Search Results

Search found 5861 results on 235 pages for 'rich pixel vector'.

Page 204/235 | < Previous Page | 200 201 202 203 204 205 206 207 208 209 210 211  | Next Page >

• Certain transformations in Open Inventor(Coin3D)

  - by Marc

  Hi, I am quite new to Open Inventor(Coin3D) and have the following problem: I have a SoSelection holding a root node(also SoSeparator). And the root node holds a number of SoSeparator nodes. Each of these SoSeparator nodes holds a SoTransform node and a SoCube node. When I select one cube node I want all other cubes within a certain distance to the selected cube to arrange in a circle arround the selected cube. (Moreover all of the cubes should be on a plane than) An additional information: My cubes are always oriented in the camera direction with (cubeTransform_-rotation.connectFrom(&camera_-orientation) Assuming the selected cube is the center of the circle, how do I translate the other cubes in a circle on a plane(perpendicular to the vector between the selected cube and the camera)? Especially how do I find coordinates on the plain on which the circle should be which have a certain distance from the Axis (from center cube to camera). What I already did is to search for the for all cubes within a certain distance as soon as one cube is selected. As a result I already have the required separators (which are holding the according SoTransforms and SoCubes) in a SoPathList. Now I want to arrange the cubes by modifing the according SoTransform-translation values. Regards Mark

  Read the article

• What AOP tools exist for doing aspect-oriented programming at the assembly language level against x8

  - by JohnnySoftware

  Looking for a tool I can use to do aspect-oriented programming at the assembly language level. For experimentation purposes, I would like the code weaver to operate native application level executable and dynamic link libraries. I have already done object-oriented AOP. I know assembly language for x86 and so forth. I would like to be able to do logging and other sorts of things using the familiar before/after/around constructs. I would like to be able to specify certain instructions or sequences/patterns of consecutive instructions as what to do a pointcut on since assembly/machine language is not exactly the most semantically rich computer language on the planet. If debugger and linker symbols are available, naturally, I would like to be able to use them to identify subroutines' entry points , branch/call/jump target addresses, symbolic data addresses, etc. I would like the ability to send notifications out to other diagnostic tools. Thus, support for sending data through connection-oriented sockets and datagrams is highly desirable. So is normal logging to files, UI, etc. This can be done using the action part of an aspect to make a function call, but then there are portability issues so the tool needs to support a flexible, well-abstracted logging/notifying mechanism with a clean, simple yet flexible. The goal is rapid-QA. The idea is to be able to share aspect source code braodly within communties as well as publicly. So, there needs to be a declarative security policy file that users can share. This insures that nothing untoward that is hidden directly or indirectly in an aspect source file slips by the execution manager. The policy file format needs to be simple to read, write, modify, understand, type-in, edit, and generate. Sort of like Java .policy files. Think the exact opposite of anything resembling XML Schema files and you get the idea. Is there such a tool in existence already?

  Read the article

• Difficulties using custom control - RichTextEditor

  - by Chris

  I am working on a school project that uses ASP.NET. I found this TextEditor control ( http://blogs.msdn.com/kirti/archive/2007/11/10/rich-text-editor-is-here.aspx ) that I am trying to include but it isn't working. The error I am getting is: Error Rendering Control - TextEditor. An unhandled exception has occurred. Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index. I see this error when I go Design part of the editor. I just don't understand this error at all. Also I am a lil bit confused as there is no parameter called index. :( What I have done is reference the binary in my project and then on the page I am trying to use it have registered its namespace and assembly with this line: <%@ Register Assembly="RichTextEditor" Namespace="AjaxControls" TagPrefix="rtt" %> I then go ahead and try to add the control to the page with this line of code: <rtt:richtexteditor ID="TextEditor" Theme="Blue" runat="server" /> Any help would be much appreciated. I haven't done anything like add a custom control before.

  Read the article

• iphone encryption not working

  - by Futur

  I have this encryption/decryption implemented and executes with no error, but i am unable to decrypt the data and im not sure whether the data is encrypted, kindly help. - (NSData *)AES256EncryptWithKey:(NSString *)key { char keyPtr[kCCKeySizeAES256+1]; bzero(keyPtr, sizeof(keyPtr)); [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding]; NSUInteger dataLength = [strData length]; data = [[NSData alloc] init]; data = [strData dataUsingEncoding:NSUTF8StringEncoding]; size_t bufferSize = dataLength + kCCBlockSizeAES128; void *pribuffer = malloc(bufferSize); size_t numBytesEncrypted = 0; CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding, keyPtr, kCCKeySizeAES256, NULL /* initialization vector (optional) */, [data bytes], dataLength, /* input */ [data bytes], bufferSize, /* output */ &numBytesEncrypted); if (cryptStatus == kCCSuccess) { return [NSData dataWithBytesNoCopy:data length:numBytesEncrypted]; }} The decryption is : -(NSData *)AES256DecryptWithKey:(NSString *)key andForData:(NSData *)objDataObject { char keyPtr[kCCKeySizeAES256+1]; bzero(keyPtr, sizeof(keyPtr)); [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding]; NSUInteger dataLength = [objDataObject length]; size_t bufferSize = dataLength + kCCBlockSizeAES128; void *buffer = malloc(bufferSize); size_t numBytesDecrypted = 0; CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding, keyPtr, kCCKeySizeAES256, NULL, [objDataObject bytes], dataLength, [objDataObject bytes], bufferSize, &numBytesDecrypted); if (cryptStatus == kCCSuccess) { return [NSData dataWithBytesNoCopy:objDataObject length:numBytesDecrypted]; } } i call the above methods like this: CryptoClass *obj = [CryptoClass new]; NSData *objData = [obj AES256EncryptWithKey:@"hell"]; NSData *val = [obj AES256DecryptWithKey:@"hell" andForData:objData ]; NSLog(@"decrypted string is : %@ AND LENGTH IS %d",[val description],[val length]); Decryption doesnt seem to happen at all and the encryption - i am not sure about it, kindly help me here.

  Read the article

• Instantiating class with custom allocator in shared memory

  - by recipriversexclusion

  I'm pulling my hair due to the following problem: I am following the example given in boost.interprocess documentation to instantiate a fixed-size ring buffer buffer class that I wrote in shared memory. The skeleton constructor for my class is: template<typename ItemType, class Allocator > SharedMemoryBuffer<ItemType, Allocator>::SharedMemoryBuffer( unsigned long capacity ){ m_capacity = capacity; // Create the buffer nodes. m_start_ptr = this->allocator->allocate(); // allocate first buffer node BufferNode* ptr = m_start_ptr; for( int i = 0 ; i < this->capacity()-1; i++ ) { BufferNode* p = this->allocator->allocate(); // allocate a buffer node } } My first question: Does this sort of allocation guarantee that the buffer nodes are allocated in contiguous memory locations, i.e. when I try to access the n'th node from address m_start_ptr + n*sizeof(BufferNode) in my Read() method would it work? If not, what's a better way to keep the nodes, creating a linked list? My test harness is the following: // Define an STL compatible allocator of ints that allocates from the managed_shared_memory. // This allocator will allow placing containers in the segment typedef allocator<int, managed_shared_memory::segment_manager> ShmemAllocator; //Alias a vector that uses the previous STL-like allocator so that allocates //its values from the segment typedef SharedMemoryBuffer<int, ShmemAllocator> MyBuf; int main(int argc, char *argv[]) { shared_memory_object::remove("MySharedMemory"); //Create a new segment with given name and size managed_shared_memory segment(create_only, "MySharedMemory", 65536); //Initialize shared memory STL-compatible allocator const ShmemAllocator alloc_inst (segment.get_segment_manager()); //Construct a buffer named "MyBuffer" in shared memory with argument alloc_inst MyBuf *pBuf = segment.construct<MyBuf>("MyBuffer")(100, alloc_inst); } This gives me all kinds of compilation errors related to templates for the last statement. What am I doing wrong?

  Read the article

• How can I change the precision of printing with the stl?

  - by mmr

  This might be a repeat, but my google-fu failed to find it. I want to print numbers to a file using the stl with the number of decimal places, rather than overall precision. So, if I do this: int precision = 16; std::vector<double> thePoint(3); thePoint[0] = 86.3671436; thePoint[0] = -334.8866574; thePoint[0] = 24.2814; ofstream file1(tempFileName, ios::trunc); file1 << std::setprecision(precision) << thePoint[0] << "\\" << thePoint[1] << "\\" << thePoint[2] << "\\"; I'll get numbers like this: 86.36714359999999\-334.8866574\24.28140258789063 What I want is this: 86.37\-334.89\24.28 In other words, truncating at two decimal points. If I set precision to be 4, then I'll get 86.37\-334.9\24.28 ie, the second number is improperly truncated. I do not want to have to manipulate each number explicitly to get the truncation, especially because I seem to be getting the occasional 9 repeating or 0000000001 or something like that that's left behind. I'm sure there's something obvious, like using the printf(%.2f) or something like that, but I'm unsure how to mix that with the stl << and ofstream.

  Read the article

• In which order is model binding and validation done in ASP.NET MVC 2?

  - by Simon Bartlett

  I am using ASP.NET MVC 2, and am using a view-model per view approach. I am also using Automapper to map properties from my domain-model to the view-model. Take this example view-model (with Required data annotation attributes for validation purposes): public class BlogPost_ViewModel { public int Id { get; set; } [Required] public string Title { get; set; } [Required] public string Text { get; set; } } In the post editor view I am using a rich text editor (CKeditor). Because CKeditor is a HTML editor, I ideally need CKeditor to HTMLencode the user's input when the form is submitted, so that ASP.NET's input validation does not complain. This is not a problem as CKeditor has this functionality built in, however I need CKeditor's output decoded before mapping back to the domain object (via Automapper). I am wanting to add a new property (to the view-model above) to solve this, as follows: public string HTMLEncodedText { get { return HTMLEncode(Text); } set { Text = HTMLDecode(value); } } I can then bind this property to CKeditor in the view, but still use Automapper to map the 'Text' property in the controller - all without having to turn input-validation off. My question is: do you know how the model binding and validation process in ASP.NET MVC 2 works? Are all model properties binded before validation is carried out? Or is each individual property get validated when it is being set. I think ideally for my idea to work, all properties need to be set before the model is validated.

  Read the article

• How to implement RSA-CBC?(I have uploaded the request document)

  - by tq0fqeu

  I don't konw more about cipher, I just want to implement RSA-CBC which maybe mean that the result of RSA encrypt in CBC mode, and I have implemented RSA. any code languages will be ok, java will be appreciated thx I copy the request as follow(maybe has spelling wrong), but that's French I don't konw that: Pr´esentation du mini-projet Le but du mini-projet est d’impl´ementer une version ´el´ementaire du chi?rement d’un bloc par RSA et d’inclure cette primitive dans un systeme de chi?rement par bloc avec chaˆinage de blocs et IV (Initial Vector ) al´eatoire. Dans ce systeme, un texte clair (`a chi?rer) est d´ecompos´e en blocs de taille t (?x´ee par l’utilisa- teur), chaque bloc (clair) est chi?r´e par RSA en un bloc crypt´e de mˆeme taille, puis le cryptogramme associ´e au texte clair initial est obtenu en chaˆinant les blocs crypt´es par la m´ethode CBC (cipher- block chaining) d´ecrite dans le cours (voir poly “Block Ciphers”) Votre programme devra demander a l’utilisateur la taille t, puis, apres g´en´eration des cl´es publique et priv´ee, lui proposer de chi?rer ou d´echi?rer un (court) ?chier ASCII. Il est indispensable que votre programme soit au moins capable de traiter le cas (tres peu r´ealiste du point de vue de la s´ecurit´e) t = 32. Pour les traiter des blocs plus grands, il vous faudra impl´ementer des routines d’arithm´etique multi-pr´ecision ; pour cela, je vous conseille de faire appela des bibliotheques libres comme GMP (GNU Multiprecision Library). Pour la g´en´eration al´eatoire des nombres premiers p et q, vous pouvez ´egalement faire appela des bibliotheques sp´ecialis´ees,a condition de me donner toutes les pr´ecisions n´ecessaires. Vous devez m’envoyer (avant une date qui reste a ?xer)a mon adresse ´electronique ([email protected]) un courriel (sujet : [MI1-crypto] : devoir, corps du message : les noms des ´etudiants ayant travaill´e sur le mini-projet) auquel sera attach´e un dossier compress´e regroupant vos sources C ou Java comment´ees, votre programme ex´ecutable, et un ?chier texte ou PDF donnant toutes les pr´ecisions sur les biblioth`eques utilis´ees, vos choix algorithmiques et d’impl´ementation, et les raisons de ces choix (complexit´e algorithmique, robus- tesse, facilit´e d’impl´ementation, etc.). Vous pouvez travailler en binˆome ou en trinˆome, mais je serai nettement plus exigeant avec les trinˆomes I have uploaded the request at http://uploading.com/files/22emmm6b/enonce_projet.pdf/ thx

  Read the article

• LocalAlloc and LocalRealloc usage

  - by PaulH

  I have a Visual Studio 2008 C++ Windows Mobile 6 application where I'm using a FindFirst() / FindNext() style API to get a collection of items. I do not know how many items will be in the list ahead of time. So, I would like to dynamically allocate an array for these items. Normally, I would use a std::vector<>, but, for other reasons, that's not an option for this application. So, I'm using LocalAlloc() and LocalReAlloc(). What I'm not clear on is if this memory should be marked fixed or moveable. The application runs fine either way. I'm just wondering what's 'correct'. int count = 0; INFO_STRUCT* info = ( INFO_STRUCT* )LocalAlloc( LHND, sizeof( INFO_STRUCT ) ); while( S_OK == GetInfo( &info[ count ] ) { ++count; info = ( INFO_STRUCT* )LocalRealloc( info, sizeof( INFO_STRUCT ) * ( count + 1 ), LHND ); } if( count > 0 ) { // use the data in some interesting way... } LocalFree( info ); Thanks, PaulH

  Read the article

• How does real-time collaboration with multiple clients work in a system using operation transformati

  - by Saikat Chakrabarti

  I just finished reading High-Latency, Low-Bandwidth Windowing in the Jupiter Collaboration System and I mostly followed everything until part 6: global consistency. This part describes how the system described in the paper can be extended to accomodate for multiple clients connected to the server. However, the explanation is very short and essentially says the system will work if the central server merely forwards client messages to all the other clients. I don't really understand how this works though. What state vector would be sent in the message that is sent to all the other clients? Does the server maintain separate state vectors for each client? Does it maintain a separate copy of the widgets locally for each client? The simple example I can think of is this setup: imagine client A, server, and client B with client A and client B both connected to the server. To start, all three have the state object "ABCD". Then, client A sends the message "insert character F at position 0" at the same time client B sends the message "insert character G at position 0" to the server. It seems like simply relaying client A's message to client B and vice versa doesn't actually handle this case. So what exactly does the server do?

  Read the article

• 1D Function into 2D Function Interpolation

  - by Drazick

  Hello. I have a 1D function which I want to interpolate into 2D function. I know the function should have "Polar Symmetry". Hence I use the following code (Matlab Syntax): Assuming the 1D function is LSF of the length 15. [x, y] = meshgrid([-7:7]); r = sqrt(x.^2 + y.^2); PSF = interp1([-7:7], LSF, r(:)); % Sometimes using 'spline' option, same results. PSF = reshape(PSF, [7, 7]); I have few problems: 1. Got some overshoot at the edges (As there some Extrapolation). 2. Can't enforce some assumptions (Monotonic, Non Negative). Is there a better Interpolation method for those circumstances? I couldn't find "Lanczos" based interpolation I can use the same way as interp1 (For a certain vector of points, in "imresize" you can only set the length). Is there such function anywhere? Has anyone encountered a function which allows enforcing some assumptions (Monotonically Decreasing, Non Negative, etc..). Thanks.

  Read the article

• [ASP.NET] Difficulties using custom control - RichTextEditor

  - by Chris

  I am working on a school project that uses ASP.NET. I found this TextEditor control ( http://blogs.msdn.com/kirti/archive/2007/11/10/rich-text-editor-is-here.aspx ) that I am trying to include but it isn't working. The error I am getting is: Error Rendering Control - TextEditor. An unhandled exception has occurred. Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index. I see this error when I go Design part of the editor. I just don't understand this error at all. Also I am a lil bit confused as there is no parameter called index. :( What I have done is reference the binary in my project and then on the page I am trying to use it have registered its namespace and assembly with this line: <%@ Register Assembly="RichTextEditor" Namespace="AjaxControls" TagPrefix="rtt" %> I then go ahead and try to add the control to the page with this line of code: <rtt:richtexteditor ID="TextEditor" Theme="Blue" runat="server" /> Any help would be much appreciated. I haven't done anything like add a custom control before.

  Read the article

• Producing Mini Dumps for _caught_ SEH exceptions in mixed code DLL

  - by Assaf Lavie

  I'm trying to use code similar to clrdump to create mini dumps in my managed process. This managed process invokes C++/CLI code which invokes some native C++ static lib code, wherein SEH exceptions may be thrown (e.g. the occasional access violation). C# WinForms -> C++/CLI DLL -> Static C++ Lib -> ACCESS VIOLATION Our policy is to produce mini dumps for all SEH exceptions (caught & uncaught) and then translate them to C++ exceptions to be handled by application code. This works for purely native processes just fine; but when the application is a C# application - not so much. The only way I see to produce dumps from SEH exceptions in a C# process is to not catch them - and then, as unhandled exceptions, use the Application.ThreadException handler to create a mini dump. The alternative is to let the CLR translate the SEH exception into a .Net exception and catch it (e.g. System.AccessViolationException) - but that would mean no dump is created, and information is lost (stack trace information in Exception isn't as rich as the mini dump). So how can I handle SEH exceptions by both creating a minidump and translating the exception into a .Net exception so that my application may try to recover?

  Read the article

• Efficient alternative to merge() when building dataframe from json files with R?

  - by Bryan

  I have written the following code which works, but is painfully slow once I start executing it over thousands of records: require("RJSONIO") people_data <- data.frame(person_id=numeric(0)) json_data <- fromJSON(json_file) n_people <- length(json_data) for(lender in 1:n_people) { person_dataframe <- as.data.frame(t(unlist(json_data[[person]]))) people_data <- merge(people_data, person_dataframe, all=TRUE) } output_file <- paste("people_data",".csv") write.csv(people_data, file=output_file) I am attempting to build a unified data table from a series of json-formated files. The fromJSON() function reads in the data as lists of lists. Each element of the list is a person, which then contains a list of the attributes for that person. For example: [[1]] person_id name gender hair_color [[2]] person_id name location gender height [[...]] structure(list(person_id = "Amy123", name = "Amy", gender = "F", hair_color = "brown"), .Names = c("person_id", "name", "gender", "hair_color")) structure(list(person_id = "matt53", name = "Matt", location = structure(c(47231, "IN"), .Names = c("zip_code", "state")), gender = "M", height = 172), .Names = c("person_id", "name", "location", "gender", "height")) The end result of the code above is matrix where the columns are every person-attribute that appears in the structure above, and the rows are the relevant values for each person. As you can see though, some data is missing for some of the people, so I need to ensure those show up as NA and make sure things end up in the right columns. Further, location itself is a vector with two components: state and zip_code, meaning it needs to be flattened to location.state and location.zip_code before it can be merged with another person record; this is what I use unlist() for. I then keep the running master table in people_data. The above code works, but do you know of a more efficient way to accomplish what I'm trying to do? It appears the merge() is slowing this to a crawl... I have hundreds of files with hundreds of people in each file. Thanks! Bryan

  Read the article

• If I wanted to make a Pac-Man Game?

  - by SoulBeaver

  I am immediately placing this as a community wiki thing. I don't want to ask for help in programming yet or have even a specific question about programming, but rather the process and the resources needed to make such a game. To put it simply: My college friend and I decided to give ourselves a really big challenge to further our skills in programming. In six months time we want to show ourselves a Pac-Man game. Pac-Man will be AI-controlled like the Ghosts and whichever Pac-Man lives the longest after a set of tries wins. This isn't like anything we've done so far. The goal here, for me, isn't to create a perfect game, but to try and complete it, learn a whole bunch in the process. Even if I don't finish in the time, which is a good possibility, I would want to have at least tried this. So my question is this: How should I start preparing myself? I already have started vector math, matrices, all that fun stuff. My desired platform would be DirectX 9.0c; is that advisable? Keep in mind that this is not a preference just for this project, but I wish to have some kind of future in graphics develepment, so I want to pick a platform that is future-safe. As for the game development in general, what should I take into consideration? I have never done a real game before, so any and all advise to development of mid-scale projects( if this would be a mid-scale project ) is greatly appreciated. My main concerns are the pit-falls and demotivators. Sorry if the question is so vague. If it doesn't belong here, then I will remove it. Otherwise, any and all advise regarding making larger projects is greatly appreciated.

  Read the article

• shared memory STL maps

  - by user306963

  Hello, I am writing an Apache module in C++. I need to store the common data that all childs need to read as a portion of shared memory. Structure is kind of map of vectors, so I want to use STL map and vectors for it. I have written a shared allocator and a shared manager for the purpose, they work fine for vectors but not for maps, below is the example: typedef vector<CustomersData, SharedAllocator<CustomersData> > CustomerVector; CustomerVector spData; //this one works fine typedef SharedAllocator< pair< const int, CustomerVector > > PairAllocator; typedef map< int, CustomerVector, less<int>, PairAllocator > SharedMap; SharedMap spIndex; //this one doesn't work I get compile time errors when I try to use the second object (spIndex), which are someting like: ../SpatialIndex.h:97: error: '((SpatialIndex*)this)-SpatialIndex::spIndex' does not have class type It looks like the compiler cannot determine a type for SharedMap template type, which is strange in my opinion, it seems to me that all the template parameters have been specified. Can you help? Thanks Benvenuto

  Read the article

• HP QTP 10: Web-app testing - SomeObj.FireEvent("OnCLick") works, SomeObj.Object.FireEvent("OnCLick") doesn't

  - by Vitaliy

  Hi all! I have rich web app btuil with ExtJS. It has multi-select list control (created with JS+CSS). I want to click on some item in that list using HP QuickTest Pro 10 with Internet Explorer 6. I added that item into Object repository and found that following code works - selects some item: Browser("blah").Page("blah").WebElement("SomeElem").Click next code also works: Browser("blah").Page("blah").WebElement("SomeElem").FireEvent("onMouseDown") Browser("blah").Page("blah").WebElement("SomeElem").FireEvent("onMouseUp") Browser("blah").Page("blah").WebElement("SomeElem").FireEvent("onClick") But I want to select several items using shift+click method. I don't know to do that :( So I have a few questions: How can perform click with mouse on several web elements with Shift key pressed? I tried to do that using CreateEventObject + shiftKey set to true, but the method (perform fireEvent on DOM object, not object from Object repository) doesn't work: Browser("blah").Page("blah").WebElement("SomeElem").Object.FireEvent("onClick") What the difference between WebElement("Element").FireEvent("OnClick") and WebElement("Element").Object.FireEvent("OnClick") ? Plsease, help someone, because I fought with that problem a lot, but had no result. Thanks!

  Read the article

• What would be the safest way to store objects of classes derived from a common interface in a common

  - by Svenstaro

  I'd like to manage a bunch of objects of classes derived from a shared interface class in a common container. To illustrate the problem, let's say I'm building a game which will contain different actors. Let's call the interface IActor and derive Enemy and Civilian from it. Now, the idea is to have my game main loop be able to do this: // somewhere during init std::vector<IActor> ActorList; Enemy EvilGuy; Civilian CoolGuy; ActorList.push_back(EvilGuy); ActorList.push_back(CoolGuy); and // main loop while(!done) { BOOST_FOREACH(IActor CurrentActor, ActorList) { CurrentActor.Update(); CurrentActor.Draw(); } } ... or something along those lines. This example obviously won't work but that is pretty much the reason I'm asking here. I'd like to know: What would be the best, safest, highest-level way to manage those objects in a common heterogeneous container? I know about a variety of approaches (Boost::Any, void*, handler class with boost::shared_ptr, Boost.Pointer Container, dynamic_cast) but I can't decide which would be the way to go here. Also I'd like to emphasize that I want to stay away as far as possible from manual memory management or nested pointers. Help much appreciated :).

  Read the article

• Best practices on using URIs as parameter value in REST calls.

  - by dafmetal

  I am designing a REST API where some resources can be filtered through query parameters. In some cases, these filter values would be resources from the same REST API. This makes for longish and pretty unreadable URIs. While this is not too much of a problem in itself because the URIs are meant to be created and manipulated programmatically, it makes for some painful debugging. I was thinking of allowing shortcuts to URIs used as filter values and I wonder if this is allowed according to the REST architecture and if there are any best practices. For example: I have a resource that gets me Java classes. Then the following request would give me all Java classes: GET http://example.org/api/v1/class Suppose I want all subclasses of the Collection Java class, then I would use the following request: GET http://example.org/api/v1/class?has-supertype=http://example.org/api/v1/class/collection That request would return me Vector, ArrayList and all other subclasses of the Collection Java class. That URI is quite long though. I could already shorten it by allowing hs as an alias for has-supertype. This would give me: GET http://example.org/api/v1/class?hs=http://example.org/api/v1/class/collection Another way to allow shorter URIs would be to allow aliases for URI prefixes. For example, I could define class as an alias for the URI prefix http://example.org/api/v1/class/. Which would give me the following possibility: GET http://example.org/api/v1/class?hs=class:collection Another possibility would be to remove the class alias entirely and always prefix the parameter value with http://example.org/api/v1/class/ as this is the only thing I would support. This would turn the request for all subtypes of Collection into: GET http://example.org/api/v1/class?hs=collection Do these "simplifications" of the original request URI still conform to the principles of a REST architecture? Or did I just go off the deep end?

  Read the article

• Solving problems involving more complex data structures with CUDA

  - by Nils

  So I read a bit about CUDA and GPU programming. I noticed a few things such that access to global memory is slow (therefore shared memory should be used) and that the execution path of threads in a warp should not diverge. I also looked at the (dense) matrix multiplication example, described in the programmers manual and the nbody problem. And the trick with the implementation seems to be the same: Arrange the calculation in a grid (which it already is in case of the matrix mul); then subdivide the grid into smaller tiles; fetch the tiles into shared memory and let the threads calculate as long as possible, until it needs to reload data from the global memory into shared memory. In case of the nbody problem the calculation for each body-body interaction is exactly the same (page 682): bodyBodyInteraction(float4 bi, float4 bj, float3 ai) It takes two bodies and an acceleration vectors. The body vector has four components it's position and the weight. When reading the paper, the calculation is understood easily. But what is if we have a more complex object, with a dynamic data structure? For now just assume that we have an object (similar to the body object presented in the paper) which has a list of other objects attached and the number of objects attached is different in each thread. How could I implement that without having the execution paths of the threads to diverge? I'm also looking for literature which explains how different algorithms involving more complex data structures can be effectively implemented in CUDA.

  Read the article

• 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?

  Read the article

• How Can I Generate Equivalent Output Using the CryptoAPI and the .NET Encryption (TripleDESCryptoSer

  - by S. Butts

  I have some C#/.NET code that encrypts and decrypts data using TripleDES encryption. It sticks to the sample code provided at MSDN pretty closely. The encryption piece looks like the following: TripleDESCryptoServiceProvider _desProvider = new TripleDESCryptoServiceProvider(); //bytes for key and initialization vector //keyBytes is 24 bytes of stuff, vectorBytes is 8 bytes of stuff byte[] keyBytes; byte[] vectorBytes; FileStream fStream = File.Open(locationOfFile, FileMode.Create, FileAccess.Write); CryptoStream cStream = new CryptoStream(fStream, _desProvider.CreateEncryptor(keyBytes, vectorBytes), CryptoStreamMode.Write); BinaryWriter bWriter = new BinaryWriter(cStream); //write out encrypted data //raw data is a few bytes of binary information byte[] rawData; bWriter.Write(rawData); With encrypting and decrypting in C#, this all works like a charm. The problem is I need to write a small Win32 utility that will duplicate the encryption above. I have tried several methods using the CryptoAPI, and I simply do not get output that the .NET piece can decrypt, no matter what I do. Can someone please tell me what the equivalent C++ code is that will produce the same output? I am not certain just what methods of the CryptoAPI the .NET functions use to encrypt the data. What options are used, and what method of generating the key is used? Before someone suggests that I just write it in C# anyway, or create some common library bridge for them, those options are unfortunately off the table. It really has to work in Win32 with .NET and without using a DLL. I have some leeway in changing the C# code. I apologize in advance if this is bone-headed, as I am new to encryption.

  Read the article

• ExecutorService - scaling

  - by Stanciu Alexandru-Marian

  I am trying to write a program in Java using ExecutorService and it's function invokeAll. My question is: does the invokeAll functions solve the tasks simultaneously? I mean, if i have two processors, there will be two workers in the same time? Because a can't make it to scale correct. It takes the same time to complete the problem if i give newFixedThreadPool(2) or 1. List<Future<PartialSolution>> list = new ArrayList<Future<PartialSolution>>(); Collection<Callable<PartialSolution>> tasks = new ArrayList<Callable<PartialSolution>>(); for(PartialSolution ps : wp) { tasks.add(new Map(ps, keyWords)); } list = executor.invokeAll(tasks); Map is a class that implements Callable and wp is a vector of Partial Solutions, a class that holds some informations in different times. Why doesn't it scale? What could be the problem? Thank you, Alex

  Read the article

• What would you like to correct and/or improve in this java implementation of Chain Of Responsibility

  - by Maciek Kreft

  package design.pattern.behavioral; import design.pattern.behavioral.ChainOfResponsibility.*; public class ChainOfResponsibility { public static class Chain { private Request[] requests = null; private Handler[] handlers = null; public Chain(Handler[] handlers, Request[] requests){ this.handlers = handlers; this.requests = requests; } public void start() { for(Request r : requests) for (Handler h : handlers) if(h.handle(r)) break; } } public static class Request { private int value; public Request setValue(int value){ this.value = value; return this; } public int getValue() { return value; } } public static class Handler<T1> { private Lambda<T1> lambda = null; private Lambda<T1> command = null; public Handler(Lambda<T1> condition, Lambda<T1> command) { this.lambda = condition; this.command = command; } public boolean handle(T1 request) { if (lambda.lambda(request)) command.lambda(request); return lambda.lambda(request); } } public static abstract class Lambda<T1>{ public abstract Boolean lambda(T1 request); } } class TestChainOfResponsibility { public static void main(String[] args) { new TestChainOfResponsibility().test(); } private void test() { new Chain(new Handler[]{ // chain of responsibility new Handler<Request>( new Lambda<Request>(){ // command public Boolean lambda(Request condition) { return condition.getValue() >= 600; } }, new Lambda<Request>(){ public Boolean lambda(Request command) { System.out.println("You are rich: " + command.getValue() + " (id: " + command.hashCode() + ")"); return true; } } ), new Handler<Request>( new Lambda<Request>(){ public Boolean lambda(Request condition) { return condition.getValue() >= 100; } }, new Lambda<Request>(){ public Boolean lambda(Request command) { System.out.println("You are poor: " + command.getValue() + " (id: " + command.hashCode() + ")"); return true; } } ), }, new Request[]{ new Request().setValue(600), // chaining method new Request().setValue(100), } ).start(); } }

  Read the article

• WPF Spellcheck Engine takes up too much memory.

  - by Matt H.

  Each datatemplate in my WPF ItemsControl contains FIVE custom bindable richtextbox controls. It is a data-driven app that for authoring multiple-choice questions -- The question and four answer choices must all support: 1) Spell check 2) Rich formatting (otherwise I'd use regular textboxes) The spell check object in .NET 4 has a Friend constructor that takes a single argument of owner As TextBoxBase This means every richtextbox in the ItemsControl has 5 Spellcheck objects! This is the problem -- every spell check engine is consuming about 500k memory. So after you favor in the spellcheck, bindings, additional controls in the DataTemplate, etc.. a single multi choice question consumes more than 3MB memory. Users with 100--200 questions will quickly see the App raise it's memory consumption to 500+ MB. Management is definitely not OK with this. Is there a way to minimimze this problem? The best suggestion I've heard is to enable/disable spellcheck if the richtextbox is in the ItemsControl's scrollviewer: I haven't gotten an answer to how to go about it: (http://stackoverflow.com/questions/2869012/possible-to-implement-an-isviewportvisible-dependencyproperty-for-an-item-in-an-i) Any good ideas?

  Read the article

< Previous Page | 200 201 202 203 204 205 206 207 208 209 210 211  | Next Page >