How to calculate multiplying two matrices using (for) and (if) loops together ???

Question

hcourah same 2018-12-14

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/435849-how-to-calculate-multiplying-two-matrices-using-for-and-if-loops-together

评论： Walter Roberson 2018-12-20

How to calculate multiplying two matrices provided that the number of line elements in the first matrix equals the number of column elements in the second matrix (using the loop (for) and (if) together) thank you

3 个评论
显示 1更早的评论隐藏 1更早的评论

Image Analyst 2018-12-15

I think you got the requirement wrong: "the number of line elements in the first matrix equals the number of column elements in the second matrix"

It should be, with r1xc1 * r2xc2, then c1 must equal r2 - the number of columns of the first matrix must equal the number of rows in the second matrix, not what you said. You'll see MATLAB using jargon like "the inner dimensions must match" meaning c1 = r2.

Anyway, see hints below in the Answers section.

Walter Roberson 2018-12-20

please do not close questions that have an answer

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Image Analyst 2018-12-15

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/435849-how-to-calculate-multiplying-two-matrices-using-for-and-if-loops-together#answer_352546

在 MATLAB Online 中打开

Hint:

if ~isequal(R, G)
        uiwait(errordlg('The matrices are not the same size'));
        return;
end

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

Answer 2

Omer Yasin Birey 2018-12-15

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/435849-how-to-calculate-multiplying-two-matrices-using-for-and-if-loops-together#answer_352547

编辑：Omer Yasin Birey 2018-12-15

在 MATLAB Online 中打开

Hi hcourah, you can add try - catch to send the message

for i=1:n
    for j=1:m
        try 
            c(i,j)=A(i,:)*b(:,j);
        catch 
            warning('The matrices are not the same dimension.')        
        end
    end
end