Buy or build, a practical example to explain my point of view

I was working on the post related to the relation between IFS fractals and Analytical Probability density, when an IT manager contacted me asking an informal opinion about a tool for Neural Networks.

I was working on the post related to the relation between IFS fractals and Analytical Probability density, when an IT manager contacted me asking an informal opinion about a tool for Neural Networks.
He told me: “we are evaluating two different tools to perform general purpose data mining tasks, and we are oriented toward the tool xxx because the neural network module seems more flexible”.
My first reaction was: “sorry, but you have to solve a specific problem (the problem is a little bit complex to explain but it is a classical  inversion function problem) and you are looking for a generic suite: I’m sincerely confused!”
He justified himself telling “If I buy a generic suite I can reuse it in a next time for other problems!”:  bloody managers! Always focused to economize 1 $ today to loose 10$ tomorrow :)            
As you can imagine the discussion fired me, so I started to investigate about this “flexibility capabilities” (this is for me the key point to evaluate a solution) and I began long emails exchange with this enterprising manager.
Let me sum up the main questions/answers about this module.
Q: What kind of Neural Network does the suite support?
A: Back Propagation (just for multilayer perceptron) and SOM.
The suite has a nice GUI where you can combine the algorithms like lego-bricks. (it is very similar to WEKA’s gui).
Q: What kind of error function does it support  (limited to BP nets)?
A: I don’t Know, but I suppose just the delta based on target vs output generated;
Q: What kind of pruning algorithms does it support?
A: It supports a weight-based algorithm, but there is no control on it.
Q: How many learning algorithms does the BP net support?
A: It supports just BP with momentum.
Q: What kind of monitors does it support to understand the net behavior?
A: It has a monitor to follow the output error on the training set.
Q: What is the cost of this suite?
A: The suite (actually it is pretty famous data mining suite ...don’t ask more about it…) price is around 10 thousand $ for limited number of users (it doesn’t embrace neither the support costs nor integration costs nor dedicate hardware).
Q: do you have the chance to visualize the error surface?
A: I’m a manager, what the hell does this question mean?

My recommendations: don’t buy it.
Here you are the key points:

1. No words, Bring real evidences!
As usual, instead of thousands words I prefer get  direct and concrete proof about my opinion, because my motto is : “don’t say I can do it in this way or in this way, but just do it!”  (…hoping that it makes sense in English!).
So during this weekend I decided to implement in Mathematica a custom tool to play with Back Propagation Neural Networks having at least the same features described above.

Continue the reading here.

Here you are the general-purpose Neural Net Application I built with mathematica: different colors for neurons to depict different energy levels., monitor to follow the learning process, fully customization for energy cost function, activation functions:




Related articles


0 Comments