Multiplying two vectors to form a matrix

2022 2 25
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更新时间：2022 2 25
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Hello, I have two vectors x and y, both 601x1. I want to multiply them to form a matrix of 601x601, but the values inside the matrix have to be sqrt(x^2+y^2). How do I do this? Thanks.

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Jan
Jan 2022-2-25
编辑：Jan 2022-2-25

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z = sqrt(x .^ 2 + y.' .^ 2)
But, of course, this does not match "multiply them". If you want a multiplication:
x .* y.'
[EDITED] For Matlab versions < R2016b:
z = sqrt(bsxfun(@plus, x.'.^2, y.^2))

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Nikola Segedin
Nikola Segedin 2022-2-25
Multiplication is not the right word, I agree. I've tried this and all I got is "Error using plus, Matrix dimensions must agree.".
Jan
Jan 2022-2-25
See my comment under Walter's answer.

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更多回答（2 个）

KSSV
KSSV 2022-2-25
Ran in:

1 个投票

Ran in:
x = rand(601,1) ;
y = rand(601,1) ;
iwant = sqrt(x.^2+y'.^2) ;
size(iwant)
ans = 1×2
601 601
Walter Roberson
Walter Roberson 2022-2-25

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D = sqrt(x.'.^2 + y.^2)

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Walter Roberson
Walter Roberson 2022-2-25
The difference between my answer and the nearly-simultaneous answers by @KSSV and @Jan is that I arranged for the x coordinates to run horizontally but they have the x coordinates run vertically.
Nikola Segedin
Nikola Segedin 2022-2-25
I've tried this and all I got is "Error using plus, Matrix dimensions must agree.".
Jan
Jan 2022-2-25
@Nikola Segedin: Which Matlab versionare you using? Since R2016b an "implicit expanding" is applied. For former versions:
D = sqrt(bsxfun(@plus, x.'.^2, y.^2))
Nikola Segedin
Nikola Segedin 2022-2-25
I'm using R2010b. Thank you, this works for me!

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