Search Results

Search found 8440 results on 338 pages for 'wms implementation'.

Page 262/338 | < Previous Page | 258 259 260 261 262 263 264 265 266 267 268 269  | Next Page >

• Problem with Boost::Asio for C++

  - by Martin Lauridsen

  Hi there, For my bachelors thesis, I am implementing a distributed version of an algorithm for factoring large integers (finding the prime factorisation). This has applications in e.g. security of the RSA cryptosystem. My vision is, that clients (linux or windows) will download an application and compute some numbers (these are independant, thus suited for parallelization). The numbers (not found very often), will be sent to a master server, to collect these numbers. Once enough numbers have been collected by the master server, it will do the rest of the computation, which cannot be easily parallelized. Anyhow, to the technicalities. I was thinking to use Boost::Asio to do a socket client/server implementation, for the clients communication with the master server. Since I want to compile for both linux and windows, I thought windows would be as good a place to start as any. So I downloaded the Boost library and compiled it, as it said on the Boost Getting Started page: bootstrap .\bjam It all compiled just fine. Then I try to compile one of the tutorial examples, client.cpp, from Asio, found (here.. edit: cant post link because of restrictions). I am using the Visual C++ compiler from Microsoft Visual Studio 2008, like this: cl /EHsc /I D:\Downloads\boost_1_42_0 client.cpp But I get this error: /out:client.exe client.obj LINK : fatal error LNK1104: cannot open file 'libboost_system-vc90-mt-s-1_42.lib' Anyone have any idea what could be wrong, or how I could move forward? I have been trying pretty much all week, to get a simple client/server socket program for c++ working, but with no luck. Serious frustration kicking in. Thank you in advance.

  Read the article

• Multiple websites, Single sign-on design

  - by Yannis

  Hi all, I have a question. A client I have been doing some work recently has a range of websites with different login mechanisms. He is looking to slowly migrate to a single sign-on mechanism for his websites (all written in asp.net mvc). I am looking at my options here, so here is a list of requirements: 1) It has to be secure (duh) 2) It needs to support extra user properties over and above the usual name, address stuff (such as money or credits for a user) 3) It has to provide a centralized user management web console for his convenience (I understand that this will be a small project on top of whatever design solution I choose to go for) 4) It has to integrate with the existing websites without re-engineering the whole product (I understand that this depends on the current product implementation). 5) It has to deal with emailing the user when he registers (in order for him to activate his account) 6) It has to deal with activating the user when he clicks the activate me link in the email (I understand that 5 and 6 require some form of email templating system to support different emails per application) I was thinking of creating a library working together with forms authentication that exposes whatever methods are required (e.g. login, logout, activate, etc. and a small restful service to implement activation from email, registration processing etc. Taking into account that loads of things have been left out to make this question brief and to the point, does this sound like a good design? But this looks like a very common problem so arent there any existing projects that I could use? Thanks for reading.

  Read the article

• C++: parsing with simple regular expression or shoud I use sscanf?

  - by Helltone

  I need to parse a string like func1(arg1, arg2); func2(arg3, arg4);. It's not a very complex parsing problem, so I would prefer to avoid resorting to flex/bison or similar utilities. My first approch was to try to use POSIX C regcomp/regexec or Boost implementation of C++ std::regex. I wrote the following regular expression, which does not work (I'll explain why further on). "^" "[ ;\t\n]*" "(" // (1) identifier "[a-zA-Z_][a-zA-Z0-9_]*" ")" "[ \t\n]*" "(" // (2) non-marking "\[" "(" // (3) non-marking "[ \t]*" "(" // (4..n-1) argument "[a-zA-Z0-9_]+" ")" "[ \t\n]*" "," ")*" "[ \t\n]*" "(" // (n) last argument "[a-zA-Z0-9_]+" ")" "]" ")?" "[ \t\n]*" ";" Note that the group 1 captures the identifier and groups 4..n-1 are intended to capture arguments except the last, which is captured by group n. When I apply this regex to, say func(arg1, arg2, arg3) the result I get is an array {func, arg2, arg3}. This is wrong because arg1 is not in it! The problem is that in the standard regex libraries, submarkings only capture the last match. In other words, if you have for instance the regex "((a*|b*))*" applied on "babb", the results of the inner match will be bb and all previous captures will have been forgotten. Another thing that annoys me here is that in case of error there is no way to know which character was not recognized as these functions provide very little information about the state of the parser when the input is rejected. So I don't know if I'm missing something here... In this case should I use sscanf or similar instead? Note that I prefer to use C/C++ standard libraries (and maybe boost).

  Read the article

• Concise C# code for gathering several properties with a non-null value into a collection?

  - by stakx

  A fairly basic problem for a change. Given a class such as this: public class X { public T A; public T B; public T C; ... // (other fields, properties, and methods are not of interest here) } I am looking for a concise way to code a method that will return all A, B, C, ... that are not null in an enumerable collection. (Assume that declaring these fields as an array is not an option.) public IEnumerable<T> GetAllNonNullAs(this X x) { // ? } The obvious implementation of this method would be: public IEnumerable<T> GetAllNonNullAs(this X x) { var resultSet = new List<T>(); if (x.A != null) resultSet.Add(x.A); if (x.B != null) resultSet.Add(x.B); if (x.C != null) resultSet.Add(x.C); ... return resultSet; } What's bothering me here in particular is that the code looks verbose and repetitive, and that I don't know the initial List capacity in advance. It's my hope that there is a more clever way, probably something involving the ?? operator? Any ideas?

  Read the article

• iPhone: Using dispatch_after to mimick NSTimer

  - by Joseph Tura

  Don't know a whole lot about blocks. How would you go about mimicking a repeating NSTimer with dispatch_after? My problem is that I want to "pause" a timer when the app moves to the background, but subclassing NSTimer does not seem to work. I tried something which seems to work. I cannot judge its performance implications or whether it could be greatly optimized. Any input is welcome. #import "TimerWithPause.h" @implementation TimerWithPause @synthesize timeInterval; @synthesize userInfo; @synthesize invalid; @synthesize invocation; + (TimerWithPause *)scheduledTimerWithTimeInterval:(NSTimeInterval)aTimeInterval target:(id)aTarget selector:(SEL)aSelector userInfo:(id)aUserInfo repeats:(BOOL)aTimerRepeats { TimerWithPause *timer = [[[TimerWithPause alloc] init] autorelease]; timer.timeInterval = aTimeInterval; NSMethodSignature *signature = [[aTarget class] instanceMethodSignatureForSelector:aSelector]; NSInvocation *aInvocation = [NSInvocation invocationWithMethodSignature:signature]; [aInvocation setSelector:aSelector]; [aInvocation setTarget:aTarget]; [aInvocation setArgument:&timer atIndex:2]; timer.invocation = aInvocation; timer.userInfo = aUserInfo; if (!aTimerRepeats) { timer.invalid = YES; } [timer fireAfterDelay]; return timer; } - (void)fireAfterDelay { dispatch_time_t delay = dispatch_time(DISPATCH_TIME_NOW, self.timeInterval * NSEC_PER_SEC); dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0); dispatch_after(delay, queue, ^{ [invocation performSelectorOnMainThread:@selector(invoke) withObject:nil waitUntilDone:NO]; if (!invalid) { [self fireAfterDelay]; } }); } - (void)invalidate { invalid = YES; [invocation release]; invocation = nil; [userInfo release]; userInfo = nil; } - (void)dealloc { [self invalidate]; [super dealloc]; } @end

  Read the article

• Is there a standard pattern for scanning a job table executing some actions?

  - by Howiecamp

  (I realize that my title is poor. If after reading the question you have an improvement in mind, please either edit it or tell me and I'll change it.) I have the relatively common scenario of a job table which has 1 row for some thing that needs to be done. For example, it could be a list of emails to be sent. The table looks something like this: ID Completed TimeCompleted anything else... ---- --------- ------------- ---------------- 1 No blabla 2 No blabla 3 Yes 01:04:22 ... I'm looking either for a standard practice/pattern (or code - C#/SQL Server preferred) for periodically "scanning" (I use the term "scanning" very loosely) this table, finding the not-completed items, doing the action and then marking them completed once done successfully. In addition to the basic process for accomplishing the above, I'm considering the following requirements: I'd like some means of "scaling linearly", e.g. running multiple "worker processes" simultaneously or threading or whatever. (Just a specific technical thought - I'm assuming that as a result of this requirement, I need some method of marking an item as "in progress" to avoid attempting the action multiple times.) Each item in the table should only be executed once. Some other thoughts: I'm not particularly concerned with the implementation being done in the database (e.g. in T-SQL or PL/SQL code) vs. some external program code (e.g. a standalone executable or some action triggered by a web page) which is executed against the database Whether the "doing the action" part is done synchronously or asynchronously is not something I'm considering as part of this question.

  Read the article

• Spring Integration 1.0 RC2: Streaming file content?

  - by gdm

  I've been trying to find information on this, but due to the immaturity of the Spring Integration framework I haven't had much luck. Here is my desired work flow: New files are placed in an 'Incoming' directory Files are picked up using a file:inbound-channel-adapter The file content is streamed, N lines at a time, to a 'Stage 1' channel, which parses the line into an intermediary (shared) representation. This parsed line is routed to multiple 'Stage 2' channels. Each 'Stage 2' channel does its own processing on the N available lines to convert them to a final representation. This channel must have a queue which ensures no Stage 2 channel is overwhelmed in the event that one channel processes significantly slower than the others. The final representation of the N lines is written to a file. There will be as many output files as there were routing destinations in step 4. *'N' above stands for any reasonable number of lines to read at a time, from [1, whatever I can fit into memory reasonably], but is guaranteed to always be less than the number of lines in the full file. How can I accomplish streaming (steps 3, 4, 5) in Spring Integration? It's fairly easy to do without streaming the files, but my files are large enough that I cannot read the entire file into memory. As a side note, I have a working implementation of this work flow without Spring Integration, but since we're using Spring Integration in other places in our project, I'd like to try it here to see how it performs and how the resulting code compares for length and clarity.

  Read the article

• What is a good automated data import method for SQL Server?

  - by Joel Potter

  I'm in the process of porting some SQL Server 2005 databases to SQL Server 2008. One of these databases has an associated import application (Windows task) which uses SSIS with a DTS package to import a large dataset from an MS Access database nightly. In upgrading to SQL Server 2008, I discovered that I can't run the same console application which has been performing the imports due to the missing manageddts DLL in SQL Server 2008. It's several years old and in need of a rewrite for various reason, plus, I've been fairly unhappy with DTS in general. The original reason DTS was chosen was for speed (5 min import time compared to 30+ for ADO.NET). The format of the data to import is out of my control (the client likes Access). I would also like to be able to run the import from a machine completely separate from the server hosting SQL Server and preferably with minimal SQL features installed. Options I've considered: Creating an Access application to connect to both databases (SQL Server and Access) and perform the import (Ugh!) Revisiting ADO.NET to see if the original implementation was poorly written. Updated SSIS packages. What other technologies should I be considering for this job?

  Read the article

• How to benchmark on multi-core processors

  - by Pascal Cuoq

  I am looking for ways to perform micro-benchmarks on multi-core processors. Context: At about the same time desktop processors introduced out-of-order execution that made performance hard to predict, they, perhaps not coincidentally, also introduced special instructions to get very precise timings. Example of these instructions are rdtsc on x86 and rftb on PowerPC. These instructions gave timings that were more precise than could ever be allowed by a system call, allowed programmers to micro-benchmark their hearts out, for better or for worse. On a yet more modern processor with several cores, some of which sleep some of the time, the counters are not synchronized between cores. We are told that rdtsc is no longer safe to use for benchmarking, but I must have been dozing off when we were explained the alternative solutions. Question: Some systems may save and restore the performance counter and provide an API call to read the proper sum. If you know what this call is for any operating system, please let us know in an answer. Some systems may allow to turn off cores, leaving only one running. I know Mac OS X Leopard does when the right Preference Pane is installed from the Developers Tools. Do you think that this make rdtsc safe to use again? More context: Please assume I know what I am doing when trying to do a micro-benchmark. If you are of the opinion that if an optimization's gains cannot be measured by timing the whole application, it's not worth optimizing, I agree with you, but I cannot time the whole application until the alternative data structure is finished, which will take a long time. In fact, if the micro-benchmark were not promising, I could decide to give up on the implementation now; I need figures to provide in a publication whose deadline I have no control over.

  Read the article

• How to move from custom to transluscent NavigationBar and back? Display problems!

  - by jd291

  So, i got this Navigation-based App (with a custom NavigationBar - Category) and I have 2 problems here... @implementation UINavigationBar (Custom) - (void)drawRect:(CGRect)rect { UIImage *image = [UIImage imageNamed: @"bg_toolbar.png"]; [image drawInRect:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)]; } @end Because of the Navigation-based App, most of the views have a height of 436px (= ScreenSize - NavigationBar height, as you probably know ;). I got one view similar to the photo app overview showing all the thumbnails, from there I push a viewcontroller containing the scroll view (like in photos app) on the stack, like so - (void)buttonPressed:(id)sender { UIButton *btn = (UIButton *)sender; PhotoSetScrollViewController *psc = [[PhotoSetScrollViewController alloc] initWithPhotoArray:photos andID:btn.tag]; [self.navigationController pushViewController:psc animated:YES]; } Problem 1: The view holding the fullscreen scrollview has a height of 480px which seems to be a problem because when poping the viewcontroller by hitting the back button, the view containing the thumbnails (height 436px) moves upward below the navigation bar. And also the Toolbar keeps showing. What could be the problem? Problem 2: How could I switch between my custom navigation bar and the standard black translucent style?

  Read the article

• Change title of UINavigationBar

  - by Lemmy

  I've created a view-based application. I've placed a Navigation Bar on the view and two buttons. I'd like to change the title of the nav bar after pressing the buttons. In IB I've connected the buttons with the corresponding actions. Debugging shows that the actions are getting called but the title of the nav bar is not changed. Kindly help! // // NavBarViewController.h #import <UIKit/UIKit.h> @interface NavBarViewController : UIViewController { } -(IBAction) clickedOne: (id)sender; -(IBAction) clickedTwo: (id)sender; @end // // NavBarViewController.m #import "NavBarViewController.h" @implementation NavBarViewController -(IBAction) clickedOne: (id)sender { self.navigationItem.title = @"1"; } -(IBAction) clickedTwo: (id)sender { self.navigationItem.title = @"2"; } - (void)didReceiveMemoryWarning { // Releases the view if it doesn't have a superview. [super didReceiveMemoryWarning]; // Release any cached data, images, etc that aren't in use. } - (void)viewDidUnload { // Release any retained subviews of the main view. // e.g. self.myOutlet = nil; } - (void)dealloc { [super dealloc]; } @end

  Read the article

• Need help make these classes use Visitor Pattern and generics

  - by Shervin

  Hi. I need help to generify and implement the visitor pattern. We are using tons of instanceof and it is a pain. I am sure it can be modified, but I am not sure how to do it. Basically we have an interface ProcessData public interface ProcessData { public setDelegate(Object delegate); public Object getDelegate(); //I am sure these delegate methods can use generics somehow } Now we have a class ProcessDataGeneric that implements ProcessData public class ProcessDataGeneric implements ProcessData { private Object delegate; public ProcessDataGeneric(Object delegate) { this.delegate = delegate; } } Now a new interface that retrieves the ProcessData interface ProcessDataWrapper { public ProcessData unwrap(); } Now a common abstract class that implements the wrapper so ProcessData can be retrieved @XmlSeeAlso( { ProcessDataMotorferdsel.class,ProcessDataTilskudd.class }) public abstract class ProcessDataCommon implements ProcessDataWrapper { protected ProcessData unwrapped; public ProcessData unwrap() { return unwrapped; } } Now the implementation public class ProcessDataMotorferdsel extends ProcessDataCommon { public ProcessDataMotorferdsel() { unwrapped = new ProcessDataGeneric(this); } } similarly public class ProcessDataTilskudd extends ProcessDataCommon { public ProcessDataTilskudd() { unwrapped = new ProcessDataGeneric(this); } } Now when I use these classes, I always need to do instanceof ProcessDataCommon pdc = null; if(processData.getDelegate() instanceof ProcessDataMotorferdsel) { pdc = (ProcessDataMotorferdsel) processData.getDelegate(); } else if(processData.getDelegate() instanceof ProcessDataTilskudd) { pdc = (ProcessDataTilskudd) processData.getDelegate(); } I know there is a better way to do this, but I have no idea how I can utilize Generics and the Visitor Pattern. Any help is GREATLY appreciated.

  Read the article

• Rails: generating URLs for actions in JSON response

  - by Chris Butler

  In a view I am generating an HTML canvas of figures based on model data in an app. In the view I am preloading JSON model data in the page like this (to avoid an initial request back): <script type="text/javascript" charset="utf-8"> <% ActiveRecord::Base.include_root_in_json = false -%> var objects = <%= @objects.to_json(:include => :other_objects) %>; ... Based on mouse (or touch) interaction I want to redirect to other parts of my app that are model specific (such as view, edit, delete, etc.). Rather than hard code the URLs in my JavaScript I want to generate them from Rails (which means it always adapts the latest routes). It seems like I have one of three options: Add an empty attr to the model that the controller fills in with the appropriate URL (we don't want to use routes in the model) before the JSON is generated Generate custom JSON where I add the different URLs manually Generate the URL as a template from Rails and replace the IDs in JavaScript as appropriate I am starting to lean towards #1 for ease of implementation and maintainability. Are there any other options that I am missing? Is #1 not the best? Thanks! Chris

  Read the article

• Pairs from single list

  - by Apalala

  Often enough, I've found the need to process a list by pairs. I was wondering which would be the pythonic and efficient way to do it, and found this on Google: pairs = zip(t[::2], t[1::2]) I thought that was pythonic enough, but after a recent discussion involving idioms versus efficiency, I decided to do some tests: import time from itertools import islice, izip def pairs_1(t): return zip(t[::2], t[1::2]) def pairs_2(t): return izip(t[::2], t[1::2]) def pairs_3(t): return izip(islice(t,None,None,2), islice(t,1,None,2)) A = range(10000) B = xrange(len(A)) def pairs_4(t): # ignore value of t! t = B return izip(islice(t,None,None,2), islice(t,1,None,2)) for f in pairs_1, pairs_2, pairs_3, pairs_4: # time the pairing s = time.time() for i in range(1000): p = f(A) t1 = time.time() - s # time using the pairs s = time.time() for i in range(1000): p = f(A) for a, b in p: pass t2 = time.time() - s print t1, t2, t2-t1 These were the results on my computer: 1.48668909073 2.63187503815 1.14518594742 0.105381965637 1.35109519958 1.24571323395 0.00257992744446 1.46182489395 1.45924496651 0.00251388549805 1.70076990128 1.69825601578 If I'm interpreting them correctly, that should mean that the implementation of lists, list indexing, and list slicing in Python is very efficient. It's a result both comforting and unexpected. Is there another, "better" way of traversing a list in pairs? Note that if the list has an odd number of elements then the last one will not be in any of the pairs. Which would be the right way to ensure that all elements are included? I added these two suggestions from the answers to the tests: def pairwise(t): it = iter(t) return izip(it, it) def chunkwise(t, size=2): it = iter(t) return izip(*[it]*size) These are the results: 0.00159502029419 1.25745987892 1.25586485863 0.00222492218018 1.23795199394 1.23572707176 Results so far Most pythonic and very efficient: pairs = izip(t[::2], t[1::2]) Most efficient and very pythonic: pairs = izip(*[iter(t)]*2) It took me a moment to grok that the first answer uses two iterators while the second uses a single one. To deal with sequences with an odd number of elements, the suggestion has been to augment the original sequence adding one element (None) that gets paired with the previous last element, something that can be achieved with itertools.izip_longest().

  Read the article

• sigleton EXC_BAD_ACCESS

  - by lclaud

  Hi, so I have a class that I decleare as a singleton and in that class I have a NSMutableArray that contains some NSDictionaries with some key/value pairs in them. The trouble is it doesn't work and I dont't know why... I mean it crashes with EXC_BAD_ACCESS but i don't know where. I followed the code and it did create a new array on first add, made it to the end of the funtion ..and crashed ... @interface dataBase : NSObject { NSMutableArray *inregistrari; } @property (nonatomic,retain) NSMutableArray *inregistrari; -(void)adaugaInregistrareCuData:(NSDate *)data siValoare:(NSNumber *)suma caVenit:(BOOL)venit cuDetaliu:(NSString *)detaliu; -(NSDictionary *)raportIntreData:(NSDate *)dataInitiala siData:(NSDate *)dataFinala; -(NSArray *)luniDisponibileIntreData:(NSDate *)dataInitiala siData:(NSDate *)dataFinala; -(NSArray *)aniDisponibiliIntreData:(NSDate *)dataInitiala siData:(NSDate *)dataFinala; -(NSArray *)vectorDateIntreData:(NSDate *)dataI siData:(NSDate *)dataF; -(void)salveazaInFisier; -(void)incarcaDinFisier; + (dataBase *)shareddataBase; @end And here is the .m file #import "dataBase.h" #import "SynthesizeSingleton.h" @implementation dataBase @synthesize inregistrari; SYNTHESIZE_SINGLETON_FOR_CLASS(dataBase); -(void)adaugaInregistrareCuData:(NSDate *)data siValoare:(NSNumber *)suma caVenit:(BOOL)venit cuDetaliu:(NSString *)detaliu{ NSNumber *v=[NSNumber numberWithBool:venit]; NSArray *input=[NSArray arrayWithObjects:data,suma,v,detaliu,nil]; NSArray *keys=[NSArray arrayWithObjects:@"data",@"suma",@"venit",@"detaliu",nil]; NSDictionary *inreg=[NSDictionary dictionaryWithObjects:input forKeys:keys]; if(inregistrari == nil) { inregistrari=[[NSMutableArray alloc ] initWithObjects:inreg,nil]; }else { [inregistrari addObject:inreg]; } [inreg release]; [input release]; [keys release]; } It made it to the end of that adaugaInregistrareCuData ... ok . said the array had one object ... and then crashed

  Read the article

• NSTimer as a timeout mechanism

  - by alexantd

  I'm pretty sure this is really simple, and I'm just missing something obvious. I have an app that needs to download data from a web service for display in a UITableView, and I want to display a UIAlertView if the operation takes more than X seconds to complete. So this is what I've got (simplified for brevity): MyViewController.h @interface MyViewController : UIViewController <UITableViewDelegate, UITableViewDataSource> { NSTimer *timer; } @property (nonatomic, retain) NSTimer *timer; MyViewController.m @implementation MyViewController @synthesize timer; - (void)viewDidLoad { timer = [NSTimer scheduledTimerWithTimeInterval:20 target:self selector:@selector(initializationTimedOut:) userInfo:nil repeats:NO]; [self doSomethingThatTakesALongTime]; [timer invalidate]; } - (void)doSomethingThatTakesALongTime { sleep(30); // for testing only // web service calls etc. go here } - (void)initializationTimedOut:(NSTimer *)theTimer { // show the alert view } My problem is that I'm expecting the [self doSomethingThatTakesALongTime] call to block while the timer keeps counting, and I'm thinking that if it finishes before the timer is done counting down, it will return control of the thread to viewDidLoad where [timer invalidate] will proceed to cancel the timer. Obviously my understanding of how timers/threads work is flawed here because the way the code is written, the timer never goes off. However, if I remove the [timer invalidate], it does.

  Read the article

• php OOP function declarations

  - by kris

  I'm a big fan of OOP in php, but i feel like defining class methods gets disorganized so fast. I have a pretty good background in OOP in C++, and i am pretty comfortable with how it is handled there, and am curious if there are ways to do it similarly in php. To be more specific, here is what i mean. I like how in C++ you can define a class header (myclass.h) and then define the actual details of the functions in the implementation file (myclass.cc). Ive found that this can easily be replicated using interfaces in php, but i havent found a good solution for the following: I like to organize my code in C++ in different files based on how they are accessed, so for example, public methods that can be called outside of the class would be in 1 place, and private methods would be organized somewhere else - this is personal preference. Ive tried to define class methods in php like: private function MyPHPClass::myFunction(){ } when the definition isnt directly inside the class block( { } ), but i havent had any success doing this. Ive been through all of the pages on php.net, but couldnt find anything like this. Im assuming that there is no support for something like this, but thought i would ask anyway. thanks

  Read the article

• Any merit to a lazy-ish juxt function?

  - by NielsK

  In answering a question about a function that maps over multiple functions with the same arguments (A: juxt), I came up with a function that basically took the same form as juxt, but used map: (defn could-be-lazy-juxt [& funs] (fn [& args] (map #(apply %1 %2) funs (repeat args)))) => ((juxt inc dec str) 1) [2 0 "1"] => ((could-be-lazy-juxt inc dec str) 1) (2 0 "1") => ((juxt * / -) 6 2) [12 3 4] => ((could-be-lazy-juxt * / -) 6 2) (12 3 4) As posted in the original question, I have little clue about the laziness or performance of it, but timing in the REPL does suggest something lazy-ish is going on. => (time (apply (juxt + -) (range 1 100))) "Elapsed time: 0.097198 msecs" [4950 -4948] => (time (apply (could-be-lazy-juxt + -) (range 1 100))) "Elapsed time: 0.074558 msecs" (4950 -4948) => (time (apply (juxt + -) (range 10000000))) "Elapsed time: 1019.317913 msecs" [49999995000000 -49999995000000] => (time (apply (could-be-lazy-juxt + -) (range 10000000))) "Elapsed time: 0.070332 msecs" (49999995000000 -49999995000000) I'm sure this function is not really that quick (the print of the outcome 'feels' about as long in both). Doing a 'take x' on the function only limits the amount of functions evaluated, which probably is limited in it's applicability, and limiting the other parameters by 'take' should be just as lazy in normal juxt. Is this juxt really lazy ? Would a lazy juxt bring anything useful to the table, for instance as a compositing step between other lazy functions ? What are the performance (mem / cpu / object count / compilation) implications ? Is that why the Clojure juxt implementation is done with a reduce and returns a vector ? Edit: Somehow things can always be done simpler in Clojure. (defn could-be-lazy-juxt [& funs] (fn [& args] (map #(apply % args) funs)))

  Read the article

• Visual Studio - Edit source code located in a database

  - by mfeingold

  I am building something similar to Server Explorer for Apache CouchDB. One of the things necessary is to be able to edit CouchDB view definitions which in CouchDB are JavaScript functions. How can I trick Visual Studio into using my object to retrieve and save the content of the JavaScript function but still use the rest of it - I am happy with editor itself and have no intention of writing my own Editor/Language Service, etc. The latter would be much bigger effort than what this project warrants Edit After more digging I am still stuck. Here is what I know: IVsUIShellOpenDocument interface provides a method OpenStandardEditor which can be used to open the standard Visual Studio editor. As one of the parameters this method takes a Pointer to the IUnknown interface of the document data object. This object is supposed to implement several interfaces described in many places all over the MSDN. Visual Studio SDK also provides a 'sample' implementation of the document data object VsTextBufferClass. I can create an instance of this class and when I pass the pointer to the instance to the OpenStandardEditor I can see my editor and it seems to work ok. When I try to implement my own class implementing the same interfaces (IVsTextBuffer, VsTextBuffer, IVsTextLines) OpenStandardEditor method returns success, but VS bombs out on call editor.Show() with an access violation. My suspicion is that VsTextBufferClass also implements some other interface(s) but not in C# way but rather in the good old COM way. I just do not know which one(s). Any thoughts?

  Read the article

• How do I send the mutable string to the NSTextField properly?

  - by Merle

  So I have all this code that I have debugged and it seems to be fine. I made a mutable string and for some reason I can not get it to be displayed on my label. the debugger says "2010-04-22 22:50:26.126 Fibonacci[24836:10b] * -[NSTextField setString:]: unrecognized selector sent to instance 0x130150" What is wrong with this? When I just send the string to NSLog, it comes out fine. here's all my code, any help would be appreciated. "elementNum" is a comboBox and "display" is a Label. Thanks #import "Controller.h" @implementation Controller - (IBAction)computeNumber:(id)sender { int x = 1; int y = 1; NSMutableString *numbers = [[NSMutableString alloc] init]; [numbers setString:@"1, 1,"]; int num = [[elementNum objectValueOfSelectedItem]intValue]; int count = 1; while (count<=num) { int z = y; y+=x; x=z; [numbers appendString:[NSString stringWithFormat:@" %d,", y]]; count++; } [display setString:numbers]; NSLog(numbers); } @end `

  Read the article

• Naive Bayesian classification (spam filtering) - Doubt in one calculation? Which one is right? Plz c

  - by Microkernel

  Hi guys, I am implementing Naive Bayesian classifier for spam filtering. I have doubt on some calculation. Please clarify me what to do. Here is my question. In this method, you have to calculate P(S|W) - Probability that Message is spam given word W occurs in it. P(W|S) - Probability that word W occurs in a spam message. P(W|H) - Probability that word W occurs in a Ham message. So to calculate P(W|S), should I do (1) (Number of times W occuring in spam)/(total number of times W occurs in all the messages) OR (2) (Number of times word W occurs in Spam)/(Total number of words in the spam message) So, to calculate P(W|S), should I do (1) or (2)? (I thought it to be (2), but I am not sure, so plz clarify me) I am refering http://en.wikipedia.org/wiki/Bayesian_spam_filtering for the info by the way. I got to complete the implementation by this weekend :( Thanks and regards, MicroKernel :) @sth: Hmm... Shouldn't repeated occurrence of word 'W' increase a message's spam score? In the your approach it wouldn't, right?. Lets take a scenario and discuss... Lets say, we have 100 training messages, out of which 50 are spam and 50 are Ham. and say word_count of each message = 100. And lets say, in spam messages word W occurs 5 times in each message and word W occurs 1 time in Ham message. So total number of times W occuring in all the spam message = 5*50 = 250 times. And total number of times W occuring in all Ham messages = 1*50 = 50 times. Total occurance of W in all of the training messages = (250+50) = 300 times. So, in this scenario, how do u calculate P(W|S) and P(W|H) ? Naturally we should expect, P(W|S) P(W|H)??? right. Please share your thought...

  Read the article

• How frequently IP packets are fragmented at the source host?

  - by Methos

  I know that if IP payload MTU then routers usually fragment the IP packet. Finally all the fragmented packets are assembled at the destination using the fields IP-ID, IP fragment offsets and fragmentation flags. Max length of IP payload is 64K. Thus its very plausible for L4 to hand over payload which is 64K. If the L2 protocol is Ethernet, which often is the case, then the MTU will be about 1600 bytes. Hence IP packet will be fragmented at the source host itself. However, a quick search about IP implementation in Linux tells me that in recent kernels, L4 protocols are fragment friendly i.e. they try to save the fragmentation work for IP by handing over buffers of size which is close to MTU. Considering these two facts, I am wondering about how frequently does the IP packet gets fragmented at the source host itself. Does it occur sometimes/rarely/never? Does anyone know if there are exceptions to the rule of fragmentation in linux kernel (i.e. are there situations where L4 protocols are not fragment friendly)? How is this handled in other common OSes like windows? In general how frequently IP packets are fragmented?

  Read the article

• Easiest way to plot values as symbols in scatter plot?

  - by AllenH

  In an answer to an earlier question of mine regarding fixing the colorspace for scatter images of 4D data, Tom10 suggested plotting values as symbols in order to double-check my data. An excellent idea. I've run some similar demos in the past, but I can't for the life of me find the demo I remember being quite simple. So, what's the easiest way to plot numerical values as the symbol in a scatter plot instead of 'o' for example? Tom10 suggested plt.txt(x,y,value)- and that is the implementation used in a number of examples. I however wonder if there's an easy way to evaluate "value" from my array of numbers? Can one simply say: str(valuearray) ? Do you need a loop to evaluate the values for plotting as suggested in the matplotlib demo section for 3D text scatter plots? Their example produces: However, they're doing something fairly complex in evaluating the locations as well as changing text direction based on data. So, is there a cute way to plot x,y,C data (where C is a value often taken as the color in the plot data- but instead I wish to make the symbol)? Again, I think we have a fair answer to this- I just wonder if there's an easier way?

  Read the article

• What's wrong with my HtmlHelper?

  - by Dejan.S

  I done a htmlhelper but I can not get it to work tho. I did like I seen on different tutorials. my MenuItemHelper static Class public static string MenuItem(this HtmlHelper helper, string linkText, string actionName, string controllerName) { var currentControllerName = (string)helper.ViewContext.RouteData.Values["controller"]; var currentActionName = (string)helper.ViewContext.RouteData.Values["action"]; var sb = new StringBuilder(); if (currentControllerName.Equals(controllerName, StringComparison.CurrentCultureIgnoreCase) && currentActionName.Equals(actionName, StringComparison.CurrentCultureIgnoreCase)) sb.Append("<li class=\"selected\">"); else sb.Append("<li>"); sb.Append(helper.ActionLink(linkText, actionName, controllerName)); sb.Append("</li>"); return sb.ToString(); } import namespace <%@ Import Namespace="MYAPP.Web.App.Helpers" %> Implementation on my master.page <%= Html.MenuItem("TEST LINK", "About", "Site") %> Errormessage I get Method not found: 'System.String System.Web.Mvc.Html.LinkExtensions.ActionLink(System.Web.Mvc.HtmlHelper, System.String, System.String, System.String)

  Read the article

• Circular dependency with generics

  - by devoured elysium

  I have defined the following interface: public interface IStateSpace<State, Action> where State : IState where Action : IAction<State, Action> // <-- this is the line that bothers me { void SetValueAt(State state, Action action); Action GetValueAt(State state); } Basically, an IStateSpace interface should be something like a chess board, and in each position of the chess board you have a set of possible movements to do. Those movements here are called IActions. I have defined this interface this way so I can accommodate for different implementations: I can then define concrete classes that implement 2D matrix, 3D matrix, graphs, etc. public interface IAction<State, Action> { IStateSpace<State, Action> StateSpace { get; } } An IAction, would be to move up(this is, if in (2, 2) move to (2, 1)), move down, etc. Now, I'll want that each action has access to a StateSpace so it can do some checking logic. Is this implementation correct? Or is this a bad case of a circular dependence? If yes, how to accomplish "the same" in a different way? Thanks

  Read the article

< Previous Page | 258 259 260 261 262 263 264 265 266 267 268 269  | Next Page >