Search Results

Search found 9017 results on 361 pages for 'efficient storage'.

Page 312/361 | < Previous Page | 308 309 310 311 312 313 314 315 316 317 318 319  | Next Page >

• Starting with versioning mysql schemata without overkill. Good solutions?

  - by tharkun

  I've arrived at the point where I realise that I must start versioning my database schemata and changes. I consequently read the existing posts on SO about that topic but I'm not sure how to proceed. I'm basically a one man company and not long ago I didn't even use version control for my code. I'm on a windows environment, using Aptana (IDE) and SVN (with Tortoise). I work on PHP/mysql projects. What's a efficient and sufficient (no overkill) way to version my database schemata? I do have a freelancer or two in some projects but I don't expect a lot of branching and merging going on. So basically I would like to keep track of concurrent schemata to my code revisions. [edit] Momentary solution: for the moment I decided I will just make a schema dump plus one with the necessary initial data whenever I'm going to commit a tag (stable version). That seems to be just enough for me at the current stage.[/edit] [edit2]plus I'm now also using a third file called increments.sql where I put all the changes with dates, etc. to make it easy to trace the change history in one file. from time to time I integrate the changes into the two other files and empty the increments.sql[/edit]

  Read the article

• Using ARIMA to model and forecast stock prices using user-friendly stats program

  - by Brian

  Hi people, Can anyone please offer some insight into this for me? I'm coming from a functional magnetic resonance imaging research background where I analyzed a lot of time series data, and I'd like to analyze the time series of stock prices (or returns) by: 1) modeling a successful stock in a particular market sector and then cross-correlating the time series of this historically successful stock with that of other newer stocks to look for significant relationships; 2) model a stock's price time series and use forecasting (e.g., exponential smoothing) to predict future values of it. I'd like to use non-linear modeling methods (ARIMA and ARCH) to do this. Several questions: How often do ARIMA and ARCH modeling methods (given that the individual who implements them does so accurately) actually fit the stock time series data they target, and what is the optimal fit I can expect? Is the extent to which this model fits the data commensurate with the extent to which it predicts this stock time series' future values? Rather than randomly selecting stocks to compare or model, if profit is my goal, what is an efficient approach, if any, to selecting the stocks I'm going to analyze? Which stats program is the most user-friendly for this? Any thoughts on this would be great and would go a long way for me. Thanks, Brian

  Read the article

• Creating spotlight in OpenGL scene

  - by Victor Oliveira

  Im studying OpenGL and trying to create a spot light at my application. The code that Im using for my #vertex-shader is below: #:vertex-shader #{ #version 150 core in vec3 in_pos; in vec2 in_tc; out vec2 tc; glLightf(GL_LIGHT0, GL_SPOT_CUTOFF, 20.0f); GLfloat spot_direction[] = { -1.0, -1.0, 0.0 }; glLightfv(GL_LIGHT0, GL_SPOT_DIRECTION, spot_direction); glEnable(GL_LIGHT0); void main() { vec4 pos= vec4(vec3(1.0)*in_pos - vec3(1.0), 1.0); pos.z=0.0; gl_Position = pos; tc = in_tc; } } The thing is, everytime Im trying to run the code an Error that says: Type: other, Source: api, ID: 131169, Severity: low Message: Framebuffer detailed info: The driver allocated storage for renderbuffer 1. len = 157, written = 0 failed to compile vertex shader of deferred: directional info log for shader deferred: directional vertex info log for shader deferred: directional: ERROR: Unbound variable: when Specifications: Renderer: GeForce GTX 580/PCIe/SSE2 Version: 3.3.0 NVIDIA 319.17 GLSL: 3.30 NVIDIA via Cg compiler Status: Using GLEW 1.9.0 1024 x 768 OS: Linux debian I guess to create this spotlight is pretty much simple, but since Im really new to OpenGL I dont have a clue how to do it until now, even reading sources like: http://www.glprogramming.com/red/chapter05.html#name3 Read also in some place that light spots can get really hard to understand, but I cant avoid this step right now since Im following my lecture schedule. Could anybody help me?

  Read the article

• WPD on XP, Vista, and 7 (need to transfer photo and video files)

  - by Bradley Dean

  I need to transfer files (still photos and videos) from any portable device that a user may connect (still camera, video camera, mobile phone, etc.) I don't need to worry about plain storage devices as these have drive letters. And I only care about existing files, I don't care about live video, preview video, taking new pictures, etc. I originally tried WIA, which works great except it can not transfer video files. So then I tried WPD, following along with dimeby8's tutorial: http://blogs.msdn.com/b/dimeby8/archive/2006/09/27/774259.aspx I haven't gotten the transfer working yet (I'm converting it over to C#), but I can at least see the device and enumerate the files in Win7. In XP I get nothing. It's pointed out in this thread that WPD won't enumerate devices on XP (see Lisa O [MSFT]'s post): http://social.msdn.microsoft.com/Forums/en/windowssdk/thread/56459945-b757-45df-8c9f-4ebdbbb18a2c So WIA is out because it won't do video. And WPD is out because it won't do XP. Has anyone gotten this to work? Am I missing something simple here? Thanks.

  Read the article

• How do I efficiently write a "toggle database value" function in AJAX?

  - by AmbroseChapel

  Say I have a website which shows the user ten images and asks them to categorise each image by clicking on buttons. A button for "funny", a button for "scary", a button for "pretty" and so on. These buttons aren't exclusive. A picture can be both funny and scary. The user clicks the "funny" button. An AJAX request is sent off to the database to mark that image as funny. The "funny" button lights up, by assigning a class in the DOM to mark it as "on". But the user made a mistake. They meant to hit the next button over. They should click "funny" again to turn it off, right? At this point I'm not sure whats the most efficient way to proceed. The database knows that the "funny" flag is set, but it's inefficient to query the database every time a button is clicked to say, is this flag set or not, then go on with a second database call to toggle it. Should I infer the state of the database flag from the DOM, i.e. if that button has the class "on" then the flag must be set, and branch at that point? Or would it be better to have a data structure in Javascript in the page which duplicates the state of each image in the database, so that every time I set the database flag to true, I also set the value in the Javascript data to true and so on?

  Read the article

• If attacker has original data and encrypted data, can they determine the passphrase?

  - by Brad Cupit

  If an attacker has several distinct items (for example: e-mail addresses) and knows the encrypted value of each item, can the attacker more easily determine the secret passphrase used to encrypt those items? Meaning, can they determine the passphrase without resorting to brute force? This question may sound strange, so let me provide a use-case: User signs up to a site with their e-mail address Server sends that e-mail address a confirmation URL (for example: https://my.app.com/confirmEmailAddress/bill%40yahoo.com) Attacker can guess the confirmation URL and therefore can sign up with someone else's e-mail address, and 'confirm' it without ever having to sign in to that person's e-mail account and see the confirmation URL. This is a problem. Instead of sending the e-mail address plain text in the URL, we'll send it encrypted by a secret passphrase. (I know the attacker could still intercept the e-mail sent by the server, since e-mail are plain text, but bear with me here.) If an attacker then signs up with multiple free e-mail accounts and sees multiple URLs, each with the corresponding encrypted e-mail address, could the attacker more easily determine the passphrase used for encryption? Alternative Solution I could instead send a random number or one-way hash of their e-mail address (plus random salt). This eliminates storing the secret passphrase, but it means I need to store that random number/hash in the database. The original approach above does not require storage in the database. I'm leaning towards the the one-way-hash-stored-in-the-db, but I still would like to know the answer: does having multiple unencrypted e-mail addresses and their encrypted counterparts make it easier to determine the passphrase used?

  Read the article

• jsTree: How to create a new ID for the new added node?

  - by marknt15

  Hi, I can normally get the ID of the default tree nodes but my problem is onCreate then jsTree will add a new node but it doesn't have an ID. My question is how can I add an ID to the newly created tree node? What I'm thinking to do is adding the ID HTML attribute to the newly created tree node but how? I need to get the ID of all of the nodes because it will serve as a reference for the node's respective div storage. HTML code: <div class="demo" id="demo_1"> <ul> <li id="phtml_1" class="file"><a href="#"><ins>&nbsp;</ins>Root node 1</a></li> <li id="phtml_2" class="file"><a href="#"><ins>&nbsp;</ins>Root node 2</a></li> </ul> </div> JS code: $("#demo_1").tree({ ui : { theme_name : "apple" }, callback : { onrename : function (NODE, TREE_OBJ) { alert(TREE_OBJ.get_text(NODE)); alert($(NODE).attr('id')); } } }); Cheers, Mark

  Read the article

• efficiently determining if a polynomial has a root in the interval [0,T]

  - by user168715

  I have polynomials of nontrivial degree (4+) and need to robustly and efficiently determine whether or not they have a root in the interval [0,T]. The precise location or number of roots don't concern me, I just need to know if there is at least one. Right now I'm using interval arithmetic as a quick check to see if I can prove that no roots can exist. If I can't, I'm using Jenkins-Traub to solve for all of the polynomial roots. This is obviously inefficient since it's checking for all real roots and finding their exact positions, information I don't end up needing. Is there a standard algorithm I should be using? If not, are there any other efficient checks I could do before doing a full Jenkins-Traub solve for all roots? For example, one optimization I could do is to check if my polynomial f(t) has the same sign at 0 and T. If not, there is obviously a root in the interval. If so, I can solve for the roots of f'(t) and evaluate f at all roots of f' in the interval [0,T]. f(t) has no root in that interval if and only if all of these evaluations have the same sign as f(0) and f(T). This reduces the degree of the polynomial I have to root-find by one. Not a huge optimization, but perhaps better than nothing.

  Read the article

• Would it be possible to have a UTF-8-like encoding limited to 3 bytes per character?

  - by dan04

  UTF-8 requires 4 bytes to represent characters outside the BMP. That's not bad; it's no worse than UTF-16 or UTF-32. But it's not optimal (in terms of storage space). There are 13 bytes (C0-C1 and F5-FF) that are never used. And multi-byte sequences that are not used such as the ones corresponding to "overlong" encodings. If these had been available to encode characters, then more of them could have been represented by 2-byte or 3-byte sequences (of course, at the expense of making the implementation more complex). Would it be possible to represent all 1,114,112 Unicode code points by a UTF-8-like encoding with at most 3 bytes per character? If not, what is the maximum number of characters such an encoding could represent? By "UTF-8-like", I mean, at minimum: The bytes 0x00-0x7F are reserved for ASCII characters. Byte-oriented find / index functions work correctly. You can't find a false positive by starting in the middle of a character like you can in Shift-JIS.

  Read the article

• Is there a Boost (or other common lib) type for matrices with string keys?

  - by mohawkjohn

  I have a dense matrix where the indices correspond to genes. While gene identifiers are often integers, they are not contiguous integers. They could be strings instead, too. I suppose I could use a boost sparse matrix of some sort with integer keys, and it wouldn't matter if they're contiguous. Or would this still occupy a great deal of space, particularly if some genes have identifiers that are nine digits? Further, I am concerned that sparse storage is not appropriate, since this is an all-by-all matrix (there will be a distance in each and every cell, provided the gene exists). I'm unlikely to need to perform any matrix operations (e.g., matrix multiplication). I will need to pull vectors out of the matrix (slices). It seems like the best type of matrix would be keyed by a Boost unordered_map (a hash map), or perhaps even simply an STL map. Am I looking at this the wrong way? Do I really need to roll my own? I thought I saw such a class somewhere before. Thanks!

  Read the article

• Self-describing file format for gigapixel images?

  - by Adam Goode

  In medical imaging, there appears to be two ways of storing huge gigapixel images: Use lots of JPEG images (either packed into files or individually) and cook up some bizarre index format to describe what goes where. Tack on some metadata in some other format. Use TIFF's tile and multi-image support to cleanly store the images as a single file, and provide downsampled versions for zooming speed. Then abuse various TIFF tags to store metadata in non-standard ways. Also, store tiles with overlapping boundaries that must be individually translated later. In both cases, the reader must understand the format well enough to understand how to draw things and read the metadata. Is there a better way to store these images? Is TIFF (or BigTIFF) still the right format for this? Does XMP solve the problem of metadata? The main issues are: Storing images in a way that allows for rapid random access (tiling) Storing downsampled images for rapid zooming (pyramid) Handling cases where tiles are overlapping or sparse (scanners often work by moving a camera over a slide in 2D and capturing only where there is something to image) Storing important metadata, including associated images like a slide's label and thumbnail Support for lossy storage What kind of (hopefully non-proprietary) formats do people use to store large aerial photographs or maps? These images have similar properties.

  Read the article

• Embedded non-relational (nosql) data store

  - by Igor Brejc

  I'm thinking about using/implementing some kind of an embedded key-value (or document) store for my Windows desktop application. I want to be able to store various types of data (GPS tracks would be one example) and of course be able to query this data. The amount of data would be such that it couldn't all be loaded into memory at the same time. I'm thinking about using sqlite as a storage engine for a key-value store, something like y-serial, but written in .NET. I've also read about FriendFeed's usage of MySQL to store schema-less data, which is a good pointer on how to use RDBMS for non-relational data. sqlite seems to be a good option because of its simplicity, portability and library size. My question is whether there are any other options for an embedded non-relational store? It doesn't need to be distributable and it doesn't have to support transactions, but it does have to be accessible from .NET and it should have a small download size. UPDATE: I've found an article titled SQLite as a Key-Value Database which compares sqlite with Berkeley DB, which is an embedded key-value store library.

  Read the article

• Hybrid EAV/CR model via WCF (and statically-typed language)?

  - by Pat

  Background I'm working on the architecture for a cloud-based LOB application, using Silverlight for the client, WCF, ASP.NET/C# for server and SQL Server for storage. The data model requires some flexibility per user (ability to add custom properties and define validation rules for them, for example), and a hybrid EAV/CR persistence model on the server side will suit nicely. Problem I need an efficient and maintainable technology and approach to handle the transformation from the persisted EAV model to/from WCF (and similarly allow the client to bind to the resulting data - DataGrid is a key UI element)? Admission: I don't yet know enough about WCF to understand if it supports ExpandoObject directly, but I suspect it will. Options I started off looking at WCF RIA services, but quickly discovered they're heavily dependent upon both static type data and compile-time code generation. Neither of these appeal. The options I'm considering include: Using WCF RIA services and pass the data over the network directly in EAV form (i.e. Dictionary), and handle the binding issue purely on the client side (like this) Using a dynamic language (probably IronPython) to handle both ends of the communication, with plumbing to generate the necessary CLR type data on the client to allow binding, and transform to/from EAV form on the server (spam preventer stopped me from posting a URL here, I'll try it in a comment). Dynamic LINQ (CreateClass() and friends), although I'm way out of my depth there and don't know what the limitations on that approach might be yet. I'm interested in comments on these approaches as well as alternative approaches that might solve the problem. Other Notes The Silverlight client will not be the only consumer of the service, making me slightly uncomfortable with option #1 above. While the data model is flexible, it's not expected to be modified heavily. For argument's sake, we could assume that we might have 25 distinct data models active at a given time, with something like 10-20 unique data fields/rules each. Modifications to the data model will happen infrequently (typically when a new user is initially configured).

  Read the article

• Reasons for & against a Database

  - by dbemerlin

  Hi, i had a discussion with a coworker about the architecture of a program i'm writing and i'd like some more opinions. The Situation: The Program should update at near-realtime (+/- 1 Minute). It involves the movement of objects on a coordinate system. There are some events that occur at regular intervals (i.e. creation of the objects). Movements can change at any time through user input. My solution was: Build a server that runs continously and stores the data internally. The server dumps a state-of-the-program at regular intervals to protect against powerfailures and/or crashes. He argued that the program requires a Database and i should use cronjobs to update the data. I can store movement information by storing startpoint, endpoint and speed and update the position in the cronjob (and calculate collisions with other objects there) by calculating direction and speed. His reasons: Requires more CPU & Memory because it runs constantly. Powerfailures/Crashes might destroy data. Databases are faster. My reasons against this are mostly: Not very precise as events can only occur at full minutes (wouldn't be that bad though). Requires (possibly costly) transformation of data on every run from relational data to objects. RDBMS are a general solution for a specialized problem so a specialized solution should be more efficient. Powerfailures (or other crashes) can leave the Data in an undefined state with only partially updated data unless (possibly costly) precautions (like transactions) are taken. What are your opinions about that? Which arguments can you add for any side?

  Read the article

• What is the fastest collection in c# to implement a prioritizing queue?

  - by Nathan Smith

  I need to implement a queue for messages on a game server so it needs to as fast as possible. The queue will have a maxiumem size. I need to prioritize messages once the queue is full by working backwards and removing a lower priority message (if one exists) before adding the new message. The appliation is asynchronous so access to the queue needs to be locked. I'm currently implementing it using a LinkedList as the underlying storage but have concerns that searching and removing nodes will keep it locked for too long. Heres the basic code I have at the moment: public class ActionQueue { private LinkedList<ClientAction> _actions = new LinkedList<ClientAction>(); private int _maxSize; /// <summary> /// Initializes a new instance of the ActionQueue class. /// </summary> public ActionQueue(int maxSize) { _maxSize = maxSize; } public int Count { get { return _actions.Count; } } public void Enqueue(ClientAction action) { lock (_actions) { if (Count < _maxSize) _actions.AddLast(action); else { LinkedListNode<ClientAction> node = _actions.Last; while (node != null) { if (node.Value.Priority < action.Priority) { _actions.Remove(node); _actions.AddLast(action); break; } } } } } public ClientAction Dequeue() { ClientAction action = null; lock (_actions) { action = _actions.First.Value; _actions.RemoveFirst(); } return action; } }

  Read the article

• How to put large text data (~20mb) into sql cs 3.5 database?

  - by Anindya Chatterjee

  I am using following query to insert some large text data : internal static string InsertStorageItem = "insert into Storage(FolderName, MessageId, MessageDate, StorageData) values ('{0}', '{1}', '{2}', @StorageData)"; and the code I am using to execute this query is as follows : string content = "very very large data"; string query = string.Format(InsertStorageItem, "Inbox", "AXOGTRR1445/DSDS587444WEE", "4/19/2010 11:11:03 AM"); var command = new SqlCeCommand(query, _sqlConnection); var paramData = command.Parameters.Add("@StorageData", System.Data.SqlDbType.NText); paramData.Value = content; paramData.SourceColumn = "StorageData"; command.ExecuteNonQuery(); But at the last line I am getting this following error : System.Data.SqlServerCe.SqlCeException was unhandled by user code Message=The data was truncated while converting from one data type to another. [ Name of function(if known) = ] Source=SQL Server Compact ADO.NET Data Provider HResult=-2147467259 NativeError=25920 StackTrace: at System.Data.SqlServerCe.SqlCeCommand.ProcessResults(Int32 hr) at System.Data.SqlServerCe.SqlCeCommand.ExecuteCommandText(IntPtr& pCursor, Boolean& isBaseTableCursor) at System.Data.SqlServerCe.SqlCeCommand.ExecuteCommand(CommandBehavior behavior, String method, ResultSetOptions options) at System.Data.SqlServerCe.SqlCeCommand.ExecuteNonQuery() at Chithi.Client.Exchange.ExchangeClient.SaveItem(Item item, Folder parentFolder) at Chithi.Client.Exchange.ExchangeClient.DownloadNewMails(Folder folder) at Chithi.Client.Exchange.ExchangeClient.SynchronizeParentChildFolder(WellKnownFolder wellknownFolder, Folder parentFolder) at Chithi.Client.Exchange.ExchangeClient.SynchronizeFolders() at Chithi.Client.Exchange.ExchangeClient.WorkerThreadDoWork(Object sender, DoWorkEventArgs e) at System.ComponentModel.BackgroundWorker.OnDoWork(DoWorkEventArgs e) at System.ComponentModel.BackgroundWorker.WorkerThreadStart(Object argument) InnerException: Now my question is how am I supposed to insert such large data to sqlce db? Regards, Anindya Chatterjee http://abstractclass.org

  Read the article

• Drawing only part of a texture OpenGL ES iPhone

  - by Ben Reeves

  ..Continued on from my previous question I have a 320*480 RGB565 framebuffer which I wish to draw using OpenGL ES 1.0 on the iPhone. - (void)setupView { glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameteriv(GL_TEXTURE_2D, GL_TEXTURE_CROP_RECT_OES, (int[4]){0, 0, 480, 320}); glEnable(GL_TEXTURE_2D); } // Updates the OpenGL view when the timer fires - (void)drawView { // Make sure that you are drawing to the current context [EAGLContext setCurrentContext:context]; //Get the 320*480 buffer const int8_t * frameBuf = [source getNextBuffer]; //Create enough storage for a 512x512 power of 2 texture int8_t lBuf[2*512*512]; memcpy (lBuf, frameBuf, 320*480*2); //Upload the texture glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 512, 512, 0, GL_RGB, GL_UNSIGNED_SHORT_5_6_5, lBuf); //Draw it glDrawTexiOES(0, 0, 1, 480, 320); [context presentRenderbuffer:GL_RENDERBUFFER_OES]; } If I produce the original texture in 512*512 the output is cropped incorrectly but other than that looks fine. However using the require output size of 320*480 everything is distorted and messed up. I'm pretty sure it's the way I'm copying the framebuffer into the new 512*512 buffer. I have tried this routine int8_t lBuf[512][512][2]; const char * frameDataP = frameData; for (int ii = 0; ii < 480; ++ii) { memcpy(lBuf[ii], frameDataP, 320); frameDataP += 320; } Which is better, but the width appears to be stretched and the height is messed up. Any help appreciated.

  Read the article

• Debugging unexpected error message - possible memory management problem?

  - by Ben Packard

  I am trying to debug an application that is throwing up strange (to my untutored eyed) errors. When I try to simply log the count of an array... NSLog(@"Array has %i items", [[self startingPlayers] count]); ...I sometimes get an error: -[NSCFString count]: unrecognized selector sent to instance 0x1002af600 or other times -[NSConcreteNotification count]: unrecognized selector sent to instance 0x1002af600 I am not sending 'count' to any NSString or NSNotification, and this line of code works fine normally. A Theory... Although the error varies, the crash happens at predictable times, immediately after I have run through some other code where I'm thinking I might have a memory management issue. Is it possible that the object reference is still pointing to something that is meant to be destroyed? Sorry if my terms are off, but perhaps it's expecting the array at the address it calls 'count' on, but finds another previous object that shouldn't still be there (eg an NSString)? Would this cause the problem? If so, what is the most efficient way to debug and find out what is that address? Most of my debugging up until now involves inserting NSLogs, so this would be a good opportunity to learn how to use the debugger.

  Read the article

• Why do System.IO.Log SequenceNumbers have variable length?

  - by Doug McClean

  I'm trying to use the System.IO.Log features to build a recoverable transaction system. I understand it to be implemented on top of the Common Log File System. The usual ARIES approach to write-ahead logging involves persisting log record sequence numbers in places other than the log (for example, in the header of the database page modified by the logged action). Interestingly, the documentation for CLFS says that such sequence numbers are always 64-bit integers. Confusingly, however, the .Net wrapper around those SequenceNumbers can be constructed from a byte[] but not from a UInt64. It's value can also be read as a byte[], but not as a UInt64. Inspecting the implementation of SequenceNumber.GetBytes() reveals that it can in fact return arrays of either 8 or 16 bytes. This raises a few questions: Why do the .Net sequence numbers differ in size from the CLFS sequence numbers? Why are the .Net sequence numbers variable in length? Why would you need 128 bits to represent such a sequence number? It seems like you would truncate the log well before using up a 64-bit address space (16 exbibytes, or around 10^19 bytes, more if you address longer words)? If log sequence numbers are going to be represented as 128 bit integers, why not provide a way to serialize/deserialize them as pairs of UInt64s instead of rather-pointlessly incurring heap allocations for short-lived new byte[]s every time you need to write/read one? Alternatively, why bother making SequenceNumber a value type at all? It seems an odd tradeoff to double the storage overhead of log sequence numbers just so you can have an untruncated log longer than a million terabytes, so I feel like I'm missing something here, or maybe several things. I'd much appreciate it if someone in the know could set me straight.

  Read the article

• Random Pairings that don't Repeat

  - by Andrew Robinson

  This little project / problem came out of left field for me. Hoping someone can help me here. I have some rough ideas but I am sure (or at least I hope) a simple, fairly efficient solution exists. Thanks in advance.... pseudo code is fine. I generally work in .NET / C# if that sheds any light on your solution. Given: A pool of n individuals that will be meeting on a regular basis. I need to form pairs that have not previously meet. The pool of individuals will slowly change over time. For the purposes of pairing, (A & B) and (B & A) constitute the same pair. The history of previous pairings is maintained. For the purpose of the problem, assume an even number of individuals. For each meeting (collection of pairs) and individual will only pair up once. Is there an algorithm that will allow us to form these pairs? Ideally something better than just ordering the pairs in a random order, generating pairings and then checking against the history of previous pairings. In general, randomness within the pairing is ok.

  Read the article

• error C3662: override specifier 'new' only allowed on member functions of managed classes

  - by William

  Okay, so I'm trying to override a function in a parent class, and getting some errors. here's a test case #include <iostream> using namespace std; class A{ public: int aba; void printAba(); }; class B: public A{ public: void printAba() new; }; void A::printAba(){ cout << "aba1" << endl; } void B::printAba() new{ cout << "aba2" << endl; } int main(){ A a = B(); a.printAba(); return 0; } And here's the errors I'm getting: Error 1 error C3662: 'B::printAba' : override specifier 'new' only allowed on member functions of managed classes c:\users\test\test\test.cpp 12 test Error 2 error C2723: 'B::printAba' : 'new' storage-class specifier illegal on function definition c:\users\test\test\test.cpp 19 test How the heck do I do this?

  Read the article

• Printing out this week's dates in perl

  - by ABach

  Hi folks, I have the following loop to calculate the dates of the current week and print them out. It works, but I am swimming in the amount of date/time possibilities in perl and want to get your opinion on whether there is a better way. Here's the code I've written: #!/usr/bin/env perl use warnings; use strict; use DateTime; # Calculate numeric value of today and the # target day (Monday = 1, Sunday = 7); the # target, in this case, is Monday, since that's # when I want the week to start my $today_dt = DateTime->now; my $today = $today_dt->day_of_week; my $target = 1; # Create DateTime copies to act as the "bookends" # for the date range my ($start, $end) = ($today_dt->clone(), $today_dt->clone()); if ($today == $target) { # If today is the target, "start" is already set; # we simply need to set the end date $end->add( days => 6 ); } else { # Otherwise, we calculate the Monday preceeding today # and the Sunday following today my $delta = ($target - $today + 7) % 7; $start->add( days => $delta - 7 ); $end->add( days => $delta - 1 ); } # I clone the DateTime object again because, for some reason, # I'm wary of using $start directly... my $cur_date = $start->clone(); while ($cur_date <= $end) { my $date_ymd = $cur_date->ymd; print "$date_ymd\n"; $cur_date->add( days => 1 ); } As mentioned, this works - but is it the quickest/most efficient/etc.? I'm guessing that quickness and efficiency may not necessarily go together, but your feedback is very appreciated.

  Read the article

• Exporting dataset to Excel file with multiple sheets in ASP.NET

  - by engg

  In C# ASP.NET 3.5 web application, I need to export multiple datatables (or a dataset) to an Excel 2007 file with multiple sheets, and then provide the user with 'Open/Save' dialog box, WITHOUT saving the Excel file on the web server. I have used Excel Interop before. I have been reading that it's not efficient and is not the best approach to achieve this and there are more ways to do it, 2 of them being: 1) Converting data in datatables to an XML string that Excel understands 2) Using OPEN XML SDK 2.0. It looks like OPEN XML SDK 2.0 is better, please let me know. Are there any other ways to do it? I don't want to use any third-party tools. If I use OPEN XML SDK, it creates an excel file, right? I don't want to save it on the (Windows 2003) server hard drive (I don't want to use Server.MapPath, these Excel files are dynamically created, and they are not required on the server, once client gets them). I directly want to prompt the user to open/save it. I know how to do it when the 'XML string' approach is used. Please help. Thank you.

  Read the article

• Python IOError: Not a gzipped file (Gzip and Blowfish Encrypt/Compress)

  - by notbad.jpeg

  I'm having some problems with python's built-in library gzip. Looked through almost every other stack question about it, and none of them seem to work. MY PROBLEM IS THAT WHEN I TRY TO DECOMPRESS I GET THE IOError I'm Getting: Traceback (most recent call last): File "mymodule.py", line 61, in return gz.read() File "/usr/lib/python2.7/gzip.py", line 245, readself._read(readsize) File "/usr/lib/python2.7/gzip.py", line 287, in _readself._read_gzip_header() File "/usr/lib/python2.7/gzip.py", line 181, in _read_gzip_header raise IOError, 'Not a gzipped file'IOError: Not a gzipped file This is my code to send it over SMB, it might not make sense why i do things, but it's normally in a while loop and memory efficient, I just simplified it. buffer = cStringIO.StringIO(output) #output is from a subprocess call small_buffer = cStringIO.StringIO() small_string = buffer.read() #need a string to write to buffer gzip_obj = gzip.GzipFile(fileobj=small_buffer,compresslevel=6, mode='wb') gzip_obj.write(small_string) compressed_str = small_buffer.getvalue() blowfish = Blowfish.new('abcd', Blowfish.MODE_ECB) remainder = '|'*(8 - (len(compressed_str) % 8)) compressed_str += remainder encrypted = blowfish.encrypt(compressed_str) #i send it over smb, then retrieve it later Then this is the code that retrieves it: #buffer is a cStringIO object filled with data from smb retrieval decrypter = Blowfish.new('abcd', Blowfish.MODE_ECB) value = buffer.getvalue() decrypted = decrypter.decrypt(value) buff = cStringIO.StringIO(decrypted) buff.seek(0) gz = gzip.GzipFile(fileobj=buff) return gz.read() Here's the problem return gz.read()

  Read the article

• jdbc query - date ranges as parameters

  - by pstanton

  Hi all, I'd like to write a single JDBC statement that can handle the equivalent of any number of NOT BETWEEN date1 AND date2 where clauses. By single query, i mean that the same SQL string will be used to create the JDBC statements and then have different parameters supplied. This is so that the underlying frameworks can efficiently cache the query (i've been stung by that before). Essentially, I'd like to find a query that is the equivalent of SELECT * FROM table WHERE mydate NOT BETWEEN ? AND ? AND mydate NOT BETWEEN ? AND ? AND mydate NOT BETWEEN ? AND ? AND mydate NOT BETWEEN ? AND ? and at the same time could be used with fewer parameters: SELECT * FROM table WHERE mydate NOT BETWEEN ? AND ? or more parameters SELECT * FROM table WHERE mydate NOT BETWEEN ? AND ? AND mydate NOT BETWEEN ? AND ? AND mydate NOT BETWEEN ? AND ? AND mydate NOT BETWEEN ? AND ? AND mydate NOT BETWEEN ? AND ? AND mydate NOT BETWEEN ? AND ? AND mydate NOT BETWEEN ? AND ? AND mydate NOT BETWEEN ? AND ? AND mydate NOT BETWEEN ? AND ? AND mydate NOT BETWEEN ? AND ? AND mydate NOT BETWEEN ? AND ? I will consider using a temporary table if that will be simpler and more efficient. thanks for the help!

  Read the article

< Previous Page | 308 309 310 311 312 313 314 315 316 317 318 319  | Next Page >