Asked by SAZZAD HOSSAIN
on 22 Jun 2013

Hello all

I have a row of 100 atoms and i am considering nearest neighbour interaction. What that means is that each atom has an interaction with itself (self interaction) of magnitude 2; and each atom interacts with its two nearest neighbour atoms from each side of magnitude 1. This 1D problem is represented in matrix as

2 1 0 0 0 0 ... -1 2 1 0 0 0 ... 0 -1 2 1 0 0 ... 0 0 -1 2 1 0 ... ............. .............

Now, my problem is that i dont know how to write this matrix when instead of a 1D problem, i have a 2D plane of atoms with the same nearest neighbour interaction condition. Can someone please help me ???

Thanks in advance.

Sazzad

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Answer by Andrei Bobrov
on 22 Jun 2013

Accepted answer

a = [-1 2 1]; n = 100; m = numel(a)-1;

out = full(spdiags(ones(n,1)*[-1 2 1],-m:m,n,n));

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