Search Results

Search found 4692 results on 188 pages for 'shuo ran'.

Page 152/188 | < Previous Page | 148 149 150 151 152 153 154 155 156 157 158 159  | Next Page >

• Would anybody recommend learning J/K/APL?

  - by ozan

  I came across J/K/APL a few months ago while working my way through some project euler problems, and was intrigued, to say the least. For every elegant-looking 20 line python solution I produced, there'd be a gobsmacking 20 character J solution that ran in a tenth of the time. I've been keen to learn some basic J, and have made a few attempts at picking up the vocabulary, but have found the learning curve to be quite steep. To those who are familiar with these languages, would you recommend investing some time to learn one (I'm thinking J in particular)? I would do so more for the purpose of satisfying my curiosity than for career advancement or some such thing. Some personal circumstances to consider, if you care to: I love mathematics, and use it daily in my work (as a mathematician for a startup) but to be honest I don't really feel limited by the tools that I use (like python + NumPy) so I can't use that excuse. I have no particular desire to work in the finance industry, which seems to be the main port of call for K users at least. Plus I should really learn C# as a next language as it's the primary language where I work. So practically speaking, J almost definitely shouldn't be the next language I learn. I'm reasonably familiar with MATLAB so using an array-based programming language wouldn't constitute a tremendous paradigm shift. Any advice from those familiar with these languages would be much appreciated.

  Read the article

• No route matches when trying to edit

  - by mmichael

  Here's the scoop: I've created a test app that allows users to create ideas and then add "bubbles" to these ideas. Currently, a bubble is just text. I've successfully linked bubbles to ideas. Furthermore, when a user goes to view an idea it lists all of the bubbles attached to that idea. The user can even delete the bubble for any given idea. My problem lies in editing bubbles. When a user views an idea, he sees the idea's content as well as any bubbles for that idea. As a result, I've set all my bubble controls (editing and deleting) inside the ideas "show" view. My code for editing a bubble for an idea is <%= link_to 'Edit Bubble', edit_idea_bubble_path %>. I ran rake routes to find the correct path for editing bubbles and that is what was listed. Here's my error: No route matches {:action=>"edit", :controller=>"bubbles"} In my bubbles controller I have: def edit @idea = Idea.find(params[:idea_id]) @bubble = @idea.bubbles.find(params[:id]) end def update @idea = Idea.find(params[:idea_id]) @bubble = @idea.bubbles.find(params[:id]) respond_to do |format| if @bubble.update_attributes(params[:bubble]) format.html { redirect_to(@bubble, :notice => 'Bubble was successfully updated.') } format.xml { head :ok } else format.html { render :action => "Edit" } format.xml { render :xml => @bubble.errors, :status => :unprocessable_entity } end end end To go a step further, I have the following in my routes.rb file resources :ideas do resources :bubbles end So far everything seems to function except when I try to edit a bubble. I'd love some guidance. Thanks!

  Read the article

• Weird Qt SSL issue -- error "No Error" shows up, nothing else, and if I ignore it, everything works

  - by houbysoft

  The issue is as follows : in my Qt app, I have a QWebView, which I use to load a HTTPS page. Everything worked fine on my development machine, so I'm now trying to get it to run on a test machine. I ran the app, but the page didn't load (the QWebView was blank). After much debugging, I found the problem is that an SSL error shows up, and the sslErrors() signal is fired. Here is my sslErrors() handling code: void blah::sslErrors(QNetworkReply *reply, const QList<QSslError> &errors) { foreach(QSslError error, errors) { qDebug() << error.errorString() << endl; } reply->ignoreSslErrors(); } The only thing the above code prints is: "No error" So there's no error, but unless I call reply->ignoreSslErrors(), the page doesn't load (on the test machine, on my developer computer no error is reported). Huh? Is this a bug? Is it safe to ignore the error, if I make sure it's of the type "No error"?

  Read the article

• Why does my .NET 4 application know .NET 4 is not installed

  - by Tergiver

  I developed an application that targeted .NET 4 the other day and XCOPY-installed it to a Windows XP machine. I had told the owner of the machine that they would need to install .NET Framework 4 to run my app and he told me he did (not a reliable source). When I ran the application I was presented with a message box that said this app requires .NET Framework 4, would I like to install it? Clicking the Yes button took me to the Microsoft web site and a few clicks later .NET 4 was installed, and the application successfully launched. Now I normally don't develop applications that target the latest version of .NET, I always target the lowest version I can (what features do I really need?). So this was my first .NET 4 app (and I only targeted 4 because it used a library that did). In the past, XCOPY-installing .NET applications to a machine that didn't have the correct version of .NET installed resulted in the application simply crashing on startup with no useful information presented to the user. Was it built into my app because I targeted .NET X? Was it something already installed on the target machine? I love the feature, I just want to know precisely how to leverage it in the future.

  Read the article

• Python C API from C++ app - know when to lock

  - by Alex

  Hi Everyone, I am trying to write a C++ class that calls Python methods of a class that does some I/O operations (file, stdout) at once. The problem I have ran into is that my class is called from different threads: sometimes main thread, sometimes different others. Obviously I tried to apply the approach for Python calls in multi-threaded native applications. Basically everything starts from PyEval_AcquireLock and PyEval_ReleaseLock or just global locks. According to the documentation here when a thread is already locked a deadlock ensues. When my class is called from the main thread or other one that blocks Python execution I have a deadlock. Python Cfunc1() - C++ func that creates threads internally which lead to calls in "my class", It stuck on PyEval_AcquireLock, obviously the Python is already locked, i.e. waiting for C++ Cfunc1 call to complete... It completes fine if I omit those locks. Also it completes fine when Python interpreter is ready for the next user command, i.e. when thread is calling funcs in the background - not inside of a native call I am looking for a workaround. I need to distinguish whether or not the global lock is allowed, i.e. Python is not locked and ready to receive the next command... I tried PyGIL_Ensure, unfortunately I see hang. Any known API or solution for this ? (Python 2.4)

  Read the article

• Variable reference problem when loading an object from a file in Java

  - by Snail

  I have a problem with the reference of a variable when loading a saved serialized object from a data file. All the variables referencing to the same object doesn't seem to update on the change. I've made a code snipped below that illustrates the problem. Tournament test1 = new Tournament(); Tournament test2 = test1; try { FileInputStream fis = new FileInputStream("test.out"); ObjectInputStream in = new ObjectInputStream(fis); test1 = (Tournament) in.readObject(); in.close(); } catch (IOException ex){ Logger.getLogger(Frame.class.getName()).log(Level.SEVERE, null, ex); } catch (ClassNotFoundException ex){ Logger.getLogger(Frame.class.getName()).log(Level.SEVERE, null, ex); } System.out.println("test1: " + test1); System.out.println("test2: " + test2); After this code is ran test1 and test2 doesn't reference to the same object anymore. To my knowledge they should do that since in the declaration of test2 makes it a reference to test1. When test1 is updated test2 should reflect the change and return the new object when called in the code. Am I missing something essential here or have I been misstaught about how the variable references in Java works?

  Read the article

• SQL Server - stored procedure suddenly become slow

  - by Barguast

  I have written a stored procedure that, yesterday, typically completed in under a second. Today, it takes about 18 seconds. I ran into the problem yesterday as well, and it seemed to be solved by DROPing and re-CREATEing the stored procedure. Today, that trick doesn't appear to be working. :( Interestingly, if I copy the body of the stored procedure and execute it as a straightforward query it completes quickly. It seems to be the fact that it's a stored procedure that's slowing it down...! Does anyone know what the problem might be? I've searched for answers, but often they recommend running it through Query Analyser, but I don't have have it - I'm using SQL Server 2008 Express for now. The stored procedure is as follows; ALTER PROCEDURE [dbo].[spGetPOIs] @lat1 float, @lon1 float, @lat2 float, @lon2 float, @minLOD tinyint, @maxLOD tinyint, @exact bit AS BEGIN -- Create the query rectangle as a polygon DECLARE @bounds geography; SET @bounds = dbo.fnGetRectangleGeographyFromLatLons(@lat1, @lon1, @lat2, @lon2); -- Perform the selection if (@exact = 0) BEGIN SELECT [ID], [Name], [Type], [Data], [MinLOD], [MaxLOD], [Location].[Lat] AS [Latitude], [Location].[Long] AS [Longitude], [SourceID] FROM [POIs] WHERE NOT ((@maxLOD < [MinLOD]) OR (@minLOD > [MaxLOD])) AND (@bounds.Filter([Location]) = 1) END ELSE BEGIN SELECT [ID], [Name], [Type], [Data], [MinLOD], [MaxLOD], [Location].[Lat] AS [Latitude], [Location].[Long] AS [Longitude], [SourceID] FROM [POIs] WHERE NOT ((@maxLOD < [MinLOD]) OR (@minLOD > [MaxLOD])) AND (@bounds.STIntersects([Location]) = 1) END END The 'POI' table has an index on MinLOD, MaxLOD, and a spatial index on Location.

  Read the article

• Drag and Drop in Silverlight with F# and Asynchronous Workflows

  - by knotig

  Hello everyone! I'm trying to implement drag and drop in Silverlight using F# and asynchronous workflows. I'm simply trying to drag around a rectangle on the canvas, using two loops for the the two states (waiting and dragging), an idea I got from Tomas Petricek's book "Real-world Functional Programming", but I ran into a problem: Unlike WPF or WinForms, Silverlight's MouseEventArgs do not carry information about the button state, so I can't return from the drag-loop by checking if the left mouse button is no longer pressed. I only managed to solve this by introducing a mutable flag. Would anyone have a solution for this, that does not involve mutable state? Here's the relevant code part (please excuse the sloppy dragging code, which snaps the rectangle to the mouse pointer): type MainPage() as this = inherit UserControl() do Application.LoadComponent(this, new System.Uri("/SilverlightApplication1;component/Page.xaml", System.UriKind.Relative)) let layoutRoot : Canvas = downcast this.FindName("LayoutRoot") let rectangle1 : Rectangle = downcast this.FindName("Rectangle1") let mutable isDragged = false do rectangle1.MouseLeftButtonUp.Add(fun _ -> isDragged <- false) let rec drag() = async { let! args = layoutRoot.MouseMove |> Async.AwaitEvent if (isDragged) then Canvas.SetLeft(rectangle1, args.GetPosition(layoutRoot).X) Canvas.SetTop(rectangle1, args.GetPosition(layoutRoot).Y) return! drag() else return() } let wait() = async { while true do let! args = Async.AwaitEvent rectangle1.MouseLeftButtonDown isDragged <- true do! drag() } Async.StartImmediate(wait()) () Thank you very much for your time!

  Read the article

• Compiling Objective-C project on Linux (Ubuntu)

  - by Alex

  How to make an Objective-C project work on Ubuntu? My files are: Fraction.h #import <Foundation/NSObject.h> @interface Fraction: NSObject { int numerator; int denominator; } -(void) print; -(void) setNumerator: (int) n; -(void) setDenominator: (int) d; -(int) numerator; -(int) denominator; @end Fraction.m #import "Fraction.h" #import <stdio.h> @implementation Fraction -(void) print { printf( "%i/%i", numerator, denominator ); } -(void) setNumerator: (int) n { numerator = n; } -(void) setDenominator: (int) d { denominator = d; } -(int) denominator { return denominator; } -(int) numerator { return numerator; } @end main.m #import <stdio.h> #import "Fraction.h" int main( int argc, const char *argv[] ) { // create a new instance Fraction *frac = [[Fraction alloc] init]; // set the values [frac setNumerator: 1]; [frac setDenominator: 3]; // print it printf( "The fraction is: " ); [frac print]; printf( "\n" ); // free memory [frac release]; return 0; } I've tried two approaches to compile it: Pure gcc: $ sudo apt-get install gobjc gnustep gnustep-devel $ gcc `gnustep-config --objc-flags` -o main main.m -lobjc -lgnustep-base /tmp/ccIQKhfH.o:(.data.rel+0x0): undefined reference to `__objc_class_name_Fraction' I created a GNUmakefile Makefile: include ${GNUSTEP_MAKEFILES}/common.make TOOL_NAME = main main_OBJC_FILES = main.m include ${GNUSTEP_MAKEFILES}/tool.make ... and ran: $ source /usr/share/GNUstep/Makefiles/GNUstep.sh $ make Making all for tool main... Linking tool main ... ./obj/main.o:(.data.rel+0x0): undefined reference to `__objc_class_name_Fraction' So in both cases compiler gets stuck at undefined reference to `__objc_class_name_Fraction' Do you have and idea how to resolve this issue?

  Read the article

• Coding the Python way

  - by Aaron Moodie

  I've just spent the last half semester at Uni learning python. I've really enjoyed it, and was hoping for a few tips on how to write more 'pythonic' code. This is the __init__ class from a recent assignment I did. At the time I wrote it, I was trying to work out how I could re-write this using lambdas, or in a neater, more efficient way, but ran out of time. def __init__(self, dir): def _read_files(_, dir, files): for file in files: if file == "classes.txt": class_list = readtable(dir+"/"+file) for item in class_list: Enrol.class_info_dict[item[0]] = item[1:] if item[1] in Enrol.classes_dict: Enrol.classes_dict[item[1]].append(item[0]) else: Enrol.classes_dict[item[1]] = [item[0]] elif file == "subjects.txt": subject_list = readtable(dir+"/"+file) for item in subject_list: Enrol.subjects_dict[item[0]] = item[1] elif file == "venues.txt": venue_list = readtable(dir+"/"+file) for item in venue_list: Enrol.venues_dict[item[0]] = item[1:] elif file.endswith('.roll'): roll_list = readlines(dir+"/"+file) file = os.path.splitext(file)[0] Enrol.class_roll_dict[file] = roll_list for item in roll_list: if item in Enrol.enrolled_dict: Enrol.enrolled_dict[item].append(file) else: Enrol.enrolled_dict[item] = [file] try: os.path.walk(dir, _read_files, None) except: print "There was a problem reading the directory" As you can see, it's a little bulky. If anyone has the time or inclination, I'd really appreciate a few tips on some python best-practices. Thanks.

  Read the article

• Python virtualenv questions

  - by orokusaki

  I'm using VirtualEnv on Windows XP. I'm wondering if I have my brain wrapped around it correctly. I ran virtualenv ENV and it created C:\WINDOWS\system32\ENV. I then changed my PATH variable to include C:\WINDOWS\system32\ENV\Scripts instead of C:\Python27\Scripts. Then, I checked out Django into C:\WINDOWS\system32\ENV\Lib\site-packages\django-trunk, updated my PYTHON_PATH variable to point the new Django directory, and continued to easy_install other things (which of course go into my new C:\WINDOWS\system32\ENV\Lib\site-packages directory). I understand why I should use VirtualEnv so I can run multiple versions of Django, and other libraries on the same machine, but does this mean that to switch between environments I have to basically change my PATH and PYTHON_PATH variable? So, I go from developing one Django project which uses Django 1.2 in an environment called ENV and then change my PATH and such so that I can use an environment called ENV2 which has the dev version of Django? Is that basically it, or is there some better way to automatically do all this (I could update my path in Python code, but that would require me to write machine-specific code in my application)? Also, how does this process compare to using VirtualEnv on Linux (I'm quite the beginner at Linux).

  Read the article

• SQL Server performance issue.

  - by Jit

  Hi Friends, I have been trying to analyze performance issue with SQL Server 2005. We have 30 jobs, one for each databases (30 databases, one per each client). The jobs run at early morning at an interval of 5 minutes. When I run the job individually for testing, for most of the databases it finishes in 7 to 9 minutes. But when these jobs run at early morning, I see few jobs taking 2 to 3 hours to finish and the same takes few minutes as mentioned above if ran independently. We dont have any other job scheduled during that time, other than these 30 jobs. If we restart the server then for 2 or so days all the jobs finishes in few minutes, but over the period of time (from 3rd day suddenly), few jobs start taking hours to finish. What could be the possible reason of performance degradation over the period of time? I verified all the SPs and we uses temp tables and I made sure none of the temp table is left without dropping at the end of SP. Let me know what are the possible reasons for such behavior. Appreciate your time and help. Thanks

  Read the article

• How do I create efficient instance variable mutators in Matlab?

  - by Trent B

  Previously, I implemented mutators as follows, however it ran spectacularly slowly on a recursive OO algorithm I'm working on, and I suspected it may have been because I was duplicating objects on every function call... is this correct? %% Example Only obj2 = tripleAllPoints(obj1) obj.pts = obj.pts * 3; obj2 = obj1 end I then tried implementing mutators without using the output object... however, it appears that in MATLAB i can't do this - the changes won't "stick" because of a scope issue? %% Example Only tripleAllPoints(obj1) obj1.pts = obj1.pts * 3; end For application purposes, an extremely simplified version of my code (which uses OO and recursion) is below. classdef myslice properties pts % array of pts nROW % number of rows nDIM % number of dimensions subs % sub-slices end % end properties methods function calcSubs(obj) obj.subs = cell(1,obj.nROW); for i=1:obj.nROW obj.subs{i} = myslice; obj.subs{i}.pts = obj.pts(1:i,2:end); end end function vol = calcVol(obj) if obj.nROW == 1 obj.volume = prod(obj.pts); else obj.volume = 0; calcSubs(obj); for i=1:obj.nROW obj.volume = obj.volume + calcVol(obj.subs{i}); end end end end % end methods end % end classdef

  Read the article

• 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 :)

  Read the article

• Question about memory allocation when initializing char arrays in C/C++.

  - by Carlos Nunez

  Before anything, I apologize if this question has been asked before. I am programming a simple packet sniffer for a class project. For a little while, I ran into the issue where the source and destination of a packet appeared to be the same. For example, the source and destination of an Ethernet frame would be the same MAC address all of the time. I custom-made ether_ntoa(char *) because Windows does not seem to have ethernet.h like Linux does. Code snippet is below: char *ether_ntoa(u_char etheraddr[ETHER_ADDR_LEN]) { int i, j; char eout[32]; for(i = 0, j = 0; i < 5; i++) { eout[j++] = etheraddr[i] >> 4; eout[j++] = etheraddr[i] & 0xF; eout[j++] = ':'; } eout[j++] = etheraddr[i] >> 4; eout[j++] = etheraddr[i] & 0xF; eout[j++] = '\0'; for(i = 0; i < 17; i++) { if(eout[i] < 10) eout[i] += 0x30; else if(eout[i] < 16) eout[i] += 0x57; } return(eout); } I solved the problem by using malloc() to have the compiler assign memory (i.e. instead of char eout[32], I used char * eout; eout = (char *) malloc (32);). However, I thought that the compiler assigned different memory locations when one sized a char-array at compile time. Is this incorrect? Thanks! Carlos Nunez

  Read the article

• Another rsAccessDenied problem with SSRS

  - by Rich.Carpenter

  I've read through a lot of posts regarding the problem, but none of the proposed solutions have worked for me. I continue to get an error stating, "The permissions granted to user '\Rich' are insufficient for performing this operation. (rsAccessDenied)." If I am logged in as the local administrator account, entering the Reporting Services URL in IE doesn't give me that error, but it takes me to a blank page. I haven't been able to get to a SSRS home page at all. Order of operations: I installed and patched Windows 7 Ultimate 64-bit I installed SQL Server Express 2008 with Advanced Services using the MS web installer. I downloaded and installed SP1 for SQL Server Express 2008. I've tried running IE as administrator, adding local machine to trusted sites, and just about every other suggestion I've found. I even ran the entire installation logged in as the local administrator. Nothing seems to work. Could someone please tell me, considering the above installation process, what I should expect to do after to make this work?

  Read the article

• 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"?

  Read the article

• C++ Exception Handling

  - by user1413793

  So I was writing some code and I noticed that apart from syntactical, type, and other compile-time errors, C++ does not throw any other exceptions. So I decided to test this out with a very trivial program: #include<iostream> int main() { std::count<<5/0<<std::endl; return 1 } When I compiled it using g++, g++ gave me a warning saying I was dividing by 0. But it still compiled the code. Then when I ran it, it printed some really large arbitrary number. When I want to know is, how does C++ deal with exceptions? Integer division by 0 should be a very trivial example of when an exception should be thrown and the program should terminate. Do I have to essentially enclose my entire program in a huge try block and then catch certain exceptions? I know in Python when an exception is thrown, the program will immediately terminate and print out the error. What does C++ do? Are there even runtime exceptions which stop execution and kill the program?

  Read the article

• RegisterClientScriptInclude doesn't work for some reason...

  - by Andrew

  Hey, I've spent at least 2 days trying anything and googling this...but for some reason I can't get RegisterClientScriptInclude to work the way everyone else has it working? First off, I am usting .NET 3.5 Ajax,...and I am including javascript in my partial page refreshes...using this code: ScriptManager.RegisterClientScriptBlock(this, typeof(Page), "MyClientCode", script, true); It works perfectly, my javascript code contained in the script variable is included every partial refresh. The javascript in script is actually quite extensive though, and I would like to store it in a .js file,..so logically I make a .js file and try to include it using RegisterClientScriptInclude ...however i can't for the life of my get this to work. here's the exact code: ScriptManager.RegisterClientScriptInclude(this, typeof(Page), "mytestscript", "/js/testscript.js"); the testscript.js file is only included in FULL page refreshes...ie. when I load the page, or do a full postback....i can't get the file to be included in partial refreshes...have no idea why..when viewing the ajax POST in firebug I don't see a difference whether I include the file or not.... both of the ScriptManager Includes are being ran from the exact same place in "Page_Load"...so they should execute every partial refresh (but only the ScriptBlock does). anyways,..any help or ideas,..or further ways I can trouble shoot this problem, would be appreciated. Thanks, Andrew

  Read the article

• SIGABRT on iPhone when changing xib

  - by Boz

  I've just finished off an app for the iPhone which, until today, ran fine on the iPhone simulator and actual devices. I tried changing the xib which is loaded in the applicationDidFinishLaunching method in my application delegate class - all I did was change the string in initWithNibName. When I launch the app on the simulator, the Default.png image is shown, then the app crashes with an uncaught exception. When running on a device, the Default.png image is shown for about 10 seconds, the UI is never loaded and I get 'GDB: Program received signal: "SIGABRT".' on the Xcode status bar. Debugging shows that applicationDidFinishLaunching is never actually reached before the app crashes. Setting the starting xib back to the original solves the issue, but now I've made a change and saved it in the Interface Builder and the app shows the same issues as above - I've made no code changes at all. Is this a memory issue, or a known issue of a common mistake? NOTE: I've made no code changes whatsoever, and the only changes I've made to the xib are cosmetic, the IBOutlets are all intact.

  Read the article

• DSP - Filter sweep effect

  - by Trap

  I'm implementing a 'filter sweep' effect (I don't know if it's called like that). What I do is basically create a low-pass filter and make it 'move' along a certain frequency range. To calculate the filter cut-off frequency at a given moment I use a user-provided linear function, which yields values between 0 and 1. My first attempt was to directly map the values returned by the linear function to the range of frequencies, as in cf = freqRange * lf(x). Although it worked ok it looked as if the sweep ran much faster when moving through low frequencies and then slowed down during its way to the high frequency zone. I'm not sure why is this but I guess it's something to do with human hearing perceiving changes in frequency in a non-linear manner. My next attempt was to move the filter's cut-off frequency in a logarithmic way. It works much better now but I still feel that the filter doesn't move at a constant perceived speed through the range of frequencies. How should I divide the frequency space to obtain a constant perceived sweep speed? Thanks in advance.

  Read the article

• Installing Ruby via rbenv fails

  - by Maximus S

  Problem: I installed ruby, but it is not recognized correctly. I'm following the deploying to VPS: https://github.com/railscasts/335-deploying-to-a-vps I am setting my server on ubuntu 12.04 LTS to deploy my rails app. I'm following the railscast on deploying to a VPS, and trying to install ruby through rbenv. It seemed everything was installed correctly, but when I tried to check the ruby version, it gave me errors. The following are the commands that I ran. deployer@max:~$ rbenv install 1.9.3-p125 Downloading yaml-0.1.4.tar.gz... -> http://cloud.github.com/downloads/sstephenson/ruby-build-download-mirror/36c852831d02cf90508c29852361d01b Installing yaml-0.1.4... Installed yaml-0.1.4 to /home/deployer/.rbenv/versions/1.9.3-p125 Downloading ruby-1.9.3-p125.tar.gz... -> http://cloud.github.com/downloads/sstephenson/ruby-build-download-mirror/e3ea86b9d3fc2d3ec867f66969ae3b92 Installing ruby-1.9.3-p125... Installed ruby-1.9.3-p125 to /home/deployer/.rbenv/versions/1.9.3-p125 Downloading rubygems-1.8.23.tar.gz... -> http://cloud.github.com/downloads/sstephenson/ruby-build-download-mirror/178b0ebae78dbb46963c51ad29bb6bd9 Installing rubygems-1.8.23... Installed rubygems-1.8.23 to /home/deployer/.rbenv/versions/1.9.3-p125 deployer@max:~$ rbenv global 1.9.3-p125 deployer@max:~$ ruby -v 'ruby' program can be found in the following packages: * ruby1.8 * ruby1.9.1 How do I solve this?

  Read the article

• How can this code throw a NullReferenceException?

  - by Davy8

  I must be going out of my mind, because my unit tests are failing because the following code is throwing a null ref exception: int pid = 0; if (parentCategory != null) { Console.WriteLine(parentCategory.Id); pid = parentCategory.Id; } The line that's throwing it is: pid = parentCategory.Id; The console.writeline is just to debug in the NUnit GUI, but that outputs a valid int. Edit: It's single-threaded so it can't be assigned to null from some other thread, and the fact the the Console.WriteLine successfully prints out the value shows that it shouldn't throw. Edit: Relevant snippets of the Category class: public class Category { private readonly int id; public Category(Category parent, int id) { Parent = parent; parent.PerformIfNotNull(() => parent.subcategories.AddIfNew(this)); Name = string.Empty; this.id = id; } public int Id { get { return id; } } } Well if anyone wants to look at the full code, it's on Google Code at http://code.google.com/p/chefbook/source/checkout I think I'm going to try rebooting the computer... I've seen pretty weird things fixed by a reboot. Will update after reboot. Update: Mystery solved. Looks like NUnit shows the error line as the last successfully executed statement... Copy/pasted test into new console app and ran in VS showed that it was the line after the if statement block (not shown) that contained a null ref. Thanks for all the ideas everyone. +1 to everyone that answered.

  Read the article

• Javascript changing source of an image

  - by Pete Herbert Penito

  Hi Everyone! I have some javascript which runs a timer that animates something on the website. It all works perfectly but I want to get an image to change when the animation is run, It uses jquery: if(options.auto && dir=="next" && !clicked) { timeout = setTimeout(function(){ if (document.images['bullet1'].src == "img/bulletwhite.png") { document.images['bullet1'].src = "img/bullet.png"; document.images['bullet2'].src = "img/bulletwhite.png"; } animate("next",false); },diff*options.speed+options.pause); } options.auto means that its automatically cycling, dir is the direction of the motion and clicked is whether or not the user clicked it. Is there something wrong with my syntax here? I ran firebug with it, and it doesn't throw any errors, it simply won't work. Any advice would help! I should mention that the src of bullet1 starts at bulletwhite.png and then I was hoping for it to change to bullet.png and have bullet2 change to bulletwhite.png.

  Read the article

• Problem importing Oracle .dmp file

  - by BitFiddler

  So I have looked at all the suggested ways of importing .dmp files and non of them seem to answer this question: where does the data go once you import it? Context: I created a user like so: SQL> create user IMPORTER identified by "12345"; SQL> grant connect, unlimited tablespace, resource to IMPORTER; I then ran the 'imp' command as follows: C:\>imp system/password FROMUSER=OVIEDOE TOUSER=IMPORTER file=c:\database1.dmp Now there were 9 .dmp files, after each one it asked me for the next one and then I received the message "Import terminated successfully with warnings." The warning was: Warning: the objects were exported by OVIEDOE, not by you import done in WE8MSWIN1252 character set and AL16UTF16 NCHAR character set export client uses WE8ISO8859P1 character set (possible charset conversion) IMP-00046: using FILESIZE value from export file of 2147483648 Now it says it was terminated successfully so my assumption (I am new to oracle so this may be wrong) is that the data was loaded. However, when I use SQL developer to connect to the database and look under the 'tables' node under the IMPORTER user, there is nothing there. What is going on? Did the data load? If so, where can I find it?

  Read the article

< Previous Page | 148 149 150 151 152 153 154 155 156 157 158 159  | Next Page >