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  • update attribute a element in arraylist on java ?

    - by tiendv
    I have a class Class TextChunks extends Token { ArrayList<Token> arrt = new ArrayList<Token>(); } extent fron class : class Token { String s; int frequency = 1 ;// Tern frequency in TextChunk } Now in token i have arraylist token , i want to update attribute frequency of token in Texchunks when have more than one tokens same . For clearly a give a example : Texchunks :" in particular in domain and range in some " So have 8 token : in,particular,in,domain,and,range,in,some i want update attribute frequency for token : in this example when i get attribute frequency of token "in" must return 3 it mean when i call : get frequency of Texchunks when dislay : in 3 particular 1 in 3 domain 1 and 1 range 1 in 3 some 1 here my code : public TextChunks updateFrequencyOfTokenInTextChunks (TextChunks tc) throws CloneNotSupportedException { TextChunks result = (TextChunks) tc.clone(); for (int i =0 ; i< result.arrt.size() ; i++ ){ int j=i+1; if (result.arrt.get(i).compareTwoToken(result.arrt.get(j))== true ) { // help here how to update attribute result.arrt.get(i) // and result.arrt.get(J) = ++ and } } return tc; } Thanks in advandce

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  • Choose build configuration for referenced subproject

    - by Jaka Jancar
    I have an iPhone project which references a framework as a subproject. The framework has the following configurations: Debug Release My app has the following configurations: Debug Release Distribution-AdHoc Distribution-AppStore I would like the framework to be built with different configurations, depending on the app configuration: Debug - Debug Release - Release Distribution-AdHoc - Release Distribution-AppStore - Release How can I achieve this?

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  • Why create a Huffman tree per character instead of a Node?

    - by Omega
    For a school assignment we're supposed to make a Java implementation of a compressor/decompresser using Huffman's algorithm. I've been reading a bit about it, specially this C++ tutorial: http://www.cprogramming.com/tutorial/computersciencetheory/huffman.html In my program, I've been thinking about having Nodes that have the following properties: Total Frequency Character (if a leaf) Right child (if any) Left child (if any) Parent (if any) So when building the Huffman tree, it is just a matter of linking a node to others, etc. However, I'm a bit confused with the following quote (emphasis mine): First, every letter starts off as part of its own tree and the trees are ordered by the frequency of the letters in the original string. Then the two least-frequently used letters are combined into a single tree, and the frequency of that tree is set to be the combined frequency of the two trees that it links together. My question: why should I create a tree per letter, instead of just a node per letter and then do the linking later? I have not begun coding, I'm just studying the algorithm first, so I guess I'm missing an important detail. What is it?

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  • DSP - Problems using the inverse Fast Fourier Transform

    - by Trap
    I've been playing around a little with the Exocortex implementation of the FFT, but I'm having some problems. First, after calculating the inverse FFT of an unchanged frequency spectrum obtained by a previous forward FFT, one would expect to get the original signal back, but this is not the case. I had to figure out that I needed to scale the FFT output to about 1 / fftLength to get the amplitudes ok. Why is this? Second, whenever I modify the amplitudes of the frequency bins before calling the iFFT the signal gets distorted at low frequencies. However, this does not happen if I attenuate all the bins by the same factor. Let me put a very simplified example of the output buffer of a 4-sample FFT: // Bin 0 (DC) FFTOut[0] = 0.0000610351563 FFTOut[1] = 0.0 // Bin 1 FFTOut[2] = 0.000331878662 FFTOut[3] = 0.000629425049 // Central bin FFTOut[4] = -0.0000381469727 FFTOut[5] = 0.0 // Bin 3, this is a negative frequency bin. FFTOut[6] = 0.000331878662 FFTOut[7] = -0.000629425049 The output is composed of pairs of floats, each representing the real and imaginay parts of a single bin. So, bin 0 (array indexes 0, 1) would represent the real and imaginary parts of the DC frequency. As you can see, bins 1 and 3 both have the same values, (except for the sign of the Im part), so I guess these are the negative frequency values, and finally indexes (4, 5) would be the central frequency bin. To attenuate the frequency bin 1 this is what I do: // Attenuate the 'positive' bin FFTOut[2] *= 0.5; FFTOut[3] *= 0.5; // Attenuate its corresponding negative bin. FFTOut[6] *= 0.5; FFTOut[7] *= 0.5; For the actual tests I'm using a 1024-length FFT and I always provide all the samples so no 0-padding is needed. // Attenuate var halfSize = fftWindowLength / 2; float leftFreq = 0f; float rightFreq = 22050f; for( var c = 1; c < halfSize; c++ ) { var freq = c * (44100d / halfSize); // Calc. positive and negative frequency locations. var k = c * 2; var nk = (fftWindowLength - c) * 2; // This kind of attenuation corresponds to a high-pass filter. // The attenuation at the transition band is linearly applied, could // this be the cause of the distortion of low frequencies? var attn = (freq < leftFreq) ? 0 : (freq < rightFreq) ? ((freq - leftFreq) / (rightFreq - leftFreq)) : 1; mFFTOut[ k ] *= (float)attn; mFFTOut[ k + 1 ] *= (float)attn; mFFTOut[ nk ] *= (float)attn; mFFTOut[ nk + 1 ] *= (float)attn; } Obviously I'm doing something wrong but can't figure out what or where.

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  • Replication Services in a BI environment

    - by jorg
    In this blog post I will explain the principles of SQL Server Replication Services without too much detail and I will take a look on the BI capabilities that Replication Services could offer in my opinion. SQL Server Replication Services provides tools to copy and distribute database objects from one database system to another and maintain consistency afterwards. These tools basically copy or synchronize data with little or no transformations, they do not offer capabilities to transform data or apply business rules, like ETL tools do. The only “transformations” Replication Services offers is to filter records or columns out of your data set. You can achieve this by selecting the desired columns of a table and/or by using WHERE statements like this: SELECT <published_columns> FROM [Table] WHERE [DateTime] >= getdate() - 60 There are three types of replication: Transactional Replication This type replicates data on a transactional level. The Log Reader Agent reads directly on the transaction log of the source database (Publisher) and clones the transactions to the Distribution Database (Distributor), this database acts as a queue for the destination database (Subscriber). Next, the Distribution Agent moves the cloned transactions that are stored in the Distribution Database to the Subscriber. The Distribution Agent can either run at scheduled intervals or continuously which offers near real-time replication of data! So for example when a user executes an UPDATE statement on one or multiple records in the publisher database, this transaction (not the data itself) is copied to the distribution database and is then also executed on the subscriber. When the Distribution Agent is set to run continuously this process runs all the time and transactions on the publisher are replicated in small batches (near real-time), when it runs on scheduled intervals it executes larger batches of transactions, but the idea is the same. Snapshot Replication This type of replication makes an initial copy of database objects that need to be replicated, this includes the schemas and the data itself. All types of replication must start with a snapshot of the database objects from the Publisher to initialize the Subscriber. Transactional replication need an initial snapshot of the replicated publisher tables/objects to run its cloned transactions on and maintain consistency. The Snapshot Agent copies the schemas of the tables that will be replicated to files that will be stored in the Snapshot Folder which is a normal folder on the file system. When all the schemas are ready, the data itself will be copied from the Publisher to the snapshot folder. The snapshot is generated as a set of bulk copy program (BCP) files. Next, the Distribution Agent moves the snapshot to the Subscriber, if necessary it applies schema changes first and copies the data itself afterwards. The application of schema changes to the Subscriber is a nice feature, when you change the schema of the Publisher with, for example, an ALTER TABLE statement, that change is propagated by default to the Subscriber(s). Merge Replication Merge replication is typically used in server-to-client environments, for example when subscribers need to receive data, make changes offline, and later synchronize changes with the Publisher and other Subscribers, like with mobile devices that need to synchronize one in a while. Because I don’t really see BI capabilities here, I will not explain this type of replication any further. Replication Services in a BI environment Transactional Replication can be very useful in BI environments. In my opinion you never want to see users to run custom (SSRS) reports or PowerPivot solutions directly on your production database, it can slow down the system and can cause deadlocks in the database which can cause errors. Transactional Replication can offer a read-only, near real-time database for reporting purposes with minimal overhead on the source system. Snapshot Replication can also be useful in BI environments, if you don’t need a near real-time copy of the database, you can choose to use this form of replication. Next to an alternative for Transactional Replication it can be used to stage data so it can be transformed and moved into the data warehousing environment afterwards. In many solutions I have seen developers create multiple SSIS packages that simply copies data from one or more source systems to a staging database that figures as source for the ETL process. The creation of these packages takes a lot of (boring) time, while Replication Services can do the same in minutes. It is possible to filter out columns and/or records and it can even apply schema changes automatically so I think it offers enough features here. I don’t know how the performance will be and if it really works as good for this purpose as I expect, but I want to try this out soon!

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  • C# Monte Carlo Simulation Package Needed

    - by Yunzhou
    I'm relative new to C# and doing a project using Monte Carlo Simulation. Basically my question is the following. I have two uncertain variable inputs, A and B, and they will go through a model and give an output C. So C = f(A,B). I know A's probability distribution (Triangular) and B's probability distribution (Discrete). How can I get the probability distribution of C? What I have done now is that I can generate random numbers based on A's triangular distribution as well as B's discrete distribution. Each pair of randomly generated A and B gives a resultant C. I've run this model 1000 times thus I can get 1000 possible values of C. The difficulty is to get the corresponding probabilities of each value of C. Obviously it's not 1/1000 unless C is uniformly distributed. Is there any Monte Carlo Simulation package/library I can use?

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  • Monitor SQL Server Replication Jobs

    - by Yaniv Etrogi
    The Replication infrastructure in SQL Server is implemented using SQL Server Agent to execute the various components involved in the form of a job (e.g. LogReader agent job, Distribution agent job, Merge agent job) SQL Server jobs execute a binary executable file which is basically C++ code. You can download all the scripts for this article here SQL Server Job Schedules By default each of job has only one schedule that is set to Start automatically when SQL Server Agent starts. This schedule ensures that when ever the SQL Server Agent service is started all the replication components are also put into action. This is OK and makes sense but there is one problem with this default configuration that needs improvement  -  if for any reason one of the components fails it remains down in a stopped state.   Unless you monitor the status of each component you will typically get to know about such a failure from a customer complaint as a result of missing data or data that is not up to date at the subscriber level. Furthermore, having any of these components in a stopped state can lead to more severe problems if not corrected within a short time. The action required to improve on this default settings is in fact very simple. Adding a second schedule that is set as a Daily Reoccurring schedule which runs every 1 minute does the trick. SQL Server Agent’s scheduler module knows how to handle overlapping schedules so if the job is already being executed by another schedule it will not get executed again at the same time. So, in the event of a failure the failed job remains down for at most 60 seconds. Many DBAs are not aware of this capability and so search for more complex solutions such as having an additional dedicated job running an external code in VBS or another scripting language that detects replication jobs in a stopped state and starts them but there is no need to seek such external solutions when what is needed can be accomplished by T-SQL code. SQL Server Jobs Status In addition to the 1 minute schedule we also want to ensure that key components in the replication are enabled so I can search for those components by their Category, and set their status to enabled in case they are disabled, by executing the stored procedure MonitorEnableReplicationAgents. The jobs that I typically have handled are listed below but you may want to extend this, so below is the query to return all jobs along with their category. SELECT category_id, name FROM msdb.dbo.syscategories ORDER BY category_id; Distribution Cleanup LogReader Agent Distribution Agent Snapshot Agent Jobs By default when a publication is created, a snapshot agent job also gets created with a daily schedule. I see more organizations where the snapshot agent job does not need to be executed automatically by the SQL Server Agent  scheduler than organizations who   need a new snapshot generated automatically. To assure this setting is in place I created the stored procedure MonitorSnapshotAgentsSchedules which disables snapshot agent jobs and also deletes the job schedule. It is worth mentioning that when the publication property immediate_sync is turned off then the snapshot files are not created when the Snapshot agent is executed by the job. You control this property when the publication is created with a parameter called @immediate_sync passed to sp_addpublication and for an existing publication you can use sp_changepublication. Implementation The scripts assume the existence of a database named PerfDB. Steps: Run the scripts to create the stored procedures in the PerfDB database. Create a job that executes the stored procedures every hour. -- Verify that the 1_Minute schedule exists. EXEC PerfDB.dbo.MonitorReplicationAgentsSchedules @CategoryId = 10; /* Distribution */ EXEC PerfDB.dbo.MonitorReplicationAgentsSchedules @CategoryId = 13; /* LogReader */ -- Verify all replication agents are enabled. EXEC PerfDB.dbo.MonitorEnableReplicationAgents @CategoryId = 10; /* Distribution */ EXEC PerfDB.dbo.MonitorEnableReplicationAgents @CategoryId = 13; /* LogReader */ EXEC PerfDB.dbo.MonitorEnableReplicationAgents @CategoryId = 11; /* Distribution clean up */ -- Verify that Snapshot agents are disabled and have no schedule EXEC PerfDB.dbo.MonitorSnapshotAgentsSchedules; Want to read more of about replication? Check at my replication posts at my blog.

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  • Introducing the Oracle Linux Playground yum repo

    - by wcoekaer
    We just introduced a new yum repository/channel on http://public-yum.oracle.com called the playground channel. What we started doing is the following: When a new stable mainline kernel is released by Linus or GregKH, we internally build RPMs to test it and do some QA work around it to keep track of what's going on with the latest development kernels. It helps us understand how performance moves up or down and if there are issues, we try to help look into them and of course send that stuff back upstream. Many Linux users out there are interested in trying out the latest features but there are some potential barriers to do this. (1) in general, you are looking at an upstream development distribution, which means that everything changes both in userspace(random applications) and kernel. Projects like Fedora are very useful and someone that wants to just see how the entire distribution evolves with all the changes, this is a great way to be current. A drawback here, though, is that if you have applications that are not part of the distribution, there's a lot of manual work involved or they might just not work because the changes are too drastic. The introduction of systemd is a good example. (2) when you look at many of our customers, that are interested in our database products or applications, the starting point of having a supported/certified userspace/distribution, like Oracle Linux, is a much easier way to get your feet wet in seeing what new/future Linux kernel enhancements could do. This is where the playground channel comes into play. When you install Oracle Linux 6 (which anyone can download and use from http://edelivery.oracle.com/linux), grab the latest public yum repository file http://public-yum.oracle.com/public-yum-ol6.repo, put it in /etc/yum.repos.d and enable the playground repo : [ol6_playground_latest] name=Latest mainline stable kernel for Oracle Linux 6 ($basearch) - Unsupported baseurl=http://public-yum.oracle.com/repo/OracleLinux/OL6/playground/latest/$basearch/ gpgkey=http://public-yum.oracle.com/RPM-GPG-KEY-oracle-ol6 gpgcheck=1 enabled=1 Now, all you need to do : type yum update and you will be downloading the latest stable kernel which will install cleanly on Oracle Linux 6. Thus you end up with a stable Linux distribution where you can install all your software, and then download the latest stable kernel (at time of writing this is 3.6.7) without having to recompile a kernel, without having to jump through hoops. There is of course a big, very important disclaimer this is NOT for PRODUCTION use. We want to try and help make it easy for people that are interested, from a user perspective, where the Linux kernel is going and make it easy to install and use it and play around with new features. Without having to learn how to compile a kernel and without necessarily having to install a complete new distribution with all the changes top to bottom. So we don't or won't introduce any new userspace changes, this project really is around making it easy to try out the latest upstream Linux kernels in a very easy way on an environment that's stable and you can keep current, since all the latest errata for Oracle Linux 6 are published on the public yum repo as well. So one repository location for all your current changes and the upstream kernels. We hope that this will get more users to try out the latest kernel and report their findings. We are always interested in understanding stability and performance characteristics. As new features are going into the mainline kernel, that could potentially be interesting or useful for various products, we will try to point them out on our blogs and give an example on how something can be used so you can try it out for yourselves. Anyway, I hope people will find this useful and that it will help increase interested in upstream development beyond reading lkml by some of the more non-kernel-developer types.

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  • ADNOC talks about 50x increase in performance

    - by KLaker
    If you are still wondering about how Exadata can revolutionise your business then I would recommend watching this great video which was recorded at this year's OpenWorld. First a little background...The Abu Dhabi National Oil Company for Distribution (ADNOC) is an integrated energy company that was founded in 1973. ADNOC Distribution markets and distributes petroleum products and services within the United Arab Emirates and internationally. As one of the largest and most innovative government-owned petroleum companies in the Arab Gulf, ADNOC Distribution is renowned and respected for the exceptional quality and reliability of its products and services. Its five corporate divisions include more than 200 filling stations (a number that is growing at 8% annually), more than 150 convenience stores, 10 vehicle inspection stations, as well as wholesale and retail sales of bulk fuel, gas, oil, diesel, and lubricants. ADNOC selected Oracle Exadata Database Machine after extensive research because it provided them with a single platform that can run mixed workloads in a single unified machine: "We chose Oracle Exadata Database Machine because it.offered a fully integrated and highly engineered system that was ready to deploy. With our infrastructure running all the same technology, we can operate any type of Oracle Database without restrictions and be prepared for business growth," said Ali Abdul Aziz Al-Ali, IT division manager, ADNOC Distribution. ".....we could consolidate our transaction processing and business intelligence onto one platform. Competing solutions are just not capable of doing that." - Awad Ahmed Ali El-Sidiq, Senior Database Administrator, ADNOC Distribution In this new video Awad Ahmen Ali El Sidddig, Senior DBA at ADNOC, talks about the impact that Exadata has had on his team and the whole business. ADNOC is using our engineered systems to drive and manage all their workloads: from transaction systems to payments system to data warehouse to BI environment. A true Disk-to-Dashboard revolution using Engineered Systems. This engineered approach is delivering 50x improvement in performance with one queries running 100x faster! The IT has even revolutionised some of their data warehouse related processes with the help of Exadata and now jobs that were taking over 4 hours now run in a few minutes.  To watch the video click on the image below which will take you to our Oracle YouTube page: (if the above link does not work, click here: http://www.youtube.com/watch?v=zcRpxc6u5Ic) Now that queries are running 100x faster and jobs are completing in minutes not hours, what is next for the IT team at ADNOC? Like many of our customers ADNOC is now looking to take advantage of big data to help them better align their business operations with customer behaviour and customer insights. To help deliver this next level of insight the IT team is looking at the new features in Oracle Database 12c such as the new in-memory feature to deliver even more performance gains.  The great news is that Awad Ahmen Ali El Sidddig was awarded DBA of the Year - EMEA within our Data Warehouse Global Leaders programme and you can see the badge for this award pop-up at the start of video. Well done to everyone at ADNOC and thanks for spending the time with us at OOW to create this great video.

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  • SQL Transactional Replication snapshot not applying

    - by dmch2
    Hi, I'm using SQL Transactional Replication with pull subscriptions to replicate databases (hosting their own distribution database) from several servers across a VPN to a central server. I've got the first 2 databases working fine but the 3rd one is causing me problems. My subscription server is SQL 2008, the source systems are all SQL 2005. The source databases are a few 100Mb in size and contain audit data so are simply growing slowly by adding new records at approx 1kb a second. As far as the replication monitor, Agent logs and event logs show everything is working fine - except that no data appears in my subscription database. The distribution agent doesn't seem to want to read the snapshot (and hence the initial state and schema) from the publisher. New transactions aren't applied although they do seem to be arriving OK as the replication monitor shows things like '5 transactions with 10 commands were delivered'. I would expect (as in previous times) to see statements about data being BCPed in the replication monitor. The snapshot is on the publisher on a shared folder. The subscriber can view the snapshot OK (\\repldata) and the alt snapshot folder is pointing at it. But the distribution agent doesn't seem to be making an attempt to do read it. I tried changing the snapshot path to something that's incorrect and didn't even get an error saying that it couldn't access it. After lots of googling etc I found that sp_MSget_repl_commands is called by the subscriber on the distribution database on the publisher. Running a profiler I can see that it's only called for one agent Id. After a reinit it's called for sequence number 0x0 as expected so I thought that would mean it's would look for the snapshot. However, looking on the publisher I see that there's data for two agents - the snapshot agent and the log reader agent (which is being queries). So I guess I need to tell the distribution agent to get the data for both. But how? and more importantly - why? It worked fine on the other two servers I've replicated. I'm not an SQL novice but this is pretty much my first go at replication so don't be afraid to accuse me of missing something obvious/stupid! I can get log files (eg from the distribution agent) if you want but they don't seem to have any errors in them - it just starts up and starts applying log reader agent changes. Cheers Dave

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  • Nivida driver install

    - by Adham
    tried black listing and every thing i could find on the internet used with root and alt+ctrl+f1 with no solution nvidia-installer log file '/var/log/nvidia-installer.log' creation time: Mon Jun 17 08:35:25 2013 installer version: 319.23 PATH: /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin nvidia-installer command line: ./nvidia-installer Using: nvidia-installer ncurses user interface -> License accepted. -> Installing NVIDIA driver version 319.23. -> Running distribution scripts executing: '/usr/lib/nvidia/pre-install'... -> done. -> The distribution-provided pre-install script failed! Continue installation anyway? (Answer: Yes) ERROR: The Nouveau kernel driver is currently in use by your system. This driver is incompatible with the NVIDIA driver, and must be disabled before proceeding. Please consult the NVIDIA driver README and your Linux distribution's documentation for details on how to correctly disable the Nouveau kernel driver. WARNING: One or more modprobe configuration files to disable Nouveau are already present at: /etc/modprobe.d/nvidia-installer-disable-nouveau.conf. Please be sure you have rebooted your system since these files were written. If you have rebooted, then Nouveau may be enabled for other reasons, such as being included in the system initial ramdisk or in your X configuration file. Please consult the NVIDIA driver README and your Linux distribution's documentation for details on how to correctly disable the Nouveau kernel driver. ERROR: Installation has failed. Please see the file '/var/log/nvidia-installer.log' for details. You may find suggestions on fixing installation problems in the README available on the Linux driver download page at www.nvidia.com.

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  • FMOD.net streaming, callback and exinfo parameters

    - by Tesserex
    I posted a question on gamedev about how to play nsf files (NES console music) in FMOD. It didn't get any results, but since then I made some progress. I decided that the easiest method was just to compile an existing player into a dll and then call it from C# to populate my buffer. The problem now is getting it to sound right, and making sure all my paremeters are correct. Here are the facts so far: The nsf dll is dealing with shorts, so the data is PCM16. The sample nsf I'm using has a playback rate of 60 Hz. Just for playing around now, I'm using a frequency of 48000. Based on 2 and 3, the dll calculates a necessary buffer size of 48000 / 60hz = 800. This means it will render 800 shorts worth of buffer for every simulated NES frame. I've so far got my C# code to play the nsf, at the correct pitch and tempo, but it's very grainy / fuzzy, which I'm attributing to the fact that the FMOD read callback is giving a data length of 1600, whereas I should be expecting 800. I've tried playing around with all the numbers and it either crashes, or the music changes pitch, tempo, or both. Here's some of my C# code: uint channels = 1, frequency = 48000; FMOD.MODE mode = (FMOD.MODE.DEFAULT | FMOD.MODE.OPENUSER | FMOD.MODE.LOOP_NORMAL); FMOD.Sound sound = new FMOD.Sound(); FMOD.CREATESOUNDEXINFO ex = new FMOD.CREATESOUNDEXINFO(); ex.cbsize = Marshal.SizeOf(ex); ex.fileoffset = 0; ex.format = FMOD.SOUND_FORMAT.PCM16; // does this even matter? It doesn't change my results as long as it's long enough for one update ex.length = frequency; ex.numchannels = (int)channels; ex.defaultfrequency = (int)frequency; ex.pcmreadcallback = pcmreadcallback; ex.dlsname = null; // eventually I will calculate this with frequency / nsf hz, but I'm just testing for now ex.decodebuffersize = 800; // from the dll load_nsf_file("file.nsf", 8, (int)frequency); // 8 is the track number to play var result = system.createSound( (string)null, (mode | FMOD.MODE.CREATESTREAM), ref ex, ref sound); channel = new FMOD.Channel(); result = system.playSound(FMOD.CHANNELINDEX.FREE, sound, false, ref channel); private FMOD.RESULT PCMREADCALLBACK(IntPtr soundraw, IntPtr data, uint datalen) { // from the dll process_buffer(data, (int)800); // if I use datalen, it usually crashes (I can't get datalen to = 800 safely) return FMOD.RESULT.OK; } So here are some of my questions: What is the relationship between exinfo.decodebuffersize, frequency, and the datalen parameter of the read callback? With this code sample, it's coming in as 3200. I don't know where that factor of 4 between it and the decodebuffersize comes from. Is datalen in the callback referring to number of bytes, or shorts? The process_buffer function takes a short array and its length. I would expect fmod is talking about shorts as well because I told it PCM16. Maybe my playback quality is bad for some totally different reason. If so I have no idea where to begin solving that. Any ideas there?

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  • Matlab: Analysis of signal

    - by Mateusz
    Hi, I have a problem with this task: For free route perform frequency analysis and give parametrs of each signal component: time of beginning and ending of each component beginning and ending frequency amplitude (in time domain) in the beginning and end of each signal's component level of noise in dB Assume, that, the parametrs of each component like amplitude, frequency is changing lineary in time. Frequency of sampling is 1000Hz For example I have signal like this: Nx=64; fs=1000; t=1/fs*(0:Nx-1); %========================== A1=1; A2=4; f1=500; f2=1000; x1=A1*cos(2*pi*f1*t); x2=A2*sin(2*pi*f2*t); %========================== x=x1+x2;

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  • algorithm q: Fuzzy matching of structured data

    - by user86432
    I have a fairly small corpus of structured records sitting in a database. Given a tiny fraction of the information contained in a single record, submitted via a web form (so structured in the same way as the table schema), (let us call it the test record) I need to quickly draw up a list of the records that are the most likely matches for the test record, as well as provide a confidence estimate of how closely the search terms match a record. The primary purpose of this search is to discover whether someone is attempting to input a record that is duplicate to one in the corpus. There is a reasonable chance that the test record will be a dupe, and a reasonable chance the test record will not be a dupe. The records are about 12000 bytes wide and the total count of records is about 150,000. There are 110 columns in the table schema and 95% of searches will be on the top 5% most commonly searched columns. The data is stuff like names, addresses, telephone numbers, and other industry specific numbers. In both the corpus and the test record it is entered by hand and is semistructured within an individual field. You might at first blush say "weight the columns by hand and match word tokens within them", but it's not so easy. I thought so too: if I get a telephone number I thought that would indicate a perfect match. The problem is that there isn't a single field in the form whose token frequency does not vary by orders of magnitude. A telephone number might appear 100 times in the corpus or 1 time in the corpus. The same goes for any other field. This makes weighting at the field level impractical. I need a more fine-grained approach to get decent matching. My initial plan was to create a hash of hashes, top level being the fieldname. Then I would select all of the information from the corpus for a given field, attempt to clean up the data contained in it, and tokenize the sanitized data, hashing the tokens at the second level, with the tokens as keys and frequency as value. I would use the frequency count as a weight: the higher the frequency of a token in the reference corpus, the less weight I attach to that token if it is found in the test record. My first question is for the statisticians in the room: how would I use the frequency as a weight? Is there a precise mathematical relationship between n, the number of records, f(t), the frequency with which a token t appeared in the corpus, the probability o that a record is an original and not a duplicate, and the probability p that the test record is really a record x given the test and x contain the same t in the same field? How about the relationship for multiple token matches across multiple fields? Since I sincerely doubt that there is, is there anything that gets me close but is better than a completely arbitrary hack full of magic factors? Barring that, has anyone got a way to do this? I'm especially keen on other suggestions that do not involve maintaining another table in the database, such as a token frequency lookup table :). This is my first post on StackOverflow, thanks in advance for any replies you may see fit to give.

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  • How can I make a group bar plot in ggplot2?

    - by maximusyoda
    I have four of these kind of dataframes each with a different name (Apple,Ball,Cat) with different values of frequency but same 4 season names Seasons Frequency DJF 9886 JJA 5408 MAM 12876 SON 6932 And I am trying to make a group bar plot. The graph I'm looking for is like this, where c,d,e,f will be the names - Apple, Ball, Cat. Y-axis will be Frequency Each group will have 4 bars: DJF,JJA,MAM,SON Filled by seasons The number of Frequency written above the bar plot. How can I format the data to make it suitable for ggplot (cbind, melt etc) and use it in ggplot?

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  • Simple wave generator with SDL in c++

    - by Vlad Popescu
    i am having problems understanding how the audio part of the sdl library works now, i know that when you initialize it, you have to specify the frequency and a callback<< function, which i think is then called automatically at the given frequency. can anyone who worked with the sdl library write a simple example that would use sdl_audio to generate a 440 hz square wave (since it is the simplest waveform) at a sampling frequency of 44000 hz? thanks in advance

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  • Retreiving multiple rows from a loop-created form... Stuck.

    - by hangston
    Hi All, Let me start by saying that I'm new to PHP, but I'm here to learn and would really appreciate your help. I use the following code to pull in data and create a form. This creates up to 40 lines for a user to fill out. Each line consists of the same information: Description, Amount, and Frequency. The remainder of the information needed is generated by the database. (See hidden fields) <?php $row = 0; do { $optid = $row_options['option_id']; echo "<tr>\n\t<td>" . htmlentities($row_options['option']) . "</td>\n"; echo "\t<td>" . "<input name='description' type='text' size='40' maxlength='120'/>" . "</td>\n"; echo "\t<td>" . "<input name='option_id' type='hidden' value='$optid' />$<input name='amount' type='text' size='10' maxlength='7'/>" . "</td>\n"; echo "\t<td>" . "<select name='assisted_frequency'> <option value='Monthly'>Monthly</option> <option value='Weekly'>Weekly</option> <option value='Daily'>Daily</option> <option value='Hourly'>Hourly</option> <option value='One-Time'>One-Time</option> </select>" . "</td>\n</tr>\n"; $array[$row] = array( $arraydesc[$row] = $_POST['description'], $arrayamto[$row] = $_POST['amount'], $arrayoptid[$row] = $optid, $arrayfreq[$row] = $_POST['frequency'], ); $row ++; } while ($row_options = mysql_fetch_assoc($options)); $counter = $row - 1; ?> I'm having troubles retrieving the information that the user inputs. My intent is to loop through each row after the user has input their information, then upload the mix of my database information and the user's information into another database. For example, the user would see, albeit prettier: form1 Option 1: description [input box] amount [input box] frequency [option box] Option 2: description [input box] amount [input box] frequency [option box] Option 3: description [input box] amount [input box] frequency [option box] Option 4: description [input box] amount [input box] frequency [option box] submit Upon submitting the form above, I'm using a query similar to the following to input the data into the database: for($row=0; $row<=$counter; $row++){ $insertSQL2 = sprintf("INSERT INTO table (option_id, amount, description, frequency) VALUES (%s, %s, %s, %s)", GetSQLValueString($arrayoptid[$row], "int"), GetSQLValueString($arrayamto[$row], "int"), GetSQLValueString($arraydesc[$row], "text"), GetSQLValueString($arrayfreq[$row], "text")); // code to submit query } I've tried for, foreach, arrays (what feels like the everything I know) to post each row (row by row) into the database. I either get just the last row of data, or no data at all. I also worry that the [$row] technique is adding characters to my data. What is the best way to retrieve each row of the user's inputs, then upload this data (row by row) into the database? Also, I would really appreciate your suggestions for improving my coding technique and the approach I'm taking. Thank you, Hangston

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  • Search-friendly way to store checkbox values in MySQL?

    - by Alex
    What is a search-friendly way to store checkbox values in the database? Currently, checkboxes are processed as an array and values are separated by a ";" As such: <input type="checkbox" name="frequency[]" value="Daily"/> Daily <input type="checkbox" name="frequency[]" value="Weekly"/> Weekly <input type="checkbox" name="frequency[]" value="Monthly"/> Monthly The PHP backend runs implode(';', $frequency) and adds the string to the database. This works fine but it's a nightmare when it comes to searching. Is there a better way to approach this?

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  • how do i design a high pass filters in matlab without using the builtin function?

    - by noura
    hello everyone, i'm just not sure how to draw the frequency response (H) of the high pass filter? after drawing the frequency response i can get the b coefficient by taking the ifft of (H). so yeah, for a low pass filter, with a cutoff frequency of say pi/2 : the frequency response code will be H = exp(-1*j*w*4).*(((0 <= w) & (w<= pi/2)) | ((2*pi - pi/2 <= w) & (w<=2*pi)); sincr the response is "1" between 0 and pi/2 and between (2*pi - pi/2) and 2*pi. can you help me write H for a high pass filter? thanx in advance.

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  • My method is too specific. How can I make it more generic?

    - by EricBoersma
    I have a class, the outline of which is basically listed below. import org.apache.commons.math.stat.Frequency; public class WebUsageLog { private Collection<LogLine> logLines; private Collection<Date> dates; WebUsageLog() { this.logLines = new ArrayList<LogLine>(); this.dates = new ArrayList<Date>(); } SortedMap<Double, String> getFrequencyOfVisitedSites() { SortedMap<Double, String> frequencyMap = new TreeMap<Double, String>(Collections.reverseOrder()); //we reverse order to sort from the highest percentage to the lowest. Collection<String> domains = new HashSet<String>(); Frequency freq = new Frequency(); for (LogLine line : this.logLines) { freq.addValue(line.getVisitedDomain()); domains.add(line.getVisitedDomain()); } for (String domain : domains) { frequencyMap.put(freq.getPct(domain), domain); } return frequencyMap; } } The intention of this application is to allow our Human Resources folks to be able to view Web Usage Logs we send to them. However, I'm sure that over time, I'd like to be able to offer the option to view not only the frequency of visited sites, but also other members of LogLine (things like the frequency of assigned categories, accessed types [text/html, img/jpeg, etc...] filter verdicts, and so on). Ideally, I'd like to avoid writing individual methods for compilation of data for each of those types, and they could each end up looking nearly identical to the getFrequencyOfVisitedSites() method. So, my question is twofold: first, can you see anywhere where this method should be improved, from a mechanical standpoint? And secondly, how would you make this method more generic, so that it might be able to handle an arbitrary set of data?

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  • Retrieving multiple rows from a loop-created form... Stuck.

    - by hangston
    Let me start by saying that I'm new to PHP, but I'm here to learn and would really appreciate your help. I use the following code to pull in data and create a form. This creates up to 40 lines for a user to fill out. Each line consists of the same information: Description, Amount, and Frequency. The remainder of the information needed is generated by the database. (See hidden fields) <?php $row = 0; do { $optid = $row_options['option_id']; echo "<tr>\n\t<td>" . htmlentities($row_options['option']) . "</td>\n"; echo "\t<td>" . "<input name='description' type='text' size='40' maxlength='120'/>" . "</td>\n"; echo "\t<td>" . "<input name='option_id' type='hidden' value='$optid' />$<input name='amount' type='text' size='10' maxlength='7'/>" . "</td>\n"; echo "\t<td>" . "<select name='assisted_frequency'> <option value='Monthly'>Monthly</option> <option value='Weekly'>Weekly</option> <option value='Daily'>Daily</option> <option value='Hourly'>Hourly</option> <option value='One-Time'>One-Time</option> </select>" . "</td>\n</tr>\n"; $array[$row] = array( $arraydesc[$row] = $_POST['description'], $arrayamto[$row] = $_POST['amount'], $arrayoptid[$row] = $optid, $arrayfreq[$row] = $_POST['frequency'], ); $row ++; } while ($row_options = mysql_fetch_assoc($options)); $counter = $row - 1; ?> I'm having troubles retrieving the information that the user inputs. My intent is to loop through each row after the user has input their information, then upload the mix of my database information and the user's information into another database. For example, the user would see, albeit prettier: form1 Option 1: description [input box] amount [input box] frequency [option box] Option 2: description [input box] amount [input box] frequency [option box] Option 3: description [input box] amount [input box] frequency [option box] Option 4: description [input box] amount [input box] frequency [option box] submit Upon submitting the form above, I'm using a query similar to the following to input the data into the database: for($row=0; $row<=$counter; $row++){ $insertSQL2 = sprintf("INSERT INTO table (option_id, amount, description, frequency) VALUES (%s, %s, %s, %s)", GetSQLValueString($arrayoptid[$row], "int"), GetSQLValueString($arrayamto[$row], "int"), GetSQLValueString($arraydesc[$row], "text"), GetSQLValueString($arrayfreq[$row], "text")); // code to submit query } I've tried for, foreach, arrays (what feels like the everything I know) to post each row (row by row) into the database. I either get just the last row of data, or no data at all. I also worry that the [$row] technique is adding characters to my data. What is the best way to retrieve each row of the user's inputs, then upload this data (row by row) into the database? Also, I would really appreciate your suggestions for improving my coding technique and the approach I'm taking.

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  • Connecting PC to TV via HDMI/DVI: Windows XP doesn't allow the appropriate screen resolution

    - by Jørgen
    I have a computer that is connected to the living room TV (a Panasonic) via HDMI. There is no other monitor connected. My problem is that the computer, which is running Windows XP, does not allow me to set the proper resolution for the TV. Both the graphics adapter and the TV should support the 1280x720 resolution, but it cannot be selected - the only available options are 1280x600 and 800x600, both in the "native" Windows dialog box and the custom Intel graphics options dialog box. Do anyone have a suggestion for a solution for this? Things I've thought of: Setting the resolution directly in the registry (where?) Installing some "custom" monitor driver (the TV manufacturer does not appear to provide any, currently the "generic" one is used) Details on the setup: Connection: DVI output on the computer via a passive DVI-HDMI adapter to the HDMI input on the TV, audio is run on a separate link, the TV is able to combine video and audio without any problem, the problem is there regardless of whether or not the audio is connected. The connection is several meters long through some walls, for this reason using a VGA cable instead is not an option. Note that the report explicitly says that the TV supports 1280x720. Still, I am not allowed to select it in Graphics Options, only 1280x600 and 800x600 is available. For 800x600, there's a lot of black around the edges; for 1280x600, the screen is "zoomed" so the edges of the monitor image (like the taskbar) is not visible. Other: The computer is running Windows XP. More recent versions of Windows are not an option (I have no licence). Linux is probably not an option (some of the video streaming sites I plan to use do not support it, I think) I wrote the rest of the details below. Thanks for any help!! TV: Panasonic TX-L32X10Y, European version; a 720p 32" quite "regular" LCD TV. Allowed resolutions according to manual: Signal name: 640x480 @60HZ Horizontal frequency: 31.47 kHz Vertical frequency: 60Hz Signal name: 750/720) /60p Horizontal frequency: 45.00 kHz Vertical frequency: 60Hz Signal name: 1,125 (1,080) / 60p Horizontal frequency: 67.50 kHz Vertical frequency: 60Hz (this is exactly how the manual presents it. PC via D-SUB (VGA cable) and "regular" HDMI have more alternatives.) Messing with the "zoom" settings on the TV does not affect the available resolution options on the computer. Computer: The following is a printout from one of the graphics adapter option pages. I think it covers most of it. The computer is a Dell. INTEL(R) EXTREME GRAPHICS 2 REPORT Report Date: 04/17/2011 Report Time[hr:mm:ss]: 20:18:02 Driver Version: 6.14.10.4396 Operating System: Windows XP* Professional, Service Pack 3 (5.1.2600) Default Language: English DirectX* Version: 9.0 Physical Memory: 1021 MB Minimum Graphics Memory: 1 MB Maximum Graphics Memory: 96 MB Graphics Memory in Use: 6 MB Processor: x86 Processor Speed: 2593 MHZ Vendor ID: 8086 Device ID: 2572 Device Revision: 02 * Accelerator Information * Accelerator in Use: Intel(R) 82865G Graphics Controller Video BIOS: 2972 Current Graphics Mode: 1280 by 600 True Color (60 Hz) * Devices Connected to the Graphics Accelerator * Active Digital Displays: 1 * Digital Display * Monitor Name: Plug and Play Monitor Display Type: Digital Gamma Value: 2.20 DDC2 Protocol: Supported Maximum Image Size: Horizontal: Not Available Vertical: Not Available Monitor Supported Modes: 1280 by 720 (50 Hz) 1280 by 720 (60 Hz) Display Power Management Support: Standby Mode: Not Supported Suspend Mode: Not Supported Active Off Mode: Not Supported (disclaimer: this question was also asked at the Wikipedia Reference Desk some time ago and might show up in a Google search. I got no useful answers there.)

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  • 12.04.1 desktop monitor "Out of Range"

    - by Zach
    I know this question has been asked many-a-times, but I cant seem to get a definite answer to it. I am running 12.04.1 on my HP Pavillion a6 109n PC. Processor is a AMD Athlon 64 x2 Dual core Processor. Every time I boot up my desktop, it runs BIOS, then it boots up Linux. After about 10 seconds, a little blue screen comes up saying: Out of Range: H. Frequency: 92.7KHz V. Frequency: 58.3Hz Can anyone help with this?

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  • Technically speaking, what is different about Ubuntu compared to other Linux distributions?

    - by Ross
    This is a question that's puzzled me for quite a while (and refers to the differences between all distributions). In my mind, a distribution is: a pre-configured OS, with some pre-installed packages, some created by the distribution's community that are unique to that distribution (e.g. apt-get). I'm not sure my definition is right as I feel there's something else. I'm really interested in setting up my own ArchLinux distro (which starts as a very minimal barebones system that you expand yourself) but feel I need to understand this first.

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  • technique for checking modifications in configuration file while starting up a program

    - by rajesh
    I'm writing a software for periodically checking a specific range of networked devices' reach-ability. I'm specifying the address range and the time frequency for checking their reachability, in an xml file. Which technique can I use to check that xml file during the start up of the program for any modifications done in either the range or the frequency and do the necessary update in specific database?

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