Thanks for this explanation. I understood most of it but could you explain why you should normalize using 1/sqrt(n) and why doing so makes the result converge in distribution?
The .appspot.com subdomain tells us his site runs on Google App Engine.
Now, as it happens, I have some experience trying to get Java to compile and run on Google App Engine. Actually, at the outset I thought it was impossible because of the way the sandboxing works on App Engine (writes to the file system are disallowed and the javax.tools. package is not part of their white list). So straightforward approaches such as invoking the Java compiler from code will not work.
Here are various approaches that I have tried and the results:
1. Use Beanshell and approximate Java:
Beanshell is a scripting language for the JVM with Java like syntax. It also has a "strict" mode where it will behave like a strongly typed language.
Pros: you can run this on App Engine and can trust Google Engineers to worry about security of their sandbox. You also get the scalability of App Engine.
Cons: It is not really Java and language features like Generics are not supported. The error messages are also not as useful as what the regular Java compiler outputs.
2. Get users to compile code on their own machines and upload the .class file. Then write a class loader that will load this class and then execute whatever method you need to.
Pros: Works perfectly and no language issues.
Cons: The interactivity is lost to an extent. Also, beginners need to start worrying about installing Java and configuring CLASSPATH etc. from get go.
3. Use an in-memory compiler like Janino.
Pros: Works like the Java compiler and error messages are useful.
Cons: it does not support generics and it also does not support other features like the for(String value : values) {} syntax.
4. Use Google App Engine as the front-end and then run a compiler-as-a-service somewhere else (Linode etc.).
Pros: Full language and you are in control.
Cons: You better know how to sandbox the code (chroot / SecurityManager etc).
5. Use Google App Engine as a front-end and outsource compilation and execution to some other service like Ideone.
Pros: Full language support and someone else worries about security issues.
Cons: Expensive (the Ideone API only allows 1000 free submissions per month).
If you know some other method, please let me know. I love trying to see how to make things work on App Engine (I learn quite a bit this way).
"Our website has over 50,000 monthly hits - programmers from all around the world visit LearnJavaOnline.org to increase their professional programming expertise in the Java programming language."
However, I notice that the domain was registered very recently (on 19-Feb-2013) and there are hardly 15 tutorials on the site and most of these pages are blank.
Edit: looks like this site is just using a template. Please see the OP's response to this comment.
You say 'trig comes up a surprising amount'. It would be great if you could give a few examples of these instances. I have always thought of trigonometry as one of the areas I really enjoyed in school but something I have never used ever since.
Is there a course on udacity that teaches you how to build apps on Google App Engine? They do have one on building web apps but it does not specify which platform they use (if any).
"Google Apps Script gives users a new level of control over Google products. Now you can access and control Google Spreadsheets and other products using JavaScript scripts that you write yourself and can share with others. Unlike browser-based JavaScript, the scripts you write run directly on Google servers in order to provide direct access to the products they control.You can also use Google Apps Script from Google Sites."
This online code editor seems to be a new and improved UI for creating / editing apps scripts. That said, this editor isn't proprietary. A quick look at the source shows that they're using CodeMirror (http://codemirror.net/). We've tried out various code editors for unclassroom.com (where I work) and code mirror has been the best to work with in terms of features, ease of use and comprehensive documentation. The second version (CodeMirror2) is really top notch compared to other alternatives out there.
One difference between different linux distros and android is that, in the former case, end users recognize that software written for another distro may not work on their specific OS. In the latter case, however, end users (especially ones that aren't technical) think that they have the same OS (when in reality they all own phones with different levels of API support / compatibility) and are upset when a specific app does not work as expected on their device.
Is there a way to style dynamically inserted <code> blocks (say inserted via an ajax call) after the page loads? I did not see an equivalent of the prettify() function of google-code-prettify that lets you do this. Looks great otherwise.
You are correct that we both teach programming and hence the blog post. That said, we've removed the pay wall for the PHP course and would appreciate your feedback. Thanks!
We're actually moving to guest login and we will be removing the necessity to login but thanks for your feedback.
The login is required because otherwise we can't save and pre-load the code for you the next time you visit the same activity.
Edit: what I mean to say is the app itself is secure and so is our sandbox that runs the code and this is more of a UI issue that we'll fix immediately by removing the login prompt.
Also, just to be clear we have nothing to do with codecademy as zds has rightly pointed out in this thread. The title might be misleading so apologies in advance if it is. Unable to change it though.
Would a google (oauth) login in additon to Facebook connect solve the problem for most users OR is it necessary to also have an option to register an account?