# Finite Element: Filling nxm matrix by extracting values from another nx1 matrix

1 view (last 30 days)
Suhaila Al-Ali on 2 Dec 2022
Answered: Fifteen12 on 2 Dec 2022
I need a loop code or a function which can fill an nxm matrix by extracting values from another nx1 matrix.
Below is an example of a known matrix size:
V(2,2:5)=W(1:4);
V(3,2:5)=W(5:8);
V(4,2:5)=W(9:12);
V(5,2:5)=W(13:16);
V is a matrix of 6x6 and W is a matrix of 16x1.

Voss on 2 Dec 2022
V(2:5,2:5) = reshape(W,4,[]).';

Fifteen12 on 2 Dec 2022
From your question, V is mxm and W is nx1. Assuming that's true going forward:
n = 16;
m = 4;
offset = 1;
W = randi(10, [n, 1]); %initialize W
V = zeros(6);
disp(myfunc(V, offset, m, W));
0 0 0 0 0 0 0 8 3 5 6 0 0 5 9 1 1 0 0 5 4 10 8 0 0 2 6 4 9 0 0 0 0 0 0 0
function V = myfunc(V, offset, m, W)
n = length(W);
numRows = floor(n/m);
for i = 1:numRows
V(offset+i, offset+1:m+offset) = W((i-1)*m+1:i*m);
end
end

### Categories

Find more on Loops and Conditional Statements 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!