Erorr in my code

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Esra Demirbilek 2022-3-18

0
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https://ww2.mathworks.cn/matlabcentral/answers/1674989-erorr-in-my-code

评论： Esra Demirbilek 2022-3-18

Hello everyone,

I am using Matlab 2015a. The code I wrote gives an error. How can I fix the error?

this is my code:

newM = birincifaz.*(1:size(birincifaz,1))';

newM(:,1)=[];

for k=1:size(newM,2)

r=unique(newM(:,k));

r=r(r~=0);

B(:,k)=r(randi(length(r),50,1));

end

----------

Error using .*

Matrix dimensions must agree.

Error in sonhal3 (line 2)

newM = birincifaz.*(1:size(birincifaz,1));

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Answer 1

Image Analyst 2022-3-18

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https://ww2.mathworks.cn/matlabcentral/answers/1674989-erorr-in-my-code#answer_921234

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You're trying to multiply a 2-D matrix by a 1-D column vector that goes from 1 to the number of rows. This will not work in R2015a but will work in later versions where implicit expansion of the column vector to a 2-D matrix will occur. Please upgrade or else use a for loop to do the multiplication

% First way using implicit expansion
birincifaz = randi(9, 3, 5)
birincifaz = 3×5
     8     1     1     2     3
     8     8     9     3     5
     1     1     9     1     3
newM = birincifaz.*(1:size(birincifaz,1))'
newM = 3×5
     8     1     1     2     3
    16    16    18     6    10
     3     3    27     3     9
% Alternate way using a for loop
[rows, columns] = size(birincifaz)
rows = 3
columns = 5
newM = zeros(rows, columns);
for col = 1 : columns
    for row = 1 : rows
        newM(row, col) = birincifaz(row, col) * row;
    end
end
newM
newM = 3×5
     8     1     1     2     3
    16    16    18     6    10
     3     3    27     3     9