Monday, April 02, 2012

model update

I'm working on other things lately, but I did finally get that multi-channel rivalry model working - main problem was that I had written the convolution equations out wrong. I had to do the convolution there in the code because the filter array is irregular - there's no function to call for 2d irregular-array convolution, much less for switching the convolution between different layers.

Here's what I had done:

Z´(x) = Z´(x) + F(x)·Z(x), where x is a vector of spatial indices, Z is the differential equation describing the change in excitation or adaptation over time, F is basically just a 2-d Gaussian representing spatial spread of activation for the inhibitory or excitatory unit, and Z´ is (supposed to be) the differential convolved with the spread function.

Now that doesn't make any sense at all. I don't know what that is. In the actual code that equation was actually 3 lines long, with lots and lots of indices going on because the system has something like five dimensions to it; so, I couldn't see what nonsense it was.

This is how it is now:

Z´(x) = Z´(x) + sum(F(x)·Z(x))*F(x)

THAT is convolution. I discovered what was going on by looking at the filter values as images rather than as time plots; Z and Z´ didn't look different at all! Z´ should look like a blurred version of Z. Such a waste of time...

Anyways, it kind of works now. Different problems. Not working on it until later in April. The 'simple' single resolution model was used to generate some images for my NRSA application. Here's a sample simulation of strabismus (with eye movements):

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