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  • best way to save data in ipod touch/iphone objective-c

    - by Leonardo
    Hi all, I am writing a very simple application, for iphone. Unfortunately I am really a newbie. What I am trying to do is to save data at the end of a user experience. These data are really simple, only string or int, or some array. Later I want to be able to retrieve that data, therefore I also need an event id (I suppose). Could you please point out the best way, api or technology to achieve that, xml, plain text, serialization... ? many thanks Leonardo

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  • Older iPhone/ iPod frame rate?

    - by Adam
    Do older iPods and iPhones have a frame rate of 60fps? I'm finding that all the methods for calculating time intervals on iPhone (cftimeinterval, nstimer, timesince1970, etc) are all giving me bad data, so I've decided assume a frame rate of 60, just not sure if older apple devices can run at this.

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  • Predicting performance for an iPhone/iPod Touch App

    - by Avizz
    I don't have an iPhone Developer Program Account yet and will be getting one in the next couple of days. Can instruments be used with the simulator to give a rough estimate on how well my app may perform? Using instruments I checked and fixed all the leaks it was detecting, and it appears that my memory usage maxes out at about 5.77mb. Is there any other tests I could perform with instruments to judge how well my app would perform? I realize there is no way other then the actual device to get a definite answer, it would be nice to get an estimate.

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  • 15 Puzzle Shuffle Method Issues

    - by Codemiester
    I am making a 15 puzzle game in C# that allows the user to enter a custom row and column value up to a maximum of a 10 x 10 puzzle. Because of this I am having problems with the shuffle method. I want to make it so the puzzle is always solvable. By first creating a winning puzzle then shuffling the empty space. The problem is it is too inefficient to call every click event each time. I need a way to invoke the click event of a button adjacent to the empty space but not diagonal. I also use an invisible static button for the empty spot. The PuzzlePiece class inherits from Button. I am not too sure how to do this. I would appreciate any help. Thanks here is what I have: private void shuffleBoard() { //5 is just for test purposes for (int i = 0; i < 5; i++) { foreach (Control item in this.Controls) { if (item is PuzzlePiece) { ((PuzzlePiece)item).PerformClick(); } } } } void PuzzlePiece_Click(object sender, EventArgs e) { PuzzlePiece piece = (PuzzlePiece)sender; if (piece.Right == puzzleForm.emptyPiece.Left && piece.Top == puzzleForm.emptyPiece.Top) { movePiece(piece); } else if (piece.Left == puzzleForm.emptyPiece.Right && piece.Top == puzzleForm.emptyPiece.Top) { movePiece(piece); } else if (piece.Top == puzzleForm.emptyPiece.Bottom && piece.Left == puzzleForm.emptyPiece.Left) { movePiece(piece); } else if (piece.Bottom == puzzleForm.emptyPiece.Top && piece.Left == puzzleForm.emptyPiece.Left) { movePiece(piece); } }

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  • How to shuffle pieces of large video files?

    - by Gabriël
    Hi Folks, For a party we want to show film-fragments using a projector. We have around 50 full-length movie avis and would like to shuffle them in shorter pieces. So every ca. 2-5 minutes another piece should begin. For example a sequence could be: Movie05-12m00s-14m30s, Movie08-55m50s-57m00s, Movie02-02m42s-06m40s, etc. So, random movies, at random positions within the movie of random lengths. What would be the kind of solution we're looking for? We were thinking 2 scenarios: Before doing this use some kind of tool to cut all avis in smaller pieces and put them on shuffle in a regular media player A sort of "VJ" program that can do this shuffle mixing realtime. Any suggestions for any of the above scenarios? Thanks!

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  • Which Ipod touch generation should I buy? 2nd or 3rd?

    - by kukabunga
    I want to create games for Iphone/Ipod touch. Unfortunately I don't have a lot of money so I can buy only one device. Ipod is cheaper than Iphone, so I decided to bought Ipod touch. But I am afraid of buying 3rd generation - because it has more memory, more faster CPU, etc. And I think if I post my app on appstore - people with 2nd generation Ipod might have trouble with my app (because I was testing it on 3rd generation). But on the other hand - I am planning to create 3d/cpu demanding game - and it would be easy for me to implement it on device with more calculation power... What should I do in this situation? Any advice is appreciate.

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  • Is there a good alternative to Videora iPod Converter?

    - by Richard
    I use Videora to convert my videos (in DivX/XviD format) to something I can play on my iPod Classic. I really dislike it. It's clunky, riddled with adverts, sometimes doesn't convert properly (the infamous "invalid public atom" error - see Google for more) and has a UI that truly stinks. On the upside, it's free, accepts a list of video files (via the oddly hard to find "1-click convert" button) and just gets on with the converting as it already knows the correct settings for my iPod. One final nice touch is that once they are converted, it'll automatically upload them into iTunes. Are there any alternatives which have all the upsides but none of the downsides? Bonus points if they can set the metadata in iTunes correctly for TV shows (season, show, episode) and delete the converted file afterwards (as my iTunes settings means that a copy is made elsewhere). I've looked at a bunch of applications (handbrake, virtualdub, mediacoder, format factory, any video converter, convertxtodvd) but many of them fail the "just select a list of files and get on with converting" test - let alone all the other features I want. I have no desire to individually set the video size of each file or the codec or the post-processing options. I'm currently using the command line version of HandBrake (handbrakecli) and a hand-written DOS batch file to go through every file in a folder and convert it. It does most of what I want, just not in a very slick way. Can anyone recommend anything better? It needs to work on Windows 7 and be free.

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  • Use your iPhone or iPod Touch as a Boxee Remote

    - by DigitalGeekery
    Are you a Boxee user looking for a remote control solution? Well, you might not need to look any further than your pocket. The free Boxee Remote App turns your iPhone or iPod Touch into a a simple and easy-to-use Boxee remote. The Boxee Remote App works over WiFi, so there is no need for to buy or install additional hardware on your PC. Plus, you don’t even need to be within the line of sight for it to work. Using the Boxee Remote App Download the free Boxee Remote App from the App Store and install it on your iPhone or iPod Touch. See download link below. Next, make sure you have Boxee running on your PC. Select the Boxee icon to open the App.   The first time you log in you’ll be greeted by an introduction screen that will explain the two modes. Click Continue. When opened in “Button” mode, you’ll be presented with 4 directional buttons, an “OK” button, and a back arrow button that works like the Esc key does in Boxee. Button mode performs just as a normal remote. Touching the directional buttons moves your on screen selection right, left, up, and down. Tap the OK button to open or select an item. To enter “Gesture” mode, tap the Gesture button along the top of the Screen. Gesture mode works similar to a touch pad or trackball on a laptop. You drag the Boxee icon with your thumb or finger across the screen to move around within Boxee. The icon will turn red while being dragged or touched. Simply tap the icon to select.   The Settings button allows you to manually add or delete a host computer, or adjust the sensitivity of the controls.     If you need to enter text, such as enter logon credentials for an App, the on screen keyboard will pop up. While watching a video you’ll have on-screen Stop and Pause buttons along with a volume slider.   The Boxee Remote App is simple and easy to use. As long as you can connect via WiFi, you can use it to control any instance of Boxee running on any computer on your network. Download the Boxee Remote App Similar Articles Productive Geek Tips Why Wait? Amazing New Add-on Turns Your iPhone into an iPad! [Comic]Getting Started with BoxeeIntegrate Boxee with Media Center in Windows 7Watch Netflix Instant Movies in BoxeeWin a Free iPod Touch in the How-To Geek Facebook Giveaway! TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Out of band Security Update for Internet Explorer 7 Cool Looking Screensavers for Windows SyncToy syncs Files and Folders across Computers on a Network (or partitions on the same drive) If it were only this easy Classic Cinema Online offers 100’s of OnDemand Movies OutSync will Sync Photos of your Friends on Facebook and Outlook

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  • Shuffle tiles position in the beginning of the game XNA Csharp

    - by GalneGunnar
    Im trying to create a puzzlegame where you move tiles to certain positions to make a whole image. I need help with randomizing the tiles startposition so that they don't create the whole image at the beginning. There is also something wrong with my offset, that's why it's set to (0,0). I know my code is not good, but Im just starting to learn :] Thanks in advance My Game1 class: { public class Game1 : Microsoft.Xna.Framework.Game { GraphicsDeviceManager graphics; SpriteBatch spriteBatch; Texture2D PictureTexture; Texture2D FrameTexture; // Offset för bildgraff Vector2 Offset = new Vector2(0,0); //skapar en array som ska hålla delar av den stora bilden Square[,] squareArray = new Square[4, 4]; // Random randomeraBilder = new Random(); //Width och Height för bilden int pictureHeight = 95; int pictureWidth = 144; Random randomera = new Random(); int index = 0; MouseState oldMouseState; int WindowHeight; int WindowWidth; public Game1() { graphics = new GraphicsDeviceManager(this); Content.RootDirectory = "Content"; //scalar Window till 800x 600y graphics.PreferredBackBufferWidth = 800; graphics.PreferredBackBufferHeight = 600; graphics.ApplyChanges(); } protected override void Initialize() { IsMouseVisible = true; base.Initialize(); } protected override void LoadContent() { spriteBatch = new SpriteBatch(GraphicsDevice); PictureTexture = Content.Load<Texture2D>(@"Images/bildgraff"); FrameTexture = Content.Load<Texture2D>(@"Images/framer"); //Laddar in varje liten bild av den stora bilden i en array for (int x = 0; x < 4; x++) { for (int y = 0; y < 4; y++) { Vector2 position = new Vector2(x * pictureWidth, y * pictureHeight); position = position + Offset; Rectangle square = new Rectangle(x * pictureWidth, y * pictureHeight, pictureWidth, pictureHeight); Square frame = new Square(position, PictureTexture, square, Offset, index); squareArray[x, y] = frame; index++; } } } protected override void UnloadContent() { } protected override void Update(GameTime gameTime) { if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed) this.Exit(); MouseState ms = Mouse.GetState(); if (oldMouseState.LeftButton == ButtonState.Pressed && ms.LeftButton == ButtonState.Released) { // ta reda på vilken position vi har tryckt på int col = ms.X / pictureWidth; int row = ms.Y / pictureHeight; for (int x = 0; x < squareArray.GetLength(0); x++) { for (int y = 0; y < squareArray.GetLength(1); y++) { // kollar om rutan är tom och så att indexet inte går utanför för "col" och "row" if (squareArray[x, y].index == 0 && col >= 0 && row >= 0 && col <= 3 && row <= 3) { if (squareArray[x, y].index == 0 * col) { //kollar om rutan brevid mouseclick är tom if (col > 0 && squareArray[col - 1, row].index == 0 || row > 0 && squareArray[col, row - 1].index == 0 || col < 3 && squareArray[col + 1, row].index == 0 || row < 3 && squareArray[col, row + 1].index == 0) { Square sqaure = squareArray[col, row]; Square hal = squareArray[x, y]; squareArray[x, y] = sqaure; squareArray[col, row] = hal; for (int i = 0; i < 4; i++) { for (int j = 0; j < 4; j++) { Vector2 goalPosition = new Vector2(x * pictureWidth, y * pictureHeight); squareArray[x, y].Swap(goalPosition); } } } } } } } } //if (oldMouseState.RightButton == ButtonState.Pressed && ms.RightButton == ButtonState.Released) //{ // for (int x = 0; x < 4; x++) // { // for (int y = 0; y < 4; y++) // { // } // } //} oldMouseState = ms; base.Update(gameTime); } protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.CornflowerBlue); WindowHeight = Window.ClientBounds.Height; WindowWidth = Window.ClientBounds.Width; Rectangle screenPosition = new Rectangle(0,0, WindowWidth, WindowHeight); spriteBatch.Begin(); spriteBatch.Draw(FrameTexture, screenPosition, Color.White); //Ritar ut alla brickorna förutom den som har index 0 for (int x = 0; x < 4; x++) { for (int y = 0; y < 4; y++) { if (squareArray[x, y].index != 0) { squareArray[x, y].Draw(spriteBatch); } } } spriteBatch.End(); base.Draw(gameTime); } } } My square class: class Square { public Vector2 position; public Texture2D grafTexture; public Rectangle square; public Vector2 offset; public int index; public Square(Vector2 position, Texture2D grafTexture, Rectangle square, Vector2 offset, int index) { this.position = position; this.grafTexture = grafTexture; this.square = square; this.offset = offset; this.index = index; } public void Draw(SpriteBatch spritebatch) { spritebatch.Draw(grafTexture, position, square, Color.White); } public void RandomPosition() { } public void Swap(Vector2 Goal ) { if (Goal.X > position.X) { position.X = position.X + 144; } else if (Goal.X < position.X) { position.X = position.X - 144; } else if (Goal.Y < position.Y) { position.Y = position.Y - 95; } else if (Goal.Y > position.Y) { position.Y = position.Y + 95; } } } }

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  • Learning Objective-C for iPad/iPhone/iPod Development

    - by Jeff Julian
    I am learning how to write apps for the iPad/iPhone/iPod!  Why, well several reasons.  One reason, I have 5 devices in my house on the platform.  I had an iPad and iPhone, Michelle has an iPhone, and each of the kids have iPod Touches.  They are excellent devices for life management, entertainment, and learning.  I am amazed at how well the kids pick up on it and how much it effects the way they learn.  My two year old knows how to use it better than any other device we own and she is learning new words and letters so quickly. Because of this saturation at home, it would be fun to write some apps my family could use.  Some games to bring the hobby of development back into my life.  Second reason is we want to have a Geekswithblogs app for the iPhone and iPad.  We are not sure if it is purely informational (blog posts and tweets) or if members want to be able to publish from the app.  Creating a blog editor would be tough stuff, but could be just the right challenge. There are so many more reasons, but the last one that really makes me excited is that it is a new domain of development where I get excited when I think about writing apps.  That excitement level where I want to see if there are User Groups and if we are just watching TV, to break out the MBP and start working on it.  That excitement level where I could really read a development book cover to cover and not just use as a reference.  I really do like this feeling. Who knows how long this will last and I am definitely not leaving .NET.  Microsoft software will always be my main focus, but for the time, my hobby is changing and I am getting excited about development again.   Technorati Tags: Apple,iPad Development,Objective-C,New Frontiers Image: Courtesy of Apple

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  • Is Collections.shuffle suitable for a poker algorithm?

    - by Kovu
    Hi, there is a poker-system in java, that uses Collections.shuffle() on all available cards before the cards are dealt. So a collection of 52 cards 2-9, J, Q, K, A in 4 types. After that we Collections.shuffle(). The problem is, that it seems (until now we didn't have big statistic, it's possible that we only see a lot of statistic inferences), that the algorithm is VERY unclearly. So, is Collections.shuffle() okay for a poker algorithm?

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  • Updating games for iOS 6 and new iPhone/iPod Touch

    - by SundayMonday
    Say I have a game that runs full-screen on iPhone 4S and older devices. The balance of the game is just right for the 480 x 320 screen and associated aspect ratio. Now I want to update my game to run full-screen on the new iPhone/iPod Touch where the aspect ratio of the screen is different. It seems like this can be challenging for some games in terms of maintaining the "balance". For example if the extra screen space was just tacked onto the right side of Jet Pack Joyride the balance would be thrown off since the user now has more time to see and react to obstacles. Also it could be challenging in terms of code maintenance. Perhaps Jet Pack Joyride would slightly increase the speed of approaching obstacles when the game is played on newer devices. However this quickly becomes messy when extra conditional statements are added all over the code. One solution is to have some parameters that are set in once place at start-up depending on the device type. What are some strategies for updating iOS games to run on the new iPhone and iPod Touch?

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  • Why would an iPod Touch and PS3 respond to netdiscover as 0.0.0.0?

    - by Iszi
    Only slightly related to this question, because it was discovered in the same scan: Can someone explain how this happened? When running netdiscover on my home network, my iPod Touch (identified by DHCP-reserved IP address and MAC address) responded to both its own IP address on our 10.x.x.x subnet and to 0.0.0.0 also. Why would this have happened? EDIT: After letting netdiscover run awhile longer, it seems one of the PS3s on the network is also answering to 0.0.0.0 - why is this?

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  • How can I use the Fisher-Yates shuffle while ensuring my permutation is even?

    - by Mithrax
    I'm interested making an implementation of the 14-15 puzzle: I'm creating an array with the values 0 - 15 in increasing order: S = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 } Now, what I want to do is shuffle them to create a new instance of the puzzle. However, I know that if I create a board with an "odd permutation" than it is unsolvable. Wikipedia says I need to create the puzzle with an even permutation. I believe this means that I simply have to do ensure I do an even number of swaps? How would I modify Fisher-Yates so I ensure I end up with an even permutation at the end? If I do a swap for every element in the array that would be 16 swaps which I believe would be an even permutation. However, do I need to be concerned about swapping with itself? Is there any other way to ensure I have a valid puzzle?

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  • How can I ensure that when I shuffle my puzzle I still end up with an even permutation?

    - by Mithrax
    I'm interested making an implementation of the 14-15 puzzle: I'm creating an array with the values 0 - 15 in increasing order: S = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 } Now, what I want to do is shuffle them to create a new instance of the puzzle. However, I know that if I create a board with an "odd permutation" than it is unsolvable. Wikipedia says I need to create the puzzle with an even permutation. I believe this means that I simply have to do ensure I do an even number of swaps? How would I modify Fisher-Yates so I ensure I end up with an even permutation at the end? If I do a swap for every element in the array that would be 16 swaps which I believe would be an even permutation. However, do I need to be concerned about swapping with itself? Is there any other way to ensure I have a valid puzzle?

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  • How to Never Use iTunes With Your iPhone, iPad, or iPod Touch

    - by Chris Hoffman
    iTunes isn’t an amazing program on Windows. There was a time when Apple device users had to plug their devices into their PCs or Macs and use iTunes for device activation, updates, and syncing, but iTunes is no longer necessary. Apple still allows you to use iTunes for these things, but you don’t have to. Your iOS device can function independently from iTunes, so you should never be forced to plug it into a PC or Mac. Device Activation When the iPad first came out, it was touted as a device that could replace full PCs and Macs for people who only needed to perform light computing tasks. Yet, to set up a new iPad, users had to plug it into a PC or Mac running iTunes and use iTunes to activate the device. This is no longer necessary. With new iPads, iPhones, and iPod Touches, you can simply go through the setup process after turning on your new device without ever having to plug it into iTunes. Just connect to a Wi-Fi or cellular data network and log in with your Apple ID when prompted. You’ll still see an option that allows you to activate the device via iTunes, but this should only be necessary if you don’t have a wireless Internet connection available for your device. Operating System Updates You no longer have to use Apple’s iTunes software to update to a new version of Apple’s iOS operating system, either. Just open the Settings app on your device, select the General category, and tap Software Update. You’ll be able to update right from your device without ever opening iTunes. Purchased iTunes Media Apple allows you to easily access content you’ve purchased from the iTunes Store on any device. You don’t have to connect your device to your computer and sync via iTunes. For example, you can purchase a movie from the iTunes Store. Then, without any syncing, you can open the iTunes Store app on any of your iOS devices, tap the Purchased section, and see stuff you’ve downloaded. You can download the content right from the store to your device. This also works for apps — apps you purchase from the App Store can be accessed in the Purchased section on the App Store on your device later. You don’t have to sync apps from iTunes to your device, although iTunes still allows you to. You can even set up automatic downloads from the iTunes & App Store settings screen. This would allow you to purchase content on one device and have it automatically download to your other devices without any hassle. Music Apple allows you to re-download purchased music from the iTunes Store in the same way. However, there’s a good chance you have your own music you didn’t purchase from iTunes. Maybe you spent time ripping it all from your old CDs and you’ve been syncing it to your devices via iTunes ever since. Apple’s solution for this is named iTunes Match. This feature isn’t free, but it’s not a bad deal at all. For $25 per year, Apple allows you to upload all your music to your iCloud account. You can then access all your music from any iPhone, IPad, or iPod Touch. You can stream all your music — perfect if you have a huge library and little storage on your device — and choose which songs you want to download to your device for offline use. When you add additional music to your computer, iTunes will notice it and upload it using iTunes Match, making it available for streaming and downloading directly from your iOS devices without any syncing. This feature is named iTunes Match because it doesn’t just upload music — if Apple already has a song you upload, it will “match” your song with Apple’s copy. This means you may get higher-quality versions of your songs if you ripped them from CD at a lower bitrate. Podcasts You don’t have to use iTunes to subscribe to podcasts and sync them to your devices. Even if you have a lowly iPod Touch, you can install APple’s Podcasts app from the app store. Use it to subscribe to podcasts and configure them to automatically download directly to your device. You can use other podcast apps for this, too. Backups You can continue backing up your device’s data through iTunes, generating local backups that are stored on your computer. However, new iOS devices are configured to automatically back up their data to iCloud. This happens automatically in the background without you even having to think about it, and you can restore such backups when setting up a device simply by logging in with your Apple ID. Personal Data In the days of PalmPilots, people would use desktop programs like iTunes to sync their email, contacts, and calendar events with their mobile devices. You probably shouldn’t have to sync this data form your computer. Just sign into your email account — for example, a Gmail account — on your device and iOS will automatically pull your email, contacts, and calendar events from your associated account. Photos Rather than connecting your iOS device to your computer and syncing photos from it, you can use an app that automatically uploads your photos to a web service. Dropbox, Google+, and even Flickr all have this feature in their apps. You’ll be able to access your photos from any computer and have a backup copy without any syncing required. You may still need to use iTunes if you want to sync local music without paying for iTunes Match or copy local video files to your device. Copying large local files over is the only real scenario where you’d need iTunes. If you don’t need to copy such files over, you can go ahead and uninstall iTunes from your Windows PC if you like. You shouldn’t need it.     

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  • Mail.app does not show new mail when iPod touch is active

    - by Debilski
    I have synchronised the e-Mail settings of the iPod touch with the settings of my IMAP account in Mail.app. Now sometimes the iPod would show there are new mails with Mail.app totally ignoring their existence for hours. Only when Mail.app is restarted would these new mails show up. Is there anything I can do that Mail.app is up-to-date even though the iPod is running?

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  • Is there any way to access the mp3 or other file type tags from within an ipod touch/iphone?

    - by quixotic1
    I am just looking for an existing app that will let me read all the tags that are stored in a particular song on my ipod touch/iphone. I'm not much of a programmer, but would be willing to learn the iphone sdk (on windows) if I could build a program that would do this for me. I would love to be able to modify the tag while on the iphone, but just viewing them would be a great use to me. I'd like to read the Year tag, the comments tag, composer, etc. It's so annoying that I can't do this. Or can I already and I just don't know how. Yes, I know how to view the lyrics tag. Seems they could have included the other tags. Help please? Thanks, Dave

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  • Is it possible to shuffle a 2D matrix while preserving row AND column frequencies?

    - by j_random_hacker
    Suppose I have a 2D array like the following: GACTG AGATA TCCGA Each array element is taken from a small finite set (in my case, DNA nucleotides -- {A, C, G, T}). I would like to randomly shuffle this array somehow while preserving both row and column nucleotide frequencies. Is this possible? Can it be done efficiently? [EDIT]: By this I mean I want to produce a new matrix where each row has the same number of As, Cs, Gs and Ts as the corresponding row of the original matrix, and where each column has the same number of As, Cs, Gs and Ts as the corresponding column of the original matrix. Permuting the rows or columns of the original matrix will not achieve this in general. (E.g. for the example above, the top row has 2 Gs, and 1 each of A, C and T; if this row was swapped with row 2, the top row in the resulting matrix would have 3 As, 1 G and 1 T.) It's simple enough to preserve just column frequencies by shuffling a column at a time, and likewise for rows. But doing this will in general alter the frequencies of the other kind. My thoughts so far: If it's possible to pick 2 rows and 2 columns so that the 4 elements at the corners of this rectangle have the pattern XY YX for some pair of distinct elements X and Y, then replacing these 4 elements with YX XY will maintain both row and column frequencies. In the example at the top, this can be done for (at least) rows 1 and 2 and columns 2 and 5 (whose corners give the 2x2 matrix AG;GA), and for rows 1 and 3 and columns 1 and 4 (whose corners give GT;TG). Clearly this could be repeated a number of times to produce some level of randomisation. Generalising a bit, any "subrectangle" induced by a subset of rows and a subset of columns, in which the frequencies of all rows are the same and the frequencies of all columns are the same, can have both its rows and columns permuted to produce a valid complete rectangle. (Of these, only those subrectangles in which at least 1 element is changed are actually interesting.) Big questions: Are all valid complete matrices reachable by a series of such "subrectangle rearrangements"? I suspect the answer is yes. Are all valid subrectangle rearrangements decomposable into a series of 2x2 swaps? I suspect the answer is no, but I hope it's yes, since that would seem to make it easier to come up with an efficient algorithm. Can some or all of the valid rearrangements be computed efficiently? This question addresses a special case in which the set of possible elements is {0, 1}. The solutions people have come up with there are similar to what I have come up with myself, and are probably usable, but not ideal as they require an arbitrary amount of backtracking to work correctly. Also I'm concerned that only 2x2 swaps are considered. Finally, I would ideally like a solution that can be proven to select a matrix uniformly at random from the set of all matrices having identical row frequencies and column frequencies to the original. I know, I'm asking for a lot :)

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  • Can an iPhone/iPod Touch application open a port for remote communication without jailbreaking?

    - by Derrick
    I'm researching remote control testing for an app that'll be installed on the new iPod Touch and can't tell for certain from everything that I've read whether or not an installed app can or can't open any ports for remote test instructions (that's a mouthful : ) We created something like this for the Android using adb port forwarding and telnet, and it worked really well. Is there any chance something similar could be done on an iPhone or iPod without jailbreaking??

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