Sum of each row?
4 views (last 30 days)
Show older comments
Hi,
I have a set
A=ones(2,3,4);
Here,
val(:,:,1) =
1 1 1
1 1 1
val(:,:,2) =
1 1 1
1 1 1
....
I want to create a matrix whose elements are the sum of each row of A.
The sum of the first row of val(:,:,1) should be a11 in A.
The sum of the second row of val(:,:,1) should be a12 in A.
The sum of the first row of val(:,:,2) should be a21 in A.
The sum of the second row of val(:,:,2) should be a22 in A....
How can i form this 4x2 matrix ?
Thanks in advance.
0 Comments
Accepted Answer
Adam Danz
on 8 Feb 2020
Edited: Adam Danz
on 8 Feb 2020
A = reshape(1:24,2,3,4); % input: [n x m x k] array
val = squeeze(sum(A,2)).'; % output: [k x n] matrix
3 Comments
Stephen23
on 9 Feb 2020
Edited: Stephen23
on 9 Feb 2020
Using squeeze is very fragile because it's output changes completely when some dimension's size happens to be one. The simple and robust alternative is to use permute (which also requires fewer operations than the above answer):
>> permute(sum(A,2),[3,1,2])
ans =
9 12
27 30
45 48
63 66
More Answers (0)
See Also
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!