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• What to use to create bar, line and pie charts with javascript compatible with all major browsers?

  - by marcgg

  I used to work with flot but it doesn't support pie charts so I'm forced to change. I just saw JS Charts, but their documentation is very obscure regarding cross browser compatibility (I need it to be IE6+ compliant :). Also this will be for commercial use, so I'd rather have something that I can use free of charge jQuery Google chart looks really nice and is well integrated with rails (the framework I'm using) but I'm not sure how good it is. So what do you guys use? What would you recommend keeping in mind that: It will be for commercial use (I can deal with a license, but I'd rather avoid that) It needs to be javascript (no svg, no flash please) It needs to be compatible with IE6+, FF, Chrome, Opera and Safari It needs to be pretty ^^ If it uses jQuery it's even better

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• linux thread synchronization

  - by johnnycrash

  I am new to linux and linux threads. I have spent some time googling to try to understand the differences between all the functions available for thread synchronization. I still have some questions. I have found all of these different types of synchronizations, each with a number of functions for locking, unlocking, testing the lock, etc. gcc atomic operations futexes mutexes spinlocks seqlocks rculocks conditions semaphores My current (but probably flawed) understanding is this: semaphores are process wide, involve the filesystem (virtually I assume), and are probably the slowest. Futexes might be the base locking mechanism used by mutexes, spinlocks, seqlocks, and rculocks. Futexes might be faster than the locking mechanisms that are based on them. Spinlocks dont block and thus avoid context swtiches. However they avoid the context switch at the expense of consuming all the cycles on a CPU until the lock is released (spinning). They should only should be used on multi processor systems for obvious reasons. Never sleep in a spinlock. The seq lock just tells you when you finished your work if a writer changed the data the work was based on. You have to go back and repeat the work in this case. Atomic operations are the fastest synch call, and probably are used in all the above locking mechanisms. You do not want to use atomic operations on all the fields in your shared data. You want to use a lock (mutex, futex, spin, seq, rcu) or a single atomic opertation on a lock flag when you are accessing multiple data fields. My questions go like this: Am I right so far with my assumptions? Does anyone know the cpu cycle cost of the various options? I am adding parallelism to the app so we can get better wall time response at the expense of running fewer app instances per box. Performances is the utmost consideration. I don't want to consume cpu with context switching, spinning, or lots of extra cpu cycles to read and write shared memory. I am absolutely concerned with number of cpu cycles consumed. Which (if any) of the locks prevent interruption of a thread by the scheduler or interrupt...or am I just an idiot and all synchonization mechanisms do this. What kinds of interruption are prevented? Can I block all threads or threads just on the locking thread's CPU? This question stems from my fear of interrupting a thread holding a lock for a very commonly used function. I expect that the scheduler might schedule any number of other workers who will likely run into this function and then block because it was locked. A lot of context switching would be wasted until the thread with the lock gets rescheduled and finishes. I can re-write this function to minimize lock time, but still it is so commonly called I would like to use a lock that prevents interruption...across all processors. I am writing user code...so I get software interrupts, not hardware ones...right? I should stay away from any functions (spin/seq locks) that have the word "irq" in them. Which locks are for writing kernel or driver code and which are meant for user mode? Does anyone think using an atomic operation to have multiple threads move through a linked list is nuts? I am thinking to atomicly change the current item pointer to the next item in the list. If the attempt works, then the thread can safely use the data the current item pointed to before it was moved. Other threads would now be moved along the list. futexes? Any reason to use them instead of mutexes? Is there a better way than using a condition to sleep a thread when there is no work? When using gcc atomic ops, specifically the test_and_set, can I get a performance increase by doing a non atomic test first and then using test_and_set to confirm? *I know this will be case specific, so here is the case. There is a large collection of work items, say thousands. Each work item has a flag that is initialized to 0. When a thread has exclusive access to the work item, the flag will be one. There will be lots of worker threads. Any time a thread is looking for work, they can non atomicly test for 1. If they read a 1, we know for certain that the work is unavailable. If they read a zero, they need to perform the atomic test_and_set to confirm. So if the atomic test_and_set is 500 cpu cycles because it is disabling pipelining, causes cpu's to communicate and L2 caches to flush/fill .... and a simple test is 1 cycle .... then as long as I had a better ratio of 500 to 1 when it came to stumbling upon already completed work items....this would be a win.* I hope to use mutexes or spinlocks to sparilngly protect sections of code that I want only one thread on the SYSTEM (not jsut the CPU) to access at a time. I hope to sparingly use gcc atomic ops to select work and minimize use of mutexes and spinlocks. For instance: a flag in a work item can be checked to see if a thread has worked it (0=no, 1=yes or in progress). A simple test_and_set tells the thread if it has work or needs to move on. I hope to use conditions to wake up threads when there is work. Thanks!

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• jQuery style Constructors in PHP

  - by McB

  Is there a way to instantiate a new PHP object in a similar manner to those in jQuery? I'm talking about assigning a variable number of arguments when creating the object. For example, I know I could do something like: ... //in my Class __contruct($name, $height, $eye_colour, $car, $password) { ... } $p1 = new person("bob", "5'9", "Blue", "toyota", "password"); But I'd like to set only some of them maybe. So something like: $p1 = new person({ name: "bob", eyes: "blue"}); Which is more along the lines of how it is done in jQuery and other frameworks. Is this built in to PHP? Is there a way to do it? Or a reason I should avoid it?

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• Optimize code perfromance when odd/even threads are doing different things in CUDA

  - by Ashraf

  Hi all! I have two large vectors, I am trying to do some sort of element multiplication, where an even-numbered element in the first vector is multiplied by the next odd-numbered element in the second vector .... and where the odd-numbered element in the first vector is multiplied by the preceding even-numbered element in the second vector Ex. vector 1 is V1(1) V1(2) V1(3) V1(4) vector 2 is V2(1) V2(2) V2(3) V2(4) V1(1) * V2(2) V1(3) * V2(4) V1(2) * V2(1) V1(4) * V2(3) I have written a Cuda code to do this: (Pds has the elements of the first vector in shared memory, Nds the second Vector) //instead of using %2 .. i check for the first bit to decide if number is odd/even -- faster if ((tx & 0x0001) == 0x0000) Nds[tx+1] = Pds[tx] * Nds[tx+1]; else Nds[tx-1] = Pds[tx] * Nds[tx-1]; __syncthreads(); Is there anyway to further accelerate this code or avoid divergence .. Thanks

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• NDIS or TDI for packet redirection to a local proxy

  - by Enrico Detoma

  I need to develop a transparent filter to redirect outgoing HTTP packets to a local proxy, to do transparent content filtering. Which is the best technology to do it, TDI or NDIS IM? My main constraint is to avoid conflicts with antivirus software, which also do some kind of packet redirection to inspect HTTP content (I don't know whether antivirus programs use TDI, NDIS IM, or both). Rather than writing the driver myself, actually, I'm also considering two commercial SDKs for packet filtering/modification: one uses a TDI driver while the other uses a NDIS IM driver, so that's the origin of my question (I was only aware of NDIS IM, before looking at the two SDKs).

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• Opposite of Bloom filter?

  - by abc

  Hi, I'm trying to optimize a piece of software which is basically running millions of tests. These tests are generated in such a way that there can be some repetitions. Of course, I don't want to spend time running tests which I already ran if I can avoid it efficiently. So, I'm thinking about using a Bloom filter to store the tests which have been already ran. However, the Bloom filter errs on the unsafe side for me. It gives false positives. That is, it may report that I've ran a test which I haven't. Although this could be acceptable in the scenario I'm working on, I was wondering if there's an equivalent to a Bloom filter, but erring on the opposite side, that is, only giving false negatives. I've skimmed through the literature without any luck.

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• Alternatives to javascript function-based iteration (e.g. jQuery.each())

  - by Colin

  I've been watching Google Tech Talks' Speed Up Your Javascript and in talking about loops, the speaker mentions to stay away from function-based iterations such as jQuery.each() (among others, at about 24:05 in the video). He briefly explains why to avoid them which makes sense, but admittedly I don't quite understand what an alternative would be. Say, in the case I want to iterate through a column of table cells and use the value to manipulate the adjacent cell's value (just a quick example). Can anyone explain and give an example of an alternative to function-based iteration?

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• Static Access To Multiple Instance Variable

  - by Qua

  I have a singleton instance that is referenced throughout the project which works like a charm. It saves me the trouble from having to pass around an instance of the object to every little class in the project. However, now I need to manage multiple instances of the previous setup, which means that the singleton pattern breaks since each instance would need it's own singleton instance. What options are there to still maintain static access to the singleton? To be more specific, we have our game engine and several components and plugins reference the engine through a static property. Now our server needs to host multiple game instances each having their own engine, which means that on the server side the singleton pattern breaks. I'm trying to avoid all the classes having the engine in the constructor.

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• Adding pdb files to VSS

  - by George

  Every time I try to compile my web app, I am prompted if i want to add pdb extensioned files to VSS. I thought pdb files do not belong in VSS see a previous post. Is there any way to prevent them from being added. I cannot even logically delete them from VSS because a previous version has been logically deleted and if I were to delete the current version, the previous version would have to be purged, for which I need vss admin rights that I do not have. I just can't get a handle on how to avoid getting a million files added to VSS that prevent otehr develoeprs from compiling their solutions because they have unchecked out read only copies. Is the only solution to check them in but flip the readonly flag off locally? This is not a good option in my mind.

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• T-SQL out of order insert

  - by tearman

  Basically I have a User-Defined Table Type (for use as a table-valued variable) which I'm referencing in a stored procedure that effectively just calls two other stored procedures, then inserts those values into the table type. Id est INSERT INTO @tableValuedVariable (var1, var2, var3, var4, var5) EXEC [dbo].StoredProcedure1; INSERT INTO @tableValuedVariable (var1, var2, var5) EXEC [dbo].StoredProcedure2; You can probably already tell what I'm going to ask. Basically StoredProcedure2 only returns a few of the values the table is set to hold, and I'd like those other variables to just be null (as defined as default). Only SQL is complaining that I'm not specifying all the variables available to that table. The return datasets can be quite sizable so I'd like to avoid loops and such for obvious reasons. Thanks for any help.

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• YII Mail Generate unwanted ascii character in HTML mail

  - by CedSha

  I use YII-Mail just by copying the sample but I always get some ascii charcters in my generated links Where they come from and how to avoid them ? $message = new YiiMailMessage; $message->view = 'mail'; $message->setBody(array('model'=>$model), 'text/html'); $message->subject = Yii::t('tr','my subject'); $message->addTo('[email protected]'); $message->from = '[email protected]'; Yii::app()->mail->send($message); and in view file 'mail' <h1><?php echo(Yii::t('tr','This is HTML mail')); ?></h1> <?php echo CHtml::link('Mylink', array('controller/view', 'id'=>$model->id)); ?> The resulted email source looks like this <h1>This is HTML mail</h1> <a href=3D"/testdrive/index.php?r=3D ....

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• Python code formatting

  - by Curious2learn

  In response to another question of mine, someone suggested that I avoid long lines in the code and to use PEP-8 rules when writing Python code. One of the PEP-8 rules suggested avoiding lines which are longer than 80 characters. I changed a lot of my code to comply with this requirement without any problems. However, changing the following line in the manner shown below breaks the code. Any ideas why? Does it have to do with the fact that what follows return command has to be in a single line? The line longer that 80 characters: def __str__(self): return "Car Type \n"+"mpg: %.1f \n" % self.mpg + "hp: %.2f \n" %(self.hp) + "pc: %i \n" %self.pc + "unit cost: $%.2f \n" %(self.cost) + "price: $%.2f "%(self.price) The line changed by using Enter key and Spaces as necessary: def __str__(self): return "Car Type \n"+"mpg: %.1f \n" % self.mpg + "hp: %.2f \n" %(self.hp) + "pc: %i \n" %self.pc + "unit cost: $%.2f \n" %(self.cost) + "price: $%.2f "%(self.price)

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• Communication between Page and User Controls

  - by Narmatha Balasundaram

  I have a main page that has multiple user controls on it. All the user controls have static text and some data to be retrieved from the DB. The aysnchronous DB call is clubbed at the page level and one call is made to avoid multiple calls (in the different user controls) to get the same data. I want the page and user controls to load initially with the static text and later refresh the contents obtained from the server. To sum it all up, Page Loads = Asyn calls fired on page load = Data received back from the server (XML/text/whatever) = User controls to load with this data using AJAX. What methods do I have to let the user controls know that I have the data from the server and they need to update with this data?

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• Ivy: Publishing all artefacts in a directory

  - by Dave Flowers

  I'm looking to move to Apache Ivy for dependency management on one of our existing projects. The project publishes many artefacts, and the artefacts it produces are likely to change in the future, so I don't want to enumerate all of the publications in the ivy.xml file -- I'd like Ivy to just publish all the files in a given directory. I considered auto-generating a list of the files built and using XSLT to insert it into the ivy.xml, but that seems a little cumbersome for what I'd expect to be a reasonably common requirement. Is there a better way to do this? Can Ivy pick up all the files in a directory and ignore the publications in the Ivy file? Or is there some way to get Ivy to use different files for publication and for fetching, so I can avoid having to use XSLT to merge the files.

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• How to compile a program which needs a newer version of glib

  - by michael

  Hi, I am trying to compile Webkit on Ubuntu 8.04. But when i run autogen.sh, I get the following error saying it needs a newer version of glib. So what is the safest way to install glib without screwing up the rest of my OS (since the rest needs 2.16 while webkit compile needs 2.21)? checking for GLIB... configure: error: Package requirements (glib-2.0 >= 2.21.3 gobject-2.0 >= 2.0 gthread-2.0 >= 2.0) were not met: Requested 'glib-2.0 >= 2.21.3' but version of GLib is 2.16.6 Consider adjusting the PKG_CONFIG_PATH environment variable if you installed software in a non-standard prefix. Alternatively, you may set the environment variables GLIB_CFLAGS and GLIB_LIBS to avoid the need to call pkg-config. See the pkg-config man page for more details.

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• Optimize code performance when odd/even threads are doing different things in CUDA

  - by Orion Nebula

  Hi all! I have two large vectors, I am trying to do some sort of element multiplication, where an even-numbered element in the first vector is multiplied by the next odd-numbered element in the second vector .... and where the odd-numbered element in the first vector is multiplied by the preceding even-numbered element in the second vector Ex. vector 1 is V1(1) V1(2) V1(3) V1(4) vector 2 is V2(1) V2(2) V2(3) V2(4) V1(1) * V2(2) V1(3) * V2(4) V1(2) * V2(1) V1(4) * V2(3) I have written a Cuda code to do this: (Pds has the elements of the first vector in shared memory, Nds the second Vector) //instead of using %2 .. i check for the first bit to decide if number is odd/even -- faster if ((tx & 0x0001) == 0x0000) Nds[tx+1] = Pds[tx] * Nds[tx+1]; else Nds[tx-1] = Pds[tx] * Nds[tx-1]; __syncthreads(); Is there anyway to further accelerate this code or avoid divergence ? Thanks

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• It's possible to don't pass in GET some fields of a form?

  - by avastreg

  I have a form with some input texts passed in GET, and i don't want to have in GET all the fields; i want to avoid empty fields. So, a concrete example for: <form method="GET" action="an_url"> <input type="text" name="field1"/> <input type="text" name="field2"/> <input type="text" name="field3"/> <input type="submit" value="submit"/> </form> I supposed that fields disabled by html attribute "disabled" shouldn't be passed to GET. So i have done a js (based on jquery) to disable empty fields on submit, something like this: $("form").submit(function() { $(this).find("input[type=text]").each( function () { if (!$.trim($(this).val())) { $(this).attr("disabled", "true"); } }); }); However, this doesn't work. Any ideas?

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• In LaTeX prefer figures on text-heavy pages.

  - by bjarkef

  Hi LaTeX seems to have a preference for placing figures together on a page, and placing surrounding text on a separate page. Can I somehow change that balance a bit, as I prefer figures to break up the text to avoid too black text-heavy pages. Example: \section{Some section} [Half a page of text] \begin{figure} [...] \caption{Figure text 1} \end{figure} [Half a page of text] \begin{figure} [...] \caption{Figure text 2} \end{figure} [More text] So what LaTeX usually does is to stack the two half pages of text on a single page, and the figures on the following page. I believe this really gives a bad balance, and bores the reader. So can I change that somehow? I know about postfixing the \begin{figure} with [ht!], but often it does not really matter. I would like to configure the balancing algorithms in LaTeX to naturally prefer pages with combined figures and text.

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• Explanation for expires header

  - by sushil bharwani

  I have a joomla application working on Apache.To improve site performace we have written a .htaccess file to root of the application with setting a far future expires header to all the static content. As desired first time the files load in fresh with 200 status code. when again click on the same link many of the files are served directly from cache. I need explanation for two things When i press f5 then a number of files load with 304 status code however i expected them to be coming directly from cache without hitting the server for a status header? When i close the browser and come back to the same page again i see the same thing happening a number of files load with 304 status code although i thought they will load directly from the browser cache? I understand that 304 also servs file from browser cache but i want to avoid the header communication between servers as my static files wont ever change. Also i want to add that my requests are over a https connection does that create any issue.

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• Minimizing SQL queries using join with one-to-many relationship

  - by Brian

  So let me preface this by saying that I'm not an SQL wizard by any means. What I want to do is simple as a concept, but has presented me with a small challenge when trying to minimize the amount of database queries I'm performing. Let's say I have a table of departments. Within each department is a list of employees. What is the most efficient way of listing all the departments and which employees are in each department. So for example if I have a department table with: id name 1 sales 2 marketing And a people table with: id department_id name 1 1 Tom 2 1 Bill 3 2 Jessica 4 1 Rachel 5 2 John What is the best way list all departments and all employees for each department like so: Sales Tom Bill Rachel Marketing Jessica John Pretend both tables are actually massive. (I want to avoid getting a list of departments, and then looping through the result and doing an individual query for each department). Think similarly of selecting the statuses/comments in a Facebook-like system, when statuses and comments are stored in separate tables.

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• Correct way to detect sequence parameter?

  - by noamtm

  I want to write a function that accepts a parameter which can be either a sequence or a single value. The type of value is str, int, etc., but I don't want it to be restricted to a hardcoded list. In other words, I want to know if the parameter X is a sequence or something I have to convert to a sequence to avoid special-casing later. I could do type(X) in (list, tuple) but there may be other sequence types I'm not aware of, and no common base class. -N. Edit: See my "answer" below for why most of these answers don't help me. Maybe you have something better to suggest.

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• ASP.Net MVC elegant UI and ModelBinder authorization

  - by SDReyes

  We know authorization stuff is a cross cutting concern, and we do anything we could to avoid merge business logic in our views. But I still not found an elegant way to filter UI components (e.g. widgets, form elements, tables, etc) using the current user roles without contaminate the view with business logic. same applies for model binding. Example Form: Product Creation Fields: Name Price Discount Roles: Role Administrator Is allowed to see and modify the Name field Is allowed to see and modify the Price field Is allowed to see and modify the Discount Role Administrator assistant Is allowed to see and modify the Name Is allowed to see and modify the Price Fields shown in each role are different, and model binding needs to ignore the discount field for 'Administrator assistant' role. How would you do it?

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• Where does complexity bloat from?

  - by AareP

  Many of our design decisions are based on our gut feeling about how to avoid complexity and bloating. Some of our complexity-fears are true, we have plenty of painful experience on throwing away deprecated code. Other times we learn that some particular task isn't really that complex as we though it to be. We notice for example that upkeeping 3000 lines of code in one file isn't that difficult... or that using special purpose "dirty flags" isn't really bad OO practice... or that in some cases it's more convenient to have 50 variables in one class that have 5 different classes with shared responsibilities... One friend has even stated that adding functions to the program isn't really adding complexity to your system. So, what do you think, where does bloated complexity creep from? Is it variable count, function count, code line count, code line count per function, or something else?

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• Best Practice Guide: Swing

  - by wishi_

  Hi! Does anybody know Swing related GUI guidelines - specifically on how to design Swing apps and which components I should use? I'm not looking for an official standard, but pragmatic tips I can use to set a good standard for my projects. I haven't used too much of Swing by myself. Surely clicking a GUI with a GUI designer isn't a big deal. However I'd like to get some insights from people who have experience with Swing and know what to avoid. Swing lately (in Java 6- 10) got decent changes. So there isn't too much specific standardization out there currently.

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• explicit copy constructor or implicit parameter by value

  - by R Samuel Klatchko

  I recently read (and unfortunately forgot where), that the best way to write operator= is like this: foo &operator=(foo other) { swap(*this, other); return *this; } instead of this: foo &operator=(const foo &other) { foo copy(other); swap(*this, copy); return *this; } The idea is that if operator= is called with an rvalue, the first version can optimize away construction of a copy. So when called with a rvalue, the first version is faster and when called with an lvalue the two are equivalent. I'm curious as to what other people think about this? Would people avoid the first version because of lack of explicitness? Am I correct that the first version can be better and can never be worse?

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