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How to perform an array multiplication for a vector and a matrix and output results as a matrix?

2 Ansichten (letzte 30 Tage)
Here is the problems and solution which seems very bad. Could anyone suggest a better solution?
M = [1 2 3];
C = [10 11 12; 13 14 15; 16 17 18; 19 20 21; 22 23 24];
K1=C(1,:).*M
K2=C(2,:).*M
K3=C(3,:).*M
K4=C(4,:).*M
K5=C(5,:).*M
B = vertcat(K1,K2,K3,K4,K5)

Akzeptierte Antwort

the cyclist
the cyclist am 5 Jul. 2013
Bearbeitet: the cyclist am 5 Jul. 2013
You might want this instead:
B = bsxfun(@times,C,M)

Weitere Antworten (2)

the cyclist
the cyclist am 5 Jul. 2013
Bearbeitet: the cyclist am 5 Jul. 2013
Matrix multiplication is a core MATLAB function. I think you just want
B = C * M'
Notice that that is just a "*", not a ".*" (which is element-by-element) multiplication, and that I had to transpose M.
  3 Kommentare
the cyclist
the cyclist am 5 Jul. 2013
Bearbeitet: the cyclist am 5 Jul. 2013
I forgot the transpose when I first posted. Also, I just looked at your B matrix, and it seems you do not want simply matrix multiplication after all.
You expect the result to be a 5x3 and not a 5x1, right?
Alex Khazaradze
Alex Khazaradze am 5 Jul. 2013
Thanks, for help, but if B=C * M' I get the answer: B =
68
86
104
122
140
While I would like to have following: B =
10 22 36
13 28 45
16 34 54
19 40 63
22 46 72

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freebil
freebil am 5 Jul. 2013
Bearbeitet: freebil am 5 Jul. 2013
I think this works:
M = [1 2 3];
C = [10 11 12; 13 14 15; 16 17 18; 19 20 21; 22 23 24];
for i=1:length(C)
result(i,:)=M.*C(i,:);
end

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