How to multiply 4D array.

2015 12 17
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更新时间：2016 1 20
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0 个投票

i want to multiply
L(:,:,k,:).*M(:,:,k,:);
i want to multiply without loop.

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Christine Tobler
Christine Tobler 2015-12-17
编辑：Christine Tobler 2015-12-17

0 个投票

You could try downloading the tensor toolbox by Kolda and Bader, where this is provided as a command ttt(L, M, 3, 3). Alternatively, you can use the following code:
permL = permute(L, [3 1 2 4]);
permM = permute(M, [3 1 2 4]);
szL = size(L);
szM = size(M);
result = permL(:, :)'*permM(:, :);
result = reshape(result, [szL([1 2 4]), szM([1 2 4])]);
This returns a 6-dimensional array result, such that
result(i1, i2, i3, j1, j2, j3)
is the same as
a = 0; for k=1:size(L, 3), a = a + L(i1, i2, k, i3)*M(j1, j2, k, j3); end; a
Is this what you wanted to compute?

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Triveni
Triveni 2015-12-18
编辑：Matt J 2016-1-20
plyangle = [45 45 45 45 45 45 0 0 0 0 0 0 0 0 45 45 45 45 45 45];
N1 = 2;
p1 = randi(numel(plyangle), [1 20 N1]);
plyangle = plyangle(p1);
for i= 1:2
for k = 1:20
a(:,:,i,k)= cosd (plyangle(:,k,i));
b(:,:,i,k)= sind (plyangle(:,k,i));
L(:,:,k,i) = [a(:,:,i,k)*b(:,:,i,k) 0 (a(:,:,i,k))^2;
0 0 b(:,:,i,k);
a(:,:,i,k)*b(:,:,i,k) 0 0;];
M(:,:,k,i) = [a(:,:,i,k)*b(:,:,i,k) 0 (a(:,:,i,k))^2;
0 0 b(:,:,i,k);
a(:,:,i,k)*b(:,:,i,k) 0 0;];
end
end
can you correct this?? I think it's wrong.
Christine Tobler
Christine Tobler 2015-12-18
I'm not sure what you want L and M to be, can you explain in more detail?

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Walter Roberson
Walter Roberson 2015-12-17

1 个投票

L.*M
Somehow I suspect that your question missed some information...

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