Matrix Multiplication is possible???

2013 8 15
4 个回答
1 次查看（30 天）

0 个投票

Hi Can i programm under matlab Matrix multiplication generally without use of general entries
C = A*B is the linear algebraic product of the matrices A and B. If A is an m-by-p and B is a p-by-n matrix
Thanks

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回答（4 个）

Image Analyst
Image Analyst 2013-8-15

0 个投票

What are "general entries"? If you want the matrix multiplication, simply do C=A*B like you said. If you want element-by-element multiplication, do C=A.*B. So I'm not sure what you're asking. Did you actually try C=A*B like you said - it's easy enough to do. If so, was there something unexpected that you observed?
Marwen
Marwen 2013-8-15

0 个投票

Hi I develop simples examples like that A = [ 1 2 3; 4 5 6] B = [-5 8 11; 3 9 21;4 0 8] C=A*B
I want now to use A and B like this http://www.mathworks.com/help/matlab/ref/eqn1299169082.png
and enter i and j manually I hope you understand me
Thanks dear

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Image Analyst
Image Analyst 2013-8-15
No, I don't. I don't even see a question in your "Answer" - do you have one? Or are you just making a comment or letting us know that you are willing to develop simple examples for people to solve their problems? Perhaps you can create a new discussion and in there ask a question, if you have one. http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer
Marwen
Marwen 2013-8-15
编辑：Azzi Abdelmalek 2013-8-15
Hi Image analyste,
I want to develop something like that with Matlab :
nt A[50][50];
printf("Donner le nombre des lignes de la matrice A\n");
scanf("%d",&l);
printf("Donner le nombre des colonnes de la matrice A\n");
scanf("%d",&c);
printf("Enter les elements de la matrice A\n");
for(i=0;i<l;i++)
for(j=0;j<c;j++)
{
printf("Enter la valeur de A[%d][%d] ",i,j);
scanf("%d",&A[i][j]);
printf("\n");
}
i wish i clear my question thks
Image Analyst
Image Analyst 2013-8-15
OK. I'm going to assume that the code you gave does what you want to do. I still don't see a question here, so I guess we're done.

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Azzi Abdelmalek
Azzi Abdelmalek 2013-8-15
编辑：Azzi Abdelmalek 2013-8-15

0 个投票

A=randi(10,5,6); % Example
B=randi(10,6,7);
p=size(A,2);
C=@(i,j) sum(A(i,:)'.*B(:,j))
% If i=2 and j=6 use
C(2,6)
Which is the same as
C=A*B
C(2,6)

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Marwen
Marwen
2013-8-15

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