Raw by column wise multiplication of matrices

Question

Sib RV 2020-7-30

0
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https://ww2.mathworks.cn/matlabcentral/answers/573052-raw-by-column-wise-multiplication-of-matrices

编辑： Sib RV 2020-7-30

I want to multiply each row of a matrix with corresponding column(only) of another matrix so that the answer is a column vector.

I know how to do it with for loop. But I am already doing it inside a loop, so want to avoid another loop. Thank you for any suggestions.

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Answer 1

Bruno Luong 2020-7-30

1
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https://ww2.mathworks.cn/matlabcentral/answers/573052-raw-by-column-wise-multiplication-of-matrices#answer_473143

编辑：Bruno Luong 2020-7-30

在 MATLAB Online 中打开

>> A=randi(10,4,3)
A =
     6     5     4
     3     4     1
     8     4    10
     2     8    10
>> B=randi(10,3,4)
B =
     2     4     3     5
     1     5     5     4
     9     8     9    10
>> c = sum(A.'.*B)
c =
    53    40   134   142
    
>> Ct = diag(A*B) % WARNING: many unnecessary calculations by this method 
Ct =
    53
    40
   134
   142
>> A(1,:)*B(:,1)
ans =
    53
>> A(4,:)*B(:,4)
ans =
   142
>> 