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  • OpenAL not playing on Max OS X 10.6

    - by Grimless
    I've been working on getting a basic audio engine running on my Mac using OpenAL. It seems relatively straightforward after working with OpenGL for a while. However, despite the fact that I believe I have everything in place, my sound will not play. Here is the order of things I am doing: //Creating a new device ALCdevice* device = alcOpenDevice(NULL); //Create a new context with the device ALCcontext* context = alcCreateContext(device, NULL); //Make that context current alcMakeContextCurrent(context); //Do lots of loading stuff to bring in an AIFF... voodooAIFF = myAIFFLoader("name"); //Then use that data ALuint buf; alGenBuffers(1, &buf); //Check for errors, but none happen... //Bind buffer data. alBufferData(buf, voodooAIFF.format, voodooAIFF.data, voodooAIFF.sizeInBytes, voodooAIFF.frequency); //Check for errors, none here either... //Create Source ALuint src; alGenSources(1, &src); //Error check again, no errors. //Bind source to buffer alSourcei(src, AL_BUFFER, buf); //Set reference distance alSourcei(sourceID, AL_REFERENCE_DISTANCE, 1); //Set source attributes including gain and pitch to 1 (direction set to 0,0,0) //Check for errors, nothing... //Set up listener attributes. //Check for errors, no errors. //Begin playing. alSourcePlay(src); Observe silence... Any insight, what steps am I missing here?

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  • Are there more secure alternatives to the .Net SQLConnection class?

    - by KeyboardMonkey
    Hi SO people, I'm very surprised this issue hasn't been discussed in-depth: This article tells us how to use windbg to dump a running .Net process strings in memory. I spent much time researching the SecureString class, which uses unmanaged pinned memory blocks, and keeps the data encrypted too. Great stuff. The problem comes in when you use it's value, and assign it to the SQLConnection.ConnectionString property, which is of the System.String type. What does this mean? Well... It's stored in plain text Garbage Collection moves it around, leaving copies in memory It can be read with windbg memory dumps That totally negates the SecureString functionality! On top of that, the SQLConnection class is non-inheritable, I can't even roll my own with a SecureString property instead; Yay for closed-source. Yay. A new DAL layer is in progress, but for a new major version and for so many users it will be at least 2 years before every user is upgraded, others might stay on the old version indefinitely, for whatever reason. Because of the frequency the connection is used, marshalling from a SecureString won't help, since the immutable old copies stick in memory until GC comes around. Integrated Windows security isn't an option, since some clients don't work on domains, and other roam and connect over the net. How can I secure the connection string, in memory, so it can't be viewed with windbg?

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  • Which is faster for large "for" loop: function call or inline coding?

    - by zaplec
    Hi, I have programmed an embedded software (using C of course) and now I'm considering ways to improve the running time of the system. The most important single module in my system is one very large nested for loop module. That module consists of two nested for loops that loops max 122500 times. That's not very much yet, but the problem is that inside that nested for loop I have a function call to a function that is in another source file. That specific function consists mostly of two another nested for loops which loops always 22500 times. So now I have to make a function call 122500 times. I have made that function that is to be called a lot lighter and shorter (yet still works as it should) and now I started to think that would it be faster to rip off that function call and write that process directly inside those first two for loops? The processor in that system is ARM7TDMI and its frequency is 55MHz. The system itself isn't very time critical so it doesn't have to be real time capable. However the faster it can process its duties the better. Also would it be also faster to use while loops instead of fors? And any piece of advice about how to improve the running time is appreciated. -zaplec

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  • Writing an audio player in C#

    - by Malki
    Hi, I have a pretty cool idea for a very special media player. I like to think about this project as a mini-startup, since I don't yet know if my idea is practical. Anyways, before implementing my idea, I first need to be able to implement a simple audio player. My preferred language for this project is C#, simply because it's so easy to use, but any other object oriented language would be fine too I guess. I started out with no knowledge whatsoever about audio. My main goals right now are: Being able to play audio files - as many formats as possible (sort of a VLC type player, but only audio for now). Being able to analyze audio files - as in, reading frequency, amplitude, volume, and other information about the audio. I think maybe a good idea here is to be able to analyze one file format (PCM?), and then temporarily converting any file I want to analyze to that format. This is in order to later implement a mechanism that compares songs and identifies similar songs to recommend to the user (this feature isn't part of my idea, but I figured since it exists in many players nowadays, I need to have it too if I want be able to compete with them). BTW - I currently don't have any knowledge about audio/wavelengths/frequencies and such, so I'd appreciate it if someone could point me in the right direction about this analyzation feature. Maybe in the future I'd expand to playing video files as well, but for now I'm concentrating on audio. After searching the Internet for a while, I've come across LAME. Problem is, it's not C#, and I'm not sure how to use it. I know there is something called "Interoperability", that is supposed to let me work with native DLL files through C#. Any information about that would be helpful as well. Any help would be much appreciated. Thanks, Malki :)

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  • Boost Asio UDP retrieve last packet in socket buffer

    - by Alberto Toglia
    I have been messing around Boost Asio for some days now but I got stuck with this weird behavior. Please let me explain. Computer A is sending continuos udp packets every 500 ms to computer B, computer B desires to read A's packets with it own velocity but only wants A's last packet, obviously the most updated one. It has come to my attention that when I do a: mSocket.receive_from(boost::asio::buffer(mBuffer), mEndPoint); I can get OLD packets that were not processed (almost everytime). Does this make any sense? A friend of mine told me that sockets maintain a buffer of packets and therefore If I read with a lower frequency than the sender this could happen. ¡? So, the first question is how is it possible to receive the last packet and discard the ones I missed? Later I tried using the async example of the Boost documentation but found it did not do what I wanted. http://www.boost.org/doc/libs/1_36_0/doc/html/boost_asio/tutorial/tutdaytime6.html From what I could tell the async_receive_from should call the method "handle_receive" when a packet arrives, and that works for the first packet after the service was "run". If I wanted to keep listening the port I should call the async_receive_from again in the handle code. right? BUT what I found is that I start an infinite loop, it doesn't wait till the next packet, it just enters "handle_receive" again and again. I'm not doing a server application, a lot of things are going on (its a game), so my second question is, do I have to use threads to use the async receive method properly, is there some example with threads and async receive? Thanks for you attention.

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  • Micro Second resolution timestamps on windows.

    - by Nikhil
    How to get micro second resolution timestamps on windows? I am loking for something better than QueryPerformanceCounter, QueryPerformanceFrequency (these can only give you an elapsed time since boot, and are not necessarily accurate if they are called on different threads - ie QueryPerformanceCounter may return different results on different CPUs. There are also some processors that adjust their frequency for power saving, which apparently isn't always reflected in their QueryPerformanceFrequency result.) There is this, http://msdn.microsoft.com/en-us/magazine/cc163996.aspx but it does not seem to be solid. This looks great but its not available for download any more. http://www.ibm.com/developerworks/library/i-seconds/ This is another resource. http://www.lochan.org/2005/keith-cl/useful/win32time.html But requires a number of steps, running a helper program plus some init stuff also, I am not sure if it works on multiple CPUs Also looked at the Wikipedia link on the subject which is interesting but not that useful. http://en.wikipedia.org/wiki/Time_Stamp_Counter If the answer is just do this with BSD or Linux, its a lot easier thats fine, but I would like to confirm this and get some explanation as to why this is so hard in windows and so easy in linux and bsd. Its the same damm hardware...

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  • How to implement a 'safe' periodical executer without using the Rails helpers?

    - by Robbie
    I am very new to Ruby on Rails and was never really big on writing JavaScript, so the built in helpers were like a tiny silce of heaven. However I have recently learned that using the helper methods creates "obtrusive javascript" so I am doing a tiny bit of refactoring to get all this messy code out of my view. I'm also using the Prototype API to figure out what all these functions do. Right now, I have: <%= periodically_call_remote(:url => {:action => "tablerefresh", :id => 1 }, :frequency => '5', :complete => "load('26', 'table1', request.responseText)")%> Which produces: <script type="text/javascript"> //<![CDATA[ new PeriodicalExecuter(function() {new Ajax.Request('/qrpsdrail/grids/tablerefresh/1', {asynchronous:true, evalScripts:true, onComplete:function(request){load('26', 'table1', request.responseText)}, parameters:'authenticity_token=' + encodeURIComponent('dfG7wWyVYEpelfdZvBWk7MlhzZoK7VvtT/HDi3w7gPM=')})}, 5) //]]> </script> My concern is that the "encodeURIComponent" and the presence of "authenticity_token" are generated by Rails. I'm assuming these are used to assure the validity of a request. (Ensuring a request comes from a currently active session?) If that is the case, how can I implement this in application.js 'safely'? It seems that the built in method, although obtrusive, does add some beneficial security. Thanks, in advance, to all who answer.

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  • Using WIndows PowerShell 1.0 or 2.0 to evaluate performance of executable files.

    - by Andry
    Hello! I am writing a simple script on Windows PowerShell in order to evaluate performance of executable files. The important hypothesisi is the following: I have an executable file, it can be an application written in any possible language (.net and not, Viual-Prolog, C++, C, everything that can be compiled as an .exe file). I want to profile it getting execution times. I did this: Function Time-It { Param ([string]$ProgramPath, [string]$Arguments) $Watch = New-Object System.Diagnostics.Stopwatch $NsecPerTick = (1000 * 1000 * 1000) / [System.Diagnostics.Stopwatch]::Frequency Write-Output "Stopwatch created! NSecPerTick = $NsecPerTick" $Watch.Start() # Starts the timer [System.Diagnostics.Process]::Start($ProgramPath, $Arguments) $Watch.Stop() # Stops the timer # Collectiong timings $Ticks = $Watch.ElapsedTicks $NSecs = $Watch.ElapsedTicks * $NsecPerTick Write-Output "Program executed: time is: $Nsecs ns ($Ticks ticks)" } This function uses stopwatch. Well, the functoin accepts a program path, the stopwatch is started, the program run and the stopwatch then stopped. Problem: the System.Diagnostics.Process.Start is asynchronous and the next instruction (watch stopped) is not executed when the application finishes. A new process is created... I need to stop the timer once the program ends. I thought about the Process class, thicking it held some info regarding the execution times... not lucky... How to solve this?

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  • Combining two data sets and plotting in matlab

    - by bautrey
    I am doing experiments with different operational amplifier circuits and I need to plot my measured results onto a graph. I have two data sets: freq1 = [.1 .2 .5 .7 1 3 4 6 10 20 35 45 60 75 90 100]; %kHz Vo1 = [1.2 1.6 1.2 2 2 2.4 14.8 20.4 26.4 30.4 53.6 68.8 90 114 140 152]; %mV V1 = 19.6; Acm = Vo1/(1000*V1); And: freq2 = [.1 .5 1 30 60 70 85 100]; %kHz Vo1 = [3.96 3.96 3.96 3.84 3.86 3.88 3.88 3.88]; %V V1 = .96; Ad = Vo1/(2*V1); (I would show my plots but apparently I need more reps for that) I need to plot the equation, CMRR vs freq: CMRR = 20*log10(abs(Ad/Acm)); The size of Ad and Acm are different and the frequency points do not match up, but the boundaries of both of these is the same, 100Hz to 100kHz (x-axis). On the line of CMRR, Matlab says that Ad and Acm matrix dimensions do not agree. How I think I would solve this is using freq1 as the x-axis for CMRR and then taking approximated points from Ad according to the value on freq1. Or I could do function approximations of Ad and Acm and then do the divide operator on those. I do not know how I would code up this two ideas. Any other ideas would helpful, especially simpler ones. Thanks

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  • [Rails] checkbox to update attribute

    - by Jeff
    [Updated a bit] I have a Task model that has a :completed boolean attribute. If I click on it I want it to execute the 'finish' method. The main problem is that I am displays a series of checkboxes in a list and subsequent checkboxes after the first one are ignored. The method is never called for the given task/checkbox combo. I have this chunk of code in my view: <% current_user.tasks.each do |t|%> <% if t.completed == false %> <%= check_box_tag :completed, true, checked = false %> <%= observe_field :completed, :url => { :controller => 'tasks', :action => :finish , :id => t.id }, :frequency => 0.25, :update => :completed, :with => true %> and my finish method looks like this: def finish @task = Task.find(params[:id]) new = {:completed => true} @task.update_attributes(new) render :update do |page| page.replace_html "taskListing", :partial => 'home/task_listing' end

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  • Reducing Dimension For SVM in Sensor Network

    - by iinception
    Hi Everyone, I am looking for some suggestions on a problem that I am currently facing. I have a set of sensor say S1-S100 which is triggered when some event E1-E20 is performed. Assume, normally E1 triggers S1-S20, E2 triggers S15-S30, E3 triggers S20-s50 etc and E1-E20 are completely independent events. Occasionally an event E might trigger any other unrelated sensor. I am using ensemble of 20 svm to analyze each event separately. My features are sensor frequency F1-F100, number of times each sensor is triggered and few other related features. I am looking for a technique that can reduce the dimensionality of the sensor feature(F1-F100)/ or some techniques that encompasses all of the sensor and reduces the dimension too(i was looking for some information theory concept for last few days) . I dont think averaging, maximization is a good idea as I risk loosing information(it did not give me good result). Can somebody please suggest what am I missing here? A paper or some starting idea... Thanks in advance.

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  • Finding What You Need in R: function arguments/parameters from outside the function's package

    - by doug
    Often in R, there are a dozen functions scattered across as many packages--all of which have the same purpose but of course differ in accuracy, performance, theoretical rigor, and so on. How do you gather all of these in one place before you start your task? So for instance: the generic plot function. Setting secondary ticks is much easier (IMHO) using a function outside of the base package, minor.tick(nx=n, ny=n, tick.ratio=n), found in Hmisc. Of course, that doesn't show up in plot's docstring. Likewise, the data-input arguments to 'plot' can be supplied by an object returned from the function 'hexbin', again, from a library outside of the base installation (where 'plot' resides). What would be great obviously is a programmatic way to gather these function arguments from the various libraries and put them in a single namespace. edit: (trying to re-state my example just above more clearly:) the arguments to plot supplied in the base package for, e.g., setting the axis tick frequency are xaxp/yaxp; however, one can also set a/t/f via a function outside of the base package, again, as in the minor.tick function from the Hmisc package--but you wouldn't know that just from looking at the plot method signature. Is there a meta function in R for this? So far, as i come across them, i've been manually gathering them in a TextMate 'snippet' (along with the attendant library imports). This isn't that difficult or time consuming, but i can only update my snippet as i find out about these additional arguments/parameters. Is there a canonical R way to do this, or at least an easier way? Just in case that wasn't clear, i am not talking about the case where multiple packages provide functions directed to the same statistic or view (e.g., 'boxplot' in the base package; 'boxplot.matrix' in gplots; and 'bplots' in Rlab). What i am talking is the case in which the function name is the same across two or more packages.

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  • Extending / changing how Zend_Search_Lucene searches

    - by Grant Collins
    Hi, I am currently using Zend_Search_Lucene to index and search a number of documents currently at around a 1000 or so. What I would like to do is change how the engine scores hits on a document, from the current default. Zend_Search_Lucene scores on the frequency of number of hits within a document, so a document that has 10 matches of the word PHP will score higher than a document with only 3 matches of PHP. What I am trying to do is pass a number of key words and score depending on the hits of those keywords. e.g. I pass 5 key words say,PHP, MySQL, Javascript, HTML and CSS that I search against the index. One document has 3 matches to those key words and one document has all 4 matches, the 4 matches scores the highest. The number of instances of those words in the document do not concern me. Now I've had a quick look at Zend_Search_Lucene_Search_Similarity however I have to confess that I am not sure (or that bright) to know how to use this to achieve what I am after. Is what I want to do possible using Lucene or is there a better solution out there?

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  • Best (Java) book for understanding 'under the bonnet' for programming?

    - by Ben
    What would you say is the best book to buy to understand exactly how programming works under the hood in order to increase performance? I've coded in assembly at university, I studied computer architecture and I obviously did high level programming, but what I really dont understand is things like: -what is happening when I perform a cast -whats the difference in performance if I declare something global as opposed to local? -How does the memory layout for an ArrayList compare with a Vector or LinkedList? -Whats the overhead with pointers? -Are locks more efficient than using synchronized? -Would creating my own array using int[] be faster than using ArrayList -Advantages/disadvantages of declaring a variable volatile I have got a copy of Java Performance Tuning but it doesnt go down very low and it contains rather obvious things like suggesting a hashmap instead of using an ArrayList as you can map the keys to memory addresses etc. I want something a bit more Computer Sciencey, linking the programming language to what happens with the assembler/hardware. The reason im asking is that I have an interview coming up for a job in High Frequency Trading and everything has to be as efficient as possible, yet I cant remember every single possible efficiency saving so i'd just like to learn the fundamentals. Thanks in advance

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  • CRM 2011 - Set/Retrieve work hours programmatically

    - by Philip Rich
    I am attempting to retrieve a resources work hours to perform some logic I require. I understand that the CRM scheduling engine is a little clunky around such things, but I assumed that I would be able to find out how the working hours were stored in the DB eventually... So a resource has associated calendars and those calendars have associated calendar rules and inner calendars etc. It is possible to look at the start/end and frequency of aforementioned calendar rules and query their codes to work out whether a resource is 'working' during a given period. However, I have not been able to find the actual working hours, the 9-5 shall we say in any field in the DB. I even tried some SQL profiling while I was creating a new schedule for a resource via the UI, but the results don't show any work hours passing to SQL. For those with the patience the intercepted SQL statement is below:- EXEC Sp_executesql N'update [CalendarRuleBase] set [ModifiedBy]=@ModifiedBy0, [EffectiveIntervalEnd]=@EffectiveIntervalEnd0, [Description]=@Description0, [ModifiedOn]=@ModifiedOn0, [GroupDesignator]=@GroupDesignator0, [IsSelected]=@IsSelected0, [InnerCalendarId]=@InnerCalendarId0, [TimeZoneCode]=@TimeZoneCode0, [CalendarId]=@CalendarId0, [IsVaried]=@IsVaried0, [Rank]=@Rank0, [ModifiedOnBehalfBy]=NULL, [Duration]=@Duration0, [StartTime]=@StartTime0, [Pattern]=@Pattern0 where ([CalendarRuleId] = @CalendarRuleId0)', N'@ModifiedBy0 uniqueidentifier,@EffectiveIntervalEnd0 datetime,@Description0 ntext,@ModifiedOn0 datetime,@GroupDesignator0 ntext,@IsSelected0 bit,@InnerCalendarId0 uniqueidentifier,@TimeZoneCode0 int,@CalendarId0 uniqueidentifier,@IsVaried0 bit,@Rank0 int,@Duration0 int,@StartTime0 datetime,@Pattern0 ntext,@CalendarRuleId0 uniqueidentifier', @ModifiedBy0='EB04662A-5B38-E111-9889-00155D79A113', @EffectiveIntervalEnd0='2012-01-13 00:00:00', @Description0=N'Weekly Single Rule', @ModifiedOn0='2012-03-12 16:02:08', @GroupDesignator0=N'FC5769FC-4DE9-445d-8F4E-6E9869E60857', @IsSelected0=1, @InnerCalendarId0='3C806E79-7A49-4E8D-B97E-5ED26700EB14', @TimeZoneCode0=85, @CalendarId0='E48B1ABF-329F-425F-85DA-3FFCBB77F885', @IsVaried0=0, @Rank0=2, @Duration0=1440, @StartTime0='2000-01-01 00:00:00', @Pattern0=N'FREQ=WEEKLY;INTERVAL=1;BYDAY=SU,MO,TU,WE,TH,FR,SA', @CalendarRuleId0='0A00DFCF-7D0A-4EE3-91B3-DADFCC33781D' The key parts in the statement are the setting of the pattern:- @Pattern0=N'FREQ=WEEKLY;INTERVAL=1;BYDAY=SU,MO,TU,WE,TH,FR,SA' However, as mentioned, no indication of the work hours set. Am I thinking about this incorrectly or is CRM doing something interesting around these work hours? Any thoughts greatly appreciated, thanks.

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  • Faster quadrature decoder loops with Python code

    - by Kelei
    I'm working with a BeagleBone Black and using Adafruit's IO Python library. Wrote a simple quadrature decoding function and it works perfectly fine when the motor runs at about 1800 RPM. But when the motor runs at higher speeds, the code starts missing some of the interrupts and the encoder counts start to accumulate errors. Do you guys have any suggestions as to how I can make the code more efficient or if there are functions which can cycle the interrupts at a higher frequency. Thanks, Kel Here's the code: # Define encoder count function def encodercount(term): global counts global Encoder_A global Encoder_A_old global Encoder_B global Encoder_B_old global error Encoder_A = GPIO.input('P8_7') # stores the value of the encoders at time of interrupt Encoder_B = GPIO.input('P8_8') if Encoder_A == Encoder_A_old and Encoder_B == Encoder_B_old: # this will be an error error += 1 print 'Error count is %s' %error elif (Encoder_A == 1 and Encoder_B_old == 0) or (Encoder_A == 0 and Encoder_B_old == 1): # this will be clockwise rotation counts += 1 print 'Encoder count is %s' %counts print 'AB is %s %s' % (Encoder_A, Encoder_B) elif (Encoder_A == 1 and Encoder_B_old == 1) or (Encoder_A == 0 and Encoder_B_old == 0): # this will be counter-clockwise rotation counts -= 1 print 'Encoder count is %s' %counts print 'AB is %s %s' % (Encoder_A, Encoder_B) else: #this will be an error as well error += 1 print 'Error count is %s' %error Encoder_A_old = Encoder_A # store the current encoder values as old values to be used as comparison in the next loop Encoder_B_old = Encoder_B # Initialize the interrupts - these trigger on the both the rising and falling GPIO.add_event_detect('P8_7', GPIO.BOTH, callback = encodercount) # Encoder A GPIO.add_event_detect('P8_8', GPIO.BOTH, callback = encodercount) # Encoder B # This is the part of the code which runs normally in the background while True: time.sleep(1)

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  • Connecting grouped dots/points on a scatter plot based on distance

    - by ToNoY
    I have 2 sets of depth point measurements, for example: > a depth value 1 2 2 2 4 3 3 6 4 4 8 5 5 16 40 6 18 45 7 20 58 > b depth value 1 10 10 2 12 20 3 14 35 I want to show both groups in one figure plotted with depth and with different symbols as you can see here plot(a$value, a$depth, type='b', col='green', pch=15) points(b$value, b$depth, type='b', col='red', pch=14) The plot seems okay, but the annoying part is that the green symbols are all connected (though I want connected lines also). I want connection only when one group has a continued data points at 2 m interval i.e. the symbols should be connected with a line from 2 to 8 m (green) and then group B symbols should be connected from 10-14 m (red) and again group A symbols should be connected (green), which means I do NOT want to see the connection between 8 m sample with the 16 m for group A. An easy solution may be dividing the group A into two parts (say, A-shallow and A-deep) and then plotting A-shallow, B, and A-deep separately. But this is completely impractical because I have thousands of data points with hundreds of groups i.e. I have to produce many depth profiles. Therefore, there has to be a way to program so that dots are NOT connected beyond a prescribed frequency/depth interval (e.g. 2 m in this case) for a particular group of samples. Any idea?

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  • How to get timestamp of tick precision in .NET / C#?

    - by Hermann
    Up until now I used DateTime.Now for getting timestamps, but I noticed that if you print DateTime.Now in a loop you will see that it increments in descrete jumps of approx. 15 ms. But for certain scenarios in my application I need to get the most accurate timestamp possible, preferably with tick (=100 ns) precision. Any ideas? Update: Apparently, StopWatch / QueryPerformanceCounter is the way to go, but it can only be used to measure time, so I was thinking about calling DateTime.Now when the application starts up and then just have StopWatch run and then just add the elapsed time from StopWatch to the initial value returned from DateTime.Now. At least that should give me accurate relative timestamps, right? What do you think about that (hack)? NOTE: StopWatch.ElapsedTicks is different from StopWatch.Elapsed.Ticks! I used the former assuming 1 tick = 100 ns, but in this case 1 tick = 1 / StopWatch.Frequency. So to get ticks equivalent to DateTime use StopWatch.Elapsed.Ticks. I just learned this the hard way. NOTE 2: Using the StopWatch approach, I noticed it gets out of sync with the real time. After about 10 hours, it was ahead by 5 seconds. So I guess one would have to resync it every X or so where X could be 1 hour, 30 min, 15 min, etc. I am not sure what the optimal timespan for resyncing would be since every resync will change the offset which can be up to 20 ms.

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  • Procesing 16bit sample audio

    - by user2431088
    Right now i have an audio file (2 Channels, 44.1kHz Sample Rate, 16bit Sample size, WAV) I would like to pass it into this method but i am not sure of any way to convert the WAV file to a byte array. /// <summary> /// Process 16 bit sample /// </summary> /// <param name="wave"></param> public void Process(ref byte[] wave) { _waveLeft = new double[wave.Length / 4]; _waveRight = new double[wave.Length / 4]; if (_isTest == false) { // Split out channels from sample int h = 0; for (int i = 0; i < wave.Length; i += 4) { _waveLeft[h] = (double)BitConverter.ToInt16(wave, i); _waveRight[h] = (double)BitConverter.ToInt16(wave, i + 2); h++; } } else { // Generate artificial sample for testing _signalGenerator = new SignalGenerator(); _signalGenerator.SetWaveform("Sine"); _signalGenerator.SetSamplingRate(44100); _signalGenerator.SetSamples(16384); _signalGenerator.SetFrequency(5000); _signalGenerator.SetAmplitude(32768); _waveLeft = _signalGenerator.GenerateSignal(); _waveRight = _signalGenerator.GenerateSignal(); } // Generate frequency domain data in decibels _fftLeft = FourierTransform.FFTDb(ref _waveLeft); _fftRight = FourierTransform.FFTDb(ref _waveRight); }

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  • Changing a Select dropdown with a jquery ui slider

    - by Chris J. Lee
    Trying to set a select dropdown with a slider. You move the jquery ui slider and then it will change the selection of the other two dropdowns. is there a current method in jquery that would set these options? Current dropdown: <select id="alert-options-frequency-opts"> <option value=""></option> <option value="1">1</option> <option value="2">2</option> <option value="3">3</option> <option value="4">4</option> <option value="5">5</option> <option value="6">6</option> <option value="7">7</option> <option value="8">8</option> <option value="9">9</option> <option value="10">10</option> </select>

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  • C++ Bubble Sorting for Singly Linked List [closed]

    - by user1119900
    I have implemented a simple word frequency program in C++. Everything but the sorting is OK, but the sorting in the following script does not work. Any emergent help will be great.. #include <stdio.h> #include <string.h> #include <stdlib.h> #include <ctype.h> #include <iostream> #include <fstream> #include <cstdio> using namespace std; #include "ProcessLines.h" struct WordCounter { char *word; int word_count; struct WordCounter *pNext; // pointer to the next word counter in the list }; /* pointer to first word counter in the list */ struct WordCounter *pStart = NULL; /* pointer to a word counter */ struct WordCounter *pCounter = NULL; /* Print statistics and words */ void PrintWords() { ... pCounter = pStart; bubbleSort(pCounter); ... } //end-PrintWords void bubbleSort(struct WordCounter *ptr) { WordCounter *temp = ptr; WordCounter *curr; for (bool didSwap = true; didSwap;) { didSwap = false; for (curr = ptr; curr->pNext != NULL; curr = curr->pNext) { if (curr->word > curr->pNext->word) { temp->word = curr->word; curr->word = curr->pNext->word; curr->pNext->word = temp->word; didSwap = true; } } } }

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  • What is the best way to implement a callback scenario using WCF and ASP.NET MVC?

    - by Mark Struzinski
    I am new to WCF. I just finished reading Learning WCF and I think I've got a pretty good grasp of the fundamentals. I am adding functionality to a line of business app that runs on ASP.NET MVC entirely inside the corporate LAN. I am calling into a service that will also send me events as they occur (and not as responses to service calls). These events can occur at any point during the user's session. I have the service written, and it is able to pick up these events. What would be the best way to deliver these events to the user? My initial thought is to run the WCF service in duplex mode over net TCP and implement the events as callbacks. Using this scenario, the best way I can think up to deliver the events to the user is a dictionary object stored in the session. The dictionary would be populated by the callbacks and polled on a set frequency for delivery via AJAX calls. Has anyone dealt with this scenario? Is there a more efficient way to implement this?

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  • Filter design for audio signal.

    - by beanyblue
    What I am trying to do is simple. I have a few .wav files. I want to remove noise and filter out specific frequencies. I don't have matlab and I intend to write my own code for all the filters. Right now, I have a way to read the .wav file and dump out the structure into a text file. My questions are the following: Can I directly apply the digital filters on this sampled data?{ ie, can I directly do a convolution between my input samples and h(n) for the filter function that i choose?). How do I choose the number of coefficients for the Window function? I have octave, so if someone can point me to anything that gives me some idea on how to process the .wav file using octave, that would be great too. I want to be able to filter out the frequency and then listen to the sound again. Is this possible with octave? I'm just a beginner with these kinds of things, so please bear with me if my questions are too naive. Any help will be great.

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  • Data base design with Blob

    - by mmuthu
    Hi, I have a situation where i need to store the binary data into database as blob column. There are three different table exists in my database where in i need to store a blob data for each record. Not every record will have the blob data all the time. It is time and user based. The table one will have to store the *.doc files almost for all the record The table two will have to store the *.xml optionally. The table three will have to store images (not sure what is frequency, etc) Now my questions is whether it is a good idea to maintain a separate table to store the blob data pointing it to the respective table PK's (Yes, there will be no FK's and assuming program will maintain it). It will be some thing like below, BLOB|PK_ID|TABLE_NAME Alternatively, is it a good idea to keep the blob column in respective tables. As for as my application runtime is concerned, The table 2 will be read very frequently. Though the blob column will not be required. The table 2 record will gets deleted frequently. Similarly other blob data in respective table will not be accessed frequently. All of the blob content will be read on-demand basis. I'm thinking first approach will work better for me. What do you guys think? Btw, I'm using Oracle.

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  • Avoiding repetition with libraries that use a setup + execute model

    - by lijie
    Some libraries offer the ability to separate setup and execution, esp if the setup portion has undesirable characteristics such as unbounded latency. If the program needs to have this reflected in its structure, then it is natural to have: void setupXXX(...); // which calls the setup stuff void doXXX(...); // which calls the execute stuff The problem with this is that the structure of setupXXX and doXXX is going to be quite similar (at least textually -- control flow will prob be more complex in doXXX). Wondering if there are any ways to avoid this. Example: Let's say we're doing signal processing: filtering with a known kernel in the frequency domain. so, setupXXX and doXXX would probably be something like... void doFilter(FilterStuff *c) { for (int i = 0; i < c->N; ++i) { doFFT(c->x[i], c->fft_forward_setup, c->tmp); doMultiplyVector(c->tmp, c->filter); doFFT(c->tmp, c->fft_inverse_setup, c->x[i]); } } void setupFilter(FilterStuff *c) { setupFFT(..., &(c->fft_forward_setup)); // assign the kernel to c->filter ... setupFFT(..., &(c->fft_inverse_setup)); }

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