R help - May 2008 - How to compare a value in a matrix with its neighbours

Hello.

I'm trying to compare a value in a 2-D matrix with its 4 neighbours.

I think I could use row() and col() and use x[row(x)] and x[row(x)-1] etc...,
but I can't see how it would work.


Also, any way of having a matrix fill itself with its own coordinates would also
work.

Any ideas please.


Simon Parker
Imperial College




       
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