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  • Is there a way to increase performance on my simple textfilter?

    - by djerry
    Hey guys, I'm writing a filter that will pick out items. I have a list of Objects. The objects contain a number, name and some other irrelevant items. At the moment, the list contains 200 items. When typing in a textbox, i'm looking if the string matches a part of the number/name of the objects in the list. If so, add them to the listbox. Here's the code for my textbox textchanged event : private void txtTelnumber_TextChanged(object sender, TextChangedEventArgs e) { lstOverview.Items.Clear(); string data = ""; foreach (ucTelListItem telList in _allUsers) { data = telList.User.H323 + telList.user.E164; if (data.Contains(txtTelnumber.Text)) lstOverview.Items.Add(telList); } } I sometimes see a little delay when entering a character, especially when i go from 4 records to 200 records (so when i had a filter and 4 records matched, and i backspace and the whole list appears again). My list is a list of usercontrols, cause i found it takes less time to load the usercontrols from a list, then to have to initialize a new usercontrol each time. Can i do something about the code, or is it just adding the usercontrol the listbox that causes the small delay (small delay = <1 sec)? Thanks in advance.

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  • Match subpatterns in any order

    - by Yaroslav
    I have long regexp with two complicated subpatters inside. How i can match that subpatterns in any order? Simplified example: /(apple)?\s?(banana)?\s?(orange)?\s?(kiwi)?/ and i want to match both of apple banana orange kiwi apple orange banana kiwi It is very simplified example. In my case banana and orange is long complicated subpatterns and i don't want to do something like /(apple)?\s?((banana)?\s?(orange)?|(orange)?\s?(banana)?)\s?(kiwi)?/ Is it possible to group subpatterns like chars in character class? UPD Real data as requested: 14:24 26,37 Mb 108.53 01:19:02 06.07 24.39 19:39 46:00 my strings much longer, but it is significant part. Here you can see two lines what i need to match. First has two values: length (14 min 24 sec) and size 26.37 Mb. Second one has three values but in different order: size 108.53 Mb, length 01 h 19 m 02 s and date June, 07 Third one has two size and length Fourth has only length There are couple more variations and i need to parse all values. I have a regexp that pretty close except i can't figure out how to match patterns in different order without writing it twice. (?<size>\d{1,3}\[.,]\d{1,2}\s+(?:Mb)?)?\s? (?<length>(?:(?:01:)?\d{1,2}:\d{2}))?\s* (?<date>\d{2}\.\d{2}))? NOTE: that is only part of big regexp that forks fine already.

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  • Cannot access Class methods from previous windows form - C#

    - by George
    I am writing an app, still, where I need to test some devices every minute for 30 minutes. It made sense to use a timer set to kick off every 60 secs and do whats required in the event handler. However, I need the app to wait for the 30 mins until I have finished with the timer since the following code alters the state of the devices I am trying to monitor. I obviously don't want to use any form of loop to do this. I thought of using another windows form, since I also display the progress, which will simply kick off the timer and wait until its complete. The problem I am having with this is that I use a device Class and cant seem to get access to the methods in the device class from the 2nd (3rd actually - see below) windows form. I have an initial windows form where I get input from the user, then call the 2nd windows form where it work out which tests need to be done and which device classes need to be used, and then I want to call the 3rd windows form to handle the timer. I will have up to 6-7 device classes and so wanted to only instantiate them when actually requiring them, from the 2nd form. Should I have put this logic into the 1st windows form (program class ??) ? Would I not still have the problem of not being able to access device class methods from there too ? Anyway, perhaps someone knows of a better way to do the checks every minute without the rest of the code executing (and changing the status of the devices) or how I should be accessing the methods in the app ?? Well that's the problem, I cant get that part of it to work correctly. Here is the definition for the calling form including the device class - namespace NdtStart { public partial class fclsNDTCalib : Form { NDTClass NDT = new NDTClass(); public fclsNDTCalib() (new fclsNDTTicker(NDT)).ShowDialog(); Here is the class def for the called form - namespace NdtStart { public partial class fclsNDTTicker : Form { public fclsNDTTicker() I tried lots but couldn't get the arguments to work.

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  • Is there a way to programatically check dependencies of an EXE?

    - by Mason Wheeler
    I've got a certain project that I build and distribute to users. I have two build configurations, Debug and Release. Debug, obviously, is for my use in debugging, but there's an additional wrinkle: the Debug configuration uses a special debugging memory manager, with a dependency on an external DLL. There's been a few times when I've accidentally built and distributed an installer package with the Debug configuration, and it's then failed to run once installed because the users don't have the special DLL. I'd like to be able to keep that from happening in the future. I know I can get the dependencies in a program by running Dependency Walker, but I'm looking for a way to do it programatically. Specifically, I have a way to run scripts while creating the installer, and I want something I can put in the installer script to check the program and see if it has a dependency on this DLL, and if so, cause the installer-creation process to fail with an error. I know how to create a simple CLI program that would take two filenames as parameters, and could run a DependsOn function and create output based on the result of it, but I don't know what to put in the DependsOn function. Does anyone know how I'd go about writing it?

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  • capturing CMD batch file parameter list; write to file for later processing

    - by BobB
    I have written a batch file that is launched as a post processing utility by a program. The batch file reads ~24 parameters supplied by the calling program, stores them into variables, and then writes them to various text files. Since the max input variable in CMD is %9, it's necessary to use the 'shift' command to repeatedly read and store these individually to named variables. Because the program outputs several similar batch files, the result is opening several CMD windows sequentially, assigning variables and writing data files. This ties up the calling program for too long. It occurs to me that I could free up the calling program much faster if maybe there's a way to write a very simple batch file that can write all the command parameters to a text file, where I can process them later. Basically, just grab the parameter list, write it and done. Q: Is there some way to treat an entire series of parameter data as one big text string and write it to one big variable... and then echo the whole big thing to one text file? Then later read the string into %n variables when there's no program waiting to resume? Parameter list is something like 25 - 30 words, less than 200 characters. Sample parameter list: "First Name" "Lastname" "123 Steet Name Way" "Cityname" ST 12345 1004968 06/01/2010 "Firstname+Lastname" 101738 "On Account" 20.67 xy-1z 1 8.95 3.00 1.39 0 0 239 8.95 Items in quotes are processed as string variables. List is space delimited. Any suggestions?

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  • Easily (as in WYSIWYG) customize the docbook output

    - by Sukima
    I've used DocBook in the past and I love the idea behind the separation of content from presentation. I am very comfortable editing XML directly. In my extensive search to find the best documenting solution for my needs I am always coming back to this one solution: DocBook - Build system (ant, make, etc.) - Output I have seen lots of information concerning the best WYSIWYG, XML, Text editors for writing DocBook including alternative markup languages like asciidoc. All these solutions focus on the creation of DocBook or the nightmare of the DocBook tool chain. No one ever addresses the Output side other then to say "Just use XSL" or "Custom scripts" When tasked to make a document or manual I don't want to worry about spending countless hours attempting to reprogram, customize, and modify the XSL, CSS, and shell scripts (i.e. O'Riely books). That is a very arduous task. My query: is there a tool that makes the customizing easier? And is there anything that could be similar to say Pages or Word in that the user creates a template and the tool chain does the rest? Attempting to do a visual task like pretty logos and fixing all the broken layouts that the default XSL comes up with (pagination is a mess) is very difficult from a text editor. Content is easy. Editing DocBook XSL was truly a nightmare when I did it in the past. I've searched and I find lots of info on XML editors but nothing on XSL editors. Or am I lacking a key understanding of the process. Thanks.

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  • Why Android for enterprise applications?

    - by mcabral
    Recently one of our clients is considering the posibility of picking up an old WinMobile 5.0 project. Several features are to be added to the point it will be a major version update. The client is worried about the mobile market, and thinks there's a chance all the effort put in this development will have to be thrown away in a couple of year due to the dinamics of the mobile market and the deprecation of mobile devices. So, the client is not sure whether he should continue with Windows Mobile (changing from WM 5.0 to 6.X) or starting from scratch with another technology. From our part we have been studing the mobile market, looking for clues for which will be the winning horse. The safe move seems to continue with WM just because re writing an entire application from scratch involves more risks and delays. On the other hand WM seems to be losing market and the ghost of an exit on their part is growing stronger everyday. But what can be say about Android? Everyone is talking about it and is growing at full speed but what avantagies will it bring to the table? Why should we start a fresh applicaction on this technology? So the question remains the same.. is Andriod mature enough for an enterprise application? Will you recomend it to one of your clients? Will you port/rewrite a WM application to Andriod? What's the trade-off? EDIT: Addressing commentaries. The app is entirely built with C# and Compact Framework. The app is for logistics/management.

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  • C/C++: feedback in analyzing a code example

    - by KaiserJohaan
    Hello, I have a piece of code from an assignment I am uncertain about. I feel confident that I know the answer, but I just want to double-check with the community incase there's something I forgot. The title is basically secure coding and the question is just to explain the results. int main() { unsigned int i = 1; unsigned int c = 1; while (i > 0) { i = i*2; c++; } printf("%d\n", c); return 0; } My reasoning is this: At first glance you could imagine the code would run forever, considering it's initialized to a positive value and ever increasing. This of course is wrong because eventually the value will grow so large it will cause an integer overflow. This in turn is not entirely true either, because eventally it will force the variable 'i' to be signed by making the last bit to 1 and therefore regarded as a negative number, therefore terminating the loop. So it is not writing to unallocated memory and therefore cause integer overflow, but rather violating the data type and therefore causing the loop to terminate. I am quite sure this is the reason, but I just want to double check. Any opinions?

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  • Detection of negative integers using bit operations

    - by Nawaz
    One approach to check if a given integer is negative or not, could be this: (using bit operations) int num_bits = sizeof(int) * 8; //assuming 8 bits per byte! int sign_bit = given_int & (1 << (num_bits-1)); //sign_bit is either 1 or 0 if ( sign_bit ) { cout << "given integer is negative"<<endl; } else { cout << "given integer is positive"<<endl; } The problem with this solution is that number of bits per byte couldn't be 8, it could be 9,10, 11 even 16 or 40 bits per byte. Byte doesn't necessarily mean 8 bits! Anyway, this problem can be easily fixed by writing, //CHAR_BIT is defined in limits.h int num_bits = sizeof(int) * CHAR_BIT; //no assumption. It seems fine now. But is it really? Is this Standard conformant? What if the negative integer is not represented as 2's complement? What if it's representation in a binary numeration system that doesn't necessitate only negative integers to have 1 in it's most significant bit? Can we write such code that will be both portable and standard conformant? Related topics: Size of Primitive data types Why is a boolean 1 byte and not 1 bit of size?

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  • Why is my code slower using #import "progid:typelib" than using "MFC Class From TypeLib"?

    - by Pakman
    I am writing an automation client in Visual C++ with MFC. If I right-click on my solution » Add » Class, I have the option to select MFC Class From TypeLib. Selecting this option generates source/header files for all interfaces. This allows me to write code such as: #include "CApplication.h" #include "CDocument.h" // ... connect to automation server ... CApplication *myApp = new CApplication(pDisp); CDocument myDoc = myApp->get_ActiveDocument(); Using this method, my benchmarking function that makes about 12000 automation calls takes 1 second. Meanwhile, the following code: #import "progid:Library.Application" Library::IApplicationPtr myApp; // ... connect to automation server ... Library::IDocumentPtr myDoc = myApp->GetActiveDocument(); takes about 2.4 seconds for the same benchmark. I assume the smart-pointer implementation is slowing me down, but I don't know why. Even worse, I'm not sure how to use #import construct to achieve the speeds that the first method yields. Is this possible? How or why not? Thanks for your time!

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  • Convert SQL to LINQ in MVC3 with Ninject

    - by Jeff
    I'm using MVC3 and still learning LINQ. I'm having some trouble trying to convert a query to LINQ to Entities. I want to return an employee object. SELECT E.EmployeeID, E.FirstName, E.LastName, MAX(EO.EmployeeOperationDate) AS "Last Operation" FROM Employees E INNER JOIN EmployeeStatus ES ON E.EmployeeID = ES.EmployeeID INNER JOIN EmployeeOperations EO ON ES.EmployeeStatusID = EO.EmployeeStatusID INNER JOIN Teams T ON T.TeamID = ES.TeamID WHERE T.TeamName = 'MyTeam' GROUP BY E.EmployeeID, E.FirstName, E.LastName ORDER BY E.FirstName, E.LastName What I have is a few tables, but I need to get only the newest status based on the EmployeeOpertionDate. This seems to work fine in SQL. I'm also using Ninject and set my query to return Ienumerable. I played around with the group by option but it then returns IGroupable. Any guidance on converting and returning the property object type would be appreciated. Edit: I started writing this out in LINQ but I'm not sure how to properly return the correct type or cast this. public IQueryable<Employee> GetEmployeesByTeam(int teamID) { var q = from E in context.Employees join ES in context.EmployeeStatuses on E.EmployeeID equals ES.EmployeeID join EO in context.EmployeeOperations on ES.EmployeeStatusID equals EO.EmployeeStatusID join T in context.Teams on ES.TeamID equals T.TeamID where T.TeamName == "MyTeam" group E by E.EmployeeID into G select G; return q; } Edit2: This seems to work for me public IQueryable<Employee> GetEmployeesByTeam(int teamID) { var q = from E in context.Employees join ES in context.EmployeeStatuses on E.EmployeeID equals ES.EmployeeID join EO in context.EmployeeOperations.OrderByDescending(eo => eo.EmployeeOperationDate) on ES.EmployeeStatusID equals EO.EmployeeStatusID join T in context.Teams on ES.TeamID equals T.TeamID where T.TeamID == teamID group E by E.EmployeeID into G select G.FirstOrDefault(); return q; }

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  • Creating parallel selenium tests in C# and using Nunit as the runner application

    - by damianmartin
    I am writing a new test suite for the company to test a very complex ASP.NET application which is heavily AJAX driven. We have decided to use Selenium (Grid & Remote Control) and Nunit to run these tests. The actually tests are dynamically created at run time from a spreadsheet. Each Column in an excel spreadsheet relates to a new test and each row relates to a selenium command (but in plain English and the dll converts this into Selenium code). My problem i have at the moment is getting the tests running in parallel. There will be 1000+ tests so it is too time consuming to have 1 test run at a time. Selenium Grid and Selenium Remote Control(s) are setup correctly because I can run there demo. From what i have read I need to use Punit but i can not find any documentation on what a test in punit should look like. Nunit tests are [SetUp] [TearDown] [Test]. Can anyone point me in the right direction. Thanks in advance.

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  • problem with fork()

    - by john
    I'm writing a shell which forks, with the parent reading the input and the child process parsing and executing it with execvp. pseudocode of main method: do{ pid = fork(); print pid; if (p<0) { error; exit; } if (p>0) { wait for child to finish; read input; } else { call function to parse input; exit; } }while condition return; what happens is that i never seem to enter the child process (pid printed is always positive, i never enter the else). however, if i don't call the parse function and just have else exit, i do correctly enter parent and child alternatingly. full code: int main(int argc, char *argv[]){ char input[500]; pid_t p; int firstrun = 1; do{ p = fork(); printf("PID: %d", p); if (p < 0) {printf("Error forking"); exit(-1);} if (p > 0){ wait(NULL); firstrun = 0; printf("\n> "); bzero(input, 500); fflush(stdout); read(0, input, 499); input[strlen(input)-1] = '\0'; } else exit(0); else { if (parse(input) != 0 && firstrun != 1) { printf("Error parsing"); exit(-1); } exit(0); } }while(strcmp(input, "exit") != 0); return 0; }

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  • Java equivalent of the VB Request.InputStream

    - by Android Addict
    I have a web service that I am re-writing from VB to a Java servlet. In the web service, I want to extract the body entity set on the client-side as such: StringEntity stringEntity = new StringEntity(xml, HTTP.UTF_8); stringEntity.setContentType("application/xml"); httppost.setEntity(stringEntity); In the VB web service, I get this data by using: Dim objReader As System.IO.StreamReader objReader = New System.IO.StreamReader(Request.InputStream) Dim strXML As String = objReader.ReadToEnd and this works great. But I am looking for the equivalent in Java. I have tried this: ServletInputStream dataStream = req.getInputStream(); byte[] data = new byte[dataStream.toString().length()]; dataStream.read(data); but all it gets me is an unintelligible string: data = [B@68514fec Please advise. Edit Per the answers, I have tried: ServletInputStream dataStream = req.getInputStream(); ByteArrayOutputStream buffer = new ByteArrayOutputStream(); int r; byte[] data = new byte[1024*1024]; while ((r = dataStream.read(data, 0, data.length)) != -1) { buffer.write(data, 0, r); } buffer.flush(); byte[] data2 = buffer.toByteArray(); System.out.println("DATA = "+Arrays.toString(data2)); whichs yields: DATA = [] and when I try: System.out.println("DATA = "+data2.toString()); I get: DATA = [B@15282c7f So what am I doing wrong? As stated earlier, the same call to my VB service gives me the xml that I pass in.

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  • How to create platform independent 3D video on 3D TV via HDMI 1.4?

    - by artif
    I am writing a real-time, interactive 3D visualization program and at each point in the program, I can compute 2 images (bitmaps) that are meant to look 3D together by means of stereoscopy. How do I get my program to display the image pairs such that they look 3D on a 3D TV? Is there a platform independent way of accomplishing it? (By platform I mean independent of GPU brand, operating system, 3D TV vendor, etc.) If not, which is preferable-- to lock in by GPU, OS, or 3D TV? I suppose I need to be using an HDMI 1.4 cable with the 3D TV? HDMI 1.4 can encode stereoscopy via side-by-side method. But how do I send such an encoded signal to the monitor? What kind of libraries do I use for this sort of thing? Windows DirectShow? If DirectShow is correct, is there a cross platform equivalent available? If anyone asks, yes I have seen this question: http://stackoverflow.com/questions/2811350/generating-3d-tv-stereoscopic-output-programmatically. However, correct me if I am wrong, it does not appear to be what I'm looking for. I do not have an OpenGL or Direct3D program that generates polygons, for which a Nvidia card can do ad-hoc impromptu stereoscopy simply by rendering the scene from 2 slightly offset points of view and then displaying those 2 images on the monitor-- my program already has those image pairs and needs to display them (and they are not the result of rendering polygons). Btw, I have never done any major multimedia programming before and know very little about HDMI, Direct Show, 3D TVs, etc so pardon me if any parts of this question did not make any sense at all.

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  • Why doesn't my test run tearDownAfterTestClass when it fails

    - by Memor-X
    in a test i am writing the setUpBeforeTests creates a new customer in the database who is then used to perform the tests with so naturally when i finish the test i should get rid of this test customer in tearDownAfterTestClass so that i can create then anew when i rerun the test and not get any false positives how when the tests all run fine i have no problem but if a test fails and i go to rerun it my setUpBeforeTests fails because i check for mysql errors in it like this try { if(!mysqli_query($connection,$query)) { $this->assertTrue(false); } } catch (Exception $exc) { $msg = '[tearDownAfterTestClass] Exception Error' . PHP_EOL . PHP_EOL; $msg .= 'Could not run query - '.mysqli_error($connection). PHP_EOL;; $this->fail($msg); } the error i get is that there is a primary key violation which is expected cause i'm trying to create a new customer using the same data (primary key is on email which is also used to log in) however that means when the test failed it didn't run tearDownAfterTestClass now i could just move everything in tearDownAfterTestClass to the start of setUpBeforeTests however to me that seems like bad programming since it defeates the purpose of even have tearDownAfterTestClass so i am wondering, why isn't my tearDownAfterTestClass running when a test fails NOTE: the database is a fundamental part of the system i'm testing and the database and system are on a separate development environment not the live one, the backup files for the database are almost 2 GBs and takes almost 1/2 an hour to restore, the purpose of the tear down is to remove any data we have added because of the test so that we don't have to restore the database every time we run the tests

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  • Downloading javascript Without Blocking

    - by doug
    The context: My question relates to improving web-page loading performance, and in particular the effect that javascript has on page-loading (resources/elements below the script are blocked from downloading/rendering). This problem is usually avoided/mitigated by placing the scripts at the bottom (eg, just before the tag). The code i am looking at is for web analytics. Placing it at the bottom reduces its accuracy; and because this script has no effect on the page's content, ie, it's not re-writing any part of the page--i want to move it inside the head. Just how to do that without ruining page-loading performance is the crux. From my research, i've found six techniques (w/ support among all or most of the major browsers) for downloading scripts so that they don't block down-page content from loading/rendering: (i) XHR + eval(); (ii) XHR + 'inject'; (iii) download the HTML-wrapped script as in iFrame; (iv) setting the script tag's 'async' flag to 'TRUE' (HTML 5 only); (v) setting the script tag's 'defer' attribute; and (vi) 'Script DOM Element'. It's the last of these i don't understand. The javascript to implement the pattern (vi) is: (function() { var q1 = document.createElement('script'); q1.src = 'http://www.my_site.com/q1.js' document.documentElement.firstChild.appendChild(q1) })(); Seems simple enough: inside this anonymous function, a script element is created, its 'src' element is set to it's location, then the script element is added to the DOM. But while each line is clear, it's still not clear to me how exactly this pattern allows script loading without blocking down-page elements/resources from rendering/loading?

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  • How to jQuery plugin effects to items created later in the DOM

    - by Dan Denney
    How do I apply jQuery plugin effects to items that are created by an event? So, what I am attempting to do is have all uls throughout a site use the jquery.scroll.js plugin for styling. I currently have it working on all active uls. However, there are some category/subcategory sections. I am still new to writing any jQuery on my own and there is a leap in logic that I don't understand on applying plugins to items when they are loaded later. In the real example, users click a category from a ul and a sub category is loaded via Rails and JSON. For a light sample, I made a jsfiddle that simulates the issue that I run into. The category ul is styled correctly, but the subcategory ul doesn't pick up the styling. I'm hoping for some assistance not just in whipping up some code to fix it, but in pointing me in the direction of what I need to learn for this functionality. http://jsfiddle.net/dandenney/25R8F/1/ Thank you in advance!

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  • C++0x rvalue references and temporaries

    - by Doug
    (I asked a variation of this question on comp.std.c++ but didn't get an answer.) Why does the call to f(arg) in this code call the const ref overload of f? void f(const std::string &); //less efficient void f(std::string &&); //more efficient void g(const char * arg) { f(arg); } My intuition says that the f(string &&) overload should be chosen, because arg needs to be converted to a temporary no matter what, and the temporary matches the rvalue reference better than the lvalue reference. This is not what happens in GCC and MSVC. In at least G++ and MSVC, any lvalue does not bind to an rvalue reference argument, even if there is an intermediate temporary created. Indeed, if the const ref overload isn't present, the compilers diagnose an error. However, writing f(arg + 0) or f(std::string(arg)) does choose the rvalue reference overload as you would expect. From my reading of the C++0x standard, it seems like the implicit conversion of a const char * to a string should be considered when considering if f(string &&) is viable, just as when passing a const lvalue ref arguments. Section 13.3 (overload resolution) doesn't differentiate between rvalue refs and const references in too many places. Also, it seems that the rule that prevents lvalues from binding to rvalue references (13.3.3.1.4/3) shouldn't apply if there's an intermediate temporary - after all, it's perfectly safe to move from the temporary. Is this: Me misreading/misunderstand the standard, where the implemented behavior is the intended behavior, and there's some good reason why my example should behave the way it does? A mistake that the compiler vendors have somehow all made? Or a mistake based on common implementation strategies? Or a mistake in e.g. GCC (where this lvalue/rvalue reference binding rule was first implemented), that was copied by other vendors? A defect in the standard, or an unintended consequence, or something that should be clarified?

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  • Should client-server code be written in one "project" or two?

    - by Ricket
    I've been beginning a client-server application. At first I naturally created two projects in Eclipse, two source control repositories, etc. But I'm quickly seeing that there is a bit of shared code between the two that would probably benefit to sharing instead of copying. In addition, I've been learning and trying test-driven development, and it seems to me that it would be easier to test based on real client components rather than having to set up a huge amount of code just to mock something, when the code is probably mostly in the client. My biggest concern in merging the client and server is of security; how do I ensure that the server pieces of the code do not reach an user's computer? So especially if you are writing client-server applications yourself (and especially in Java, though this can turn into a language-agnostic question if you'd like to share your experience with this in other languages), what sort of separation do you keep between your client and server code? Are they just in different packages/namespaces or completely different binaries using shared libraries, or something else entirely? How do you test the code together and yet ship separately?

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  • Modeling complex hierarchies

    - by jdn
    To gain some experience, I am trying to make an expert system that can answer queries about the animal kingdom. However, I have run into a problem modeling the domain. I originally considered the animal kingdom hierarchy to be drawn like -animal -bird -carnivore -hawk -herbivore -bluejay -mammals -carnivores -herbivores This I figured would allow me to make queries easily like "give me all birds", but would be much more expensive to say "give me all carnivores", so I rewrote the hierarchy to look like: -animal -carnivore -birds -hawk -mammals -xyz -herbivores -birds -bluejay -mammals But now it will be much slower to query "give me all birds." This is of course a simple example, but it got me thinking that I don't really know how to model complex relationships that are not so strictly hierarchical in nature in the context of writing an expert system to answer queries as stated above. A directed, cyclic graph seems like it could mathematically solve the problem, but storing this in a relational database and maintaining it (updates) would seem like a nightmare to me. I would like to know how people typically model such things. Explanations or pointers to resources to read further would be acceptable and appreciated.

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  • I need to speed up a function. Should I use cython, ctypes, or something else?

    - by Peter Stewart
    I'm having a lot of fun learning Python by writing a genetic programming type of application. I've had some great advice from Torsten Marek, Paul Hankin and Alex Martelli on this site. The program has 4 main functions: generate (randomly) an expression tree. evaluate the fitness of the tree crossbreed mutate As all of generate, crossbreed and mutate call 'evaluate the fitness'. it is the busiest function and is the primary bottleneck speedwise. As is the nature of genetic algorithms, it has to search an immense solution space so the faster the better. I want to speed up each of these functions. I'll start with the fitness evaluator. My question is what is the best way to do this. I've been looking into cython, ctypes and 'linking and embedding'. They are all new to me and quite beyond me at the moment but I look forward to learning one and eventually all of them. The 'fitness function' needs to compare the value of the expression tree to the value of the target expression. So it will consist of a postfix evaluator which will read the tree in a postfix order. I have all the code in python. I need advice on which I should learn and use now: cython, ctypes or linking and embedding. Thank you.

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  • Python raw strings and trailing back slashes.

    - by dash-tom-bang
    I ran across something once upon a time and wondered if it was a Python "bug" or at least a misfeature. I'm curious if anyone knows of any justifications for this behavior. I thought of it just now reading "Code Like a Pythonista," which has been enjoyable so far. I'm only familiar with the 2.x line of Python. Raw strings are strings that are prefixed with an r. This is great because I can use backslashes in regular expressions and I don't need to double everything everywhere. It's also handy for writing throwaway scripts on Windows, so I can use backslashes there also. (I know I can also use forward slashes, but throwaway scripts often contain content cut&pasted from elsewhere in Windows.) So great! Unless, of course, you really want your string to end with a backslash. There's no way to do that in a 'raw' string. In [9]: r'\n' Out[9]: '\\n' In [10]: r'abc\n' Out[10]: 'abc\\n' In [11]: r'abc\' ------------------------------------------------ File "<ipython console>", line 1 r'abc\' ^ SyntaxError: EOL while scanning string literal In [12]: r'abc\\' Out[12]: 'abc\\\\' So one slash before the closing quote is an error, but two slashes gives you two slashes! Certainly I'm not the only one that is bothered by this? Thoughts on why 'raw' strings are 'raw, except for slash-quote'? I mean, if I wanted to embed a single quote in there I'd just use double quotes around the string, and vice versa. If I wanted both, I'd just triple quote. If I really wanted three quotes in a row in a raw string, well, I guess I'd have to deal, but is this considered "proper behavior"?

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  • How can I show print statements in debug mode of OPNET Modeler?

    - by Here now
    I'm writing C++ code in OPNET Modeler. I try to simulate my scenario in debugger mode & I need to trace the function that I wrote it. I need to show print statements which I put it in my code. I used in debugger mode: ***ltr function_name()*** then ***c*** But the result looks like: Type 'help' for Command Summary ODB> ltr enqueue_packet() Added trace #0: trace on label (enqueue_packet()) ODB> c |-----------------------------------------------------------------------------| | Progress: Time (1 min. 52 sec.); Events (500,002) | | Speed: Average (82,575 events/sec.); Current (82,575 events/sec.) | | Time : Elapsed (6.1 sec.) | | DES Log: 28 entries | |-----------------------------------------------------------------------------| |-----------------------------------------------------------------------------| | Progress: Time (1 min. 55 sec.); Events (1,000,002) | | Speed: Average (69,027 events/sec.); Current (59,298 events/sec.) | | Time : Elapsed (14 sec.) | | DES Log: 28 entries | |-----------------------------------------------------------------------------| |-----------------------------------------------------------------------------| | Progress: Time (1 min. 59 sec.); Events (1,500,002) | | Speed: Average (51,464 events/sec.); Current (34,108 events/sec.) | | Time : Elapsed (29 sec.) | | DES Log: 28 entries | |-----------------------------------------------------------------------------| |-----------------------------------------------------------------------------| | Simulation Completed - Collating Results. | | Events: Total (1,591,301); Average Speed (48,803 events/sec.) | | Time : Elapsed (33 sec.); Simulated (2 min. 0 sec.) | | DES Log: 29 entries | |-----------------------------------------------------------------------------| |-----------------------------------------------------------------------------| | Reading network model. | |-----------------------------------------------------------------------------| I need to show the print statements in my code. Where it has to be appeared? Is there any step before run the simulation to insure that OPNET debugger using Visual Studio & go through my code??

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  • Best practices, PHP, tracking millions of impressions per day.

    - by John
    What do I have to do to make 20k mysql inserts per second possible (during peak hours around 1k/sec during slower times)? I've been doing some research and I've seen the "INSERT DELAYED" suggestion, writing to a flat file, "fopen(file,'a')", and then running a chron job to dump the "needed" data into mysql, etc. I've also heard you need multiple servers and "load balancers" which I've never heard of, to make something like this work. I've also been looking at these "cloud server" thing-a-ma-jigs, and their automatic scalability, but not sure about what's actually scalable. The application is just a tracker script, so if I have 100 websites that get 3 million page loads a day, there will be around 300 million inserts a day. The data will be ran through a script that will run every 15-30 minutes which will normalize the data and insert it into another mysql table. How do the big dogs do it? How do the little dogs do it? I can't afford a huge server anymore so any intuitive ways, if there are multiple ways of going at it, you smart people can think of.. please let me know :)

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