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• ASP.NET retrieve Average CPU Usage

  - by Sam

  Last night I did a load test on a site. I found that one of my shared caches is a bottleneck. I'm using a ReaderWriterLockSlim to control the updates of the data. Unfortunately at one point there are ~200 requests trying to update the data at approximately the same time. This also coincided with CPU usage spikes. The data being updated is in the ASP.NET Cache. What I'd like to do is if the CPU usage is around 75%, I'd like to just skip the cache and hit the database on another machine. My problem is that I don't know how expensive it is to create a new performance counter to check the cpu usage. Also, if I would probably like the average cpu usage over the last 2 or 3 seconds. However, I can't sit there and calculate the cpu time as that would take longer than it's taking to update the cache currently. Is there an easy way to get the average CPU usage? Are there any drawbacks to this? I'm also considering totaling the wait count for the lock and then at a certain threshold switch over to the database. The concern I had with this approach would be that changing hardware might allow more locks with less of a strain on the system. And also finding the right balance for the threshold would be cumbersome and it doesn't take into account any other load on the machine. But it's a simple approach, and simple is 99% of the time better.

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• Can't Display Bitmap of Higher Resolution than CDC area

  - by T. Jones

  Hi there dear gurus and expert coders. i am not gonna start with im a newbie and don't know much about image programming but unfortunately those are the facts :( I am trying to display an image from a bitmap pointer *ImageData which is of resolution 1392x1032. I am trying to draw that at an area of resolution or size 627x474. However, repeated trying doesnt seem to work. It works when I change the bitmap image I created from *ImageData width and height to resolution or size of around 627x474 I really do not know how to solve this after trying all possible solutions from various forums and google. pDC is a CDC* and memDC is a CDC initialized in an earlier method Anything uninitialized here was initialized in other methods. Here is my code dear humble gurus. Do provide me with guidance Yoda and Obi-Wan provided to Luke Skywalker. void DemoControl::ShowImage( void *ImageData ) { int Width; //Width of Image From Camera int Height; //Height of Image From Camera int m_DisplayWidth = 627 ;//width of rectangle area to display int m_DisplayHeight = 474;//height of rectangle area to display GetImageSize( &Width, &Height ) ; //this will return Width = 1392, Height 1032 CBitmap bitmap; bitmap.CreateBitmap(Width,Height,32,1,ImageData); CBitmap* pOldBitmap = memDC.SelectObject((CBitmap*)&bitmap); pDC->BitBlt(22, 24, 627, 474, &memDC, 0, 0, SRCCOPY); memDC.SelectObject((CBitmap*)pOldBitmap); ReleaseDC(pDC); }

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• How can I print text fields at the right coordinates?

  - by Milad

  I don't have any background in programming and this is my first shot. I wrote a Delphi program that is supposed to print on a result sheet. I work in an institute and we have to establish hundreds of result sheets every 2 months. It's really difficult to do that and different handwriting is also an important issue. I have this code: if PrintDialog.Execute() then begin with MyPrinter do begin MyPrinter.BeginDoc();//Start Printing //Prints First Name MyPrinter.Canvas.TextOut(FirstNameX,FirstNameY,EditFirstName.Text); //Prints Last Name MyPrinter.Canvas.TextOut(LastNameX,LastNameY,EditLastName.Text); //Prints Level MyPrinter.Canvas.TextOut(LevelX,LevelY,EditLevel.Text); //Prints Date MyPrinter.Canvas.TextOut(DateX,DateY,MEditDate.Text); //Prints Student Number MyPrinter.Canvas.TextOut(StdNumX,StdNumY,EditStdnumber.Text); .... MyPrinter.EndDoc();//End Printing end; end; I can't get the right coordinates to print properly. Am I missing something? How can I set the right coordinates? You know TPrinter uses pixels to get the coordinates but papers are measured in inches or centimeters. I'm really confused. I appreciate any help.

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• How can I SETF an element in a tree by an accessor?

  - by Willi Ballenthin

  We've been using Lisp in my AI course. The assignments I've received have involved searching and generating tree-like structures. For each assignment, I've ended up writing something like: (defun initial-state () (list 0 ; score nil ; children 0 ; value 0)) ; something else and building my functions around these "states", which are really just nested lists with some loosely defined structure. To make the structure more rigid, I've tried to write accessors, such as: (defun state-score ( state ) (nth 2 state)) This works for reading the value (which should be all I need to do in a nicely functional world. However, as time crunches, and I start to madly hack, sometimes I want a mutable structure). I don't seem to be able to SETF the returned ...thing (place? value? pointer?). I get an error with something like: (setf (state-score *state*) 10) Sometimes I seem to have a little more luck writing the accessor/mutator as a macro: (defmacro state-score ( state ) `(nth 2 ,state)) However I don't know why this should be a macro, so I certainly shouldn't write it as a macro (except that sometimes it works. Programming by coincidence is bad). What is an appropriate strategy to build up such structures? More importantly, where can I learn about whats going on here (what operations affect the memory in what way)?

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• Given 4 objects, how to figure out whether exactly 2 have a certain property

  - by Cocorico

  Hi guys! I have another question on how to make most elegant solution to this problem, since I cannot afford to go to computer school right so my actual "pure programming" CS knowledge is not perfect or great. This is basically an algorhythm problem (someone please correct me if I am using that wrong, since I don't want to keep saying them and embarass myself) I have 4 objects. Each of them has an species property that can either be a dog, cat, pig or monkey. So a sample situation could be: object1.species=pig object2.species=cat object3.species=pig object4.species=dog Now, if I want to figure out if all 4 are the same species, I know I could just say: if ( (object1.species==object2.species) && (object2.species==object3.species) && (object3.species==object4.species) ) { // They are all the same animal (don't care WHICH animal they are) } But that isn't so elegant right? And if I suddenly want to know if EXACTLY 3 or 2 of them are the same species (don't care WHICH species it is though), suddenly I'm in spaghetti code. I am using Objective C although I don't know if that matters really, since the most elegant solution to this is I assume the same in all languages conceptually? Anyone got good idea? Thanks!!

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• SQLite for personal use

  - by ALife

  What are the applications for your personal use that needs a small database like SQLite? I am thinking of trying a few popular databases and SQLite is surely the first one I am planning to try since I know barely nothing about database except some simple programming years ago. I learned that SQLite is good for personal use. But embarrassingly I do not see any application except maybe managing my list of phone numbers/contact info, which has probably a few hundred items. What's your experience? FYI, I use EndNote for my reference and softcopy of books, and I feel iTunes' music/media management is ok since I am not a frequent user anyway. And others? I do lots of coding, but I just use some simple etags tools for that. And I pretty much use .txt file (sometimes in the asciidoc style) for my notes. I have quite a bunch of notes, but not that many either. So, really, what are your personal applications that need a small database instead of existing tools and plain text files?

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• Can I cross compile with gcc for an old version of a Linux distro on my Ubuntu 9.10?

  - by Johan

  Hi, I have some old hardware with an old version of say SuSE linux running on it. Now I have this fancy development machine running Ubuntu 9.10. Some of the tools I use to compile my C app (written in Python 2.6.x) are not available on the old SuSe box. So... is it possible to compile for that old machine on my dev box? I have the following steps in mind, but would like to cross-check before venturing off into this quest: 1. Find out which static/shared libs my app needs and find/build target version of them 2. Also find the corresponding header files 3. Feed the correct flags to gcc to use the target headers and libraries 4. Feed the correct flags to gcc to use the correct architecture (i386/i686), or do I need a cross-compilation toolchain. 5. Compile, upload and enjoy ;-) I regularly use avr-gcc and cc65, both are cross compiling. I know that you set up a coss compiler for developing something like a gumstix, so it should be possible to do the same for old/other Linux distros, not? C

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• How to debug PHP?

  - by NutMotion

  Anyone's been trying himself at object oriented programming ? Most probably every developer I guess:D I for one have never studied OO design patterns thoroughly, and trying to put it all together now does prove at times thrilling, and many times frustrating also. Even more so when trying to do it in : PHP! All-in-all, my boss asked me to add some Database persistence functions to her server, but most of all, she asked me to translate her already working procedural code into a working Object Oriented code. Here I am, still standing on my PHP OO project. I'm (already) fed up with this "file logging only" PHP capability. I believe there must be some (free or not too much expansive) PHP debugging utility ? I've heard about Zend Studio and PHPEd so far, which didn't quite do the trick for whatever reasons. WIRCW("Which I don't Remember Correctly Why" lol) What say yé? on debugging PHP ? Is there a tool that provides a good debug mode? what's more, don't forget I'm not speaking about the classical web Request/response model. Talking about a debugging facility which can enable you to trigger a web service (aka client request) and go into debug mode on the SOAP web service side. Thks for any input.

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• Querying a database using Cocoa.

  - by S1syphus

  Hello everybody. Before I start a disclaimer, I should add a little disclaimer, that I am relatively new to Cocoa development and C in general. However I do have a copy of 'Cocoa Programming for Mac OS X 3rd edition' by Aaron Hillegass, which I am working through and using as a base, if anybody has a copy I am using the 'AmaZone' example on page 346 as a template and base. I trying to develop a small client app that takes a search string then displays results from a database accordingly. The database will contain a: list of files, their location, description & creation date, so for the moment the field number and types will remain the same. After looking around on SO, I saw something like: NSURL *myURL = [NSURL URLWithString:@"http://www.myserver.com/results.php"]; NSArray *sqlResults = [[NSArray alloc] initWithContentsOfURL:myURL]; I've worked with php before, so my current thinking after seeing this is create a php script on the server that queries the database, and creates an XML output. And with the XML response, just parse it. Would this be ok? as is there any major pitfalls anybody can see, that I can't. I know there are some database bundles, I've had a look at BaseTen for Postgres, but being relatively new to this, didn't want to get in over my head. Or if anybody else has any other suggestions and ideas, they would be greatly appreciated.

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• I want my logs sent to my mail with logrotate

  - by lericson

  Not strictly a question about programming as such, more of a log handling question. Anyway. My company has multiple clients, and each of these clients have a set of logs that I'd rather much want to get sent to by e-mail to me. Now, another prerequisite is that they're hilighted by simple HTML. All that is very well, I've managed to make a hilighter for the given log types. So, what I do is I use logrotate's prerotate stuff to send the logs as an e-mail message. Example: /var/log/a.log /var/log/b.log { daily missingok copytruncate prerotate /usr/bin/python /home/foo/hilight_logs /var/log/{a,b}.log | /usr/sbin/sendmail -FLog\ mailer [email protected] [email protected] endscript } The problem with this approach is basically that logrotate sucks: it'll run the command for every log file specified in the specifier, and to my knowledge there's no way to know which of the log files is being handled. (Which wouldn't really help anyway.) Short of repeating the exact same logrotate up to 10 times on different machines, the only thing I can do is just to get bogged down with log spam every night. And I grew tired of it today, so I ask.

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• Does this language feature already exists?

  - by Pindatjuh

  I'm currently developing a new language for programming in a continuous environment (compare it to electrical engineering), and I've got some ideas on a certain language construction. Let me explain the feature by explanation and then by definition; x = a | b; Where x is a variable and a and b are other variables (or static values). if(x == a) { // all references to "x" are essentially references to "a". } if(x == b) { // same but with "b" } if(x != a) { // ... } if(x == a | b) { // guaranteed that "x" is '"a" | "b"'; interacting with "x" // will interact with both "a" and "b". } // etc. In the above, all code-blocks are executed, but the "scope" changes in each block how x is interpreted. In the first block, x is guaranteed to be a: thus interacting with x inside that block will interact on a. The second and the third code-block are only equal in this situation (because not b only remains a). The last block guarantees that x is at least a or b. Further more; | is not the "bitwise or operator", but I've called it the "and/or"-operator. It's definition is: "|" = "and" | "or" (On my blog, http://cplang.wordpress.com/2009/12/19/binop-and-or/, is more (mathematical) background information on this operator. It's loosely based on sets.) I do not know if this construction already exists, so that's my question: does this language feature already exists?

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• correct format for function prototype

  - by yCalleecharan

  Hi, I'm writing to a text file using the following declaration: void create_out_file(char file_name[],long double *z1){ FILE *out; int i; if((out = fopen(file_name, "w+")) == NULL){ fprintf(stderr, "***> Open error on output file %s", file_name); exit(-1); } for(i = 0; i < ARRAY_SIZE; i++) fprintf(out, "%.16Le\n", z1[i]); fclose(out); } Where z1 is an long double array of length ARRAY_SIZE. The calling function is: create_out_file("E:/first67/jz1.txt", z1); I defined the prototype as: void create_out_file(char file_name[], long double z1[]); which I'm putting before "int main" but after the preprocessor directives. My code works fine. I was thinking of putting the prototype as void create_out_file(char file_name[],long double *z1). Is this correct? *z1 will point to the first array element of z1. Is my declaration and prototype good programming practice? Thanks a lot...

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• Will Apple bundle the Mono Touch runtime with every iPhone?

  - by Zoran Simic

  It strikes me as a good idea for Apple to negotiate with Novell and bundle the Mono Touch runtime (only the runtime of course) into every iPhone and iPod Touch. Perhaps even make it a "one time install" that automatically gets downloaded from the App Store the first time one downloads an app build with Mono Touch, making every subsequent Mono Touch app much lighter to download (without the runtime). Doing so would be similar in a way to adding Bootcamp to OS X: it would make it easier for C# developers to join the party, but that wouldn't mean these developers will all stick to C#... What convinced me to buy a Mac is Bootcamp - I figured I could always install Windows if I didn't like OS X (and I liked the hardware, so no problem there). 6 months later, I'm using OS X full time... Would there be any technical issues in doing so? I see only advantages for all parties, not one disadvantage to anyone (except maybe for the few unfortunate Apple employees who would have to test the crap out of the Mono Touch runtime before bundling it): Novell wins because Mono Touch becomes much more viable (Mono Touch apps become much lighter all of the sudden) Developers win because now there's one more tool in the tool belt Many C# Developers would be very interested by this Apple wins because that would bring even more attention to the platform, more revenue in developer fees, more potential great apps, etc Users win because less space is used by different Apps having copies of the same runtime accumulating on their devices Would there be a major technical obstacle in bundling Mono Touch to iPhone OS? Edit: Changed the title from "Should" to "Will Apple bundle the runtime?", I think the consensus on predicting that means a lot to those considering going with Mono Touch.

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• Unable to ping server from client B but able to ping from client A. Please help

  - by Soundar Rajan

  This is not really a programming question, but I am at my wit's end ... I am trying to configure a IIS 6.0/Windows Server 2003 web server with a ASP.net application. When I try to ping the server from client computer A I get the following: PING 74.208.192.xxx ==> Ping fails PING 74.208.192.xxx:80 ==> Ping succeeds! From client computer B, BOTH the pings fail. PING 74.208.192.xxx ==> Ping fails PING 74.208.192.xxx:80 ==> Ping fails with a message "Ping request could not find host 74.208.192.xxx:80" Both clients A and B are on the same subnet. The server is outside (a virtual server hosted by an ISP) I have an ASP.NET application in a virtual directory on the server. In IE or firefox, if I enter http://74.208.192.xxx/subdir/subdir/../Default.aspx, it works from both the clients! The server has default firewall settings but web server enabled (Port 80 is open).

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• JSF works only with the .xhtml ending

  - by ThreeFingerMark

  Hello, i start with the programming of a JSF Website. At the moment all files have the .xhtml ending. When i go to http://localhost:8080/myProject/start.jsf everything is all right. But when i rename the file from start.xhtml to start.jsf i became a NoClassDefFound Error. What is my mistake? <servlet-name>Faces Servlet</servlet-name> <servlet-class>javax.faces.webapp.FacesServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>Faces Servlet</servlet-name> <url-pattern>*.jsf</url-pattern> </servlet-mapping> <context-param> <param-name>javax.faces.PROJECT_STAGE</param-name> <param-value>Development</param-value> </context-param>

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• Systems design question: DB connection management in load-balanced n-tier

  - by aoven

  I'm wondering about the best approach to designing a DB connection manager for a load-balanced n-tier system. Classic n-tier looks like this: Client -> BusinessServer -> DBServer A load-balancing solution as I see it would then look like this: +--> ... +--+ +--> BusinessServer +--+--> SessionServer --+ Client -> Gateway --+--> BusinessServer +--| +--> DBServer +--> BusinessServer +--+--------------------+ +--> ... +--+ As pictured, the business server component is being load-balanced via multiple instances, and a hardware gateway is distributing the load among them. Session server probably needs to be situated outside the load-balancing array, because it manages state, which mustn't be duplicated. Barring any major errors in design so far, what is the best way to implement DB connection management? I've come up with a couple of options, but there may be others I'm not aware of: Introduce a new Broker component between the DBServer and the other components and let it handle the DB connections. The upside is that all the connections can be managed from a single point, which is very convenient. The downside is that now there is an additional "single point of failure" in the system. Other components must go through it for every request that involves DB in some way, which also makes this a bottleneck. Move the DB connection management into BusinessServer and SessionServer components and let each handle its own DB connections. The upside is that there is no additional "single point of failure" or bottleneck components. The downside is that there is also no control over possible conflicts and deadlocks apart from what DBServer itself can provide. What else can be done? FWIW: Technology is .NET, but none of the vendor-specific stacks are used (e.g. no WCF, MSMQ or the like).

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• How to contain the Deepwater Horizon oil spill? [closed]

  - by Yarin

  This is obviously not programming, but it's important and we're smart people, so let's give it a shot. (BP has actually begun soliciting suggestions for how to deal with the crisis http://www.deepwaterhorizonresponse.com/go/doc/2931/546759/, confirming that they don't have a clue) I'll start with my own proposal... Anchored Chute: A large-diameter, collapsible, flexible tube/hose with a wide mouth on one end is anchored over the leak. There's no need for a hermetic seal, the opening just needs to be big enough to form a canopy over the leak area. The rest of the tubing can just be dumped on the sea floor. Since oil is denser than water, the oily water that flows into the mouth eventually inflates the tube and raises the opposite end to the surface, where it can be collected (Like those inflatable dancing air socks at car dealerships). Further buoyancy could be added with floats attached to the tube at intervals. I think this method would not be as susceptible to the problems BP had with the containment dome, where a rigid, metal casing froze up with crystallized hydrates, as we would not be trying to contain the full pressure of the well, but would be using the natural buoyancy of the oil to channel its flow, and with a much larger opening.

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• Formatting Parameters for Ajax POST request to Rails Controller - for jQuery-UI sortable list

  - by Hung Luu

  I'm using the jQuery-UI Sortable Connected Lists. I'm saving the order of the connected lists to a Rails server. My approach is to grab the list ID, column ID and index position of each list item. I want to then wrap this into an object that can be passed as a parameter back to the Rails Controller to be saved into the database. So ideally i'm looking to format the parameter like this: Parameters: {"Activity"=>[{id:1,column:2,position:1},{id:2,column:2,position:2} ,...]} How do I properly format my parameters to be passed in this Ajax POST request? Right now, with the approach below, I'm passing on Parameters: {"undefined"=>""} This is my current jQuery code (Coffeescript) which doesn't work: jQuery -> $('[id*="day"]').sortable( connectWith: ".day" placeholder: "ui-state-highlight" update: (event, ui) -> neworder = new Array() $('[id*="day"] > li').each -> column = $(this).attr("id") index = ui.item.index() + 1 id = $("#" + column + " li:nth-child(" + index + ") ").attr('id') passObject={} passObject.id = id passObject.column = column passObject.index = index neworder.push(passObject) alert neworder $.ajax url: "sort" type: "POST" data: neworder ).disableSelection() My apologies because this seems like a really amateur question but I'm just getting started with programming jQuery and Javascript.

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• I want to read program content from command line.

  - by Alexandre Dominos

  I am trying to update a program which was wrotten in 1995 with pascal or c. I am not sure about programming language. Command line program. Now I am coded in C#. And I want to read program command line content. Is it possible? I tried something. But not succesfull. They are: private void aboutToolStripMenuItem_Click(object sender, EventArgs e) { // Redirect the output stream of the child process. p.StartInfo.UseShellExecute = false; p.StartInfo.RedirectStandardOutput = true; p.StartInfo.FileName = "osl.exe"; p.Start(); logs.AppendText("Timer Started\n"); timer1.Enabled = true; } private void timer1_Tick(object sender, EventArgs e) { // write somethingg and read what is the program doing on command line? // What is the program printint? etc... // I try this code but not enough for mo. // logs.AppendText("d:" + p.StandardOutput.ReadToEnd()+"\n"); } private void p_Exited(object sender, EventArgs e) { timer1.Enabled = false; } i am open to any idea in java,cpp,c,c#.

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• Automatic testing of GUI related private methods

  - by Stein G. Strindhaug

  When it comes to GUI programming (at least for web) I feel that often the only thing that would be useful to unit test is some of the private methods*. While unit testing makes perfect sense for back-end code, I feel it doesn't quite fit the GUI classes. What is the best way to add automatic testing of these? * Why I think the only methods useful to test is private: Often when I write GUI classes they don't even have any public methods except for the constructor. The public methods if any is trivial, and the constructor does most of the job calling private methods. They receive some data from server does a lot of trivial output and feeds data to the constructor of other classes contained inside it, adding listeners that calls a (more or less directly) calls the server... Most of it pretty trivial (the hardest part is the layout: css, IE, etc.) but sometimes I create some private method that does some advanced tricks, which I definitely do not want to be publicly visible (because it's closely coupled to the implementation of the layout, and likely to change), but is sufficiently complicated to break. These are often only called by the constructor or repeatedly by events in the code, not by any public methods at all. I'd like to have a way to test this type of methods, without making it public or resorting to reflection trickery. (BTW: I'm currently using GWT, but I feel this applies to most languages/frameworks I've used when coding for GUI)

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• JAVASCRIPT ENABLED [closed]

  - by kirchoffs415

  HI, I hope somebody can help, i keep getting the following message when i log on-- Your Javascript is disabled. Limited functionality is available. it will stay for maybe a day sometimes two.I have uninstalled javascript and reinstalled but still the same. Iam using chrome. any help would be gratefull many thanks Dominic p.s. my system spec is as follows System InformationOS Name Microsoft® Windows Vista™ Home Premium Version 6.0.6002 Service Pack 2 Build 6002 Other OS Description Not Available OS Manufacturer Microsoft Corporation System Name DOM-PC System Manufacturer Dell Inc. System Model Inspiron 1545 System Type X86-based PC Processor Pentium(R) Dual-Core CPU T4200 @ 2.00GHz, 2000 Mhz, 2 Core(s), 2 Logical Processor(s) BIOS Version/Date Dell Inc. A05, 25/02/2009 SMBIOS Version 2.4 Windows Directory C:\Windows System Directory C:\Windows\system32 Boot Device \Device\HarddiskVolume3 Locale United Kingdom Hardware Abstraction Layer Version = "6.0.6002.18005" User Name DOM-PC\DOM Time Zone GMT Standard Time Installed Physical Memory (RAM) 3.00 GB Total Physical Memory 2.96 GB Available Physical Memory 1.38 GB Total Virtual Memory 5.89 GB Available Virtual Memory 4.25 GB Page File Space 3.00 GB Page File C:\pagefile.sys My System Specs

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• Python: Beginning problems

  - by Blogger

  ok so basically i very new to programming and have no idea how to go about these problems help if you will ^^ Numerologists claim to be able to determine a person’s character traits based on the “numeric value” of a name. The value of a name is determined by summing up the values of the letters of the name, where ‘a’ is 1, ‘b’ is 2, ‘c’ is 3 etc., up to ‘z’ being 26. For example, the name “Zelle” would have the value 26 + 5 + 12 + 12 + 5 = 60 (which happens to be a very suspicious number, by the way). Write a program that calculates the numeric value of a single name provided as input. Word count. A common utility on Unix/Linux systems is a small program called “wc”. This program counts the number of lines, words (strings of characters separated by blanks, tabs, or new lines), and characters in a file. Write your own version of this program. The program should accept a file name as input and then print three numbers showing the count of lines, words, and characters in the file.

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• When to choose which machine learning classifier?

  - by LM

  Suppose I'm working on some classification problem. (Fraud detection and comment spam are two problems I'm working on right now, but I'm curious about any classification task in general.) How do I know which classifier I should use? (Decision tree, SVM, Bayesian, logistic regression, etc.) In which cases is one of them the "natural" first choice, and what are the principles for choosing that one? Examples of the type of answers I'm looking for (from Manning et al.'s "Introduction to Information Retrieval book": http://nlp.stanford.edu/IR-book/html/htmledition/choosing-what-kind-of-classifier-to-use-1.html): a. If your data is labeled, but you only have a limited amount, you should use a classifier with high bias (for example, Naive Bayes). [I'm guessing this is because a higher-bias classifier will have lower variance, which is good because of the small amount of data.] b. If you have a ton of data, then the classifier doesn't really matter so much, so you should probably just choose a classifier with good scalability. What are other guidelines? Even answers like "if you'll have to explain your model to some upper management person, then maybe you should use a decision tree, since the decision rules are fairly transparent" are good. I care less about implementation/library issues, though. Also, for a somewhat separate question, besides standard Bayesian classifiers, are there 'standard state-of-the-art' methods for comment spam detection (as opposed to email spam)? [Not sure if stackoverflow is the best place to ask this question, since it's more machine learning than actual programming -- if not, any suggestions for where else?]

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• how to implement a really efficient bitvector sorting in python

  - by xiao

  Hello guys! Actually this is an interesting topic from programming pearls, sorting 10 digits telephone numbers in a limited memory with an efficient algorithm. You can find the whole story here What I am interested in is just how fast the implementation could be in python. I have done a naive implementation with the module bitvector. The code is as following: from BitVector import BitVector import timeit import random import time import sys def sort(input_li): return sorted(input_li) def vec_sort(input_li): bv = BitVector( size = len(input_li) ) for i in input_li: bv[i] = 1 res_li = [] for i in range(len(bv)): if bv[i]: res_li.append(i) return res_li if __name__ == "__main__": test_data = range(int(sys.argv[1])) print 'test_data size is:', sys.argv[1] random.shuffle(test_data) start = time.time() sort(test_data) elapsed = (time.time() - start) print "sort function takes " + str(elapsed) start = time.time() vec_sort(test_data) elapsed = (time.time() - start) print "sort function takes " + str(elapsed) start = time.time() vec_sort(test_data) elapsed = (time.time() - start) print "vec_sort function takes " + str(elapsed) I have tested from array size 100 to 10,000,000 in my macbook(2GHz Intel Core 2 Duo 2GB SDRAM), the result is as following: test_data size is: 1000 sort function takes 0.000274896621704 vec_sort function takes 0.00383687019348 test_data size is: 10000 sort function takes 0.00380706787109 vec_sort function takes 0.0371489524841 test_data size is: 100000 sort function takes 0.0520560741425 vec_sort function takes 0.374383926392 test_data size is: 1000000 sort function takes 0.867373943329 vec_sort function takes 3.80475401878 test_data size is: 10000000 sort function takes 12.9204008579 vec_sort function takes 38.8053860664 What disappoints me is that even when the test_data size is 100,000,000, the sort function is still faster than vec_sort. Is there any way to accelerate the vec_sort function?

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• Is there a Scheduler/Calendar JS Widget library?

  - by Ravi Chhabra

  I am looking for some JavaScript based component to be used as a course scheduler which would be a cross between Google Calendar and the login time. I do not know if the right term for this is Course Scheduler but I shall describe this in more detail here. Course Scheduler The widget would be used to enter date and times of a course, as an example if I run a programming course 3 days a week on Mon, Tue and Wed every 7:00 am to 9:00am, 2 hours every day from 1st September to 30th November. I could answer various questions and the course data would be displayed in the calendar. It would also allow for non pattern based timings where each week is different from the other week etc. Question So would I end up creating something from scratch? Would it be sensible to use Google Calendar API for this? I did a Google search for some widgets, but I believe I need better keywords, as I could not find anything close to what I am looking for. Any tips? Commercial libraries would also work for me. Thanks.

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