how to generate matrix with any size in same pattern

15 views (last 30 days)
-2 1 0 0 0 0
1 -2 1 0 0 0
0 1 -2 1 0 0
0 0 1 -2 1 0
0 0 0 1 -2 1
0 0 0 0 1 -2
i need to generate a matrix with pattern like this. how to write a script that the required pattern
for example, if i need 5*5 matrix with the required pattern it will be like this
-2 1 0 0 0
1 -2 1 0 0
0 1 -2 1 0
0 0 1 -2 1
0 0 0 1 -2
or i need 7*7 matrix
-2 1 0 0 0 0 0
1 -2 1 0 0 0 0
0 1 -2 1 0 0 0
0 0 1 -2 1 0 0
0 0 0 1 -2 1 0
0 0 0 0 1 -2 1
0 0 0 0 0 1 -2

Answers (3)

Walter Roberson
Walter Roberson on 22 Apr 2013

Andrei Bobrov
Andrei Bobrov on 22 Apr 2013
Edited: Andrei Bobrov on 12 Dec 2019
n = 5;
out = full(spdiags(ones(n,1)*[1 -2 1],-1:1,n,n));
or
out = zeros(n);
out([2:n+1:end,n+1:n+1:end]) = 1;
out(1:n+1:end) = -2;
or
out = zeros(n);
z = diag(true(n-1,1),-1);
out(z | z') = 1;
out(eye(n) > 0) = -2;
and (after 6.5 years ;)
n = 10;
out = toeplitz([-2 1 zeros(1,n-2)]);

Bandar
Bandar on 12 Dec 2019
n=5;
v =-2*ones(1,n);
p =ones(1,n-1);
B =diag(v);
C =diag(p,1);
D =diag(p,-1);
A=B+C+D
The result is
A =
-2 1 0 0 0
1 -2 1 0 0
0 1 -2 1 0
0 0 1 -2 1
0 0 0 1 -2

Categories

Find more on Operating on Diagonal Matrices in Help Center and File Exchange

Tags

Community Treasure Hunt

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

Start Hunting!

Translated by