[R] Neural networks

Marcus Gry
2009-09-03T20:08:45Z

Dear list members.

I am trying to make a sensitivity analysis (as derived by Zurada 1994,
Engelbrecht 1995) of input parameters (gene expression data) when
applying a neural network to classify different cancer subtypes. Since
I am no expert in the field, (rather a newbie), I wonder if there
exists an implementation in R that can be used to measure the relative
importance of the input variables for the neural network. The created
network has (after PCA dimension reduction) 8 inputs,  2 nodes in the
hidden layer and two outputs.

I read somewhere that the sensitivity matrix is calculated by using a
Jacobian matrix of the output parameters over the input parameters. I
think that somehow I can grasp the concept, I just don?t know how to
implement it in R. Any help, or guidelines would be greatly appreciated.

Best regards

Marcus