Prototyping neural networks

I would also highly recommend python. For a prototype, python is a great choice: it is easier and faster to program in, there are a huge number of libraries available, and it widely used in the scientific community.

Also, if you are using python, you can also take advantage of the excellent PyBrain package which contains algorithms for neural networks, reinforcement learning, unsupervised learning, and other machine learning tasks, which should help you build a prototype quickly.

This depends on your current setup. When I used to work on them back in college days, I had to use C++ + MPI+numerical recipes. This was done because I had to load share on big beowulf cluster.

If your computation needs are not big, anything would do. Prepackaged libraries are available on all the platforms (R, Python(numPy, scipy), C/C++(Numerical recipes) etc). If you are comfortable programming in any one of them, it should not be a big deal.

If I had to prototype anything now, I'd probably go with Python (just because I find it much more easier for prototyping)

"Encog is an advanced neural network and machine learning framework. Encog contains classes to create a wide variety of networks, as well as support classes to normalize and process data for these neural networks. Encog trains using multithreaded resilient propagation. Encog can also make use of a GPU to further speed processing time. A GUI based workbench is also provided to help model and train neural networks. Encog has been in active development since 2008."

Encog is available for Java, C#.Net and Silverlight.

http://www.heatonresearch.com/encog

In my nn classes in school we used matlab and then I used java for my thesis.

I would suggest java or matlab. Matlab because it probably already has alot of what you might need. And java because it is quick to implement what might be missing in open source projects. And besided since besides implementing the neural networks you might need some way to visualize them. And for that I personally believe that java or matlab is quite easy.

I like flood. It's free, comprehensive, and written in C++.

The implementations in Matlab are sophisticated and complete. I have found it to be sufficient for evaluating different types of networks. It is also very programmable using external interfaces.

However, since the implementations of the algorithms are not open source, it is sometimes more difficult when you need to move a particular piece of code into an application outside of Matlab, as my hand coded implementations of different neural network types produced different results.

I have started writing a NN implementation using C++ and found that I didn't know enough about the maths involved in the beginning. What ended up hapenning was that it was too hard to refactor the code as I was tweaking the calculation model.

Eventually I gave into MATLAB as it was definitely a better companion to learning how neural networks work. I was able to make huge changes to the algorithm using a few key strokes and graph the results too.

Perhaps my experience would have been better if I had used an already built matrix computation framework. Considering that's how you do 3D there should be a few really optimized libraries out there for most languages. Heck you might as well leverage Direct3D or OpenGL for that, but I am sure there is something more suitable for Neural Networks out there.

I guess I am not providing much information on what you should do. I can however tell what you should not do - and that's trying to write matrix manipulation code yourself.

You might want to give Weka a look. It has some built-in tools for things like data visualization, and it's been around for years now (some screenshots).

In my view in working with neural networks the key is getting the training set right not so much how the network itself is actualised in code. I would choose a language based on the type of problem you are trying to solve using the network. For the network itself c++, c#, python and java are all viable.

Are you using this in connection with a problem requiring image processing? In which case you will probably want something that hooks up to an image processing library like OpenCV easily. Or is there some audio processing involved?

You may need to easily visualise the training sets so how easy would this be with the language of choice? Can you work with either OpenGL or DirectX libraries either directly or using a wrapper of some kind? For DirectX the choices are C++ and C#. Will a higher level of abstraction say using WPF work?

I have used C# because I am familiar with it and can leverage the numerous data handling technologies in .net and use wpf for any visualisations needed.