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• Delphi: Error when starting MCI

  - by marco92w

  I use the TMediaPlayer component for playing music. It works fine with most of my tracks. But it doesn't work with some tracks. When I want to play them, the following error message is shown: Which is German but roughly means that: In the project pMusicPlayer.exe an exception of the class EMCIDeviceError occurred. Message: "Error when starting MCI.". Process was stopped. Continue with "Single Command/Statement" or "Start". The program quits directly after calling the procedure "Play" of TMediaPlayer. This error occurred with the following file for example: file size: 7.40 MB duration: 4:02 minutes bitrate: 256 kBit/s I've encoded this file with a bitrate of 128 kBit/s and thus a file size of 3.70 MB: It works fine! What's wrong with the first file? Windows Media Player or other programs can play it without any problems. Is it possible that Delphi's TMediaPlayer cannot handle big files (e.g. 5 MB) or files with a high bitrate (e.g. 128 kBit/s)? What can I do to solve the problem?

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• ArrayList<Int> Collections.Sort and LineNumberReader Help How to

  - by user1819551

  I have a issue i can't get it to work now let going to the point a explain in the code thanks. This is my class: what I want to do is insert the Integers sort the list and buffer writer in a column with out coma. Now I getting this: [1110018, 1110032, 1110056, 1110059, 1110063, 1110085, 1110096, 1110123, 1110125, 1110185, 1110456, 1110459] I want like this: 111xxxxx 111xxxx xxxx....... I can't do it in single array, have to be in ArrayList. This is my collecting: list.addNumbers(numbers); list.display(); This is my writer: Is buffered coma.write("\n"+list.display()); coma.flush();<br/> Here is my class: public class IdCount {<br/> private ArrayList<Integer> properNumber = new ArrayList<>(); public void addNumbers(Integer numbers) { properNumber.add(numbers); Collections.sort(properNumber); } public String display() { //(I try .toString() Not work) return properNumber.toString(); } My second issue is LineNumberReader: This is my collecting and my writing: try { Reader input = new BufferedReader( new FileReader(inputFile)); try (Scanner in = new Scanner(input)) { while (in.hasNext()) { //(More Code) asp = new LineNumberReader(input); int rom = 0; while (asp.readLine()!=null){ rom++; } System.out.println(rom); coma.write(rom); This one will not write anything an my System Print give me only 12 0 in column.

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• R : remove columns from dataframe where ALL values are NA

  - by Sophomore

  hello everybody! I'm having some trouble with my huge data frame and couldn't really resolve that question myself: The dataframe has some properties as columns and each row represents one data set. I've done some sanatizing to this dataframe (e.g. get rid of datasets which are not to be included in evaluation). (Whoever might be interested: Beforehand I aggregate around 5000 single text files and put them in a tsv, some of the proerties have a sequence number like "button.pressed.1" ... ""button.pressed.n". Some of the sets excluded had really high numbers for n but got excluded, all sets left have much smaller numbers for n but the property "button.presed.50" is still there and all remaining sets have an NA in that column. Actually its a different property but the example should clarify my intention...) So the question is quite simple (for some sophisticated R pro): I need to get rid of columns where for ALL rows the value is NA. Could someone please help me out? (All I have managed to get rid of columns where at least one NA exists which dropped about half my columns)...

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• Does Android AsyncTaskQueue or similar exist?

  - by Ben L.

  I read somewhere (and have observed) that starting threads is slow. I always assumed that AsyncTask created and reused a single thread because it required being started inside the UI thread. The following (anonymized) code is called from a ListAdapter's getView method to load images asynchronously. It works well until the user moves the list quickly, and then it becomes "janky". final File imageFile = new File(getCacheDir().getPath() + "/img/" + p.image); image.setVisibility(View.GONE); view.findViewById(R.id.imageLoading).setVisibility(View.VISIBLE); (new AsyncTask<Void, Void, Bitmap>() { @Override protected Bitmap doInBackground(Void... params) { try { Bitmap image; if (!imageFile.exists() || imageFile.length() == 0) { image = BitmapFactory.decodeStream(new URL( "http://example.com/images/" + p.image).openStream()); image.compress(Bitmap.CompressFormat.JPEG, 85, new FileOutputStream(imageFile)); image.recycle(); } image = BitmapFactory.decodeFile(imageFile.getPath(), bitmapOptions); return image; } catch (MalformedURLException ex) { // TODO Auto-generated catch block ex.printStackTrace(); return null; } catch (IOException ex) { // TODO Auto-generated catch block ex.printStackTrace(); return null; } } @Override protected void onPostExecute(Bitmap image) { if (view.getTag() != p) // The view was recycled. return; view.findViewById(R.id.imageLoading).setVisibility( View.GONE); view.findViewById(R.id.image) .setVisibility(View.VISIBLE); ((ImageView) view.findViewById(R.id.image)) .setImageBitmap(image); } }).execute(); I'm thinking that a queue-based method would work better, but I'm wondering if there is one or if I should attempt to create my own implementation.

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• how to split a very large database on sql server

  - by ken jackson

  I have a 90 GB SQL Server database that I want to make more manageable. It stores stock data from 50+ different stocks from 2009 and 2010, and each stock is a separate table. Some tables have hundreds of millions of rows, and other have just a few million. What I want to do is somehow split the database, so that I don't have a single database file that is 90 GB. What I want is to be able to somehow magically split all the tables so that I can backup the 2009 data once and not have to keep on including it in the backup every time I backup the entire database, however, I would like the 2009 data to be included whenever I do a query. Is partitioning the database the way to go? Will it do the above for me, or will I need some other solution? I research partitioning, but I wasn't sure if that would solve all my problems. I wasn't able to find anything that would tell me whether or not it would migrate prexisting data, or whether it only worked for newly inserted data. Any help or pointers would be much appreciated. Thanks in advance, Ken

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• "Android Create" call fails in windows 7 - missing JDK

  - by reuscam

  I'm having a problem getting my android dev environment setup in Windows 7. I follow the instructions here, as well as several environment sublinks. I am using Eclipse with the Android plugin. I have installed the Java JDK several times, in various locations (jdk-6u20-windows-i586.exe) - but I am obviously missing something. Every time I run "android create avd --target 2 --name my_avd" I get an error: C:\Users\andrew>android create avd --target 2 --name my_avd WARNING: Java not found in your path. Checking it it's installed in C:\Program Files\Java instead. ERROR: No suitable Java found. In order to properly use the Android Developer Tools, you need a suitable version of Java installed on your system. We recommend that you install the JDK version of JavaSE, available here: http://java.sun.com/javase/downloads/ You can find the complete Android SDK requirements here: http://developer.android.com/sdk/requirements.html This error message is the reason for me installing the JDK several times over. First I tried installing to a location on my e: drive. I then moved it to the default loc (program files (x86)\java\jdk.6.something. I also tried forcing it to go into the program files\ path, but it still automatically installs into the (x86) path. I have added the install path to my path environment variable every single time, yet I still continue to get this error. My suspicion is that windows 7 and the android tools are not playing together well in terms of finding the JDK, but who knows, it may be something entirely different. If you have seen this error before, I would appreciate a hint.

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• confused about how to use JSON in C#

  - by Josh

  The answer to just about every single question about using C# with json seems to be "use JSON.NET" but that's not the answer I'm looking for. the reason I say that is, from everything I've been able to read in the documentation, JSON.NET is basically just a better performing version of the DataContractSerializer built into the .net framework... Which means if I want to deserialize a JSON string, I have to define the full, strongly-typed class for EVERY request I might have. so if I have a need to get categories, posts, authors, tags, etc, I have to define a new class for every one of these things. This is fine if I built the client and know exactly what the fields are, but I'm using someone else's api, so I have no idea what the contract is unless I download a sample response string and create the class manually from the JSON string. Is that the only way it's done? Is there not a way to have it create a kind of hashtable that can be read with json["propertyname"]? Finally, if I do have to build the classes myself, what happens when the API changes and they don't tell me (as twitter seems to be notorious for doing)? I'm guessing my entire project will break until I go in and update the object properties... So what exactly is the general workflow when working with JSON? And by general I mean library-agnostic. I want to know how it's done in general, not specifically to a target library... I hope that made sense, this has been a very confusing area to get into... thanks!

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• Hierarchical/Nested Database Structure for Comments

  - by Stephen Melrose

  Hi, I'm trying to figure out the best approach for a database schema for comments. The problem I'm having is that the comments system will need to allow nested/hierarchical comments, and I'm not sure how to design this out properly. My requirements are, Comments can be made on comments, so I need to store the tree hierarchy I need to be able to query the comments in the tree hierarchy order, but efficiently, preferably in a fast single query, but I don't know if this is possible I'd need to make some wierd queries, e.g. pull out the latest 5 root comments, and a maximum of 3 children for each one of those I read an article on the MySQL website on this very subject, http://dev.mysql.com/tech-resources/articles/hierarchical-data.html The "Nested Set Model" in theory sounds like it will do what I need, except I'm worried about querying the thing, and also inserting. If this is the right approach, How would I do my 3rd requirement above? If I have 2000 comments, and I add a new sub-comment on the first comment, that will be a LOT of updating to do. This doesn't seem right to me? Or is there a better approach for the type of data I'm wanting to store and query? Thank you

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• Counting string length in javascript and Ruby on Rails

  - by williamjones

  I've got a text area on a web site that should be limited in length. I'm allowing users to enter 255 characters, and am enforcing that limit with a Rails validation: validates_length_of :body, :maximum => 255 At the same time, I added a javascript char counter like you see on Twitter, to give feedback to the user on how many characters he has already used, and to disable the submit button when over length, and am getting that length in Javascript with a call like this: element.length Lastly, to enforce data integrity, in my Postgres database, I have created this field as a varchar(255) as a last line of defense. Unfortunately, these methods of counting characters do not appear to be directly compatible. Javascript counts the best, in that it counts what users consider as number of characters where everything is a single character. Once the submission hits Rails, however, all of the carriage returns have been converted to \r\n, now taking up 2 characters worth of space, which makes a close call fail Rails validations. Even if I were to handcode a different length validation in Rails, it would still fail when it hits the database I think, though I haven't confirmed this yet. What's the best way for me to make all this work the way the user would want? Best Solution: an approach that would enable me to meet user expectations, where each character of any type is only one character. If this means increasing the length of the varchar database field, a user should not be able to sneakily send a hand-crafted post that creates a row with more than 255 letters. Somewhat Acceptable Solution: a javascript change that enables the user to see the real character count, such that hitting return increments the counter 2 characters at a time, while properly handling all symbols that might have these strange behaviors.

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• C++: select argmax over vector of classes w.r.t. arbitrary expression

  - by karpathy

  Hello, I have trouble describing my problem so I'll give an example: I have a class description that has a couple of variables in it, for example: class A{ float a, b, c, d; } Now, I maintain a vector<A> that contains many of these classes. What I need to do very very often is to find the object inside this vector that satisfies that one of it's parameters is maximal w.r.t to the others. i.e code looks something like: int maxi=-1; float maxa=-1000; for(int i=0;i<vec.size();i++){ res= vec[i].a; if(res > maxa) { maxa= res; maxi=i; } } return vec[maxi]; However, sometimes I need to find class with maximal a, sometimes with maximal b, sometimes the class with maximal 0.8*a + 0.2*b, sometimes I want a maximal a*VAR + b, where VAR is some variable that is assigned in front, etc. In other words, I need to evaluate an expression for every class, and take the max. I find myself copy-pasting this everywhere, and only changing the single line that defines res. What makes it even more complicated is that even the name of the vector changes. Sometimes it's vec, sometimes it can be something else. I have many vectors that contain A's. This could be changed if this makes the problem too hard. Is there some nice way to avoid this insanity in C++? What's the neatest way to handle this? Thank you!

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• Oracle DBMS_PROFILER only shows Anonymous in the results tables

  - by Greg Reynolds

  I am new to DBMS_PROFILER. All the examples I have seen use a simple top-level procedure to demonstrate the use of the profiler, and from there get all the line numbers etc. I deploy all code in packages, and I am having great difficulty getting my profile session to populate the plsql_profiler_units with useful data. Most of my runs look like this: RUNID RUN_COMMENT UNIT_OWNER UNIT_NAME SECS PERCEN ----- ----------- ----------- -------------- ------- ------ 5 Test <anonymous> <anonymous> .00 2.1 Profiler 5 Test <anonymous> <anonymous> .00 2.1 Profiler 5 Test <anonymous> <anonymous> .00 2.1 Profiler I have just embedded the calls to the dbms_profiler.start_profiler, flush_data and stop_profiler as per all the examples. The main difference is that my code is in a package, and calls in to other package. Do you have to profile every single stored procedure in your call stack? If so that makes this tool a little useless! I have checked http://www.dba-oracle.com/t_plsql_dbms_profiler.htm for hints, among other similar sites.

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• Access 2007 and Special/Unicode Characters in SQL

  - by blockcipher

  I have a small Access 2007 database that I need to be able to import data from an existing spreadsheet and put it into our new relational model. For the most part this seems to work pretty well. Part of the process is attempting to see if a record already exists in a target table using SQL. For example, if I extract book information out of the current row in the spreadsheet, it may contain a title and abstract. I use SQL to get the ID of a matching record, if it exists. This works fine except when I have data that's in a non-English language. In this case, it seems that there is some punctuation that is causing me problems. At least I think it's punctuation as I do have some fields that do not have punctuation and are non-English that do not give me any problems. Is there a built-in function that can escape these characters? Currently I have a small function that will escape the single quote character, but that isn't enough. Or, is there a list of Unicode characters that can interfere with how SQL wants data quoted? Thanks in advance.

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• Python raw strings and trailing back slashes.

  - by dash-tom-bang

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

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• Looking for all-in-one drm/installer/CD creation kit.

  - by user30997

  The company I work for has a download manager in place that handles distribution, DRM, installation of our products - when a user gets them off our website. However, we're using an clunky system for packaging and protecting our products when we do press releases or make retail CDs. Part of the antiquation problem is the fact that the automated system that works with the installer- and DRM-creation software we have is a disaster that needs to be put out of my misery. The list of products that we currently produce, that I would like a new system MUST be capable of producing: Retail CDs, with a certain level of obfuscation to make copying difficult. Downloadable installers that time out after a few hours of use of the product. After the time has expired, removing and reinstalling the product will leave you still blocked from use. Installers that will fail to work after a certain date. I'd love to be able to just feed a tool the directory where a complete product resides and have the installer generated with a couple command-line operations. (The command-line issue is non-negotiable this well be called by an automated tool.) A single-solution package would be far preferable. Software with royalty-based or per-unit based licensing is not an option.

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• Query to MySQL from c# returns System.Byte[]

  - by karthik

  I am using the below SP to return the value of Generated Insert statement and it works fine when executed in Query browser. When i try to get the value from C#, it give's me "System.Byte[]" as return value. When i try to get the value from MySql query browser, it give's me return value as : 'insert into admindb.accounts values("54321","2","karthik2","karthik2","1");' I guess the problem is with the single quotes of the returned value. Is it so ? DELIMITER $$ DROP PROCEDURE IF EXISTS `admindb`.`InsGen` $$ CREATE DEFINER=`root`@`localhost` PROCEDURE `InsGen`( in_db varchar(20), in_table varchar(20), in_ColumnName varchar(20), in_ColumnValue varchar(20) ) BEGIN declare Whrs varchar(500); declare Sels varchar(500); declare Inserts varchar(2000); declare tablename varchar(20); declare ColName varchar(20); set tablename=in_table; # Comma separated column names - used for Select select group_concat(concat('concat(\'"\',','ifnull(',column_name,','''')',',\'"\')')) INTO @Sels from information_schema.columns where table_schema=in_db and table_name=tablename; # Comma separated column names - used for Group By select group_concat('`',column_name,'`') INTO @Whrs from information_schema.columns where table_schema=in_db and table_name=tablename; #Main Select Statement for fetching comma separated table values set @Inserts=concat("select concat('insert into ", in_db,".",tablename," values(',concat_ws(',',",@Sels,"),');') as MyColumn from ", in_db,".",tablename, " where ", in_ColumnName, " = " , in_ColumnValue, " group by ",@Whrs, ";"); PREPARE Inserts FROM @Inserts; EXECUTE Inserts; END $$ DELIMITER ;

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• Trying to find a PHP5 API-based embeddable CMS

  - by StrangeElement

  I've been making the rounds for a CMS that I can use as an API, in a sort of "embedded" mode. I mean by this that I don't want the CMS to do any logic or presentation. I want it to be used as an API, which I can then use within an existing site. I don't want to be tied to the architecture of the CMS. A good example of this is NC-CMS (http://www.nconsulting.ca/nc-cms/). All it needs is an include at the top, then wherever editable content is desired it's only a function call with a unique label. It's also perfect in the sense that it allows to differentiate between small strings (like titles, labels) and texts (which require a rich-text editor). It's the only CMS I found that fits this description, but it is a little too light as it does not handle site structure. I need to be able to allow my client to add pages, choosing an existing template for the layout. A minimal back-end is required. Wordpress also fits some requirements in that it handles only content editing and allows freedom for the themes by letting them call the content where and how they want it. But it is article-based and backwards, in that it embeds sites (as themes) within its structure, rather than being embeddable in sites like NC. It's funny how checking out all the CMS out there, almost all of them claim that most CMS are not self-sufficient, that they do not handle application logic, while (almost) every single on I found with only one exception do so. Many are mostly article-based blog engines, which does not fit my need. I would appreciate any CMS that fits the general description.

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• Creating a json array and json items with jquery?

  - by user246114

  Hi, I made a simple javascript class like this: function Horse() { this.color = 'brown'; this.speed = 'somewhat slow'; } I attached a few instances to some elements, like this: $("#horse1").data('d', new Horse()); $("#horse2").data('d', new Horse()); $("#horse3").data('d', new Horse()); now I want to create a JSON array with a JSON representation of each horse object. So I'm doing this: // How do I create an empty JSON array here?: var myJsonArray = ?; var children = $("#horses").children(); for (var i = 0, m = children.size(); i < m; i++) { var panel = children[i]; var horse = $(panel).data('h'); // And how do I create a JSON rep of my horse here? var myJsonHorse = new JsonHorse(?); // Finally, how do I add it to the json array? myJsonArray.push(myJsonHorse); } yeah my end goal is to have a single json array of all the horses after iterating over all the children - not sure if this should be done in plain javascript or in jquery? Thanks

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• Divide and conquer of large objects for GC performance

  - by Aperion

  At my work we're discussing different approaches to cleaning up a large amount of managed ~50-100MB memory.There are two approaches on the table (read: two senior devs can't agree) and not having the experience the rest of the team is unsure of what approach is more desirable, performance or maintainability. The data being collected is many small items, ~30000 which in turn contains other items, all objects are managed. There is a lot of references between these objects including event handlers but not to outside objects. We'll call this large group of objects and references as a single entity called a blob. Approach #1: Make sure all references to objects in the blob are severed and let the GC handle the blob and all the connections. Approach #2: Implement IDisposable on these objects then call dispose on these objects and set references to Nothing and remove handlers. The theory behind the second approach is since the large longer lived objects take longer to cleanup in the GC. So, by cutting the large objects into smaller bite size morsels the garbage collector will processes them faster, thus a performance gain. So I think the basic question is this: Does breaking apart large groups of interconnected objects optimize data for garbage collection or is better to keep them together and rely on the garbage collection algorithms to processes the data for you? I feel this is a case of pre-optimization, but I do not know enough of the GC to know what does help or hinder it.

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• Is it possible to wrap an asynchronous event and its callback in a function that returns a boolean?

  - by Rob Flaherty

  I'm trying to write a simple test that creates an image element, checks the image attributes, and then returns true/false. The problem is that using the onload event makes the test asynchronous. On it own this isn't a problem (using a callback as I've done in the code below is easy), but what I can't figure out is how to encapsulate this into a single function that returns a boolean. I've tried various combinations of closures, recursion, and self-executing functions but have had no luck. So my question: am I being dense and overlooking something simple, or is this in fact not possible, because, no matter what, I'm still trying to wrap an asynchronous function in synchronous expectations? Here's the code: var supportsImage = function(callback) { var img = new Image(); img.onload = function() { //Check attributes and pass true or false to callback callback(true); }; img.src = 'data:image/gif;base64,R0lGODlhAQABAAD/ACwAAAAAAQABAAACADs='; }; supportsImage(function(status){ console.log(status); }); To be clear, what I want is to be able to wrap this in something such that it can be used like: if (supportsImage) { //Do some crazy stuff } Thanks! (Btw, I know there are a ton of SO questions regarding confusion about synchronous vs. asynchronous. Apologies if this can be reduced to something previously answered.)

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• How much effort do you have to put in to get gains from using SSE?

  - by John

  Case One Say you have a little class: class Point3D { private: float x,y,z; public: operator+=() ...etc }; Point3D &Point3D::operator+=(Point3D &other) { this->x += other.x; this->y += other.y; this->z += other.z; } A naive use of SSE would simply replace these function bodies with using a few intrinsics. But would we expect this to make much difference? MMX used to involve costly state cahnges IIRC, does SSE or are they just like other instructions? And even if there's no direct "use SSE" overhead, would moving the values into SSE registers and back out again really make it any faster? Case Two Instead, you're working with a less OO-based code base. Rather than an array/vector of Point3D objects, you simply have a big array of floats: float coordinateData[NUM_POINTS*3]; void add(int i,int j) //yes it's unsafe, no overlap check... example only { for (int x=0;x<3;++x) { coordinateData[i*3+x] += coordinateData[j*3+x]; } } What about use of SSE here? Any better? In conclusion Is trying to optimise single vector operations using SSE actually worthwhile, or is it really only valuable when doing bulk operations?

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• What can cause my code to run slower when the server JIT is activated?

  - by durandai

  I am doing some optimizations on an MPEG decoder. To ensure my optimizations aren't breaking anything I have a test suite that benchmarks the entire codebase (both optimized and original) as well as verifying that they both produce identical results (basically just feeding a couple of different streams through the decoder and crc32 the outputs). When using the "-server" option with the Sun 1.6.0_18, the test suite runs about 12% slower on the optimized version after warmup (in comparison to the default "-client" setting), while the original codebase gains a good boost running about twice as fast as in client mode. While at first this seemed to be simply a warmup issue to me, I added a loop to repeat the entire test suite multiple times. Then execution times become constant for each pass starting at the 3rd iteration of the test, still the optimized version stays 12% slower than in the client mode. I am also pretty sure its not a garbage collection issue, since the code involves absolutely no object allocations after startup. The code consists mainly of some bit manipulation operations (stream decoding) and lots of basic floating math (generating PCM audio). The only JDK classes involved are ByteArrayInputStream (feeds the stream to the test and excluding disk IO from the tests) and CRC32 (to verify the result). I also observed the same behaviour with Sun JDK 1.7.0_b98 (only that ist 15% instead of 12% there). Oh, and the tests were all done on the same machine (single core) with no other applications running (WinXP). While there is some inevitable variation on the measured execution times (using System.nanoTime btw), the variation between different test runs with the same settings never exceeded 2%, usually less than 1% (after warmup), so I conclude the effect is real and not purely induced by the measuring mechanism/machine. Are there any known coding patterns that perform worse on the server JIT? Failing that, what options are available to "peek" under the hood and observe what the JIT is doing there?

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• R: manipulating data.frames containing strings and booleans.

  - by Mike Dewar

  Hello. I have a data.frame in R; it's called p. Each element in the data.frame is either True or False. My variable p has, say, m rows and n columns. For every row there is strictly only one TRUE element. It also has column names, which are strings. What I would like to do is the following: For every row in p I see a TRUE I would like to replace with the name of the corresponding column I would then like to collapse the data.frame, which now contains FALSEs and column names, to a single vector, which will have m elements. I would like to do this in an R-thonic manner, so as to continue my enlightenment in R and contribute to a world without for-loops. I can do step 1 using the following for loop: for (i in seq(length(colnames(p)))) { p[p[,i]==TRUE,i]=colnames(p)[i] } but theres's no beauty here and I have totally subscribed to this for-loops-in-R-are-probably-wrong mentality. Maybe wrong is too strong but they're certainly not great. I don't really know how to do step 2. I kind of hoped that the sum of a string and FALSE would return the string but it doesn't. I kind of hoped I could use an OR operator of some kind but can't quite figure that out (Python responds to False or 'bob' with 'bob'). Hence, yet again, I appeal to you beautiful Rstats people for help!

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• Special characters stripped by mySQL/PHP JSON

  - by Will Gill

  Hi, I have a simple PHP script to extract data from a mySQL database and encode it as JSON. The problem is that special characters (for example German ä or ß characters) are stripped from the JSON response. Everything after the first special character for any single field is just stripped. The fields are set to utf8_bin, and in phpMyAdmin the characters display correctly. The PHP script looks like this: <?php header("Content-type: application/json; charset=utf-8"); $con = mysql_connect('database', 'username', 'password'); if (!$con) { die('Could not connect: ' . mysql_error()); } mysql_select_db("sql01_5789willgil", $con); $sql="SELECT * FROM weightevent"; $result = mysql_query($sql); $row = mysql_fetch_array($result); $events = array(); while($row = mysql_fetch_array($result)) { $eventid = $row['eventid']; $userid = $row['userid']; $weight = $row['weight']; $sins = $row['sins']; $gooddeeds = $row['gooddeeds']; $date = $row['date']; $event = array("eventid"=>$eventid, "userid"=>$userid, "weight"=>$weight, "sins"=>$sins, "gooddeeds"=>$gooddeeds, "date"=>$date); array_push($events, $event); } $myJSON = json_encode($events); echo $myJSON; mysql_close($con); ?> Sample output: [{"eventid":"2","userid":"1","weight":"70.1","sins":"Weihnachtspl","gooddeeds":"situps! lots and lots of situps!","date":"2011-01-02"},{"eventid":"3","userid":"2","weight":"69.9","sins":"A second helping of pasta...","gooddeeds":"I ate lots of salad","date":"2011-01-01"}] -- in the first record the value for field 'sins' should be "Weihnachtsplätzchen". thanks very much!

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• Design for a Debate club assignment application

  - by Amir Rachum

  Hi all, For my university's debate club, I was asked to create an application to assign debate sessions and I'm having some difficulties as to come up with a good design for it. I will do it in Java. Here's what's needed: What you need to know about BP debates: There are four teams of 2 debaters each and a judge. The four groups are assigned a specific position: gov1, gov2, op1, op2. There is no significance to the order within a team. The goal of the application is to get as input the debaters who are present (for example, if there are 20 people, we will hold 2 debates) and assign them to teams and roles with regards to the history of each debater so that: Each debater should debate with (be on the same team) as many people as possible. Each debater should uniformly debate in different positions. The debate should be fair - debaters have different levels of experience and this should be as even as possible - i.e., there shouldn't be a team of two very experienced debaters and a team of junior debaters. There should be an option for the user to restrict the assignment in various ways, such as: Specifying that two people should debate together, in a specific position or not. Specifying that a single debater should be in a specific position, regardless of the partner. etc... If anyone can try to give me some pointers for a design for this application, I'll be so thankful! Also, I've never implemented a GUI before, so I'd appreciate some pointers on that as well, but it's not the major issue right now.

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• Is there really such a thing as a char or short in modern programming?

  - by Dean P

  Howdy all, I've been learning to program for a Mac over the past few months (I have experience in other languages). Obviously that has meant learning the Objective C language and thus the plainer C it is predicated on. So I have stumbles on this quote, which refers to the C/C++ language in general, not just the Mac platform. With C and C++ prefer use of int over char and short. The main reason behind this is that C and C++ perform arithmetic operations and parameter passing at integer level, If you have an integer value that can fit in a byte, you should still consider using an int to hold the number. If you use a char, the compiler will first convert the values into integer, perform the operations and then convert back the result to char. So my question, is this the case in the Mac Desktop and IPhone OS environments? I understand when talking about theses environments we're actually talking about 3-4 different architectures (PPC, i386, Arm and the A4 Arm variant) so there may not be a single answer. Nevertheless does the general principle hold that in modern 32 bit / 64 bit systems using 1-2 byte variables that don't align with the machine's natural 4 byte words doesn't provide much of the efficiency we may expect. For instance, a plain old C-Array of 100,000 chars is smaller than the same 100,000 ints by a factor of four, but if during an enumeration, reading out each index involves a cast/boxing/unboxing of sorts, will we see overall lower 'performance' despite the saved memory overhead?

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