The sum of stacked matrices
조회 수: 2 (최근 30일)
이전 댓글 표시
I have a 3-d matrix and I want to find the sum so that every element in the sum matrix is the sum of all the elements in that corresponding i,j location. I know that sounds confusing probably so for example:
>> A=zeros(3,3,3);
>> A(:,:,1)=[1 1 1; 1 0 1; 0 0 0];
>> A(:,:,2)=[1 1 1; 0 0 1; 0 1 0];
>> A(:,:,3)=[1 0 1; 0 1 0; 0 1 0];
Would give me a sum matrix that would be:
[ 3 2 3
1 1 2
0 2 0 ]
I realize I could reshape the matrices into a vector, sum them, and then reshape them back into the matrix, and that I could use for loops, but both of those seem over complicated and I would be doing this with a pretty large amount of data so speed is ideal :)
Thanks in advance!
-Shaun
댓글 수: 0
채택된 답변
Roger Stafford
2012년 12월 22일
sum(A,3)
Roger Stafford
댓글 수: 2
Roger Stafford
2012년 12월 22일
No, it sums along the third dimension, which is what you asked for. That is what the '3' refers to.
To get the entire sum of a two-dimensional array you need to either use two calls to 'sum' or convert the array to one-dimension and sum that:
sum(sum(A))
or
sum(A(:))
Roger Stafford
추가 답변 (0개)
참고 항목
카테고리
Help Center 및 File Exchange에서 Characters and Strings에 대해 자세히 알아보기
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!