How to combine two matrices
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Hello,
I want matrix d to go into matrix A.
Thanks in advance
n=4
A = 4*diag(ones(n^2,1)) - diag(ones(n^2-1,1),-1) - diag(ones(n^2-1,1),1)
d1=diag(-1*ones(n^2,1),-3);
d2=diag(-1*ones(n^2,1),3);
d=d1+d2
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Walter Roberson
2020-12-10
Where in A should d go?
Note that A is going to be an n^2 by n^2 array as you put something of length n^2 along the main diagonal, and the other two diagonals have had their length adjusted properly to be consistent.
Note that d is going to be an (n^2+3) by (n^2+3) array, as the length of the third diagonal is n^2, so the length of the second diagonal would be n^2 + 1 so the length of the first diagonal would be n^2 + 2 so the length of the main diagonal would be n^2 + 3.
So you cannot put d within A. You could put A within d.
What I suspect you want is to fix your sizes for d1 and d2, and then use
A = A + d
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