Create a loop for this matrix

1 view (last 30 days)
1 -1 0 0 0 ...
-1 2 -1 0 0 ...
0 -1 2 -1 0 ...
0 0 -1 2 -1 ...
0 0 0 -1 2 ...
As you can see, this can go on forever, I and would like to find a way to write loop for a dynamic matrix where this just keeps going unitl a certain number 'N'
  4 Comments
David Fletcher
David Fletcher on 4 Jun 2021
Edited: David Fletcher on 4 Jun 2021
I think they are asking what the end of the final row should be - I would guess [zeros(N-2,1) -1 1]

Sign in to comment.

Accepted Answer

David Fletcher
David Fletcher on 4 Jun 2021
Edited: David Fletcher on 4 Jun 2021
Just writing something with a loop on the fly (and I stress this is neither robust, nor particularly efficient), but it may be something you can work on in the absence of better answers
clear;
N=10;
base=[1 -1 0;-1 2 -1;0 -1 1];
spliceL=0;
spliceR=N-3;
reform(1,:)=[zeros(1,spliceL) base(1,:) zeros(1,spliceR)];
for iter=2:N-1
reform(iter,:)=[zeros(1,spliceL) base(2,:) zeros(1,spliceR)];
spliceL=spliceL+1;
spliceR=spliceR-1;
end
reform(end+1,:)=[zeros(1,spliceL) base(3,end-1:end) zeros(1,spliceR-1)];
reform
reform = 10×10
1 -1 0 0 0 0 0 0 0 0 -1 2 -1 0 0 0 0 0 0 0 0 -1 2 -1 0 0 0 0 0 0 0 0 -1 2 -1 0 0 0 0 0 0 0 0 -1 2 -1 0 0 0 0 0 0 0 0 -1 2 -1 0 0 0 0 0 0 0 0 -1 2 -1 0 0 0 0 0 0 0 0 -1 2 -1 0 0 0 0 0 0 0 0 -1 2 -1 0 0 0 0 0 0 0 0 -1 1

More Answers (0)

Categories

Find more on Creating and Concatenating Matrices in Help Center and File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!