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  • JQuery QuickSearch: Searching on load if the input isn't blank

    - by ckm-88
    I have used the jquery quicksearch plugin and it works fine, except for one problem. I would like the quicksearch to run when the page is loaded. I have created a second quicksearch function (which is called when the page is loaded) and changed the bind to something else, but it won't work on "load" or "ready". If I change the bind to "focus" and put the focus onto the textfield it works, but only in IE. The reason I want to do this is because there is a "view" link where the user leaves the page. When they come back, I would like the search results to be as they left them.

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  • Load custom class properly

    - by LinusAn
    I have a custom class which I want to "load" inside the firstViewController and then access it from other classes by segues. My Problem is, I can't even access and change the instance variable inside the firstViewController. Somehow I'm "loading" it wrong. Here is the code I used until now: inside viewController.h @property (strong, nonatomic) myClass *newClass; inside viewController.m @synthesize newClass; I then try to access it by: self.newClass.string = @"myString"; if(newClass.string == @"myString"){ NSLog(@"didn't work"); } Well, I get "didn't work". Why is that? When I write myClass *newClass = [myClass new]; It does work. But the class and its properties gets overwritten every time the ViewController loads again. What would you recommend? Thank you very much.

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  • DOMDocument::load in PHP 5

    - by Abs
    Hello all, I open a 10MB+ XML file several times in my script in different functions: $dom = DOMDocument::load( $file ) or die('couldnt open'); 1) Is the above the old style of loading a document? I am using PHP 5. Oppening it statically? 2) Do I need to close the loading of the XML file, if possible? I suspect its causing memory problems because I loop through the nodes of the XML file several thousand times and sometimes my script just ends abruptly. Thanks all for any help

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  • Javascript handle 2 data attribute

    - by user3530661
    I need to use data attribute in my html like <div id="userlist" data-user="A.A.M"></div> then I need to alert the data-user I used var userlist = document.getElementById("userlist"); var show = userlist.getAttribute("data-user"); alert(show); My question is how to handle many data-user in the html like <div id="userlist" data-user="A.A.M"></div> <div id="userlist2" data-user="A.A.M2"></div> to alert A.A.M and A.A.M2 Thanks in advance and sorry for my bad English.

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  • WPF animation/UI features performance and benchmarking

    - by Rich
    I'm working on a relatively small proof-of-concept for some line of business stuff with some fancy WPF UI work. Without even going too crazy, I'm already seeing some really poor performance when using a lot of the features that I thought were the main reason to consider WPF for UI building in the first place. I asked a question on here about why my animation was being stalled the first time it was run, and at the end what I found was that a very simple UserControl was taking almost half a second just to build its visual tree. I was able to get a work around to the symptom, but the fact that it takes that long to initialize a simple control really bothers me. Now, I'm testing my animation with and without the DropShadowEffect, and the result is night and day. A subtle drop shadow makes my control look so much nicer, but it completely ruins the smoothness of the animation. Let me not even start with the font rendering either. The calculation of my animations when the control has a bunch of gradient brushes and a drop shadow make the text blurry for about a full second and then slowly come into focus. So, I guess my question is if there are known studies, blog posts, or articles detailing which features are a hazard in the current version of WPF for business critical applications. Are things like Effects (ie. DropShadowEffect), gradient brushes, key frame animations, etc going to have too much of a negative effect on render quality (or maybe the combinations of these things)? Is the final version of WPF 4.0 going to correct some of these issues? I've read that VS2010 beta has some of these same issues and that they are supposed to be resolved by final release. Is that because of improvements to WPF itself or because half of the application will be rebuilt with the previous technology?

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  • Compiler optimization causing the performance to slow down

    - by aJ
    I have one strange problem. I have following piece of code: template<clss index, class policy> inline int CBase<index,policy>::func(const A& test_in, int* srcPtr ,int* dstPtr) { int width = test_in.width(); int height = test_in.height(); double d = 0.0; //here is the problem for(int y = 0; y < height; y++) { //Pointer initializations //multiplication involving y //ex: int z = someBigNumber*y + someOtherBigNumber; for(int x = 0; x < width; x++) { //multiplication involving x //ex: int z = someBigNumber*x + someOtherBigNumber; if(soemCondition) { // floating point calculations } *dstPtr++ = array[*srcPtr++]; } } } The inner loop gets executed nearly 200,000 times and the entire function takes 100 ms for completion. ( profiled using AQTimer) I found an unused variable double d = 0.0; outside the outer loop and removed the same. After this change, suddenly the method is taking 500ms for the same number of executions. ( 5 times slower). This behavior is reproducible in different machines with different processor types. (Core2, dualcore processors). I am using VC6 compiler with optimization level O2. Follwing are the other compiler options used : -MD -O2 -Z7 -GR -GX -G5 -X -GF -EHa I suspected compiler optimizations and removed the compiler optimization /O2. After that function became normal and it is taking 100ms as old code. Could anyone throw some light on this strange behavior? Why compiler optimization should slow down performance when I remove unused variable ? Note: The assembly code (before and after the change) looked same.

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  • Figuring out the performance limitation of an ADC on a PIC microcontroller

    - by AKE
    I'm spec-ing the suitability of a microcontroller like PIC for an analog-to-digital application. This would be preferable to using external A/D chips. To do that, I've had to run through some computations, pulling the relevant parameters from the datasheets. I'm not sure I've got it right -- would appreciate a check! Here's the simplest example: PIC10F220 is the simplest possible PIC with an ADC. Runs at clock speed of 8MHz. Has an instruction cycle of 0.5us (4 clock steps per instruction) So: Taking Tacq = 6.06 us (acquisition time for ADC, assume chip temp. = 50*C) [datasheet p34] Taking Fosc = 8MHz (? clock speed) Taking divisor = 4 (4 clock steps per CPU instruction) This gives TAD = 0.5us (TAD = 1/(Fosc/divisor) ) Conversion time is 13*TAD [datasheet p31] This gives conversion time 6.5us ADC duration is then 12.56 us [? Tacq + 13*TAD] Assuming at least 2 instructions for load/store: This is another 1 us [0.5 us per instruction] Which would give max sampling rate of 73.7 ksps (1/13.56) Supposing 8 more instructions for real-time processing: This is another 4 us Thus, total ADC/handling time = 17.56us (12.56us + 1us + 4us) So expected upper sampling rate is 56.9 ksps. Nyquist frequency for this sampling rate is therefore 28 kHz. If this is right, it suggests the (theoretical) performance suitability of this chip's A/D is for signals that are bandlimited to 28 kHz. Is this a correct interpretation of the information given in the data sheet? Any pointers would be much appreciated! AKE

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  • Average performance of binary search algorithm?

    - by Passionate Learner
    http://en.wikipedia.org/wiki/Binary_search_algorithm#Average_performance BinarySearch(int A[], int value, int low, int high) { int mid; if (high < low) return -1; mid = (low + high) / 2; if (A[mid] > value) return BinarySearch(A, value, low, mid-1); else if (A[mid] < value) return BinarySearch(A, value, mid+1, high); else return mid; } If the integer I'm trying to find is always in the array, can anyone help me write a program that can calculate the average performance of binary search algorithm? I know I can do this by actually running the program and counting the number of calls, but what I'm trying to do here is to do it without calling the function. I'm not asking for a time complexity, I'm trying to calculate the average number of calls. For example, the average number of calls to find a integer in A[2], it would be 1.67 (5/3).

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  • Load image dynamically on Silverlight

    - by FelixMM
    I have a Silverlight app that has to load an image dynamically, depending on the image name. The approach that im taking right now is passing the image name by query string to the page and passing that as a param to the Silverlight objet tag This is the query string passed Response.Redirect("Build.aspx?img=" + this.PictureUploader.PostedFile.FileName; And I try to pass it to Silverlight like this: <object id="SilverlightObject" data="data:application/x-silverlight-2," type="application/x-silverlight-2" width="100%" height="100%"> <param name="source" value="Silverlight/iMapsSL.xap"/> <param name="onError" value="onSilverlightError" /> <param name="background" value="white" /> <param name="minRuntimeVersion" value="3.0.40624.0" /> <param name="autoUpgrade" value="true" /> <param name="image" value="<%# Request.QueryString["img"] %>" /> <a href="http://go.microsoft.com/fwlink/?LinkID=149156&v=3.0.40624.0" style="text-decoration:none"> <img src="http://go.microsoft.com/fwlink/?LinkId=108181" alt="Get Microsoft Silverlight" style="border-style:none"/> </a> </object><iframe id="_sl_historyFrame" style="visibility:hidden;height:0px;width:0px;border:0px"></iframe> in the last param tag with name=image value= Requerst.QueryString I catch the image inside the Silverlight app like this private void Application_Startup(object sender, StartupEventArgs e) { string pictureName = ""; if (e.InitParams != null && e.InitParams.Count > 0) { pictureName = e.InitParams["image"]; this.RootVisual = new MainPage(pictureName); } else { this.RootVisual = new MainPage(); } } And when MainPage starts, I set the image source of the Image control like this this.Image.Source = new BitmapImage(new Uri(pictureName, UriKind.RelativeOrAbsolute)); But Silverlight loads without an image, any help someone?

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  • Aggregate Pattern and Performance Issues

    - by Mosh
    Hello, I have read about the Aggregate Pattern but I'm confused about something here. The pattern states that all the objects belonging to the aggregate should be accessed via the Aggregate Root, and not directly. And I'm assuming that is the reason why they say you should have a single Repository per Aggregate. But I think this adds a noticeable overhead to the application. For example, in a typical Web-based application, what if I want to get an object belonging to an aggregate (which is NOT the aggregate root)? I'll have to call Repository.GetAggregateRootObject(), which loads the aggregate root and all its child objects, and then iterate through the child objects to find the one I'm looking for. In other words, I'm loading lots of data and throwing them out except the particular object I'm looking for. Is there something I'm missing here? PS: I know some of you may suggest that we can improve performance with Lazy Loading. But that's not what I'm asking here... The aggregate pattern requires that all objects belonging to the aggregate be loaded together, so we can enforce business rules.

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  • performance of large number calculations in python (python 2.7.3 and .net 4.0)

    - by g36
    There is a lot of general questions about python performance in comparison to other languages. I've got more specific example: There are two simple functions wrote in python an c#, both checking if int number is prime. python: import time def is_prime(n): num =n/2 while num >1: if n % num ==0: return 0 num-=1 return 1 start = time.clock() probably_prime = is_prime(2147483629) elapsed = (time.clock() - start) print 'time : '+str(elapsed) and C#: using System.Diagnostics; public static bool IsPrime(int n) { int num = n/2; while(num >1) { if(n%num ==0) { return false; } num-=1; } return true; } Stopwatch sw = new Stopwatch(); sw.Start(); bool result = Functions.IsPrime(2147483629); sw.Stop(); Console.WriteLine("time: {0}", sw.Elapsed); And times ( which are surprise for me as a begginer in python:)): Python: 121s; c#: 6s Could You explain where does this big diffrence come from ?

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  • Important question about linq to SQL performance on high loaded web applications

    - by Alex
    I started working with linq to SQL several weeks ago. I got really tired of working with SQL server directly through the SQL queries (sqldatareader, sqlcommand and all this good stuff).  After hearing about linq to SQL and mvc I quickly moved all my projects to these technologies. I expected linq to SQL work slower but it suprisongly turned out to be pretty fast, primarily because I always forgot to close my connections when using datareaders. Now I don't have to worry about it. But there's one problem that really bothers me. There's one page that's requested thousands of times a day. The system gets data in the beginning, works with it and updates it. Primarily the updates are ++ @ -- (increase and decrease values). I used to do it like this UPDATE table SET value=value+1 WHERE ID=@I'd It worked with no problems obviously. But with linq to SQL the data is taken in the beginning, moved to the class, changed and then saved. Stats.registeredusers++; Db.submitchanges(); Let's say there were 100 000 users. Linq will say "let it be 100 001" instead of "let it be increased by 1". But if there value of users has already been increased (that happens in my site all the time) then linq will be like oops, this value is already 100 001. Whatever I'll throw an exception" You can change this behavior so that it won't throw an exception but it still will not set the value to 100 002. Like I said, it happened with me all the time. The stas value was increased twice a second on average. I simply had to rewrite this chunk of code with classic ado net. So my question is how can you solve the problem with linq

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  • Improving field get and set performance with ASM or Javassist

    - by ng
    I would like to avoid reflection in an open source project I am developing. Here I have classes like the following. public class PurchaseOrder { @Property private Customer customer; @Property private String name; } I scan for the @Property annotation to determine what I can set and get from the PurchaseOrder reflectively. There are many such classes all using java.lang.reflect.Field.get() and java.lang.reflect.Field.set(). Ideally I would like to generate for each property an invoker like the following. public interface PropertyAccessor<S, V> { public void set(S source, V value); public V get(S source); } Now when I scan the class I can create a static inner class of PurchaseOrder like so. static class customer_Field implements PropertyAccessor<PurchaseOrder, Customer> { public void set(PurchaseOrder order, Customer customer) { order.customer = customer; } public Customer get(PurchaseOrder order) { return order.customer; } } With these I totally avoid the cost of reflection. I can now set and get from my instances with native performance. Can anyone tell me how I would do this. A code example would be great. I have searched the net for a good example but can find nothing like this. The ASM and Javasist examples are pretty poor also. The key here is that I have an interface that I can pass around. So I can have various implementations, perhaps one with Java Reflection as a default, one with ASM, and one with Javassist? Any help would be greatly appreciated.

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  • How to lazy load scripts in YUI that accompany ajax html fragments

    - by Chris Beck
    I have a web app with Tabs for Messages and Contacts (think gmail). Each Tab has a Y.on('click') event listener that retrieves an HTML fragment via Y.io() and renders the fragment via node.setContent(). However, the Contact Tab also requires contact.js to enable an Edit button in the fragment. How do I defer the cost of loading contact.js until the user clicks on the Contacts tab? How should contact.js add it's listener to the Edit button? The Complete function of my Tab's on('click') event could serialize Get.script('contact.js') after Y.io('fragment'). However, for better performance, I would prefer to download the script in parallel to downloading the HTML fragment. In that case, I would need to defer adding an event listener to the Edit button until the Edit button is available. This seems like a common RIA design pattern. What is the best way to implement this with YUI? How should I get the script? How should I defer sections of the script until elements in the fragment are available in the DOM?

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  • Improving Performance on this Image Creation function

    - by Abs
    Hello all, I am making use of GD2 and the image functions to take in a string and then convert that into an image using different fonts at different sizes. The function I use is below. Currently, its pretty quick but not quick enough. The function gets called about 20 times per user and the images generated are always new ones (different) so caching isn't going to help! I was hoping to get some ideas on how to make this function faster. Maybe supply more RAM to the script running? Anything else that is specific to this PHP function? Anything else that I can do to tweak performance of this function? function generate_image($save_path, $text, $font_path, $font_size){ $font = $font_path; /* * I have simplifed the line below, its actually a function that works out the size of the box * that is need for each image as the image size is different based on font type, font size etc */ $measure = array('width' => 300, 'height'=> 120); if($measure['width'] > 900){ $measure['width'] = 900; } $im = imagecreatetruecolor($measure['width'], $measure['height']); $white = imagecolorallocate($im, 255, 255, 255); $black = imagecolorallocate($im, 0, 0, 0); imagefilledrectangle($im, 0, 0, $measure['width'], $measure['height'], $white); imagettftext($im, $font_size, 0, $measure['left'], $measure['top'], $black, $font, ' '.$text); if(imagepng($im, $save_path)){ $status = true; }else{ $status = false; } imagedestroy($im); return $status; } Thanks all for any help

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  • Improving field get and set performance with ASM

    - by ng
    I would like to avoid reflection in an open source project I am developing. Here I have classes like the following. public class PurchaseOrder { @Property private Customer customer; @Property private String name; } I scan for the @Property annotation to determine what I can set and get from the PurchaseOrder reflectively. There are many such classes all using java.lang.reflect.Field.get() and java.lang.reflect.Field.set(). Ideally I would like to generate for each property an invoker like the following. public interface PropertyAccessor<S, V> { public void set(S source, V value); public V get(S source); } Now when I scan the class I can create a static inner class of PurchaseOrder like so. static class customer_Field implements PropertyAccessor<PurchaseOrder, Customer> { public void set(PurchaseOrder order, Customer customer) { order.customer = customer; } public Customer get(PurchaseOrder order) { return order.customer; } } With these I totally avoid the cost of reflection. I can now set and get from my instances with native performance. Can anyone tell me how I would do this. A code example would be great. I have searched the net for a good example but can find nothing like this. The ASM examples are pretty poor also. The key here is that I have an interface that I can pass around. So I can have various implementations, perhaps one with Java Reflection as a default, one with ASM, and maybe one with Javassist? Any help would be greatly appreciated.

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  • lots of backbone views - performance issues?

    - by ksol
    tl;dr: I wonder if having lots (100+ for the moment, potentially up to 1000/2000 or more) of backbone views (as a cell of a table) is too heavy or not The project I'm working on revolves around a planning view. There one row per user that covers 6 hours of a day, each hour splitted in 4 slots of 15mn. This planning is used to add "reservations" when clicking on a slot, and should handle hovering of the correct slots, and also handle when it is NOT possible to make a reservation - ie. prevent user click on an "unavailable" slot. There is many reasons why a slot can't be clicked on: the user is not available at this time, or the user is in a reservation; or the app needs to "force" a delay slot between two reservations. Reservations (a div) are rendered in a slot (a cell of a table), and by toying with dimensions, hovers the right number of slots. All this screen is handled with backbone. So For each slot I'm hovering on, I need to check wether I can do a reservation here or not. As of this moment, I use this by toying with the data attributes on the slots : when a reservation object is added, the slots covered are "enhanced with (among others) the reservation object (the backbone view object). But in some cases I don't quite have a grasp on now, it mixes up, and when the reservation view is removed, the slots are not "cleaned up" : the previous class is not reset correctly. It is probably something I've done wrong or badly, but this is only going to get heavier; I think I should use another class of Backbone views here, but I'm afraid the number of slots and thereof of views objects will be high and cause performance issue. I don't know mush about js perf so I'd like to have some feedback before jumping on that train. Any other advice on how to do this would be quite welcomed too. Thanks for your time. If this is not clear enough, tell me, I'll try and rephrase it.

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  • linq: SQL performance on high loaded web applications

    - by Alex
    I started working with linq to SQL several weeks ago. I got really tired of working with SQL server directly through the SQL queries (sqldatareader, sqlcommand and all this good stuff).  After hearing about linq to SQL and mvc I quickly moved all my projects to these technologies. I expected linq to SQL work slower but it suprisongly turned out to be pretty fast, primarily because I always forgot to close my connections when using datareaders. Now I don't have to worry about it. But there's one problem that really bothers me. There's one page that's requested thousands of times a day. The system gets data in the beginning, works with it and updates it. Primarily the updates are ++ @ -- (increase and decrease values). I used to do it like this UPDATE table SET value=value+1 WHERE ID=@I'd It worked with no problems obviously. But with linq to SQL the data is taken in the beginning, moved to the class, changed and then saved. Stats.registeredusers++; Db.submitchanges(); Let's say there were 100 000 users. Linq will say "let it be 100 001" instead of "let it be increased by 1". But if there value of users has already been increased (that happens in my site all the time) then linq will be like oops, this value is already 100 001. Whatever I'll throw an exception" You can change this behavior so that it won't throw an exception but it still will not set the value to 100 002. Like I said, it happened with me all the time. The stas value was increased twice a second on average. I simply had to rewrite this chunk of code with classic ado net. So my question is how can you solve the problem with linq

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  • Performance impact when using XML columns in a table with MS SQL 2008

    - by Sam Dahan
    I am using a simple table with 6 columns, 3 of which are of XML type, not schema-constrained. When the table reaches a size around 120,000 or 150,000 rows, I see a dramatic performance cost in doing any query in the table. For comparison, I have another table, which grows in size at about the same rate, but only contain scalar types (int, datetime, a few float columns). That table performs perfectly fine even after 200,000 rows. And by the way, I am not using XQuery on the xml columns, i am only using regular SQL query statements. Some specifics: both tables contain a DateTime field called SampleTime. a statement like (it's in a stored procedure but I show you the actual statement) SELECT MAX(sampleTime) SampleTime FROM dbo.MyRecords WHERE PlacementID=@somenumber takes 0 seconds on the table without xml columns, and anything from 13 to 20 seconds on the table with XML columns. That depends on which drive I set my database on. At the moment it sits on a different spindle (not C:) and it takes 13 seconds. Has anyone seen this behavior before, or have any hint at what I am doing wrong? I tried this with SQL 2008 EXPRESS and the full-blown SQL Server 2008, that made no difference. Oh, one last detail: I am doing this from a C# application, .NET 3.5, using SqlConnection, SqlReader, etc.. I'd appreciate some insight into that, thanks! Sam

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  • jqtouch load content with ajax

    - by ndrizza
    I am loading this page directly inside of jqtouch. First the page shows "Loading..." Then it should execute a GET Request and refresh the content of the div ("tagcloud") as soon as it get's the content from another php file. (I prefer to load the content this way as otherwise jqtouch freezes for 2 seconds until the content is loaded and then animates to the next page.) <?php $link = $_GET['link']; ?> <div id="TagNews"> <div class="toolbar"> <h1>TagNews</h1> <a href="#" class="back">NZZ</a> </div> <div id="tagcloud">Loading...</div> <script type="text/javascript"> $.get("cloudnews2.php?link=<?php echo $link; ?>", function(data){ document.getElementById("tagcloud").innerHTML = data; }); </script> </div> Howewer, the request never gets loaded. The code is working outside of jqtouch. But inside jqtouch the GET Request doesn't work. I can't figure out why. Could you please help me to do this request?

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  • Slow performance with MVC2 DisplayFor

    - by PretzelSteelersFan
    I'm iterating through a collection on my view model. The collection contains HealthLifeDentalRates which implement IBeginsEnds. I have a Display Template BeginsEnds that displays the date range. This results in very slow performance. If I simply the date range (see commented code), it's fine. I think how I'm defining the lambda is the problem but not sure how to change it. <% foreach (var item in Model.Data.OrderBy(x=x.HealthLifeDentalRateCode)) { % <tr> <td> <%= Html.Encode(item.FiscalPeriodString()) %> </td> <td> <%= Html.Encode(item.HealthLifeDentalRateCode) %> </td> <td> <%= Html.Encode(item.Rate) %> </td> <td> <%= Html.Encode(item.IsDental.YesNo()) %> </td> <td> <%= Html.DisplayFor(i = item, "BeginsEnds") % - <%= Html.Encode(item.Ends.ToDateString()) % -- <%= Html.Encode(String.Format("{0:g}", item.Loaded)) % - <%= Html.Encode(item.LoadedBy) % <% } %>

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  • psqlODBC won't load after installing MS SQL ODBC driver on RHEL 6

    - by Kapil Vyas
    I had the PostgreSQL drivers working on my RHEL 6. But after I installed Microsoft® SQL Server® ODBC Driver 1.0 for Linux I can no longer connect to PosgreSQL data sources. I can connect to SQL Server data sources fine. When I had this same issue a week ago I uninstalled MS SQL Server ODBC driver from Linux and it fixed the issue. I had to copy the psqlodbcw.so files from another machine to replenish the files. I don't want to do the same this time. I want both drivers to work on Linux. This time around the setup files got deleted: /usr/lib64/libodbcpsqlS.so. Replenishing it did not fix the issue. I kept getting the following error in spite of the file being present with rwx permisions: [root@localhost lib64]# isql -v STUDENT dsname pwd12345 [01000][unixODBC][Driver Manager]Can't open lib '/usr/lib64/psqlodbc.so' : file not found [ISQL]ERROR: Could not SQLConnect [root@localhost lib64]# Here is a printout of the file permissions: [root@localhost lib64]# ls -al p*.so lrwxrwxrwx. 1 root root 12 Dec 7 09:15 psqlodbc.so -> psqlodbcw.so -rwxr-xr-x. 1 root root 519496 Dec 7 09:35 psqlodbcw.so and my odbcinst.ini file looks as follows: [PostgreSQL] Description=ODBC for PostgreSQL Driver=/usr/lib/psqlodbc.so Driver64=/usr/lib64/psqlodbc.so Setup=/usr/lib/libodbcpsqlS.so Setup64=/usr/lib64/libodbcpsqlS.so FileUsage=1 UsageCount=4 I also referred to this link: http://mailman.unixodbc.org/pipermail/unixodbc-support/2010-September.txt

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  • STL vector performance

    - by iAdam
    STL vector class stores a copy of the object using copy constructor each time I call push_back. Wouldn't it slow down the program? I can have a custom linkedlist kind of class which deals with pointers to objects. Though it would not have some benefits of STL but still should be faster. See this code below: #include <vector> #include <iostream> #include <cstring> using namespace std; class myclass { public: char* text; myclass(const char* val) { text = new char[10]; strcpy(text, val); } myclass(const myclass& v) { cout << "copy\n"; //copy data } }; int main() { vector<myclass> list; myclass m1("first"); myclass m2("second"); cout << "adding first..."; list.push_back(m1); cout << "adding second..."; list.push_back(m2); cout << "returning..."; myclass& ret1 = list.at(0); cout << ret1.text << endl; return 0; } its output comes out as: adding first...copy adding second...copy copy The output shows the copy constructor is called both times when adding and when retrieving the value even then. Does it have any effect on performance esp when we have larger objects?

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  • Using std::ifstream to load in an array of struct data type into a std::vector

    - by Sent1nel
    I am working on a bitmap loader in C++ and when moving from the C style array to the std::vector I have run into an usual problem of which Google does not seem to have the answer. 8 Bit and 4 bit, bitmaps contain a colour palette. The colour palette has blue, green, red and reserved components each 1 byte in size. // Colour palette struct BGRQuad { UInt8 blue; UInt8 green; UInt8 red; UInt8 reserved; }; The problem I am having is when I create a vector of the BGRQuad structure I can no longer use the ifstream read function to load data from the file directly into the BGRQuad vector. // This code throws an assert failure! std::vecotr quads; if (coloursUsed) // colour table available { // read in the colours quads.reserve(coloursUsed); inFile.read( reinterpret_cast(&quads[0]), coloursUsed * sizeof(BGRQuad) ); } Does anyone know how to read directly into the vector without having to create a C array and copy data into the BGRQuad vector?

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  • Load PHP function with jQuery Ajax

    - by brandon14_99
    I have a file which is loaded at the top of my document, which is called Videos.php. Inside that file are several functions, such as getYoutubeVideos. On some pages, I need to call upon that function several times (up to 50), and it of course creates major lag on load times. So I have been trying to figure out how to call that function in, only when it is need (when someone clicks the show videos button). I have very little experience with jQuery's ajax abilities. I would like the ajax call to be made inside of something like this: jQuery('a[rel=VideoPreview1).click(function(){ jQuery ("a[rel=VideoPreview1]").hide(); jQuery ("a[rel=HideVideoPreview1]").show(); jQuery ("#VideoPreview1").show(); //AJAX STUFF HERE preventDefault(); }); Ok I have created this based on the responses, but it is still not working: jQuery Code: jQuery(document).ready(function(){ jQuery("a[rel=VideoPreview5]").click(function(){ jQuery("a[rel=VideoPreview5]").hide(); jQuery("a[rel=HideVideoPreview5]").show(); jQuery.post("/Classes/Video.php", {action: "getYoutubeVideos", artist: "Train", track: "Hey, Soul Sister"}, function(data){ jQuery("#VideoPreview5").html(data); }, 'json'); jQuery("#VideoPreview5").show(); preventDefault(); }); jQuery("a[rel=HideVideoPreview5]").click(function(){ jQuery("a[rel=VideoPreview5]").show(); jQuery("a[rel=HideVideoPreview5]").hide(); jQuery("#VideoPreview5").hide(); preventDefault(); }); }); And the PHP code: $Action = isset($_POST['action']); $Artist = isset($_POST['artist']); $Track = isset($_POST['track']); if($Action == 'getYoutubeVideos') { echo 'where are the videos'; echo json_encode(getYoutubeVideos($Artist.' '.$Track, 1, 5, 'relevance')); }

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