Matrix column subtraction problem

1 次查看（过去 30 天）
Jakub Nosek
Jakub Nosek 2018-3-11
评论： Jakub Nosek 2018-3-11
I know this is really basic stuff but unfortunately I can't get to the right solution.
I have for example these 2 matrices:
matrixA=[1 5;5 2;0 0;3 2;3 6]
and
matrixB=[4 5 6;8 5 2;3 3 2;1 2 1;2 5 4]
What I want to do is to subtract all columns in matrixB from column 1 and column 2 respectively in matrixA. So I want to make
matrixC=[1-4 1-5 1-6 5-4 5-5 5-6;5-8 5-5 5-2 2-8 2-5 2-2;....;....;.....]

请先登录，再回答此问题。

采纳的回答

Roger Stafford
Roger Stafford 2018-3-11
编辑：Roger Stafford 2018-3-11
C = zeros(5,2*3);
for p = 1:2
for q = 1:3
C(:,3*p+q-3) = A(:,p)-B(:,q);
end
end
Or this:
C = reshape(repmat(reshape(A,5,1,2),1,3,1)-repmat(reshape(B,5,3,1),1,1,2),5,[]);
  4 个评论
显示 2更早的评论
Roger Stafford
Roger Stafford 2018-3-11
@Jakub: For matrices A and B of general size:
[m,n1] = size(A);
n2 = size(B,2); % size(B,1) must also be m
C = reshape(repmat(reshape(A,m,1,n1),1,n2,1)-repmat(reshape(B,m,n2,1),1,1,n1),m,[]);

请先登录，再进行评论。

更多回答（1 个）

Walter Roberson
Walter Roberson 2018-3-11
[matrixA(:,1)-matrixB,matrixA(:,2)-matrixB]
This might require R2016b or later.
  2 个评论
Jakub Nosek
Jakub Nosek 2018-3-11
Thanks, is there any other solution for older versions of MATLAB?
Walter Roberson
Walter Roberson 2018-3-11
cell2mat(arrayfun(@(COLIDX) bsxfun(@minus, matrixA(:,COLIDX), matrixB), 1:size(matrixA,2), 'uniform', 0))

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Linear Equations 的更多信息

标签

Community Treasure Hunt

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

Start Hunting!

Translated by