. I need these scores sorted so that i know who is the first preferred woman/man, 2nd preferred and so on for a man/woman. I hope to get good suggestions on the data structures i use.. I prefer php or perl. Thank you in advance

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  • Finding values from a table that are *not* in a grouping of another table and what group that value

    - by Bkins
    I hope I am not missing something very simple here. I have done a Google search(es) and searched through stackoverflow. Here is the situation: For simplicity's sake let's say I have a table called "PeoplesDocs", in a SQL Server 2008 DB, that holds a bunch of people and all the documents that they own. So one person can have several documents. I also have a table called "RequiredDocs" that simply holds all the documents that a person should have. Here is sort of what it looks like: PeoplesDocs: PersonID DocID -------- ----- 1 A 1 B 1 C 1 D 2 C 2 D 3 A 3 B 3 C RequiredDocs: DocID DocName ----- --------- A DocumentA B DocumentB C DocumentC D DocumentD How do I write a SQL query that returns some variation of: PersonID MissingDocs -------- ----------- 2 DocumentA 2 DocumentB 3 DocumentD I have tried, and most of my searching has pointed to, something like: SELECT DocID FROM DocsRequired WHERE NOT EXIST IN ( SELECT DocID FROM PeoplesDocs) but obviously this will not return anything in this example because everyone has at least one of the documents. Also, if a person does not have any documents then there will be one record in the PeoplesDocs table with the DocID set to NULL. Thank you in advance for any help you can provide, Ben

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  • Neural Network settings for fast training

    - by danpalmer
    I am creating a tool for predicting the time and cost of software projects based on past data. The tool uses a neural network to do this and so far, the results are promising, but I think I can do a lot more optimisation just by changing the properties of the network. There don't seem to be any rules or even many best-practices when it comes to these settings so if anyone with experience could help me I would greatly appreciate it. The input data is made up of a series of integers that could go up as high as the user wants to go, but most will be under 100,000 I would have thought. Some will be as low as 1. They are details like number of people on a project and the cost of a project, as well as details about database entities and use cases. There are 10 inputs in total and 2 outputs (the time and cost). I am using Resilient Propagation to train the network. Currently it has: 10 input nodes, 1 hidden layer with 5 nodes and 2 output nodes. I am training to get under a 5% error rate. The algorithm must run on a webserver so I have put in a measure to stop training when it looks like it isn't going anywhere. This is set to 10,000 training iterations. Currently, when I try to train it with some data that is a bit varied, but well within the limits of what we expect users to put into it, it takes a long time to train, hitting the 10,000 iteration limit over and over again. This is the first time I have used a neural network and I don't really know what to expect. If you could give me some hints on what sort of settings I should be using for the network and for the iteration limit I would greatly appreciate it. Thank you!

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  • List of objects or parallel arrays of properties?

    - by Headcrab
    The question is, basically: what would be more preferable, both performance-wise and design-wise - to have a list of objects of a Python class or to have several lists of numerical properties? I am writing some sort of a scientific simulation which involves a rather large system of interacting particles. For simplicity, let's say we have a set of balls bouncing inside a box so each ball has a number of numerical properties, like x-y-z-coordinates, diameter, mass, velocity vector and so on. How to store the system better? Two major options I can think of are: to make a class "Ball" with those properties and some methods, then store a list of objects of the class, e. g. [b1, b2, b3, ...bn, ...], where for each bn we can access bn.x, bn.y, bn.mass and so on; to make an array of numbers for each property, then for each i-th "ball" we can access it's 'x' coordinate as xs[i], 'y' coordinate as ys[i], 'mass' as masses[i] and so on; To me it seems that the first option represents a better design. The second option looks somewhat uglier, but might be better in terms of performance, and it could be easier to use it with numpy and scipy, which I try to use as much as I can. I am still not sure if Python will be fast enough, so it may be necessary to rewrite it in C++ or something, after initial prototyping in Python. Would the choice of data representation be different for C/C++? What about a hybrid approach, e.g. Python with C++ extension?

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