A question about product operation

2013 9 16
2 个回答
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1 个投票

Hello all!
I'm not sure if this was explained before, but I could not find any answer to this.
So, if i have x=[a b c] and y=[d e f] I'd like to know (if it's possible) how I could obtain:
.
z=
h i j
k l m
n o p
where:
h=a*d k=a*e n=a*f
i=b*d l=b*e o=b*f
j=c*d m=c*e p=c*f
Thanks!

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Jan
Jan 2013-9-16
编辑：Jan 2013-9-16

1 个投票

x = [1, 2, 3]
y = [10, 20, 30]
z = x' * y
The matrix multiplication of a column vector with a row vector replies the dyadic product. x*y' would reply the dot-product.
Slower alternative:
z = bsxfun(@times, x', y)

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Simon
Simon 2013-9-16
Beaten by 1 minute ... ;-)
Dan P
Dan P 2013-9-17
Could you tell me how i could implement this in Simulink?
I put two constant blocks (one with x and one with y) and i put a product block. At the output of X, before connecting to the first input of the product i have to put a transpose block. I've tried "Transpose" and "Reshape" blocks but they didn't do the job. (the result it's not a 3x3 matrix) I also tried to use the blocks from the "User-defined functions" but I did not succeed.
Yes, if i make a .m file or simply type in command line z=x'*y it works (i have a 3x3 vector in workspace called z).
Any idea how this can be done in Simulink?
Jan
Jan 2013-9-17
As described in the documentation, you can set the product block to "Matrix Mode". I've never worked with Simulink, but Google showed me this information after a few seconds of searching. Does it help already?
Sean de Wolski
Sean de Wolski 2013-9-17
Of course you could also put this inside of a MATLAB function block.
Jan
Jan 2013-9-17
Dan p wrote:
I also tried to use the blocks from the "User-defined functions" but I did not succeed.
Please show us, what you have tried and explain "did not succeed" with details.

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更多回答（1 个）

Simon
Simon 2013-9-16
编辑：Simon 2013-9-16

0 个投票

Hi!
x = [1, 2, 3]; % row vector
y = [2; 3; 4]; % column vector
z = y * x;

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