Search Results

Search found 4501 results on 181 pages for 'interesting'.

Page 149/181 | < Previous Page | 145 146 147 148 149 150 151 152 153 154 155 156  | Next Page >

• Can redirection of screen output to file change the result of a C++ code?

  - by Biga

  I am having this very weird behaviour with a C++ code: It gives me different results when running with and without redirecting the screen output to a file (reproducible in cygwin and linux). I mean, if I get the same executable and run it like ./run or run it like ./run >out.log, I get different results! I use std::cout to output to screen, all lines ending with endl; I use ifstream for the input file; I use ofstream for output, all lines ending with endl. I am using g++ 4. Any idea what is going on? UPDATE: I have hard-coded the input data, so 'ifstream' is not used, and problem persists. UPDATE 2: That's getting interesting. I have probed three variables that are computed initially, and that's what I get when using with and without redirecting the output to file redirected to file: 0 -0.02 0 direct to screen: 0 -0.02 1.04083e-17 So there's a round-off difference in the code variables with and without redirecting the output! Now, why redirecting would interefere with an internal computation of the code? UPDATE 3: If I redirect to /dev/null, I get the sam behaviour as outputing direct to screen, instead of redirecting to file.

  Read the article

• PyGTK: Manually render an existing widget at a given Rectangle? (TextView in a custom CellRenderer)

  - by NicDumZ

  Hello! I am trying to draw a TextView into the cell of a TreeView. (Why? I would like to have custom tags on text, so they can be clickable and trigger different actions/popup menus depending on where user clicks). I have been trying to write a customized CellRenderer for this purpose, but so far I failed because I find it extremely difficult to find generic documentation on rendering design in gtk. More than an answer at the specific question (that might be hard/not doable, and I'm not expecting you to do everything for me), I am first looking for documentation on how a widget is rendered, to understand how one is supposed to implement a CellRenderer. Can you share any link that explains, either for gtk or for pygtk, the rendering mechanism? More specifically: size allocation mechanism (should I say protocol?). I understand that a window has a defined size, and then queries its children, saying "my size is w x h, what would be your ideal size, buddy?", and then sometimes shrinks children when all children cant fit together at their ideal sizes. Any specific documentation on that, and on particular on when this happens during rendering? How are rendered "builtin" widgets? What kind of methods do they call on Widget base class? On the parent Window? When? Do they use pango.Layout? can you manually draw a TextView onto a pango.Layout object? This link gives an interesting example showing how you can draw content in a pango.Layout object and use it in a CellRenderer. I guess that I could adapt it if only I understood how TextView widget are rendered. Or perhaps, to put it more simply: given an existing widget instance, how does one render it at a specific gdk.Rectangle? Thanks a lot.

  Read the article

• How should I deal with floating numbers that numbers that can get so small that the become zero

  - by Tristan Havelick

  So I just fixed an interesting bug in the following code, but I'm not sure the approach I took it the best: p = 1 probabilities = [ ... ] # a (possibly) long list of numbers between 0 and 1 for wp in probabilities: if (wp > 0): p *= wp # Take the natural log, this crashes when 'probabilites' is long enough that p ends up # being zero try: result = math.log(p) Because the result doesn't need to be exact, I solved this by simply keeping the smallest non-zero value, and using that if p ever becomes 0. p = 1 probabilities = [ ... ] # a long list of numbers between 0 and 1 for wp in probabilities: if (wp > 0): old_p = p p *= wp if p == 0: # we've gotten so small, its just 0, so go back to the smallest # non-zero we had p = old_p break # Take the natural log, this crashes when 'probabilites' is long enough that p ends up # being zero try: result = math.log(p) This works, but it seems a bit kludgy to me. I don't do a ton of this kind of numerical programming, and I'm not sure if this is the kind of fix people use, or if there is something better I can go for.

  Read the article

• which is better: a lying copy constructor or a non-standard one?

  - by PaulH

  I have a C++ class that contains a non-copyable handle. The class, however, must have a copy constructor. So, I've implemented one that transfers ownership of the handle to the new object (as below) class Foo { public: Foo() : h_( INVALID_HANDLE_VALUE ) { }; // transfer the handle to the new instance Foo( const Foo& other ) : h_( other.Detach() ) { }; ~Foo() { if( INVALID_HANDLE_VALUE != h_ ) CloseHandle( h_ ); }; // other interesting functions... private: /// disallow assignment const Foo& operator=( const Foo& ); HANDLE Detach() const { HANDLE h = h_; h_ = INVALID_HANDLE_VALUE; return h; }; /// a non-copyable handle mutable HANDLE h_; }; // class Foo My problem is that the standard copy constructor takes a const-reference and I'm modifying that reference. So, I'd like to know which is better (and why): a non-standard copy constructor: Foo( Foo& other ); a copy-constructor that 'lies': Foo( const Foo& other ); Thanks, PaulH

  Read the article

• C struct written in file, open with Java

  - by DaunnC

  For example in C I have structure: typedef struct { int number; double x1; double y1; double x2; double y2; double x3; double y3; } CTRstruct;` Then I write it to file fwrite(&tr, 1, sizeof(tr), fp); (tr - its CTRstruct var, fp - File pointer); Then I need to read it with Java! I really don't know how to read struct from file... I tried to read it with ObjectInputStream(), last idea is to read with RandomAccessFile() but I also don't know how to... (readLong(), readDouble() also doesn't work, it works ofcource but doesn't read correct data). So, any idea how to read C struct from binary file with Java? If it's interesting, my version to read integer (but it's ugly, & I don't know what to do with double): public class MyDataInputStream extends DataInputStream{ public MyDataInputStream(InputStream AIs) { super(AIs); } public int readInt1() throws IOException{ int ch1 = in.read(); int ch2 = in.read(); int ch3 = in.read(); int ch4 = in.read(); if ((ch1 | ch2 | ch3 | ch4) < 0) throw new EOFException(); return ((ch4 << 24) + (ch3 << 16) + (ch2 << 8) + (ch1 << 0)); } with double we can deal the same way (like with int or with long (8bytes) & then convert to double with native func).

  Read the article

• Using block around a static/singleton resource reference

  - by byte

  This is interesting (to me anyway), and I'd like to see if anyone has a good answer and explanation for this behavior. Say you have a singleton database object (or static database object), and you have it stored in a class Foo. public class Foo { public static SqlConnection DBConn = new SqlConnection(ConfigurationManager.ConnectionStrings["BAR"].ConnectionString); } Then, lets say that you are cognizant of the usefulness of calling and disposing your connection (pretend for this example that its a one-time use for purposes of illustration). So you decide to use a 'using' block to take care of the Dispose() call. using (SqlConnection conn = Foo.DBConn) { conn.Open(); using (SqlCommand cmd = new SqlCommand()) { cmd.Connection = conn; cmd.CommandType = System.Data.CommandType.StoredProcedure; cmd.CommandText = "SP_YOUR_PROC"; cmd.ExecuteNonQuery(); } conn.Close(); } This fails, with an error stating that the "ConnectionString property is not initialized". It's not an issue with pulling the connection string from the app.config/web.config. When you investigate in a debug session you see that Foo.DBConn is not null, but contains empty properties. Why is this?

  Read the article

• Is this linear search implementation actually useful?

  - by Helper Method

  In Matters Computational I found this interesting linear search implementation (it's actually my Java implementation ;-)): public static int linearSearch(int[] a, int key) { int high = a.length - 1; int tmp = a[high]; // put a sentinel at the end of the array a[high] = key; int i = 0; while (a[i] != key) { i++; } // restore original value a[high] = tmp; if (i == high && key != tmp) { return NOT_CONTAINED; } return i; } It basically uses a sentinel, which is the searched for value, so that you always find the value and don't have to check for array boundaries. The last element is stored in a temp variable, and then the sentinel is placed at the last position. When the value is found (remember, it is always found due to the sentinel), the original element is restored and the index is checked if it represents the last index and is unequal to the searched for value. If that's the case, -1 (NOT_CONTAINED) is returned, otherwise the index. While I found this implementation really clever, I wonder if it is actually useful. For small arrays, it seems to be always slower, and for large arrays it only seems to be faster when the value is not found. Any ideas?

  Read the article

• DirectX: Game loop order, draw first and then handle input?

  - by Ricket

  I was just reading through the DirectX documentation and encountered something interesting in the page for IDirect3DDevice9::BeginScene : To enable maximal parallelism between the CPU and the graphics accelerator, it is advantageous to call IDirect3DDevice9::EndScene as far ahead of calling present as possible. I've been accustomed to writing my game loop to handle input and such, then draw. Do I have it backwards? Maybe the game loop should be more like this: (semi-pseudocode, obviously) while(running) { d3ddev->Clear(...); d3ddev->BeginScene(); // draw things d3ddev->EndScene(); // handle input // do any other processing // play sounds, etc. d3ddev->Present(NULL, NULL, NULL, NULL); } According to that sentence of the documentation, this loop would "enable maximal parallelism". Is this commonly done? Are there any downsides to ordering the game loop like this? I see no real problem with it after the first iteration... And I know the best way to know the actual speed increase of something like this is to actually benchmark it, but has anyone else already tried this and can you attest to any actual speed increase?

  Read the article

• Multiple leaf methods problem in composite pattern

  - by Ondrej Slinták

  At work, we are developing an PHP application that would be later re-programmed into Java. With some basic knowledge of Java, we are trying to design everything to be easily re-written, without any headaches. Interesting problem came out when we tried to implement composite pattern with huge number of methods in leafs. What are we trying to achieve (not using interfaces, it's just an example): class Composite { ... } class LeafOne { public function Foo( ); public function Moo( ); } class LeafTwo { public function Bar( ); public function Baz( ); } $c = new Composite( Array( new LeafOne( ), new LeafTwo( ) ) ); // will call method Foo in all classes in composite that contain this method $c->Foo( ); It seems like pretty much classic Composite pattern, but problem is that we will have quite many leaf classes and each of them might have ~5 methods (of which few might be different than others). One of our solutions, which seems to be the best one so far and might actually work, is using __call magic method to call methods in leafs. Unfortunately, we don't know if there is an equivalent of it in Java. So the actual question is: Is there a better solution for this, using code that would be eventually easily re-coded into Java? Or do you recommend any other solution? Perhaps there's some different, better pattern I could use here. In case there's something unclear, just ask and I'll edit this post.

  Read the article

• objective C underscore property vs self

  - by user1216838

  I'm was playing around with the standard sample split view that gets created when you select a split view application in Xcode, and after adding a few fields i needed to add a few fields to display them in the detail view. and something interesting happend in the original sample, the master view sets a "detailItem" property in the detail view and the detail view displays it. - (void)setDetailItem:(id) newDetailItem { if (_detailItem != newDetailItem) { _detailItem = newDetailItem; // Update the view. [self configureView]; } i understand what that does and all, so while i was playing around with it. i thought it would be the same if instead of _detailItem i used self.detailItem, since it's a property of the class. however, when i used self.detailItem != newDetailItem i actually got stuck in a loop where this method is constantly called and i cant do anything else in the simulator. my question is, whats the actual difference between the underscore variables(ivar?) and the properties? i read some posts here it seems to be just some objective C convention, but it actually made some difference.

  Read the article

• SQL Server 2008 R2

  - by kevchadders

  Hi all, I heard on the grapevine that Microsoft will be releasing SQL Server 2008 R2 within a year. Though I initially thought this was a patch for the just released 2008 version, I realised that it’s actually a completely different version that you would have to pay for. (Am I correct, if you had SQL Server 2008, would you have to pay again if you wanted to upgrade to 2008 R2?) If you’re already running SQL Server 2008, would you say it’s still worth the upgrade? Or does it depend on the size of your company and current setup. For what I’ve initially read, I do get the impression that this version would be more useful for the very high end hardware setup where you want to have very good scalability. With regard to programming, is there any extra enhancements/support in there which you’re aware of that will significantly help .NET Products/Web Development? Initially found a couple of links on it, but I was wondering if anyone had anymore info to share on subject as I couldn’t find nothing on SO about it? Thanks. New SQL Server R2 Microsoft Link on it. Microsoft SQL 2008 R2 EDIT: More information based on the Express Edition One very interesting thing about SQL Server 2008 R2 concerns the Express edition. Previous express versions of SQL Server Express had a database size limit of 4GB. With SQL Server Express 2008 R2, this has now been increased to 10GB !! This now makes the FREE express edition a much more viable option for small & medium sized applications that are relatively light on database requirements. Bear in mind, that this limit is per database, so if you coded your application cleverly enough to use a separate database for historical/archived data, you could squeeze even more out of it! For more information, see here: http://blogs.msdn.com/sqlexpress/archive/2010/04/21/database-size-limit-increased-to-10gb-in-sql-server-2008-r2-express.aspx

  Read the article

• Subversion Partial Export

  - by Jared

  I have somewhat interesting development situation. The client and deployment server are inside a firewall without access to the Subversion server. But the developers are outside the firewall and are able to use the Subversion server. Right now the solution I have worked out is to update my local copy of the code and then pull out the most recently updated files using UnleashIT. The question is how to get just the updated files out of Subversion so that they can be physically transported through the firewall and put on the deployment server. I'm not worried about trying to change the firewall setup or trying to figure out an easier way to get to the Subversion server from inside the firewall. I'm just interested in a way to get a partial export from the repository of the most recently changed files. Are there any other suggestions? Answer found: In addition to the answer I marked as Answer, I've also found the following here to be able to do this from TortoiseSVN: from http://svn.haxx.se/tsvn/archive-2006-08/0051.shtml * select the two revisions * right-click, "compare revisions" * select all files in the list * right-click, choose "export to..."

  Read the article

• WCF with MANY database connections

  - by Jorge Dominguez

  I'm working in the development of an ERP type .Net WinForms application consuming a WCF service. It's to be used by many small companies (in the range of 100-200). Database is SQL Server 2008 and the service will be hosted as a Windows service. Even thought there will be a single DB Server, our customer insists in having separate databases for each company. That is because of stability/support concerns (like DB being damaged or took offline for some reason thus affecting all clients). Concerns coming from previous experiences (not necessarily with same platform). With a single database, connections to the DB would be opened at service start up and pooling used, but, I'm not sure how connections could be managed in a multiple DB scenario: Could a connection to the corresponding DB be opened and closed for each service request? would performance be acceptable? If a connection is opened and maintained for each company accessing the system, what's the practical limit of opened connections (to different databases)? It would be very interesting to hear your opinions and suggestions for this situation. Tanks

  Read the article

• Why can't we just use a hash of passphrase as the encryption key (and IV) with symmetric encryption algorithms?

  - by TX_

  Inspired by my previous question, now I have a very interesting idea: Do you really ever need to use Rfc2898DeriveBytes or similar classes to "securely derive" the encryption key and initialization vector from the passphrase string, or will just a simple hash of that string work equally well as a key/IV, when encrypting the data with symmetric algorithm (e.g. AES, DES, etc.)? I see tons of AES encryption code snippets, where Rfc2898DeriveBytes class is used to derive the encryption key and initialization vector (IV) from the password string. It is assumed that one should use a random salt and a shitload of iterations to derive secure enough key/IV for the encryption. While deriving bytes from password string using this method is quite useful in some scenarios, I think that's not applicable when encrypting data with symmetric algorithms! Here is why: using salt makes sense when there is a possibility to build precalculated rainbow tables, and when attacker gets his hands on hash he looks up the original password as a result. But... with symmetric data encryption, I think this is not required, as the hash of password string, or the encryption key, is never stored anywhere. So, if we just get the SHA1 hash of password, and use it as the encryption key/IV, isn't that going to be equally secure? What is the purpose of using Rfc2898DeriveBytes class to generate key/IV from password string (which is a very very performance-intensive operation), when we could just use a SHA1 (or any other) hash of that password? Hash would result in random bit distribution in a key (as opposed to using string bytes directly). And attacker would have to brute-force the whole range of key (e.g. if key length is 256bit he would have to try 2^256 combinations) anyway. So either I'm wrong in a dangerous way, or all those samples of AES encryption (including many upvoted answers here at SO), etc. that use Rfc2898DeriveBytes method to generate encryption key and IV are just wrong.

  Read the article

• std::stringstream GCC Abnormal Behavior

  - by FlorianZ

  I have a very interesting problem with compiling a short little program on a Mac (GCC 4.2). The function below would only stream chars or strings into the stringstream, but not anything else (int, double, float, etc.) In fact, the fail flag is set if I attempt to convert for example an int into a string. However, removing the preprocessor flag: _GLIBCXX_DEBUG=1, which is set by default in XCode for the debug mode, will yield the desired results / correct behavior. Here is the simple function I am talking about. value is template variable of type T. Tested for int, double, float (not working), char and strings (working). template < typename T > const std::string Attribute<T>::getValueAsString() const { std::ostringstream stringValue; stringValue << value; return stringValue.str(); } Any ideas what I am doing wrong, why this doesn't work, or what the preprocessor flag does to make this not work anymore? Thanks!

  Read the article

• Strange befaviour of spring transaction support for JPA + Hibernate +@Transactional annotation

  - by abovesun

  I found out really strange behavior on relatively simple use case, probably I can't understand it because of not deep knowledges of spring @Transactional nature, but this is quite interesting. I have simple User dao that extends spring JpaDaoSupport class and contains standard save method: @Transactional public User save(User user) { getJpaTemplate().persist(user); return user; } If was working fine until I've add new method to same class: User getSuperUser(), this method should return user with isAdmin == true, and if there is no super user in db, method should create one. Thats how it was looking like: public User createSuperUser() { User admin = null; try { admin = (User) getJpaTemplate().execute(new JpaCallback() { public Object doInJpa(EntityManager em) throws PersistenceException { return em.createQuery("select u from UserImpl u where u.admin = true").getSingleResult(); } }); } catch (EmptyResultDataAccessException ex) { User admin = new User('login', 'password'); admin.setAdmin(true); save(admin); // THIS IS THE POINT WHERE STRANGE THING COMING OUT } return admin; } As you see code is strange forward and I was very confused when found out that no transaction was created and committed on invocation of save(admin) method and no new user wasn't actually created despite @Transactional annotation. In result we have situation: when save() method invokes from outside of UserDAO class - @Transactional annotation counted and user successfully created, but if save() invokes from inside of other method of the same dao class - @Transactional annotation ignored. Here how I was change save() method to force it always create transaction. public User save(User user) { getJpaTemplate().execute(new JpaCallback() { public Object doInJpa(EntityManager em) throws PersistenceException { em.getTransaction().begin(); em.persist(user); em.getTransaction().commit(); return null; } }); return user; } As you see I manually invoke begin and commit. Any ideas?

  Read the article

• Book/topic recommendations for a programmer returning to programming.

  - by Jason Tan

  I used to be a developer in Java, PHP, perl and C/C++ (the C++ bit badly - the others not too badly, I hope). This was back in the Java 1.3/1.4 days. We used raw JDBC, swing, servlets, JSP and ant (sometimes even make). Eclipse was new. Then I joined a deployment team and became a deployment engineer and then after the deployment engineer work became a full time sys admin.You get the idea - my experience is a generation or two old in programming terms - maybe older. I'm interested in getting back into Java and perhaps Ruby development, but feel I will be waaaaay behind the technological 8 ball. Can you folks suggest some books (or sites) that would be worth reading to catch up with the last 5-10 years of the development world. I.e. what should I read to try and catch up with where development is now? I see lots of stuff on the web, but what are people in the fabled "real world" using? (are lots of people being SOA based apps? Are they using XP methodology) The sorts of things I'm interested in finding out about/catching up on are: Methodologies Design patterns APIs/Frameworks/Technologies Other stuff you deem current/interesting/relevant. So if you have any thoughts or can recommend any books (especially new classics - you know the 's equivalent to K&R C or "The mythical man month"). Thanks for any thoughts you might share.

  Read the article

• Datastructure choices for highspeed and memory efficient detection of duplicate of strings

  - by Jonathan Holland

  I have a interesting problem that could be solved in a number of ways: I have a function that takes in a string. If this function has never seen this string before, it needs to perform some processing. If the function has seen the string before, it needs to skip processing. After a specified amount of time, the function should accept duplicate strings. This function may be called thousands of time per second, and the string data may be very large. This is a highly abstracted explanation of the real application, just trying to get down to the core concept for the purpose of the question. The function will need to store state in order to detect duplicates. It also will need to store an associated timestamp in order to expire duplicates. It does NOT need to store the strings, a unique hash of the string would be fine, providing there is no false positives due to collisions (Use a perfect hash?), and the hash function was performant enough. The naive implementation would be simply (in C#): Dictionary<String,DateTime> though in the interest of lowering memory footprint and potentially increasing performance I'm evaluating a custom data structures to handle this instead of a basic hashtable. So, given these constraints, what would you use? EDIT, some additional information that might change proposed implementations: 99% of the strings will not be duplicates. Almost all of the duplicates will arrive back to back, or nearly sequentially. In the real world, the function will be called from multiple worker threads, so state management will need to be synchronized.

  Read the article

• What's wrong with output parameters?

  - by Chris McCall

  Both in SQL and C#, I've never really liked output parameters. I never passed parameters ByRef in VB6, either. Something about counting on side effects to get something done just bothers me. I know they're a way around not being able to return multiple results from a function, but a rowset in SQL or a complex datatype in C# and VB work just as well, and seem more self-documenting to me. Is there something wrong with my thinking, or are there resources from authoritative sources that back me up? What's your personal take on this and why? What can I say to colleagues that want to design with output parameters that might convince them to use different structures? EDIT: interesting turn- the output parameter I was asking this question about was used in place of a return value. When the return value is "ERROR", the caller is supposed to handle it as an exception. I was doing that but not pleased with the idea. A coworker wasn't informed of the need to handle this condition and as a result, a great deal of money was lost as the procedure failed silently!

  Read the article

• C++ AI Design Question

  - by disney

  Hi, I am currently writing a bot for a MMORPG. Though, currently I am stuck at trying to figure out how to nicely implement this. The design problem is related to casting the character spells in the correct order. Here is a simple example to what I need to archieve. It's not related to casting them, but doing it in the correct order. I would know how simply cast them randomly, by checking which skill has not yet been casted, but in right order as being shown in the GUI, not really. note: the skill amount may differ, it's not always 3, maximum 10 though. Charactername < foobar has 3 skills. Skill 1: Name ( random1 ) cooldown ( 1000 ms ) cast duration ( 500 ms ) Skill 2: Name ( random2 ) cooldown ( 1500 ms ) cast duration ( 700 ms ) Skill 3: Name ( random3 ) cooldown ( 2000 ms ) cast duration ( 900 ms ) I don't really know how I could implement this, if anyone has some thoughts, feel free to share. I do know that most of the people don't like the idea of cheating in games, I don't like it either, nor I am actually playing the game, but its an interesting field for me. Thank you.

  Read the article

• Smart way to execute function in flash from an imported html (or XML) plain text

  - by DomingoSL

  Ok, here is the think. I have a very simple flash program code in AS3, inside this program there is a dynamic textfield html capable. Also i have a database were i will put some information. Each element in the database can be linked to other. For example, this database will contain tourist spots, and they can be related with others in the same database. Ramdom place 1 This interesting spot is near <link to="ramdo2">ramdom place2</link>. And so, so so... The information in the database is retrived by the flash application and it shows the text on the dynamic textfield. I need somehow to tell my flash application that have to be a link to other part of the database, so when the user click the link a function in flash call this new data. The database is a simple Mysql server, and the data is not yet in there, waiting for your suggestions of how to format it and develop the solution. Im a php developer too, so i can make a gateway in PHP to read the MySQL and then retrive some format to flash, an XML for example.

  Read the article

• How to add additional condition to the JOIN generated by include?

  - by KandadaBoggu

  I want to add additional criteria to the LEFT OUTER JOIN generated by the :include option in ActiveRecord finder. class Post has_many :comments end class Comment belongs_to :post has_many :comment_votes end class CommentVote belongs_to :comment end Now lets say I want to find last 10 posts with their associated comments and the up comment votes. Post.find.all(:limit => 10, :order => "created_at DESC", :include => [{:comments => :comment_votes]) I cant add the condition to check for up votes as it will ignore the posts without the up votes. So the condition has to go the ON clause of the JOIN generated for the comment_votes. I am wishing for a syntax such as: Post.find.all(:limit => 10, :order => "created_at DESC", :include => [{:comments => [:comment_votes, :on => "comment_votes.vote > 0"]) Have you faced such problems before? Did you managed to solve the problem using the current finder? I hope to hear some interesting ideas from the community. PS: I can write a join SQL to get the expected result and stitch the results together. I want to make sure there is no other alternative before going down that path.

  Read the article

• Best way to build an application based on R?

  - by Prasad Chalasani

  I'm looking for suggestions on how to go about building an application that uses R for analytics, table generation, and plotting. What I have in mind is an application that: displays various data tables in different tabs, somewhat like in Excel, and the columns should be sortable by clicking. takes user input parameters in some dialog windows. displays plots dynamically (i.e. user-input-dependent) either in a tab or in a new pop-up window/frame Note that I am not talking about a general-purpose fron-end/GUI for exploring data with R (like say Rattle), but a specific application. Some questions I'd like to see addressed are: Is an entirely R-based approach even possible ( on Windows ) ? The following passage from the Rattle article in R-Journal intrigues me: It is interesting to note that the first implementation of Rattle actually used Python for implementing the callbacks and R for the statistics, using rpy. The release of RGtk2 allowed the interface el- ements of Rattle to be written directly in R so that Rattle is a fully R-based application If it's better to use another language for the GUI part, which language is best suited for this? I'm looking for a language where it's relatively "painless" to build the GUI, and that also integrates very well with R. From this StackOverflow question How should I do rapid GUI development for R and Octave methods (possibly with Python)? I see that Python + PyQt4 + QtDesigner + RPy2 seems to be the best combo. Is that the consensus ? Anyone have pointers to specific (open source) applications of the type I describe, as examples that I can learn from?

  Read the article

• Project Euler #119 Make Faster

  - by gangqinlaohu

  Trying to solve Project Euler problem 119: The number 512 is interesting because it is equal to the sum of its digits raised to some power: 5 + 1 + 2 = 8, and 8^3 = 512. Another example of a number with this property is 614656 = 28^4. We shall define an to be the nth term of this sequence and insist that a number must contain at least two digits to have a sum. You are given that a2 = 512 and a10 = 614656. Find a30. Question: Is there a more efficient way to find the answer than just checking every number until a30 is found? My Code int currentNum = 0; long value = 0; for (long a = 11; currentNum != 30; a++){ //maybe a++ is inefficient int test = Util.sumDigits(a); if (isPower(a, test)) { currentNum++; value = a; System.out.println(value + ":" + currentNum); } } System.out.println(value); isPower checks if a is a power of test. Util.sumDigits: public static int sumDigits(long n){ int sum = 0; String s = "" + n; while (!s.equals("")){ sum += Integer.parseInt("" + s.charAt(0)); s = s.substring(1); } return sum; } program has been running for about 30 minutes (might be overflow on the long). Output (so far): 81:1 512:2 2401:3 4913:4 5832:5 17576:6 19683:7 234256:8 390625:9 614656:10 1679616:11 17210368:12 34012224:13 52521875:14 60466176:15 205962976:16 612220032:17

  Read the article

• Can g++ fill uninitialized POD variables with known values?

  - by Bob Lied

  I know that Visual Studio under debugging options will fill memory with a known value. Does g++ (any version, but gcc 4.1.2 is most interesting) have any options that would fill an uninitialized local POD structure with recognizable values? struct something{ int a; int b; }; void foo() { something uninitialized; bar(uninitialized.b); } I expect uninitialized.b to be unpredictable randomness; clearly a bug and easily found if optimization and warnings are turned on. But compiled with -g only, no warning. A colleague had a case where code similar to this worked because it coincidentally had a valid value; when the compiler upgraded, it started failing. He thought it was because the new compiler was inserting known values into the structure (much the way that VS fills 0xCC). In my own experience, it was just different random values that didn't happen to be valid. But now I'm curious -- is there any setting of g++ that would make it fill memory that the standard would otherwise say should be uninitialized?

  Read the article

< Previous Page | 145 146 147 148 149 150 151 152 153 154 155 156  | Next Page >