how to multiply one array of vector in another ?

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Amin Gan
Amin Gan 2016-2-10
评论： Star Strider 2016-2-10
There are two same size vectors,A and B (1*2000 in size).
for each value of A must be used in equation below for all B values:
equation=A+A^2+B
for example:
A=[1 2 3]
B=[10 20 30]
I want following results:
1+1^2+10 , 1+1^2+20, 1+1^2+30
2+2^2+10 , 2+2^2+20, 2+2^2+30
3+3^2+10 , 3+3^2+20, 3+3^2+30
But, A and B both are 2000 in size, I expect to get 2000*2000 matrix for eqn.
can you please advise?
Thnks

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Star Strider
Star Strider 2016-2-10
Use bsxfun:
A=[1 2 3];
B=[10 20 30];
equation = bsxfun(@plus, (A'+A'.^2), B)
equation =
12 22 32
16 26 36
22 32 42
  2 个评论
Amin Gan
Amin Gan 2016-2-10
Thank you for your reply.
If I had a more complex equation such as:
eqn=A+sqrt(A^2-B), can I use bsxfun ?
thank you
Star Strider
Star Strider 2016-2-10
My pleasure.
Yes. You can ‘nest’ the bsxfun calls:
eqn = bsxfun(@plus, A', sqrt(bsxfun(@minus, A'.^2, B)));
or break them out into two or three lines to make them easier to read and (if necessary) troubleshoot:
eqn1 = bsxfun(@minus, A'.^2, B);
eqn2 = sqrt(eqn1);
eqn = bsxfun(@plus, A', eqn2)
Both produce:
eqn =
1 + 3i 1 + 4.3589i 1 + 5.3852i
2 + 2.4495i 2 + 4i 2 + 5.099i
3 + 1i 3 + 3.3166i 3 + 4.5826i
The results are complex, because you’re taking the square root of negative numbers.

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