# How to create a Aij matrix with the commands 'for', 'function output=name_of_code' and 'imagesc'?

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Ariane on 27 Jan 2023
Moved: Matt J on 27 Jan 2023
I have to built a Aij matrix where Aij=i^2+j^2 when i=j and Aij=(i-j)^2 when i≠j. After that, I need to execute the code with m=100 and n=150. My teacher said the useful commands are 'for', 'function output=name_of_code' and 'imagesc'. I don't know how to do it and I didn't find any example. I write the code: for A=i^2+j^2
i=j
end
for A=(i-j)^2
i~=j
end
This appear on the command window: i =
0.0000 + 1.0000i
ans =
0
I don't know if what I've done is good. After I write m=[1:100]
n=[1:150]
A=[m,n]
imagesc(A)
function [A]=matrice_A
end
for A=i^2+j^2
i=j
end
It gives me this figure. I don't know if it is good but it doesn't look like a matrix.
##### 2 CommentsShowHide 1 older comment
Matt J on 27 Jan 2023
Edited: Matt J on 27 Jan 2023
Ariane wrote:
I have to built a Aij matrix where Aij=i^2+j^2 when i=j and Aij=(i-j)^2 when i≠j. After that, I need to execute the code with m=100 and n=150. My teacher said the useful commands are 'for', 'function output=name_of_code' and 'imagesc'. I don't know how to do it and I didn't find any example. I write the code: for A=i^2+j^2
i=j
end
for A=(i-j)^2
i~=j
end
This appear on the command window: i =
0.0000 + 1.0000i
ans =
logical
0
I don't know if what I've done is good. After I write m=[1:100]
n=[1:150]
A=[m,n]
imagesc(A)
function [A]=matrice_A
end
for A=i^2+j^2
i=j
end
It gives me this figure. I don't know if it is good but it doesn't look like a matrix.

Matt J on 27 Jan 2023
m=100; n=150;
A=((1:m)'-(1:n)).^2;
for i=1:min(m,n)
A(i,i)=2*i.^2;
end
imagesc(A)

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