How to do a quick division between a column array and a matrix?
显示 更早的评论
Hello, All,
I want to divid a column array b (N x 1) by each column in a big sparse matrix A (N x M). My code is as follows:
dividCol = zeros(N,M);
for i = 1 : M
nonCol = find(abs(A(:,i))>0);
dividCol(nonCol,i) = b(nonCol)./A(nonCol,i);
end
But it is very slow. I do know if there exist a faster approach to write this code.
Thanks a lot in advance.
Benson
采纳的回答
Omer Yasin Birey
2019-1-28
编辑：Omer Yasin Birey
2019-1-28
Hi Benson, try this
% b = randi(25,25,1);
% A = randi(25,25,5);
[row,col] = find(abs(A(:,:))>0);
dividCol = bsxfun(@rdivide,b(row,1),A(row,col));
3 个评论
Benson Gou
2019-1-28
Omer Yasin Birey
2019-1-28
Yes I checked the code and it does every operation twice. I had to use loop and updated the code. Try it instead.
% b = randi(25,7,1);
% A = randi(25,7,14);
for i = 1:M
nonCol = find(abs(A(:,i))>0);
dividCol = bsxfun(@rdivide,b(nonCol),A(nonCol,i));
end
Benson Gou
2019-1-28
更多回答（0 个）
类别
在 帮助中心 和 File Exchange 中查找有关 Electrophysiology 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
