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  • Php using unserialize() and serialize() changing values in a saved file

    - by Doodle
    I have a serialized array of values saved to a file and need to change the value of one of the variables. In the example I change the value of $two and then save the whole array back into the file with the new value. Is there a more efficient way of altering just the single value with out having to read and write the entire file/array. $data = file_get_contents('./userInfo'); $data = unserialize($data); extract($data); $two="this is a altered value"; $userData = array( 'one' => $one, 'two' => $two, 'three' => $three ); $file=fopen("../userInfo",'w'); fwrite($file, $userData); fclose($file);

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  • The fastest way to do a collection subtraction

    - by Tony
    I have two Sets. Set<B> b is the subset of Set<A> a. they're both very huge Sets. I want to subtract b from a , what's the best practice to do this common operation ? I've written to many codes like this , and I don't think it's efficient. what's your idea ? for(int i = 0 ; i < a.size(); i++) { for (int j=0 ; j < b.size() ;j++) { // do comparison , if found equals ,remove from a break; } } And I want to find an algorithm , not only applies to Sets, also works for Array.

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  • Are there any programs to aid in the mass-editing of Visual SourceSafe checkin comments?

    - by Schnapple
    I know that in Visual SourceSafe you can go in and drill down to the history of an individual file and then drill down to an individual check-in and apply a comment to the check-in that way but that's tedious and time consuming - if you have a lot of files that were checked in at the same time and you want the same comment to apply to all of them this will take forever. I use the tool VSSReporter to generate reports of checkins and other stuff from VSS, but it cannot edit anything, only report on them. Are there any tools which will let you go back and retroactively apply comments to check-ins in an efficient and easy manner?

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  • Concurrent web requests with Ruby (Sinatra?)?

    - by cbmeeks
    I have a Sinatra app that basically takes some input values and then finds data matching those values from external services like Flickr, Twitter, etc. For example: input:"Chattanooga Choo Choo" Would go out and find images at Flickr on the Chattanooga Choo Choo and tweets from Twitter, etc. Right now I have something like: @images = Flickr::...find...images.. @tweets = Twitter::...find...tweets... @results << @images @results << @tweets So my question is, is there an efficient way in Ruby to run those requests concurrently? Instead of waiting for the images to finish before the tweets finish. Thanks.

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  • Efficiency of checking for null varbinary(max) column ?

    - by Moe Sisko
    Using SQL Server 2008. Example table : CREATE table dbo.blobtest (id int primary key not null, name nvarchar(200) not null, data varbinary(max) null) Example query : select id, name, cast((case when data is null then 0 else 1 end) as bit) as DataExists from dbo.blobtest Now, the query needs to return a "DataExists" column, that returns 0 if the blob is null, else 1. This all works fine, but I'm wondering how efficient it is. i.e. does SQL server need to read in the whole blob to its memory, or is there some optimization so that it just does enough reads to figure out if the blob is null or not ? (FWIW, the sp_tableoption "large value types out of row" option is set to OFF for this example).

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  • bi-directional o2m/m2o beats uni-directional o2m in SQL efficiency?

    - by Henry
    Use these 2 persistent CFCs for example: // Cat.cfc component persistent="true" { property name="id" fieldtype="id" generator="native"; property name="name"; } // Owner.cfc component persistent="true" { property name="id" fieldtype="id" generator="native"; property name="cats" type="array" fieldtype="one-to-many" cfc="cat" cascade="all"; } When one-to-many (unidirectional) Note: inverse=true on unidirectional will yield undesired result: insert into cat (name) values (?) insert into Owner default values update cat set Owner_id=? where id=? When one-to-many/many-to-one (bi-directional, inverse=true on Owner.cats): insert into Owner default values insert into cat (name, ownerId) values (?, ?) Does that mean setting up bi-directional o2m/m2o relationship is preferred 'cause the SQL for inserting the entities is more efficient?

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  • Check if BigDecimal is integer value

    - by Adamski
    Can anyone recommend an efficient way of determining whether a BigDecimal is an integer value in the mathematical sense? At present I have the following code: private boolean isIntegerValue(BigDecimal bd) { boolean ret; try { bd.toBigIntegerExact(); ret = true; } catch (ArithmeticException ex) { ret = false; } return ret; } ... but would like to avoid the object creation overhead if necessary. Previously I was using bd.longValueExact() which would avoid creating an object if the BigDecimal was using its compact representation internally, but obviously would fail if the value was too big to fit into a long. Any help appreciated.

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  • How to use Haar wavelet to detect LINES on an image?

    - by Ole Jak
    So I have Image like this I want to get something like this (I hevent drawn all lines I want but I hope you can get my idea) I want to use SURF ( (Speeded Up Robust Features) is a robust image descriptor, first presented by Herbert Bay et al. in 2006 ) or something that is based on sums of 2D Haar wavelet responses and makes an efficient use of integral images for finding all straight lines on image. I want to get relative to picture pixel coords start and end points of lines. So on this picture to find all lines between tiles and thouse 2 black lines on top. Is there any such Code Example (with lines search capability) to start from? I love C and C++ but any other readable code will probably work for me=)

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  • Distributed datastore

    - by Julien Genestoux
    We're trying to add some kind of persistence in our app. The app generates about 250 entries per second. Each of these entries belong to one of 2M files. For each file, we want to keep the last 10 entries, so we can look them up later. The way our client application works : it gets a stream of all the data it fetches the right file (GET) it adds the new content it saves the file back (PUT) We're looking for an efficient way to store this data that can scale horizontally as the amount of data we're getting is doubling every few weeks. We initially looked at S3. It works fine, but becomes very expensive very fast ($1000 monthly just in PUT operations!) We then gave a shot at Riak. But it seems we can't get more than 60 write/sec on each node, which is very very slow. Any other solution out there?

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  • Optimization of running total calculation in SQL for multiple values per join condition

    - by Kiril
    I have the following table (test_table): date value --------------- d1 10.0 d1 20.0 d2 60.0 d2 10.0 d2 -20.0 d3 40.0 I calculate the running total as follows. I use the same query twice, because first I need to calculate the values for a specifi date, and afterwards I can calculate the running total. Otherwise, joining the two tables where date is not unique, I would get too many results from the join: SELECT t1.date, SUM(t2.value) AS total FROM (SELECT date, SUM(value) AS value FROM test_table GROUP BY date) AS t1 JOIN (SELECT date, SUM(value) AS value FROM test_table GROUP BY date) AS t2 ON t1.date >= t2.date GROUP BY t1.date ORDER BY t1.date This gives me (which is fine): date total ------------- d1 30.0 d2 80.0 d3 120.0 BUT, this query isn't very efficient, because I need to change conditions in two places, if necessary. In production, the test_table is a lot bigger ( 4 Mio. rows), and the query takes too much time to complete. Question: How can I avoid using the same query twice?

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  • How to achieve a palette effect on iPhone using OpenGL

    - by Joe
    I'm porting a 2d retro game to iPhone that has the following properties: targets OpenGL ES 1.1 entire screen is filled with tiles (textured triangle strip tile textured using a single 256x256 RGBA texture image the texture is passed to OpenGL once at the start of the game only 4 displayed colours are used one of the displayed colours is black The original game flashed the screen when time starts to run out by toggling the black pixels to white using an indexed palette. What is the best (i.e. most efficient) way to achieve this in OpenGL ES 1.1? My thoughts so far: Generate an alternative texture with white instead of black pixels, and pass to OpenGL when the screen is flashing Render a white poly underneath the background and render the texture with alpha on to display it Try and render a poly on top with some blending that achieves the effect (not sure this is possible) I'm fairly new to OpenGL so I'm not sure what the performance drawbacks of each of these are, or if there's a better way of doing this.

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  • Remove Duplicates from List of HashMap Entries

    - by HonorGod
    I have a List<HashMap<String,Object>> which represents a database where each list record is a database row. I have 10 columns in my database. There are several rows where the values of 2 particular columns are equals. I need to remove the duplicates from the list after the list is updated with all the rows from database. What is the efficient way? FYI - I am not able to do distinct while querying the database, because the GroupName is added at a later stage to the Map after the database is loaded. And since Id column is not primary key, once you add GroupName to the Map. You will have duplicates based on Id + GroupName combination! Hope my question makes sense. Let me know if we need more clarification.

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  • Detecting syllables in a word

    - by user50705
    I need to find a fairly efficient way to detect syllables in a word. E.g., invisible - in-vi-sib-le There are some syllabification rules that could be used: V CV VC CVC CCV CCCV CVCC *where V is a vowel and C is a consonant. e.g., pronunciation (5 Pro-nun-ci-a-tion; CV-CVC-CV-V-CVC) I've tried few methods, among which were using regex (which helps only if you want to count syllables) or hard coded rule definition (a brute force approach which proves to be very inefficient) and finally using a finite state automata (which did not result with anything useful). The purpose of my application is to create a dictionary of all syllables in a given language. This dictionary will later be used for spell checking applications (using Bayesian classifiers) and text to speech synthesis. I would appreciate if one could give me tips on an alternate way to solve this problem besides my previous approaches. I work in Java, but any tip in C/C++, C#, Python, Perl... would work for me.

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  • How can I efficiently group a large list of URLs by their host name in Perl?

    - by jesper
    I have text file that contains over one million URLs. I have to process this file in order to assign URLs to groups, based on host address: { 'http://www.ex1.com' = ['http://www.ex1.com/...', 'http://www.ex1.com/...', ...], 'http://www.ex2.com' = ['http://www.ex2.com/...', 'http://www.ex2.com/...', ...] } My current basic solution takes about 600 MB of RAM to do this (size of file is about 300 MB). Could you provide some more efficient ways? My current solution simply reads line by line, extracts host address by regex and puts the url into a hash. EDIT Here is my implementation (I've cut off irrelevant things): while($line = <STDIN>) { chomp($line); $line =~ /(http:\/\/.+?)(\/|$)/i; $host = "$1"; push @{$urls{$host}}, $line; } store \%urls, 'out.hash';

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  • Coordinate geometry operations in images/discrete space

    - by avd
    I have images which have line segments, rays etc. I am representing these line segments using Bresenham algorithm (means whatever coordinates I get using this algorithm between two points). Now I want to do operations such as finding intersection point between two line segments, finding the projection of one vector onto other etc... The problem is I am not working in continuous space. The line segments are being approximated using Bresenham algorithm. So I want suggestions on what are the best and most efficient ways to do this? A link to C++ library or implementation would also be good enough. Please suggest some books which deal with such problems.

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  • Re-using jQuery widgets

    - by Micor
    I am looking for a most efficient way to re-use widgets with different selectors... For example if I have: $("#selector1").datepicker({ beforeShow: function(var1,var2) { // do stuff }, onClose: function(var1,var2) { // do stuff }, onSelect: function(var1,var2) { // do stuff } }) And later I am looking to assign this same widget with same functions inside to other selectors which are not known at load time. Since its not about choosing a better selector and I want to avoid: $("#new-selector2").datepicker({ beforeShow: function(var1,var2) { // do stuff }, onClose: function(var1,var2) { // do stuff }, onSelect: function(var1,var2) { // do stuff } }) $("#new-selector3").datepicker({ beforeShow: function(var1,var2) { // do stuff }, onClose: function(var1,var2) { // do stuff }, onSelect: function(var1,var2) { // do stuff } }) What would be the best way of doing something like: var reusableDatepicker = datepicker({ beforeShow: function(var1,var2) { // do stuff }, onClose: function(var1,var2) { // do stuff }, onSelect: function(var1,var2) { // do stuff } }) $("#selector1").attach(reusableDatepicker); $("#new-selector2").attach(reusableDatepicker); $("#new-selector3").attach(reusableDatepicker); I know it has to be obvious to all jQuery devs out there, so obvious I cannot find it in docs :) Thank you!

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  • use dll from remote computer

    - by maraheem
    i have two computer PC1 and PC2 in PC1 i have a .Net C# dll file that provides operations on sql server database. my question is - "how can i use this dll file on PC2 through VBScript within Outlook 2003". I tried this same task on PC1 and i succeeded using the CreateObject("dllfilename.classname") method of VBScript within outlook 2003. but now i want to use that dll file on PC2. is there any efficient way by which i can use that dll on PC2 without having to copy dll on PC2.

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  • Doing a "Diff" on an Associative Array in javascript / jQuery?

    - by Matrym
    If I have two associative arrays, what would be the most efficient way of doing a diff against their values? For example, given: array1 = { foreground: 'red', shape: 'circle', background: 'yellow' }; array2 = { foreground: 'red', shape: 'square', angle: '90', background: 'yellow' }; How would I check one against the other, such that the items missing or additional are the resulting array. In this case, if I wanted to compare array1 within array2, it would return: array3 = {shape: 'circle'} Whilst if I compared array2 within array1, it would return: array3 = {shape: 'square', angle: '90'} Thanks in advance for your help!

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  • Searching Techniques/Algorithms for Resources over a given area

    - by Raydon
    I have a flat area with nodes randomly placed on this flat surface. I need techniques which are able to take a starting point, move in a certain way (the algorithm), find nodes and continue searching. I do not have an overall view of the surface (i.e. I cannot see everything), only a limited view (i.e. 4 cells in any direction). Ideally, these methods would be efficient in the way that they work. Any points in the right direction would be greatly appreciated.

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  • MySQL slow query

    - by andrhamm
    SELECT items.item_id, items.category_id, items.title, items.description, items.quality, items.type, items.status, items.price, items.posted, items.modified, zip_code.state_prefix, zip_code.city, books.isbn13, books.isbn10, books.authors, books.publisher FROM ( ( items LEFT JOIN bookitems ON items.item_id = bookitems.item_id ) LEFT JOIN books ON books.isbn13 = bookitems.isbn13 ) LEFT JOIN zip_code ON zip_code.zip_code = items.item_zip WHERE items.rid = $rid` I am running this query to get the list of a user's items and their location. The zip_code table has over 40k records and this might be the issue. It currently takes up to 15 seconds to return a list of about 20 items! What can I do to make this query more efficient?

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  • Silverlight 3-4 reference kind (e-)book.

    - by Bubba88
    Hello! I'm looking for a source of information about Microsoft Silverlight to begin practically efficient programming custom functionality applications. I want to pretend just for now that I don't need any ideologically correct refresher (SL tips, top patterns, VS tutorials :) and etc.). Basically, what I want is a reference kind e-book, where I could find any practically relevant info outlined in a minimalistic manner. If you do remember something fitting the above description, I ask you to give me a hint. Thank you very much!

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  • What do I use when a cron job isn't enough? (php)

    - by mike
    I'm trying to figure out the most efficient way to running a pretty hefty PHP task thousands of times a day. It needs to make an IMAP connection to Gmail, loop over the emails, save this info to the database and save images locally. Running this task every so often using a cron isn't that big of a deal, but I need to run it every minute and I know eventually the crons will start running on top of each other and cause memory issues. What is the next step up when you need to efficiently run a task multiple times a minute? I've been reading about beanstalk & pheanstalk and I'm not entirely sure if that will do what I need. Thoughts???

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  • SDK for writing DVD's

    - by Matt Warren
    I need to add DVD writing functionality to an application I'm working on. However it needs to be able to write out files that are being grabbed "live" from a camera, over a long period of time. I can't wait until all the files are captured before I start writing them to the DVD, I need to write them out in chunks as I go along. I've looked at IMAPI v2, but the main problems seems to be that you need to point it to all the files you plan to write out to disk before you start the burning process. I know it has to concept of "sessions", which means you can write to the DVD in several parts, before you finally "close" it. But I was wondering if there were any other DVD writing SDK's that allow you to be constantly writing files to a DVD and in particular files that are only in memory. It would be more efficient if I didn't have to write the captured images out to hard before they are burned to DVD. The solution needs to work under .NET on Windows XP and vista

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  • Algorithm to aggregate values from child tree nodes

    - by user222164
    I have objects in a tree structure, I would like to aggregate status information from children nodes and update parent node with aggregated status. Lets say node A has children B1, B2, and B1 has C1, C2, C3 as children. Each of the nodes have a status attribute. Now if C1, C2, C3 are all complete then I would like to mark B1 as completed. And if C4, C5,C6,C7 are complete make B2 as complete. When B1 and B2 are both complete mark A as complete. I can go through these nodes in brute force method and make updates, could someone suggest an efficient algorithm to do it. A { B1 { C1, C2, C3}, B2 { C4, C5, C6, C7} }

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  • Matrix Comparison algorithm

    - by SysAdmin
    If you have 2 Matrices of dimensions N*M. what is the best way to get the difference Rect? Example: 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 4 5 4 3 2 3 <---> 2 3 2 3 2 3 2 3 2 3 4 5 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 2 3 | | \ / Rect([2,2] , [3,4]) 4 5 4 4 5 2-> A (2 x 3 Matrix) The best I could think of is to scan from Top-Left hit the point where there is difference. Then scan from Bottom Right and hit the point where there is a difference. But In worst case, this is O(N*M). is there a better efficient algorithm?

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