Search Results

Search found 7618 results on 305 pages for 'named graph'.

Page 255/305 | < Previous Page | 251 252 253 254 255 256 257 258 259 260 261 262  | Next Page >

• Need help with WCF design

  - by Jason

  I have been tasked with creating a set of web services. We are a Microsoft shop, so I will be using WCF for this project. There is an interesting design consideration that I haven't been able to figure out a solution for yet. I'll try to explain it with an example: My WCF service exposes a method named Foo(). 10 different users call Foo() at roughly the same time. I have 5 special resources called R1, R2, R3, R4, and R5. We don't really need to know what the resource is, other than the fact that a particular resource can only be in use by one caller at a time. Foo() is responsible to performing an action using one of these special resources. So, in a round-robin fashion, Foo() needs to find a resource that is not in use. If no resources are available, it must wait for one to be freed up. At first, this seems like an easy task. I could maybe create a singleton that keeps track of which resources are currently in use. The big problem is the fact that I need this solution to be viable in a web farm scenario. I'm sure there is a good solution to this problem, but I've just never run across this scenario before. I need some sort of resource tracker / provider that can be shared between multiple WCF hosts. Any ideas from the architects out there would be greatly appreciated!

  Read the article

• Linear feedback shift register?

  - by Mattia Gobbi

  Lately I bumped repeatedly into the concept of LFSR, that I find quite interesting because of its links with different fields and also fascinating in itself. It took me some effort to understand, the final help was this really good page, much better than the (at first) cryptic wikipedia entry. So I wanted to write some small code for a program that worked like a LFSR. To be more precise, that somehow showed how a LFSR works. Here's the cleanest thing I could come up with after some lenghtier attempts (Python): def lfsr(seed, taps): sr, xor = seed, 0 while 1: for t in taps: xor += int(sr[t-1]) if xor%2 == 0.0: xor = 0 else: xor = 1 print xor sr, xor = str(xor) + sr[:-1], 0 print sr if sr == seed: break lfsr('11001001', (8,7,6,1)) #example I named "xor" the output of the XOR function, not very correct. However, this is just meant to show how it circles through its possible states, in fact you noticed the register is represented by a string. Not much logical coherence. This can be easily turned into a nice toy you can watch for hours (at least I could :-) def lfsr(seed, taps): import time sr, xor = seed, 0 while 1: for t in taps: xor += int(sr[t-1]) if xor%2 == 0.0: xor = 0 else: xor = 1 print xor print time.sleep(0.75) sr, xor = str(xor) + sr[:-1], 0 print sr print time.sleep(0.75) Then it struck me, what use is this in writing software? I heard it can generate random numbers; is it true? how? So, it would be nice if someone could: explain how to use such a device in software development come up with some code, to support the point above or just like mine to show different ways to do it, in any language Also, as theres not much didactic stuff around about this piece of logic and digital circuitry, it would be nice if this could be a place for noobies (like me) to get a better understanding of this thing, or better, to understand what it is and how it can be useful when writing software. Should have made it a community wiki? That said, if someone feels like golfing... you're welcome.

  Read the article

• ASP.Net HttpModule List<> content

  - by test

  We have created an http module that loads data on initialize into a list, and uses that list on every endrequest event of application. However we got a null reference exception on the module at endRequest event complaining that the content is null. Yet we are sure that at module initialization we have put non-null objects correctly. How is this possible? Any ideas? Thanks in advance. The place where i fill the data into the list what named as "Pages" : using (SqlDataReader reader = cmd.ExecuteReader()) { while (reader.Read()) { LandingPageDetails details = new LandingPageDetails(); details.DomainId = Convert.ToInt32(reader["DomainId"]); details.PageId = Convert.ToInt32(reader["TrackingPageId"]); details.PageAddress = Convert.ToString(reader["PageAddress"]); if (!string.IsNullOrEmpty(details.PageAddress)) { Pages.Add(details); } } } // Find the related record on EndRequesst event LandingPageDetails result = Pages.Find ( delegate(LandingPageDetails current) { return current.PageAddress.Equals(url, StringComparison.InvariantCultureIgnoreCase); } ); The line what we get the error return current.PageAddress.Equals(url, StringComparison.InvariantCultureIgnoreCase); "current" is the null object P.S : It works properly, but one day later contents become null. Possibly, there is something wrong on IIS. Our server is Windows 2003, IIS 6.0

  Read the article

• django+mod_wsgi on virtualenv not working

  - by jwesonga

  I've just finished setting up a django app on virtualenv, deployment went smoothly using a fabric script, but now the .wsgi is not working, I've tried every variation on the internet but no luck. My .wsgi file is: import os import sys import django.core.handlers.wsgi # put the Django project on sys.path root_path = os.path.abspath(os.path.dirname(__file__) + '../') sys.path.insert(0, os.path.join(root_path, 'kcdf')) sys.path.insert(0, root_path) os.environ['DJANGO_SETTINGS_MODULE'] = 'kcdf.settings' application = django.core.handlers.wsgi.WSGIHandler() I keep getting the same error: [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] mod_wsgi (pid=16938): Exception occurred processing WSGI script '/home/kcdfweb/webapps/kcdf.web/releases/current/kcdf/apache/kcdf.wsgi'. [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] Traceback (most recent call last): [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] File "/usr/local/lib/python2.6/dist-packages/django/core/handlers/wsgi.py", line 230, in __call__ [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] self.load_middleware() [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] File "/usr/local/lib/python2.6/dist-packages/django/core/handlers/base.py", line 33, in load_middleware [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] for middleware_path in settings.MIDDLEWARE_CLASSES: [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] File "/usr/local/lib/python2.6/dist-packages/django/utils/functional.py", line 269, in __getattr__ [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] self._setup() [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] File "/usr/local/lib/python2.6/dist-packages/django/conf/__init__.py", line 40, in _setup [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] self._wrapped = Settings(settings_module) [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] File "/usr/local/lib/python2.6/dist-packages/django/conf/__init__.py", line 75, in __init__ [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] raise ImportError, "Could not import settings '%s' (Is it on sys.path? Does it have syntax errors?): %s" % (self.SETTINGS_MODULE, e) [Sun Apr 18 12:44:30 2010] [error] [client 41.215.123.159] ImportError: Could not import settings 'kcdf.settings' (Is it on sys.path? Does it have syntax errors?): No module named kcdf.settings my virtual environment is on /home/user/webapps/kcdfweb my app is /home/user/webapps/kcdf.web/releases/current/project_name my wsgi file home/user/webapps/kcdf.web/releases/current/project_name/apache/project_name.wsgi

  Read the article

• Getting Started with Ruby & Ruby on Rails

  - by JakeTheSnake

  Some background: I'm a jack-of-all traits, one of which is programming. I learned VB6 through Excel and PHP for creating websites and so far it's worked out just fine for me. I'm not CS major or even mathematically inclined - logic is what interests me. Current status: I'm willing to learn new and more powerful languages; my first foray into such a route is learning Ruby. I went to the main Ruby website and did the interactive intro. (by the way, I'm currently getting redirected to google.com when I try the link...it's happening to other websites as well...is my computer infected?) I liked what I learned and wanted to get started using Ruby to create websites. I downloaded InstantRails and installed it; everything so far has been fine - the program starts up just fine, and I can test some Ruby code in the console. However my troubles begin when I try and view a web page with Ruby code present. Lastly, my problem: As in PHP, I can browse to the .php file directly and through using PHP tags and some simple 'echo' statements I can be on my way in making dynamic web pages. However with the InstantRails app working, accessing a .rb or .rhtml page doesn't produce similar results. I made a simple text file named 'test.rb' and put basic HTML tags in there (html, head, body) and the Ruby tags <%= and % with some ruby code inside. The web page actually shows the tags and the code - as if it's all just plain HTML. I take it Ruby isn't parsing the page before it is displayed to the user, but this is where my lack of understanding of the Ruby environment stops me short. Where do I go from here?

  Read the article

• DBD::CSV: Problem with file-name-extensions

  - by sid_com

  In this script I have problems with file-name-extensions: if I use /home/mm/test_x it works, with file named /home/mm/test_x.csv it doesn't: #!/usr/bin/env perl use warnings; use strict; use 5.012; use DBI; my $table_1 = '/home/mm/test_1.csv'; my $table_2 = '/home/mm/test_2.csv'; #$table_1 = '/home/mm/test_1'; #$table_2 = '/home/mm/test_2'; my $dbh = DBI->connect( "DBI:CSV:" ); $dbh->{RaiseError} = 1; $table_1 = $dbh->quote_identifier( $table_1 ); $table_2 = $dbh->quote_identifier( $table_2 ); my $sth = $dbh->prepare( "SELECT a.id, a.name, b.city FROM $table_1 AS a NATURAL JOIN $table_2 AS b" ); $sth->execute; $sth->dump_results; $dbh->disconnect; Output with file-name-extention: DBD::CSV::st execute failed: Execution ERROR: No such column '"/home/mm/test_1.csv".id' called from /usr/local/lib/perl5/site_perl/5.12.0/x86_64-linux/DBD/File.pm at 570. Output without file-name-extension: '1', 'Brown', 'Laramie' '2', 'Smith', 'Watertown' 2 rows Is this a bug?

  Read the article

• Django 'ImproperlyConfigured' error after deployment on google app engine

  - by oreon

  Hello, I'm currently trying to get my first django project running on Google App Engine. I followed the instructions given here http://www.allbuttonspressed.com/projects/djangoappengine as best I could. Unfortunately I have run into some issues. Locally everything runs fine, no problems. I then tried to deploy my project to the cloud. This is where I'm totally stuck. I always receive 500 Server Errors coupled with google.appengine.runtime.DeadlineExceededError's. Every now and then I get the following error message in my logs, which I think is the root of the problem : <class 'django.core.exceptions.ImproperlyConfigured'>: ImportError projectyalanda.pricecompare: No module named projectyalanda.pricecompare Obviously something is wrong in the way I reference my django app. Why this is only an issue in the cloud is a mystery to me. The interesting part in the settings.py file is setup as following: INSTALLED_APPS = ( 'djangotoolbox', # 'django.contrib.auth', 'django.contrib.contenttypes', 'django.contrib.sessions', 'projectyalanda.pricecompare', ) I absolutely can't figure out why django/appengine wouldn't be able to find the module, especially since everything works perfectly locally. So where else can I look? The local folder structure is of course also correct as automatically done by django, so maybe something is messed up during deployment? How would I be able to find out? Please help me ;-) Thanks

  Read the article

• sql query - how to apply limit within group by

  - by Raj

  hey guys assuming i have a table named t1 with following fields: ROWID, CID, PID, Score, SortKey it has the following data: 1, C1, P1, 10, 1 2, C1, P2, 20, 2 3, C1, P3, 30, 3 4, C2, P4, 20, 3 5, C2, P5, 30, 2 6, C3, P6, 10, 1 7, C3, P7, 20, 2 what query do i write so that it applies group by on CID, but instead of returning me 1 single result per group, it returns me a max of 2 results per group. also where condition is score = 20 and i want the results ordered by CID and SortKey. If I had to run my query on above data, i would expect the following result: RESULTS FOR C1 - note: ROWID 1 is not considered as its score < 20 C1, P2, 20, 2 C1, P3, 30, 3 RESULTS FOR C2 - note: ROWID 5 appears before ROWID 4 as ROWID 5 has lesser value SortKey C2, P5, 30, 2 C2, P4, 20, 3 RESULTS FOR C3 - note: ROWID 6 does not appear as its score is less than 20 so only 1 record returned here C3, P7, 20, 2 IN SHORT, I WANT A LIMIT WITHIN A GROUP BY. I want the simplest solution and want to avoid temp tables. sub queries are fine. also note i am using sqlite for this

  Read the article

• How do I Extend Blogengine.Net to collect statistics of visitors?

  - by Stefan

  I love BlogEngine. But from what I can se it does not collect the standard information about the visitors I would like to see (referrer, browser-type and so on). When I log in as Admin I have a menu item named "Referrer". I can choose a weekday and then I'll be presented with 1 or 2 rows with "google.com 4 hits, "itmaskinen.se 6 hits" and so on, But that's not what I want to se, I want to se where my visitors come from, country, IP if possible, how many visitors and so on. If someone of you are familiar with Blogengine.Net and can point me in the right direction to where I would put my own log-code or if you know any visitor-statistic-extension that can do it for me, I would be really happy to know. I prefer an extension, because if I make changes myself to BlogEngine it may break later updates I install. Blogengine.Net is a blog software made in .Net found here: http://www.dotnetblogengine.net/ And yes, I prefer to take this question here rather then in the Blogengine.Net forum, you know why. ;) (Anyone, feel free to edit my (bad) english in this post and after that delete this sentence)

  Read the article

• C & MinGW: Hello World gives me the error "programm too big to fit in memory"

  - by user1692088

  I'm new here. Here's my problem: I installed MinGW on my Windows 7 Home Premium 32-bit Netbook with Intel Atom CPU N550, 1.50GHz and 2GB RAM. Now I made a file named hello.h and tried to compile it via CMD with the following command: "gcc c:\workspace\c\helloworld\hello.h -o out.exe" It compiles with no error, but when I try to run out.exe, it gives me following error: "program too big to fit in memory" Things I have checked: I have added "C:\MinGW\bin" to the Windows PATH Variable I have googled for about one hour, but ever since I'm a newbie, I can't really figure out what the problem is. I have compiled the same code on my 64-bit machine, compiles perfectly, but cannot be run due to 64-bit <- 16-bit problematic. I'd really appreciate, if someone could figure out, what the problem is. Btw, here's my hello.h: #include <stdio.h> int main(void){ printf("Hello, World\n"); } ... That's it. Thanks for your replies. Cheers, Boris

  Read the article

• Literal ampersands in System.Uri query string

  - by Nathan Baulch

  I'm working on a client app that uses a restful service to look up companies by name. It's important that I'm able to include literal ampersands in my queries since this character is quite common in company names. However whenever I pass %26 (the URI escaped ampersand character) to System.Uri, it converts it back to a regular ampersand character! On closer inspection, the only two characters that aren't converted back are hash (%23) and percent (%25). Lets say I want to search for a company named "Pierce & Pierce": var endPoint = "http://localhost/companies?where=Name eq '{0}'"; var name = "Pierce & Pierce"; Console.WriteLine(new Uri(string.Format(endPoint, name))); Console.WriteLine(new Uri(string.Format(endPoint, Uri.EscapeUriString(name)))); Console.WriteLine(new Uri(string.Format(endPoint, Uri.EscapeDataString(name)))); All three of the above combinations return: http://localhost/companies?where=Name eq 'Pierce & Pierce' This causes errors on the server side since the ampersand is (correctly) interpreted as a query arg delimiter. What I really need it to return is the original string: http://localhost/companies?where=Name eq 'Pierce %26 Pierce' How can I work around this behavior without discarding System.Uri entirely? I can't replace all ampersands with %26 at the last moment because there will usually be multiple query args involved and I don't want to destroy their delimiters. Note: A similar problem was discussed in this question but I'm specifically referring to System.Uri.

  Read the article

• Calling method on category included from iPhone static library causes NSInvalidArgumentException

  - by Corey Floyd

  I have created a static library to house some of my code like categories. I have a category for UIViews in "UIView-Extensions.h" named Extensions. In this category I have a method called: - (void)fadeOutWithDelay:(CGFloat)delay duration:(CGFloat)duration; Calling this method works fine on the simulator on Debug configuration. However, if try to run the app on the device I get a NSInvalidArgumentException: [UIView fadeOutWithDelay:duration:]: unrecognized selector sent to instance 0x1912b0 *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[UIView fadeOutWithDelay:duration:]: unrecognized selector sent to instance 0x1912b0 It seems for some reason UIView-Extensions.h is not being included in the device builds. What I have checked/tried I did try to include another category for NSString, and had the same issue. Other files, like whole classes and functions work fine. It is an issue that only happens with categories. I did a clean all targets, which did not fix the problem. I checked the static library project, the categories are included in the target's "copy headers" and "compile sources" groups. The static library is included in the main projects "link binary with library" group. Another project I have added the static library to works just fine. I deleted and re-added the static library with no luck -ObjC linker flag is set Any ideas? nm output libFJSCodeDebug.a(UIView-Extensions.o): 000004d4 t -[UIView(Extensions) changeColor:withDelay:duration:] 00000000 t -[UIView(Extensions) fadeInWithDelay:duration:] 000000dc t -[UIView(Extensions) fadeOutWithDelay:duration:] 00000abc t -[UIView(Extensions) firstResponder] 000006b0 t -[UIView(Extensions) hasSubviewOfClass:] 00000870 t -[UIView(Extensions) hasSubviewOfClass:thatContainsPoint:] 000005cc t -[UIView(Extensions) rotate:] 000002d8 t -[UIView(Extensions) shrinkToSize:withDelay:duration:] 000001b8 t -[UIView(Extensions) translateToFrame:delay:duration:] U _CGAffineTransformRotate 000004a8 t _CGPointMake U _CGRectContainsPoint U _NSLog U _OBJC_CLASS_$_UIColor U _OBJC_CLASS_$_UIView U ___CFConstantStringClassReference U ___addsf3vfp U ___divdf3vfp U ___divsf3vfp U ___extendsfdf2vfp U ___muldf3vfp U ___truncdfsf2vfp U _objc_enumerationMutation U _objc_msgSend U _objc_msgSend_stret U dyld_stub_binding_helper

  Read the article

• Subclassing NSArrayController in order to limit size of arrangedObjects

  - by Simone Manganelli

  I'm trying to limit the number of objects in an array controller, but I still want to be able to access the full array, if necessary. A simple solution I came up with was to subclass NSArrayController, and define a new method named "limitedArrangedObjects", that returns a limited number of objects from the real set of arranged objects. (I've seen http://stackoverflow.com/questions/694493/limiting-the-number-of-objects-in-nsarraycontroller , but that doesn't address my problem.) I want this property to be observable via bindings, so I set a dependency to arrangedObjects on it. Problem is, when arrangedObjects is updated, limitedArrangedObjects seems not to be observing the value change in arrangedObjects. I've hooked up an NSCollectionView to limitedArrangedObjects, and zero objects are being displayed. (If I bind it to arrangedObjects instead, all the objects show up as expected.) What's the problem? Here's the relevant code: @property (readonly) NSArray *limitedArrangedObjects; - (NSArray *)limitedArrangedObjects; { NSArray *arrangedObjects = [super arrangedObjects]; NSUInteger upperLimit = 10000; NSUInteger count = [arrangedObjects count]; if (count > upperLimit) count = upperLimit; arrayToReturn = [arrangedObjects subarrayWithRange:NSMakeRange(0, count)]; return arrayToReturn; } + (NSSet *)keyPathsForValuesAffectingValueForKey:(NSString *)key; { NSSet *keyPaths = [super keyPathsForValuesAffectingValueForKey:key]; if ([key isEqualToString:@"limitedArrangedObjects"]) { NSSet *affectingKeys = [NSSet setWithObjects:@"arrangedObjects",nil]; keyPaths = [keyPaths setByAddingObjectsFromSet:affectingKeys]; } return keyPaths; }

  Read the article

• NHibernate stored procedure problem

  - by Calvin

  I'm having a hard time trying to get my stored procedure works with NHibernate. The data returned from the SP does not correspond to any database table. This is my mapping file: <?xml version="1.0" encoding="utf-8" ?> <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="DomainModel" namespace="DomainModel.Entities"> <sql-query name="DoSomething"> <return class="SomeClass"> <return-property name="ID" column="ID"/> </return> exec [dbo].[sp_doSomething] </sql-query> </hibernate-mapping> Here is my domain class: namespace DomainModel.Entities { public class SomeClass { public SomeClass() { } public virtual Guid ID { get; set; } } } When I run the code, it fails with Exception Details: NHibernate.HibernateException: Errors in named queries: {DoSomething} at line 80 Line 78: config.Configure(Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "NHibernate.config")); Line 79: Line 80: g_sessionFactory = config.BuildSessionFactory(); When I debug into NHibernate code, it seems that SomeClass is not added to the persister dictionary because there isn't a class mapping (only sql-query) defined in hbm.xml. And later on in CheckNamedQueries function, it is not able to find the persistor for SomeClass. I've checked all the obvious things (e.g. make hbm as an embedded resource) and my code isn't too much different from other samples I found on the web, but somehow I just can't get it working. Any idea how I can resolve this issue?

  Read the article

• Creating a draft version of the page before publishing in Drupal 6?

  - by Marco

  I've been looking for a good way to handle revisions in Drupal, but I am yet to succeed. For some reason there is no built in way to save a draft (that I've found so far), and the modules I've tried so far do not seem to fully work. First I tried save_as_draft, which seemed to do almost what I wanted, and if I'm not mistaken, also handles CCK fields. Sadly it seems to be broken somehow, so I can't edit a page once I've saved it as a draft.. maybe I could fix it by going through the code, but that would not be my preferred solution. The other module I tried is aptly named draft, but from what I can tell, this module only handles the title and body fields, and does this in a way that appear odd to me. Is there some common practice to solve this? I couldn't imagine that nobody had to solve this before, but I haven't found any good solution to it yet. Clarification I need this functionality for already existing content, that is, I want to be able to create and edit a draft version of an already published page, while the "old" version would still be available to anonymous users.

  Read the article

• widget within module in Yii

  - by Karolis

  I'm trying to create a widget within the module and then load that widget from 'outside' of the module. More particularly I'm using user module written by someone else. I don't want to have a separate page for displaying a login form, therefore I tried to make a CPortlet/widget (confusion) displaying the login form. Basically, I've moved the code from LoginController into that widget. Then I try to display the widget on some random page by <?php $this->widget('user.components.LoginForm'); ?> However, I get an error CWebApplication does not have a method named "encrypting". in UserIdentity class in this line: else if(Yii::app()->controller->module->encrypting($this->password)!==$user->password) This happens, because I'm basically trying to execute this code within context of the app and not the module. Thus the "Yii::app()-controller-module" trick doesn't really work as expected. What am I doing wrong:-\ Is there a better way to achieve this. I.e. display that login form in some other page, which is normally displayed by accessing login controller within user module (user/login) or is a widget the right way of doing it? Thanks.

  Read the article

• Qt - QWebView Problem

  - by user547057

  Hi, I have a PyQt gui script which consists of a QWebView widget. I'm trying to send a GET request, i.e go to a page, fill a form and hit click using the code at the bottom of this question. Since i'm dealing with the documentElement(a QWebElement) of the webview, I need to place all DOM actions in a separate function(which I have named fillForm) and connect the loadFinished() signal into the function. Without connecting the signal, the document will not have loaded and I won't be able to get the elements I want. I'm able to submit the form correctly and get the proper response from the webpage. The problem i'm having is that, the above leads to a sort of infinite loop. This is because the webpage gets reloaded each time a new page is loaded, so the form gets filled each and every single time without stopping. I'd like to know if there's some way of finding out whether the WebView's page has loaded fully, non-asynchronously or maybe pause execution of the script(without freezing the gui) until the whole document has loaded. I'm unable to come up with a satisfactory solution(my idea consisted of keeping a global variable to track clicks) to this problem. I would appreciate it if someone could help me out with a better way to tackle this. Thanks! Here's the code i'm using import sys from PyQt4.QtCore import * from PyQt4.QtGui import * from PyQt4.QtWebKit import * from PyQt4 import QtCore app = QApplication(sys.argv) web = QWebView() web.load(QUrl("http://mywebsite.com")) def fillForm(): doc = web.page().mainFrame().documentElement() searchform = doc.findFirst("input[type=text]") searchform.setAttribute("value", "hello") button = doc.findFirst("input[type=submit]") button.evaluateJavaScript("click()") QtCore.QObject.connect(web, QtCore.SIGNAL("loadFinished"), fillForm) web.show() sys.exit(app.exec_())

  Read the article

• Algorithm(s) for rearranging simple symbolic algebraic expressions

  - by Gabe Johnson

  Hi, I would like to know if there is a straightforward algorithm for rearranging simple symbolic algebraic expressions. Ideally I would like to be able to rewrite any such expression with one variable alone on the left hand side. For example, given the input: m = (x + y) / 2 ... I would like to be able to ask about x in terms of m and y, or y in terms of x and m, and get these: x = 2*m - y y = 2*m - x Of course we've all done this algorithm on paper for years. But I was wondering if there was a name for it. It seems simple enough but if somebody has already cataloged the various "gotchas" it would make life easier. For my purposes I won't need it to handle quadratics. (And yes, CAS systems do this, and yes I know I could just use them as a library. I would like to avoid such a dependency in my application. I really would just like to know if there are named algorithms for approaching this problem.)

  Read the article

• How do I draw the points in an ESRI Polyline, given the bounding box as lat/long and the "points" as

  - by Aaron

  I'm using OpenMap and I'm reading a ShapeFile using com.bbn.openmap.layer.shape.ShapeFile. The bounding box is read in as lat/long points, for example 39.583642,-104.895486. The bounding box is a lower-left point and an upper-right point which represents where the points are contained. The "points," which are named "radians" in OpenMap, are in a different format, which looks like this: [0.69086486, -1.8307719, 0.6908546, -1.8307716, 0.6908518, -1.8307717, 0.69085056, -1.8307722, 0.69084936, -1.8307728, 0.6908477, -1.8307738, 0.69084626, -1.8307749, 0.69084185, -1.8307792]. How do I convert the points like "0.69086486, -1.8307719" into x,y coordinates that are usable in normal graphics? I believe all that's needed here is some kind of conversion, because bringing the points into Excel and graphing them creates a line whose curve matches the curve of the road at the given location (lat/long). However, the axises need to be adjusted manually and I have no reference as how to adjust the axises, since the given bounding box appears to be in a different format than the given points. The ESRI Shapefile technical description doesn't seem to mention this (http://www.esri.com/library/whitepapers/pdfs/shapefile.pdf).

  Read the article

• GCC Dynamic library building problem

  - by Sirish Kumar

  I am new to linux, while compiling with dynamic library I am getting the segmentationfault error. I have two files ctest1.c void ctest1(int *i) { *i =10; } ctest2.c void ctest2(int *i) { *i =20; } I have compiled both files to a shared library named libtest.so using following command gcc -shared -W1,-soname,libtest.so.1 -o libtest.so.1.0.1 ctest1.o ctest2.o -lc And I have wrote another program prog.c which uses functions exported by this library prog.c #include void (ctest1)(int); void (ctest2)(int*); int main() { int a; ctest1(&a); printf("%d",a); return 0; } And when I have built the executable with following command gcc -Wall prog.c -L. -o prog But when I run the generated executable I get the SegmentationFault error. When I checked the header of prog with ldd it shows linux-vdso.so.1 = (0x00007f99dff000) libc.so.6 = /lib64/libc.so.6 (0x0007feeaa8c1000) /lib64/ld-linux-x86-64.so.2 (0x00007feeaac1c000) Can somebody tell what is the problem

  Read the article

• SQL Query with multiple values in one column

  - by lp1

  I've been beating my head on the desk tring to figure this one out. I have a table that stores job information, and reasons for a job not being completed. The reasons are numeric,01,02,03,etc. You can have two reason for a pending job. If you select two reasons, they are stored in the same column, seperated by a comma. This is anExample from the JOBID table: Job_Number User_Assigned PendingInfo 1 user1 01,02 Now, there is another table named Pending, that stores what those values actually represent. 01=Not enough info, 02=Not enough time, 03=Waiting Review. Example: Pending_Num PendingWord 01 Not Enough Info 02 Not Enough Time What I'm trying to do is query the database to give me all the job numbers, users, pendinginfo, and pending reason. I can break out the first value, but can't figure out how to do the second. What my limited skills have so far: *select Job_number,user_assigned,SUBSTRING(pendinginfo,0,3),pendingword from jobid,pending where SUBSTRING(pendinginfo,0,3)=pending.pending_num and pendinginfo!='00,00' and pendinginfo!='NULL'* What I would like to see for this example would be: Job_Number User_Assigned PendingInfo PendingWord PendingInfo PendingWord 1 User1 01 Not Enough Info 02 Not Enough Time Thanks in advance

  Read the article

• What do I name this class whose sole purpose is to report failure?

  - by Blair Holloway

  In our system, we have a number of classes whose construction must happen asynchronously. We wrap the construction process in another class that derives from an IConstructor class: class IConstructor { public: virtual void Update() = 0; virtual Status GetStatus() = 0; virtual int GetLastError() = 0; }; There's an issue with the design of the current system - the functions that create the IConstructor-derived classes are often doing additional work which can also fail. At that point, instead of getting a constructor which can be queried for an error, a NULL pointer is returned. Restructuring the code to avoid this is possible, but time-consuming. In the meantime, I decided to create a constructor class which we create and return in case of error, instead of a NULL pointer: class FailedConstructor : public IConstructor public: virtual void Update() {} virtual Status GetStatus() { return STATUS_ERROR; } virtual int GetLastError() { return m_errorCode; } private: int m_errorCode; }; All of the above this the setup for a mundane question: what do I name the FailedConstructor class? In our current system, FailedConstructor would indicate "a class which constructs an instance of Failed", not "a class which represents a failed attempt to construct another class". I feel like it should be named for one of the design patterns, like Proxy or Adapter, but I'm not sure which.

  Read the article

• Connection

  - by pepersview

  Hello, I would like to ask you about NSURLConnection in objective-c for iPhone. I have one app that needs to connect to one webservice to receive data (about YouTube videos), Then I have all the things that I need to connect (Similar to Hello_Soap sample code in the web). But now, my problem is that I create a class (inherits from NSObject) named Connection and I have implemented the methods: didReceiveResponse, didReceiveData, didFailWithError and connectionDidFinishLoading. Also the method: -(void)Connect:(NSString *) soapMessage{ NSLog(soapMessage); NSURL *url = [NSURL URLWithString:@"http://....."]; NSMutableURLRequest *theRequest = [NSMutableURLRequest requestWithURL:url]; NSString *msgLength = [NSString stringWithFormat:@"%d", [soapMessage length]]; [theRequest addValue: @"text/xml; charset=utf-8" forHTTPHeaderField:@"Content-Type"]; [theRequest addValue: msgLength forHTTPHeaderField:@"Content-Length"]; [theRequest setHTTPMethod:@"POST"]; [theRequest setHTTPBody: [soapMessage dataUsingEncoding:NSUTF8StringEncoding]]; NSURLConnection *theConnection = [[NSURLConnection alloc] initWithRequest:theRequest delegate:self]; if( theConnection ) { webData = [[NSMutableData data] retain]; } else { NSLog(@"theConnection is NULL"); } } But when from my AppDelegate I create one Connection object: Connection * connect = [[Connection alloc] Init:num]; //It's only one param to test. [connect Connect:method.soapMessage]; And I call this method, when this finishes, it doesn't continue calling didReceiveResponse, didReceiveData, didFailWithError or connectionDidFinishLoading. I'm trying to do this but I can't for the moment. The thing I would like to do is to be able to call this class "Connection" each time that I want to receive data (after that to be parsed and displayed in UITableViews). Thank you.

  Read the article

• Why does Hibernate 2nd level cache only cache within a session?

  - by Synesso

  Using a named query in our application and with ehcache as the provider, it seems that the query results are tied to the session. Any attempt to access the value from the cache for a second time results in a LazyInitializationException We have set lazy=true for the following mapping because this object is also used by another part of the system which does not require the reference... and we want to keep it lean. <class name="domain.ReferenceAdPoint" table="ad_point" mutable="false" lazy="false"> <cache usage="read-only"/> <id name="code" type="long" column="ad_point_id"> <generator class="assigned" /> </id> <property name="name" column="ad_point_description" type="string"/> <set name="synonyms" table="ad_point_synonym" cascade="all-delete-orphan" lazy="true"> <cache usage="read-only"/> <key column="ad_point_id" /> <element type="string" column="synonym_description" /> </set> </class> <query name="find.adpoints.by.heading">from ReferenceAdPoint adpoint left outer join fetch adpoint.synonyms where adpoint.adPointField.headingCode = ?</query> Here's a snippet from our hibernate.cfg.xml <property name="hibernate.cache.provider_class">net.sf.ehcache.hibernate.SingletonEhCacheProvider</property> <property name="hibernate.cache.use_query_cache">true</property> It doesn't seem to make sense that the cache would be constrained to the session. Why are the cached queries not usable outside of the (relatively short-lived) sessions?

  Read the article

• php (rar) i want to rar a folder using rar on Ubuntu (linux) by php (on dedi server) noob

  - by Steve

  hey guyz i want rar (not tar) my folder on my server by using php RAR RAR 3.93 Copyright (c) 1993-2010 Alexander Roshal 15 Mar 2010 Registered to my real name OS Ubuntu Release (Karmic) kernel linux 2.6.32.2-xxxx-grs-ipv4-32 Gnome 2.28.1 latest php an lighthttpd i have tried these things http://php.net/manual/en/function.escapeshellarg.php // may be wrong code http://php.net/manual/en/function.exec.php http://php.net/manual/en/function.shell-exec.php my command (working in ssh and nautilus script) rar a -m0 /where/file/will/saved/file_name.rar /location/ti/data/dir/datafolder php code $log=Shell_exec("rar a -m0 /where/file/will/saved/file_name.rar /location/ti/data/dir/datafolder"); echo $log; one method is left which i don't know how to use and its working on server that is by somefile_to_execute_command.sh i have to execute .sh file from php need to send some variables (command) and i tried this method can rar file with a script named RapidLeech but its rar from only its own files dir only :( but i want to do in different directories. Rapid Leech rar class http://paste2.org/p/791668 i m able run shell command with php (cp(copy),mv(move),ls(directory list),rm(remove aka delete)) but got failed to run rar i gives no output i also tried to given path rar and i used alot commands with php Shell_exec function and working like they work with ssh and i have tried almost 80 % method given on net and failed from last 3days i m over now plz help me i need php script file working plz reply if u have any info n code and experience about rar and this kinda :( problem i m 99% noob just used code mean search Google collect script make my own working thing (for personal use only) n now i m failed to rar folder and file :(( now plz provide me code plz don't talk in technical language because i m just reading my first php book (for dummies :D) mean noob and 0.1 plz help me as much u can thankx

  Read the article

< Previous Page | 251 252 253 254 255 256 257 258 259 260 261 262  | Next Page >