Search Results

Search found 7213 results on 289 pages for 'multi processor'.

Page 259/289 | < Previous Page | 255 256 257 258 259 260 261 262 263 264 265 266  | Next Page >

  • Multisite Enabling a Table

    - by Joe Fitzgibbons
    I am creating a table (table A) that will have a number of columns(of course) and there will be another table (table B) that holds metadata associated to rows in table A. I am working with a multi site implementation that has one database for the whole shabang. Rows in table A could belong to any number of sites but must belong to at least one. The problem I have is I am not sure what the best practice is for defining what site each row in table A belongs to. I want performance and scalability. There is no finite number of sites going forward. Rows in table A could belong to any number of sites in the future. Right now there are only 3. My initial thoughts are to have a primary site ID in Table A and then metadata in table B will have rows defining additional sites as needed. Another thought is to have a column in Table A for each site and it is a boolean as to wether it belongs to that site. Lastly I have thought about having another table to map rows in Table A to each site. What is the best way to associate rows in a table with any number of sites with performance and scalability in mind?

    Read the article

  • (Java) Is there a type of object that can handle anything from primitives to arrays?

    - by Michael
    I'm pretty new to Java, so I'm hoping one of you guys knows how to do this. I'm having the user specify both the type and value of arguments, in any XML-like way, to be passed to methods that are external to my application. Example: javac myAppsName externalJavaClass methodofExternalClass [parameters] Of course, to find the proper method, we have to have the proper parameter types as the method may be overloaded and that's the only way to tell the difference between the different versions. Parameters are currently formatted in this manner: (type)value(/type), e.g. (int)71(/int) (string)This is my string that I'm passing as a parameter!(/string) I parse them, getting the constructor for whatever type is indicated, then execute that constructor by running its method, newInstance(<String value>), loading the new instance into an Object. This works fine and dandy, but as we all know, some methods take arrays, or even multi-dimensional arrays. I could handle the argument formatting like so: (array)(array)(int)0(/int)(int)1(/int)(/array)(array)(int)2(/int)(int)3(/int)(/array)(/array)... or perhaps even better... {{(int)0(/int)(int)1(/int)}{(int)2(/int)(int)3(/int)}}. The question is, how can this be implemented? Do I have to start wrapping everything in an Object[] array so I can handle primitives, etc. as argObj[0], but load an array as I normally would? (Unfortunately, I would have to make it an Object[][] array if I wanted to support two-dimensional arrays. This implementation wouldn't be very pretty.)

    Read the article

  • Drupal 7: How can I create a key/value field(or field group, if that's even possible)?

    - by Su'
    Let's say I'm creating some app documentation. In creating a content type for functions, I have a text field for name, a box for a general description, and a couple other basic things. Now I need something for storing arguments to the function. Ideally, I'd like to input these as key-value pairs, or just two related fields, which can then be repeated as many times as needed for the given function. But I can't find any way to accomplish this. The closest I've gotten is an abandonded field multigroup module that says to wait for CCK3, which hasn't even produced an alpha yet as far as I can tell and whose project page makes no obvious mention of this multi-group functionality. I also checked the CCK issue queue and don't think I saw it in there, either. Is there a current viable way of doing this I'm not seeing? Viable includes "you're thinking of this the wrong way and do X instead." I've considered using a "Long text and summary" field, but that smells hackish and I don't know if I'd be setting myself up for side-effects. I'm new to Drupal.

    Read the article

  • linux process scheduling delayed for long time

    - by Medicine
    I have done strace on my multi-threaded c++ application running on linux after couple hours of running, none of the threads got run, for about 12 seconds. I have seen that the unfinished select system call which is called with a timeout was unfinished before the thread was suspended, reported after it resumed that, it took 11.x seconds for the operation to finish. This is clear indication that the process got starved for a long time. All threads in the process are created with default scheduling policy(SCHED_OTHER) of linux and default priority. There are another 5 similar apps running on the same box which are also heavy I/O bound like this app due to heavy data received on the socket. But most of the time, this app is getting scheduled delay. The other apps are created with same sched policy and priority as this i.e. the defaults. why is only this process gets blocked almost all of the time? Could it be because this process is more I/O intensive as in more busy due to may be higher rates of data? So, the linux dynamic priority adjusting in play here which pushed this process down?

    Read the article

  • C# remote web request certificate error

    - by Ben
    Hi. I am currently integrating a payment gateway into an application. Following a successful transaction the remote payment gateway posts details of the transaction back to my application (ITN). It posts to a HttpHandler that is used to read and validate the data. Part of the validation performed is a POST made by the handler to a validation service provided by the payment gateway. This effectively posts some of the original form values received back to the payment gateway to ensure they are valid. The url that I am posting back to is: "https://sandbox.payfast.co.za/eng/query/validate" and the code I am using: /// <summary> /// Posts the data back to the payment processor to validate the data received /// </summary> public static bool ValidateITNRequestData(NameValueCollection formVariables) { bool isValid = true; try { using (WebClient client = new WebClient()) { string validateUrl = (UseSandBox) ? SandboxValidateUrl : LiveValidateUrl; byte[] responseArray = client.UploadValues(validateUrl, "POST", formVariables); // get the resposne and replace the line breaks with spaces string result = Encoding.ASCII.GetString(responseArray); result = result.Replace("\r\n", " ").Replace("\r", "").Replace("\n", " "); if (result == null || !result.StartsWith("VALID")) { isValid = false; LogManager.InsertLog(LogTypeEnum.OrderError, "PayFast ITN validation failed", "The validation response was not valid."); } } } catch (Exception ex) { LogManager.InsertLog(LogTypeEnum.Unknown, "Unable to validate ITN data. Unknown exception", ex); isValid = false; } return isValid; } However, on calling WebClient.UploadValues the following exception is raised: System.Net.WebException: The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel. ---> System.Security.Authentication.AuthenticationException: The remote certificate is invalid according to the validation procedure. at System.Net.Security.SslState.StartSendAuthResetSignal(ProtocolToken message, AsyncProtocolRequest asyncRequest, Exception exception) at For the sake of brevity I haven't listed the full call stack (I can do if anyone thinks it will help). The remote certificate does appear to be valid. To get around the problem I did try adding a new RemoteCertificateValidationCallback that always returned true but just ended up getting the following exception: System.Security.SecurityException: Request for the permission of type 'System.Security.Permissions.SecurityPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed. at System.Security.CodeAccessSecurityEngine.Check(Object demand, StackCrawlMark& stackMark, Boolean isPermSet) at System.Security.CodeAccessPermission.Demand() at System.Net.ServicePointManager.set_ServerCertificateValidationCallback(RemoteCertificateValidationCallback value) at NopSolutions.NopCommerce.Payment.Methods.PayFast.PayFastPaymentProcessor.ValidateITNRequestData(NameValueCollection formVariables) The action that failed was: Demand The type of the first permission that failed was: System.Security.Permissions.SecurityPermission The Zone of the assembly that failed was: MyComputer So I am not sure this will work in medium trust? Any help would be much appreciated. Thanks Ben

    Read the article

  • Asp.NET MVC ActionFilter cannot get Form Submit data

    - by Goden
    I want to use custom action filter to manipulate parameters to one action. User inputs: 2 names in a form ; Action: actually needs to take 2 ids; Action Filter (onExecuting, will verify the input names and if valid, convert them into 2 ids and replace in the routedata) because i don't want to put validation logic in Action Controller. here's part of the code: Routing Info routes.MapRoute( "Default", // Route name "{controller}/{action}", // URL with parameters new { controller = "Home", action = "Index"} // Parameter defaults ); routes.MapRoute( "RelationshipResults", // Route Name "Relationship/{initPersonID}/{targetPersonID}", // URL with parameters new { controller = "Relationship", action = "Results" }); Form to submit (Create 2 input box and submit via jquery) <% using (Html.BeginForm("Results", "Relationship", FormMethod.Post, new { id = "formSearch" })) {% ... <td align="left"><%: MvcWeibookWeb.Properties.Resource.Home_InitPersonName%></td> <td align="right"> <%= Html.TextBox("initPersonName")%></td> <td rowspan="3" valign="top"> <div id="sinaIntro"> <%: MvcWeibookWeb.Properties.Resource.Home_SinaIntro %> <br /> <%: MvcWeibookWeb.Properties.Resource.Genearl_PromotionSina %> </div> </td> </tr> <tr> <td align="left" width="90px"><%: MvcWeibookWeb.Properties.Resource.Home_TargetPersonName%></td> <td align="right"><%= Html.TextBox("targetPersonName")%></td> </tr> <tr> <td colspan="2" align="right"> <a href="#" class="btn-HomeSearch" onclick="$('#formSearch').submit();"><%: MvcWeibookWeb.Properties.Resource.Home_Search%></a> </td> Action Filter public override void OnActionExecuting(ActionExecutingContext filterContext) { Sina.Searcher searcher = new Sina.Searcher(Sina.Processor.UserNetwork); String initPersonName, targetPersonName; // form submit names, we need to process them and convert them to IDs before it enters the real controller. initPersonName = filterContext.RouteData.Values["initPersonName"] as String; targetPersonName = filterContext.RouteData.Values["targetPersonName"] as String; // do sth to convert it to ids and replace Action/Controller [ValidationActionFilter] [HandleError] public ActionResult Results( Int64 initPersonName, Int64 targetPersonName) { ... My problem is: in the actionFilter, it never gets the 2 parameter "initPersonName" and "targetPersonName", the RouteData.Values don't contain these 2 keys... :(

    Read the article

  • rmagick error on heroku

    - by nvano
    i'm cropping images with paperclip. i have a custom module which works great on my local machine (copied from railscast 182). //file: lib/paperclip_processors/cropper.rb module Paperclip class Cropper < Thumbnail def transformation_command if crop_command crop_command + super.sub(/ -crop \S+/, '') else super end end def crop_command target = @attachment.instance if target.cropping? " -crop '#{target.crop_w.to_i}x#{target.crop_h.to_i}+#{target.crop_x.to_i}+# {target.crop_y.to_i}'" end end end end on heroku i get the following error: NoMethodError (private method `sub' called for ["-resize", "220x", "-crop", "220x220+0+18", "+repage"]:Array): lib/paperclip_processors/cropper.rb:12:in `transformation_command' paperclip (2.3.3) lib/paperclip/thumbnail.rb:55:in `make' paperclip (2.3.3) lib/paperclip/processor.rb:33:in `make' paperclip (2.3.3) lib/paperclip/attachment.rb:295:in `post_process_styles' paperclip (2.3.3) lib/paperclip/attachment.rb:294:in `each' paperclip (2.3.3) lib/paperclip/attachment.rb:294:in `inject' paperclip (2.3.3) lib/paperclip/attachment.rb:294:in `post_process_styles' paperclip (2.3.3) lib/paperclip/attachment.rb:291:in `each' paperclip (2.3.3) lib/paperclip/attachment.rb:291:in `post_process_styles' paperclip (2.3.3) lib/paperclip/attachment.rb:285:in `post_process' paperclip (2.3.3) lib/paperclip/callback_compatability.rb:23:in `call' paperclip (2.3.3) lib/paperclip/callback_compatability.rb:23:in `run_paperclip_callbacks' paperclip (2.3.3) lib/paperclip/attachment.rb:284:in `post_process' paperclip (2.3.3) lib/paperclip/callback_compatability.rb:23:in `call' paperclip (2.3.3) lib/paperclip/callback_compatability.rb:23:in `run_paperclip_callbacks' paperclip (2.3.3) lib/paperclip/attachment.rb:283:in `post_process' paperclip (2.3.3) lib/paperclip/attachment.rb:214:in `reprocess!' app/models/user.rb:339:in `reprocess_avatar' app/controllers/user_controller.rb:57:in `update_avatar' haml (2.2.3) rails/./lib/sass/plugin/rails.rb:19:in `process' /home/heroku_rack/lib/static_assets.rb:9:in `call' /home/heroku_rack/lib/last_access.rb:25:in `call' /home/heroku_rack/lib/date_header.rb:14:in `call' thin (1.0.1) lib/thin/connection.rb:80:in `pre_process' thin (1.0.1) lib/thin/connection.rb:78:in `catch' thin (1.0.1) lib/thin/connection.rb:78:in `pre_process' thin (1.0.1) lib/thin/connection.rb:57:in `process' thin (1.0.1) lib/thin/connection.rb:42:in `receive_data' eventmachine (0.12.6) lib/eventmachine.rb:240:in `run_machine' eventmachine (0.12.6) lib/eventmachine.rb:240:in `run' thin (1.0.1) lib/thin/backends/base.rb:57:in `start' thin (1.0.1) lib/thin/server.rb:150:in `start' thin (1.0.1) lib/thin/controllers/controller.rb:80:in `start' thin (1.0.1) lib/thin/runner.rb:173:in `send' thin (1.0.1) lib/thin/runner.rb:173:in `run_command' thin (1.0.1) lib/thin/runner.rb:139:in `run!' thin (1.0.1) bin/thin:6 /usr/local/bin/thin:20:in `load' /usr/local/bin/thin:20

    Read the article

  • Downloading Python 2.5.4 (from official website) in order to install it

    - by brilliant
    I was quite hesitant about whether I should post this question here on "StackOverflow" or on "SuperUser", but finally decided to post it here as Python is more a programming language rather than a piece of software. I've been recently using Python 2.5.4 that is installed on my computer, but at the moment I am not at home (and won't be for about two weeks from now), so I need to install the same version of Python on another computer. This computer has Windows XP installed – just like the one that I have at home. The reason why I need Python 2.5.4 is because I am using “Google App Engine”, and I was told that it only supports Python 2.5 However, when I went to the official Python page for the download, I discovered that certain things have changed, and I don’t quite remember where exactly from that site I had downloaded Python 2.5.4 on my computer at home. I found this page: http://www.python.org/download/releases/2.5.4/ Here is how it looks: (If you can’t see it here, please check it out at this address: http://brad.cwahi.net/some_pictures/python_page.jpg ) A few things here are not clear to me. It says: “For x86 processors: python-2.5.4.msi For Win64-Itanium users: python-2.5.4.ia64.msi For Win64-AMD64 users: python-2.5.4.amd64.msi” First of all, I don’t know what processor I am using – whether mine is “x86” or not; and also, I don’t know whether I am an “Win64-Itanium” or an “Win64-AMD64” user. Are Itanium and AMD64 also processors? Later it says: “Windows XP and later already have MSI; many older machines will already have MSI installed.” I guess, it is my case, but then I am totally puzzled as to which link I should click as it seems now that I don’t need those three previous links (as MSI is already installed on Windows XP), but there is no fourth link provided for those who use “Windows XP” or older machines. Of course, there are these words after that: “Windows users may also be interested in Mark Hammond's win32all package, available from Sourceforge.” but it seems to me that it is something additional rather than the main file. So, my question is simple: Where in the official Python website I can download Python 2.5.4, precisely, which link I should click?

    Read the article

  • Making an XSL stylesheet work with paged XML

    - by fudgey
    First off, here is the situation. I'm using a guild hosting site that allows you to input the URL to an XSL file and another input for the XML. All well and good when all of the XML you want is contained in one file. My problem is this Game Roster XML which is paginated... look near the bottom of the file and you will find a <page_links> section that contains a pager written in HTML with links to /xml?page=2 etc. Since the guild hosting site is set up to only process one XML page I can't get to the other XML pages. So, I can only think of two solutions, but I have no idea how to get started Set up a php page that combines all XML pages into one, then output that file. I can then use this URL in the guild hosting site XSL processor. Somehow combine all the XML files within the XSL stylesheet. I found this question on SO (I don't really understand it, because I don't know what the document($pXml1) is doing), but I don't think it will work since the number of pages will be variable. I think this might be possible by loading the next page until the <members_to> value equals the <members_total>. Any other ideas? I don't know XSL or php that well so any help with code examples would be greatly appreciated. Update: I'm trying method 2 above and here is a snippet of XSLT with which I am having trouble. The first page of the code displays without problems, but the I am having trouble with this xsl:if, or maybe it's the document() statement. Update #2: changed the document to use the string & concat functions, but it's still not working. <xsl:template name="morepages"> <xsl:param name="page">1</xsl:param> <xsl:param name="url"> <xsl:value-of select="concat(SuperGroup/profule_url,'/xml?page=')"/> </xsl:param> <xsl:if test="document(string(concat($url,$page)))/SuperGroup/members_to &lt; document(string(concat($url,$page)))/SuperGroup/members_total"> <xsl:for-each select="document(string(concat($url,$page + 1)))/SuperGroup/members/members_node"> <xsl:call-template name="addrow" /> </xsl:for-each> <!-- Increment page index--> <xsl:call-template name="morepages"> <xsl:with-param name="page" select="$page + 1"/> </xsl:call-template> </xsl:if> </xsl:template>

    Read the article

  • Is this asking too much of a browser?

    - by Matt Ball
    I'm embedding a large array in <script> tags in my HTML, like this (nothing surprising): <script> var largeArray = [/* lots of stuff in here */]; </script> In this particular example, the array has 210,000 elements. That's well below the theoretical maximum of 231 - by 4 orders of magnitude. Here's the fun part: if I save JS source for the array to a file, that file is 44 megabytes (46,573,399 bytes, to be exact). If you want to see for yourself, you can download it from my Dropbox. (All the data in there is canned, so much of it is repeated. This will not be the case in production.) Now, I'm really not concerned about serving that much data. My server gzips its responses, so it really doesn't take all that long to get the data over the wire. However, there is a really nasty tendency for the page, once loaded, to crash the browser. I'm not testing at all in IE (this is an internal tool). My primary targets are Chrome 8 and Firefox 3.6. In Firefox, I can see a reasonably useful error in the console: Error: script stack space quota is exhausted In Chrome, I simply get the sad-tab page: Cut to the chase, already Is this really too much data for our modern, "high-performance" browsers to handle? Is there anything I can do* to gracefully handle this much data? Incidentally, I was able to get this to work (read: not crash the tab) on-and-off in Chrome. I really thought that Chrome, at least, was made of tougher stuff, but apparently I was wrong... Edit 1 @Crayon: I wasn't looking to justify why I'd like to dump this much data into the browser at once. Short version: either I solve this one (admittedly not-that-easy) problem, or I have to solve a whole slew of other problems. I'm opting for the simpler approach for now. @various: right now, I'm not especially looking for ways to actually reduce the number of elements in the array. I know I could implement Ajax paging or what-have-you, but that introduces its own set of problems for me in other regards. @Phrogz: each element looks something like this: {dateTime:new Date(1296176400000), terminalId:'terminal999', 'General___BuildVersion':'10.05a_V110119_Beta', 'SSM___ExtId':26680, 'MD_CDMA_NETLOADER_NO_BCAST___Valid':'false', 'MD_CDMA_NETLOADER_NO_BCAST___PngAttempt':0} @Will: but I have a computer with a 4-core processor, 6 gigabytes of RAM, over half a terabyte of disk space ...and I'm not even asking for the browser to do this quickly - I'm just asking for it to work at all! ? *other than the obvious: sending less data to the browser

    Read the article

  • Efficiency of data structures in C99 (possibly affected by endianness)

    - by Ninefingers
    Hi All, I have a couple of questions that are all inter-related. Basically, in the algorithm I am implementing a word w is defined as four bytes, so it can be contained whole in a uint32_t. However, during the operation of the algorithm I often need to access the various parts of the word. Now, I can do this in two ways: uint32_t w = 0x11223344; uint8_t a = (w & 0xff000000) >> 24; uint8_t b = (w & 0x00ff0000) >> 16; uint8_t b = (w & 0x0000ff00) >> 8; uint8_t d = (w & 0x000000ff); However, part of me thinks that isn't particularly efficient. I thought a better way would be to use union representation like so: typedef union { struct { uint8_t d; uint8_t c; uint8_t b; uint8_t a; }; uint32_t n; } word32; Using this method I can assign word32 w = 0x11223344; then I can access the various parts as I require (w.a=11 in little endian). However, at this stage I come up against endianness issues, namely, in big endian systems my struct is defined incorrectly so I need to re-order the word prior to it being passed in. This I can do without too much difficulty. My question is, then, is the first part (various bitwise ands and shifts) efficient compared to the implementation using a union? Is there any difference between the two generally? Which way should I go on a modern, x86_64 processor? Is endianness just a red herring here? I could inspect the assembly output of course, but my knowledge of compilers is not brilliant. I would have thought a union would be more efficient as it would essentially convert to memory offsets, like so: mov eax, [r9+8] Would a compiler realise that is what happening in the bit-shift case above? If it matters, I'm using C99, specifically my compiler is clang (llvm). Thanks in advance.

    Read the article

  • Xcache - No different after using it

    - by Charles Yeung
    Hi I have installed Xcache in my site(using xampp), I have tested more then 10 times on several page and the result is same as default(no any cache installed), is it something wrong with the configure? Updated [xcache-common] ;; install as zend extension (recommended), normally "$extension_dir/xcache.so" zend_extension = /usr/local/lib/php/extensions/non-debug-non-zts-xxx/xcache.so zend_extension_ts = /usr/local/lib/php/extensions/non-debug-zts-xxx/xcache.so ;; For windows users, replace xcache.so with php_xcache.dll zend_extension_ts = C:\xampp\php\ext\php_xcache.dll ;; or install as extension, make sure your extension_dir setting is correct ; extension = xcache.so ;; or win32: ; extension = php_xcache.dll [xcache.admin] xcache.admin.enable_auth = On xcache.admin.user = "mOo" ; xcache.admin.pass = md5($your_password) xcache.admin.pass = "" [xcache] ; ini only settings, all the values here is default unless explained ; select low level shm/allocator scheme implemenation xcache.shm_scheme = "mmap" ; to disable: xcache.size=0 ; to enable : xcache.size=64M etc (any size > 0) and your system mmap allows xcache.size = 60M ; set to cpu count (cat /proc/cpuinfo |grep -c processor) xcache.count = 1 ; just a hash hints, you can always store count(items) > slots xcache.slots = 8K ; ttl of the cache item, 0=forever xcache.ttl = 0 ; interval of gc scanning expired items, 0=no scan, other values is in seconds xcache.gc_interval = 0 ; same as aboves but for variable cache xcache.var_size = 4M xcache.var_count = 1 xcache.var_slots = 8K ; default ttl xcache.var_ttl = 0 xcache.var_maxttl = 0 xcache.var_gc_interval = 300 xcache.test = Off ; N/A for /dev/zero xcache.readonly_protection = Off ; for *nix, xcache.mmap_path is a file path, not directory. ; Use something like "/tmp/xcache" if you want to turn on ReadonlyProtection ; 2 group of php won't share the same /tmp/xcache ; for win32, xcache.mmap_path=anonymous map name, not file path xcache.mmap_path = "/dev/zero" ; leave it blank(disabled) or "/tmp/phpcore/" ; make sure it's writable by php (without checking open_basedir) xcache.coredump_directory = "" ; per request settings xcache.cacher = On xcache.stat = On xcache.optimizer = Off [xcache.coverager] ; per request settings ; enable coverage data collecting for xcache.coveragedump_directory and xcache_coverager_start/stop/get/clean() functions (will hurt executing performance) xcache.coverager = Off ; ini only settings ; make sure it's readable (care open_basedir) by coverage viewer script ; requires xcache.coverager=On xcache.coveragedump_directory = "" Thanks you

    Read the article

  • Performance Optimization for Matrix Rotation

    - by Summer_More_More_Tea
    Hello everyone: I'm now trapped by a performance optimization lab in the book "Computer System from a Programmer's Perspective" described as following: In a N*N matrix M, where N is multiple of 32, the rotate operation can be represented as: Transpose: interchange elements M(i,j) and M(j,i) Exchange rows: Row i is exchanged with row N-1-i A example for matrix rotation(N is 3 instead of 32 for simplicity): ------- ------- |1|2|3| |3|6|9| ------- ------- |4|5|6| after rotate is |2|5|8| ------- ------- |7|8|9| |1|4|7| ------- ------- A naive implementation is: #define RIDX(i,j,n) ((i)*(n)+(j)) void naive_rotate(int dim, pixel *src, pixel *dst) { int i, j; for (i = 0; i < dim; i++) for (j = 0; j < dim; j++) dst[RIDX(dim-1-j, i, dim)] = src[RIDX(i, j, dim)]; } I come up with an idea by inner-loop-unroll. The result is: Code Version Speed Up original 1x unrolled by 2 1.33x unrolled by 4 1.33x unrolled by 8 1.55x unrolled by 16 1.67x unrolled by 32 1.61x I also get a code snippet from pastebin.com that seems can solve this problem: void rotate(int dim, pixel *src, pixel *dst) { int stride = 32; int count = dim >> 5; src += dim - 1; int a1 = count; do { int a2 = dim; do { int a3 = stride; do { *dst++ = *src; src += dim; } while(--a3); src -= dim * stride + 1; dst += dim - stride; } while(--a2); src += dim * (stride + 1); dst -= dim * dim - stride; } while(--a1); } After carefully read the code, I think main idea of this solution is treat 32 rows as a data zone, and perform the rotating operation respectively. Speed up of this version is 1.85x, overwhelming all the loop-unroll version. Here are the questions: In the inner-loop-unroll version, why does increment slow down if the unrolling factor increase, especially change the unrolling factor from 8 to 16, which does not effect the same when switch from 4 to 8? Does the result have some relationship with depth of the CPU pipeline? If the answer is yes, could the degrade of increment reflect pipeline length? What is the probable reason for the optimization of data-zone version? It seems that there is no too much essential difference from the original naive version. EDIT: My test environment is Intel Centrino Duo processor and the verion of gcc is 4.4 Any advice will be highly appreciated! Kind regards!

    Read the article

  • How do I de-duplicate a list of nodes in XSLT - and return the last node encountered?

    - by Broam
    I've seen lots of "de-duplicate this xml" questions but everyone wants the first node or the nodes are identical. I have a bit of a bigger puzzle. I have a list of articles in XML, a relevant snippet is shown: <item><key>Article1</key><stamp>100</stamp></item> <item><key>Article1</key><stamp>130</stamp></item> <item><key>Article2</key><stamp>800</stamp></item> <item><key>Article1</key><stamp>180</stamp></item> <item><key>Article3</key><stamp>900</stamp></item> <item><key>Article3</key><stamp>950</stamp></item> <item><key>Article4</key><stamp>990</stamp></item> <item><key>Article5</key><stamp>999</stamp></item> I'd like a list of nodes where the keys are unique and where the last instance is returned, not the first: Stamp (integer) is always increasing for elements of a particular key. Ideally I'd like "largest stamp" but they're always in order so the shortcut is ok. Desired result: (Order doesn't really matter.) <item><key>Article2</key><stamp>800</stamp></item> <item><key>Article1</key><stamp>180</stamp></item> <item><key>Article3</key><stamp>950</stamp></item> <item><key>Article4</key><stamp>990</stamp></item> <item><key>Article5</key><stamp>999</stamp></item> I'm somewhat confused on how to get this list. Any ideas? I'm using the Saxon processor if it matters.

    Read the article

  • Programming graphics and sound on PC - Total newbie questions, and lots of them!

    - by Russel
    Hello, This isn't exactly specifically a programming question (or is it?) but I was wondering: How are graphics and sound processed from code and output by the PC? My guess for graphics: There is some reserved memory space somewhere that holds exactly enough room for a frame of graphics output for your monitor. IE: 800 x 600, 24 bit color mode == 800x600x3 = ~1.4MB memory space Between each refresh, the program writes video data to this space. This action is completed before the monitor refresh. Assume a simple 2D game: the graphics data is stored in machine code as many bytes representing color values. Depending on what the program(s) being run instruct the PC, the processor reads the appropriate data and writes it to the memory space. When it is time for the monitor to refresh, it reads from each memory space byte-for-byte and activates hardware depending on those values for each color element of each pixel. All of this of course happens crazy-fast, and repeats x times a second, x being the monitor's refresh rate. I've simplified my own likely-incorrect explanation by avoiding talk of double buffering, etc Here are my questions: a) How close is the above guess (the three steps)? b) How could one incorporate graphics in pure C++ code? I assume the practical thing that everyone does is use a graphics library (SDL, OpenGL, etc), but, for example, how do these libraries accomplish what they do? Would manual inclusion of graphics in pure C++ code (say, a 2D spite) involve creating a two-dimensional array of bit values (or three dimensional to include multiple RGB values per pixel)? Is this how it would be done waaay back in the day? c) Also, continuing from above, do libraries such as SDL etc that use bitmaps actual just build the bitmap/etc files into machine code of the executable and use them as though they were build in the same matter mentioned in question b above? d) In my hypothetical step 3 above, is there any registers involved? Like, could you write some byte value to some register to output a single color of one byte on the screen? Or is it purely dedicated memory space (=RAM) + hardware interaction? e) Finally, how is all of this done for sound? (I have no idea :) )

    Read the article

  • Event sourcing: Write event before or after updating the model

    - by Magnus
    I'm reasoning about event sourcing and often I arrive at a chicken and egg problem. Would be grateful for some hints on how to reason around this. If I execute all I/O-bound processing async (ie writing to the event log) then how do I handle, or sometimes even detect, failures? I'm using Akka Actors so processing is sequential for each event/message. I do not have any database at this time, instead I would persist all the events in an event log and then keep an aggregated state of all the events in a model stored in memory. Queries are all against this model, you can consider it to be a cache. Example Creating a new user: Validate that the user does not exist in model Persist event to journal Update model (in memory) If step 3 breaks I still have persisted my event so I can replay it at a later date. If step 2 breaks I can handle that as well gracefully. This is fine, but since step 2 is I/O-bound I figured that I should do I/O in a separate actor to free up the first actor for queries: Updating a user while allowing queries (A0 = Front end/GUI actor, A1 = Processor Actor, A2 = IO-actor, E = event bus). (A0-E-A1) Event is published to update user 'U1'. Validate that the user 'U1' exists in model (A1-A2) Persist event to journal (separate actor) (A0-E-A1-A0) Query for user 'U1' profile (A2-A1) Event is now persisted continue to update model (A0-E-A1-A0) Query for user 'U1' profile (now returns fresh data) This is appealing since queries can be processed while I/O-is churning along at it's own pace. But now I can cause myself all kinds of problems where I could have two incompatible commands (delete and then update) be persisted to the event log and crash on me when replayed up at a later date, since I do the validation before persisting the event and then update the model. My aim is to have a simple reasoning around my model (since Actor processes messages sequentially single threaded) but not be waiting for I/O-bound updates when Querying. I get the feeling I'm modeling a database which in itself is might be a problem. If things are unclear please write a comment.

    Read the article

  • How to configure the framesize using AudioUnit.framework on iOS

    - by Piperoman
    I have an audio app i need to capture mic samples to encode into mp3 with ffmpeg First configure the audio: /** * We need to specifie our format on which we want to work. * We use Linear PCM cause its uncompressed and we work on raw data. * for more informations check. * * We want 16 bits, 2 bytes (short bytes) per packet/frames at 8khz */ AudioStreamBasicDescription audioFormat; audioFormat.mSampleRate = SAMPLE_RATE; audioFormat.mFormatID = kAudioFormatLinearPCM; audioFormat.mFormatFlags = kAudioFormatFlagIsPacked | kAudioFormatFlagIsSignedInteger; audioFormat.mFramesPerPacket = 1; audioFormat.mChannelsPerFrame = 1; audioFormat.mBitsPerChannel = audioFormat.mChannelsPerFrame*sizeof(SInt16)*8; audioFormat.mBytesPerPacket = audioFormat.mChannelsPerFrame*sizeof(SInt16); audioFormat.mBytesPerFrame = audioFormat.mChannelsPerFrame*sizeof(SInt16); The recording callback is: static OSStatus recordingCallback(void *inRefCon, AudioUnitRenderActionFlags *ioActionFlags, const AudioTimeStamp *inTimeStamp, UInt32 inBusNumber, UInt32 inNumberFrames, AudioBufferList *ioData) { NSLog(@"Log record: %lu", inBusNumber); NSLog(@"Log record: %lu", inNumberFrames); NSLog(@"Log record: %lu", (UInt32)inTimeStamp); // the data gets rendered here AudioBuffer buffer; // a variable where we check the status OSStatus status; /** This is the reference to the object who owns the callback. */ AudioProcessor *audioProcessor = (__bridge AudioProcessor*) inRefCon; /** on this point we define the number of channels, which is mono for the iphone. the number of frames is usally 512 or 1024. */ buffer.mDataByteSize = inNumberFrames * sizeof(SInt16); // sample size buffer.mNumberChannels = 1; // one channel buffer.mData = malloc( inNumberFrames * sizeof(SInt16) ); // buffer size // we put our buffer into a bufferlist array for rendering AudioBufferList bufferList; bufferList.mNumberBuffers = 1; bufferList.mBuffers[0] = buffer; // render input and check for error status = AudioUnitRender([audioProcessor audioUnit], ioActionFlags, inTimeStamp, inBusNumber, inNumberFrames, &bufferList); [audioProcessor hasError:status:__FILE__:__LINE__]; // process the bufferlist in the audio processor [audioProcessor processBuffer:&bufferList]; // clean up the buffer free(bufferList.mBuffers[0].mData); //NSLog(@"RECORD"); return noErr; } With data: inBusNumber = 1 inNumberFrames = 1024 inTimeStamp = 80444304 // All the time same inTimeStamp, this is strange However, the framesize that i need to encode mp3 is 1152. How can i configure it? If i do buffering, that implies a delay, but i would like to avoid this because is a real time app. If i use this configuration, each buffer i get trash trailing samples, 1152 - 1024 = 128 bad samples. All samples are SInt16.

    Read the article

  • How do I do high quality scaling of a image?

    - by pbhogan
    I'm writing some code to scale a 32 bit RGBA image in C/C++. I have written a few attempts that have been somewhat successful, but they're slow and most importantly the quality of the sized image is not acceptable. I compared the same image scaled by OpenGL (i.e. my video card) and my routine and it's miles apart in quality. I've Google Code Searched, scoured source trees of anything I thought would shed some light (SDL, Allegro, wxWidgets, CxImage, GD, ImageMagick, etc.) but usually their code is either convoluted and scattered all over the place or riddled with assembler and little or no comments. I've also read multiple articles on Wikipedia and elsewhere, and I'm just not finding a clear explanation of what I need. I understand the basic concepts of interpolation and sampling, but I'm struggling to get the algorithm right. I do NOT want to rely on an external library for one routine and have to convert to their image format and back. Besides, I'd like to know how to do it myself anyway. :) I have seen a similar question asked on stack overflow before, but it wasn't really answered in this way, but I'm hoping there's someone out there who can help nudge me in the right direction. Maybe point me to some articles or pseudo code... anything to help me learn and do. Here's what I'm looking for: 1. No assembler (I'm writing very portable code for multiple processor types). 2. No dependencies on external libraries. 3. I am primarily concerned with scaling DOWN, but will also need to write a scale up routine later. 4. Quality of the result and clarity of the algorithm is most important (I can optimize it later). My routine essentially takes the following form: DrawScaled( uint32 *src, uint32 *dst, src_x, src_y, src_w, src_h, dst_x, dst_y, dst_w, dst_h ); Thanks! UPDATE: To clarify, I need something more advanced than a box resample for downscaling which blurs the image too much. I suspect what I want is some kind of bicubic (or other) filter that is somewhat the reverse to a bicubic upscaling algorithm (i.e. each destination pixel is computed from all contributing source pixels combined with a weighting algorithm that keeps things sharp. EXAMPLE: Here's an example of what I'm getting from the wxWidgets BoxResample algorithm vs. what I want on a 256x256 bitmap scaled to 55x55. And finally: the original 256x256 image

    Read the article

  • Bad_alloc exception when using new for a struct c++

    - by bsg
    Hi, I am writing a query processor which allocates large amounts of memory and tries to find matching documents. Whenever I find a match, I create a structure to hold two variables describing the document and add it to a priority queue. Since there is no way of knowing how many times I will do this, I tried creating my structs dynamically using new. When I pop a struct off the priority queue, the queue (STL priority queue implementation) is supposed to call the object's destructor. My struct code has no destructor, so I assume a default destructor is called in that case. However, the very first time that I try to create a DOC struct, I get the following error: Unhandled exception at 0x7c812afb in QueryProcessor.exe: Microsoft C++ exception: std::bad_alloc at memory location 0x0012f5dc.. I don't understand what's happening - have I used up so much memory that the heap is full? It doesn't seem likely. And it's not as if I've even used that pointer before. So: first of all, what am I doing that's causing the error, and secondly, will the following code work more than once? Do I need to have a separate pointer for each struct created, or can I re-use the same temporary pointer and assume that the queue will keep a pointer to each struct? Here is my code: struct DOC{ int docid; double rank; public: DOC() { docid = 0; rank = 0.0; } DOC(int num, double ranking) { docid = num; rank = ranking; } bool operator>( const DOC & d ) const { return rank > d.rank; } bool operator<( const DOC & d ) const { return rank < d.rank; } }; //a lot of processing goes on here; when a matching document is found, I do this: rank = calculateRanking(table, num); //if the heap is not full, create a DOC struct with the docid and rank and add it to the heap if(q.size() < 20) { doc = new DOC(num, rank); q.push(*doc); doc = NULL; } //if the heap is full, but the new rank is greater than the //smallest element in the min heap, remove the current smallest element //and add the new one to the heap else if(rank > q.top().rank) { q.pop(); cout << "pushing doc on to queue" << endl; doc = new DOC(num, rank); q.push(*doc); } Thank you very much, bsg.

    Read the article

  • Sanitizing DB inputs with XSLT

    - by azathoth
    Hello I've been looking for a method to strip my XML content of apostrophes (') like: <name> Jim O'Connor</name> since my DBMS is complaining of receiving those. By looking at the example described here, that is supposed to replace ' with '', I constructed the following script: <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <xsl:output omit-xml-declaration="yes" indent="yes" /> <xsl:template match="node()|@*"> <xsl:copy> <xsl:apply-templates select="node()|@*" /> </xsl:copy> </xsl:template> <xsl:template name="sqlApostrophe"> <xsl:param name="string" /> <xsl:variable name="apostrophe">'</xsl:variable> <xsl:choose> <xsl:when test="contains($string,$apostrophe)"> <xsl:value-of select="concat(substring-before($string,$apostrophe), $apostrophe,$apostrophe)" disable-output-escaping="yes" /> <xsl:call-template name="sqlApostrophe"> <xsl:with-param name="string" select="substring-after($string,$apostrophe)" /> </xsl:call-template> </xsl:when> <xsl:otherwise> <xsl:value-of select="$string" disable-output-escaping="yes" /> </xsl:otherwise> </xsl:choose> </xsl:template> <xsl:template match="node()|@*"> <xsl:apply-templates name="sqlApostrophe"/> </xsl:template> </xsl:stylesheet> However, the processor isn't accepting it. What am I missing here? Is there a better way to get rid of the apostrophes? Perhaps another approach for sanitizing DB inputs by using XSLT? Thanks for your help

    Read the article

  • check if directory exists c#

    - by Ant
    I am trying to see if a directory exists based on an input field from the user. When the user types in the path, I want to check if the path actually exists. I have some c# code already. It returns 1 for any local path, but always returns 0 when I am checking a network path. static string checkValidPath(string path) { //Insert your code that runs under the security context of the authenticating user here. using (ImpersonateUser user = new ImpersonateUser(user, "", password)) { //DirectoryInfo d = new DirectoryInfo(quotelessPath); bool doesExist = Directory.Exists(path); //if (d.Exists) if(doesExist) { user.Dispose(); return "1"; } else { user.Dispose(); return "0"; } } } public class ImpersonateUser : IDisposable { [DllImport("advapi32.dll", SetLastError = true)] private static extern bool LogonUser(string lpszUsername, string lpszDomain, string lpszPassword, int dwLogonType, int dwLogonProvider, out IntPtr phToken); [DllImport("kernel32", SetLastError = true)] private static extern bool CloseHandle(IntPtr hObject); private IntPtr userHandle = IntPtr.Zero; private WindowsImpersonationContext impersonationContext; public ImpersonateUser(string user, string domain, string password) { if (!string.IsNullOrEmpty(user)) { // Call LogonUser to get a token for the user bool loggedOn = LogonUser(user, domain, password, 9 /*(int)LogonType.LOGON32_LOGON_NEW_CREDENTIALS*/, 3 /*(int)LogonProvider.LOGON32_PROVIDER_WINNT50*/, out userHandle); if (!loggedOn) throw new Win32Exception(Marshal.GetLastWin32Error()); // Begin impersonating the user impersonationContext = WindowsIdentity.Impersonate(userHandle); } } public void Dispose() { if (userHandle != IntPtr.Zero) CloseHandle(userHandle); if (impersonationContext != null) impersonationContext.Undo(); } } Any help is appreciated. Thanks! EDIT 3: updated code to use BrokenGlass's impersonation functions. However, I need to initialize "password" to something... EDIT 2: I updated the code to try and use impersonation as suggested below. It still fails everytime. I assume I am using impersonation improperly... EDIT: As requested by ChrisF, here is the function that calls the checkValidPath function. Frontend aspx file... $.get('processor.ashx', { a: '7', path: x }, function(o) { alert(o); if (o=="0") { $("#outputPathDivValid").dialog({ title: 'Output Path is not valid! Please enter a path that exists!', width: 500, modal: true, resizable: false, buttons: { 'Close': function() { $(this).dialog('close'); } } }); } }); Backend ashx file... public void ProcessRequest (HttpContext context) { context.Response.Cache.SetExpires(DateTime.Now); string sSid = context.Request["sid"]; switch (context.Request["a"]) {//a bunch of case statements here... case "7": context.Response.Write(checkValidPath(context.Request["path"].ToString())); break;

    Read the article

  • Can MySQL reasonably perform queries on billions of rows?

    - by haxney
    I am planning on storing scans from a mass spectrometer in a MySQL database and would like to know whether storing and analyzing this amount of data is remotely feasible. I know performance varies wildly depending on the environment, but I'm looking for the rough order of magnitude: will queries take 5 days or 5 milliseconds? Input format Each input file contains a single run of the spectrometer; each run is comprised of a set of scans, and each scan has an ordered array of datapoints. There is a bit of metadata, but the majority of the file is comprised of arrays 32- or 64-bit ints or floats. Host system |----------------+-------------------------------| | OS | Windows 2008 64-bit | | MySQL version | 5.5.24 (x86_64) | | CPU | 2x Xeon E5420 (8 cores total) | | RAM | 8GB | | SSD filesystem | 500 GiB | | HDD RAID | 12 TiB | |----------------+-------------------------------| There are some other services running on the server using negligible processor time. File statistics |------------------+--------------| | number of files | ~16,000 | | total size | 1.3 TiB | | min size | 0 bytes | | max size | 12 GiB | | mean | 800 MiB | | median | 500 MiB | | total datapoints | ~200 billion | |------------------+--------------| The total number of datapoints is a very rough estimate. Proposed schema I'm planning on doing things "right" (i.e. normalizing the data like crazy) and so would have a runs table, a spectra table with a foreign key to runs, and a datapoints table with a foreign key to spectra. The 200 Billion datapoint question I am going to be analyzing across multiple spectra and possibly even multiple runs, resulting in queries which could touch millions of rows. Assuming I index everything properly (which is a topic for another question) and am not trying to shuffle hundreds of MiB across the network, is it remotely plausible for MySQL to handle this? UPDATE: additional info The scan data will be coming from files in the XML-based mzML format. The meat of this format is in the <binaryDataArrayList> elements where the data is stored. Each scan produces = 2 <binaryDataArray> elements which, taken together, form a 2-dimensional (or more) array of the form [[123.456, 234.567, ...], ...]. These data are write-once, so update performance and transaction safety are not concerns. My naïve plan for a database schema is: runs table | column name | type | |-------------+-------------| | id | PRIMARY KEY | | start_time | TIMESTAMP | | name | VARCHAR | |-------------+-------------| spectra table | column name | type | |----------------+-------------| | id | PRIMARY KEY | | name | VARCHAR | | index | INT | | spectrum_type | INT | | representation | INT | | run_id | FOREIGN KEY | |----------------+-------------| datapoints table | column name | type | |-------------+-------------| | id | PRIMARY KEY | | spectrum_id | FOREIGN KEY | | mz | DOUBLE | | num_counts | DOUBLE | | index | INT | |-------------+-------------| Is this reasonable?

    Read the article

  • Connection between Properties of Entities in Data Oriented Design

    - by sharethis
    I want to start with an example illustrating my question. The following way it is done in the most games. class car { vec3 position; vec3 rotation; mesh model; imge texture; void move(); // modify position and rotation void draw(); // use model, texture, ... }; vector<car> cars; for(auto i = cars.begin(); i != cars.end(); ++i) { i->move(); i->draw(); } Data oriented design means to process the same calculation on the hole batch of data at once. This way it takes more advantage out of the processor cache. struct movedata { vec3 position; vec3 rotation; }; struct drawdata { mesh model; imge texture; }; vector<movedata> movedatas; vector<drawdata> drawdatas; for(auto i = movedatas.begin(); i != movedatas.end(); ++i) { // modify position and rotation } for(auto i = drawdatas.begin(); i != drawdatas.end(); ++i) { // use model, texture, ... } But there comes a point where you need to find other properties according to an entity. For example if the car crashes, I do not need the drawdata and the movedata any more. So I need to delete the entries of this entity in all vectors. The entries are not linked by code. So my question is the following. How are properties of the same entity conceptually linked in a data oriented design?

    Read the article

  • C++ Vector vs Array (Time)

    - by vsha041
    I have got here two programs with me, both are doing exactly the same task. They are just setting an boolean array / vector to the value true. The program using vector takes 27 seconds to run whereas the program involving array with 5 times greater size takes less than 1 s. I would like to know the exact reason as to why there is such a major difference ? Are vectors really that inefficient ? Program using vectors #include <iostream> #include <vector> #include <ctime> using namespace std; int main(){ const int size = 2000; time_t start, end; time(&start); vector<bool> v(size); for(int i = 0; i < size; i++){ for(int j = 0; j < size; j++){ v[i] = true; } } time(&end); cout<<difftime(end, start)<<" seconds."<<endl; } Runtime - 27 seconds Program using Array #include <iostream> #include <ctime> using namespace std; int main(){ const int size = 10000; // 5 times more size time_t start, end; time(&start); bool v[size]; for(int i = 0; i < size; i++){ for(int j = 0; j < size; j++){ v[i] = true; } } time(&end); cout<<difftime(end, start)<<" seconds."<<endl; } Runtime - < 1 seconds Platform - Visual Studio 2008 OS - Windows Vista 32 bit SP 1 Processor Intel(R) Pentium(R) Dual CPU T2370 @ 1.73GHz Memory (RAM) 1.00 GB Thanks Amare

    Read the article

  • Database design advice needed.

    - by user346271
    Hi all, I'm a lone developer for a telecoms company, and am after some database design advice from anyone with a bit of time to answer. I am inserting into one table ~2 million rows each day, these tables then get archived and compressed on a monthly basis. Each monthly table contains ~15,000,000 rows. Although this is increasing month on month. For every insert I do above I am combining the data from rows which belong together and creating another "correlated" table. This table is currently not being archived, as I need to make sure I never miss an update to the correlated table. (Hope that makes sense) Although in general this information should remain fairly static after a couple of days of processing. All of the above is working perfectly. However my company now wishes to perform some stats against this data, and these tables are getting too large to provide the results in what would be deemed a reasonable time. Even with the appropriate indexes set. So I guess after all the above my question is quite simple. Should I write a script which groups the data from my correlated table into smaller tables. Or should I store the queries result sets in something like memcache? I'm already using mysqls cache, but due to having limited control over how long the data is stored for, it's not working ideally. The main advantages I can see of using something like memcache: No blocking on my correlated table after the query has been cashed. Greater flexibility of sharing the collected data between the backend collector and front end processor. (i.e custom reports could be written in the backend and the results of these stored in the cache under a key which then gets shared with anyone who would want to see the data of this report) Redundancy and scalability if we start sharing this data with a large amount of customers. The main disadvantages I can see of using something like memcache: Data is not persistent if machine is rebooted / cache is flushed. The main advantages of using MySql Persistent data. Less code changes (although adding something like memcache is trivial anyway) The main disadvantages of using MySql Have to define table templates every time I want to store provide a new set of grouped data. Have to write a program which loops through the correlated data and fills these new tables. Potentially will still grow slower as the data continues to be filled. Apologies for quite a long question. It's helped me to write down these thoughts here anyway, and any advice/help/experience with dealing with this sort of problem would be greatly appreciated. Many thanks. Alan

    Read the article

< Previous Page | 255 256 257 258 259 260 261 262 263 264 265 266  | Next Page >