## Why are my array dimensions being changed?

Scott Hunter

### Scott Hunter (view profile)

さんによって質問されました 2019 年 6 月 19 日

### Star Strider (view profile)

さんによって コメントされました 2019 年 6 月 19 日
Star Strider

### Star Strider (view profile)

さんの 回答が採用されました
I have a 3D array cart = s x 3 x p double, where s and p are variables chosen as integers by an optimiser. I'm converting this array to the array sph = s x 3 x p through cart2sph;
[sph(:,1,:), sph(:,2,:), sph(:,3,:)] = cart2sph(cart(:,1,:), cart(:,2,:), cart(:,3,:));
This works fine, unless the case happens to be the optimiser choses to set s = 1. Instead of outputting sph = 1 x 3 x p, it outputs sph = p x 3, which causes issues with my code calling the function I do this in.
It only happens with s, I've tried limiting p to 1 only it seems to run fine, can anyone help?

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## 1 件の回答

### Star Strider (view profile)

2019 年 6 月 19 日
採用された回答

You can add the missing dimension.
Experiment with this:
x1 = rand(3,4);
x2(1,:,:) = x1;
To check:
x1s = size(x1)
x2s = size(x2)
produces:
x1s =
3 4
x2s =
1 3 4
You will have to set up the appropriate tests to check the dimensions, then do the assignment.

Star Strider

### Star Strider (view profile)

2019 年 6 月 19 日
That wasn’t in the code you posted, so I didn’t see it.
The optimiser could be using the squeeze function to eliminate the singleton dimensions. If that’s the situation, you would have to add it back.
Scott Hunter

### Scott Hunter (view profile)

2019 年 6 月 19 日
No no as in I adder it after your comment, it gave me the idea. Thanks!
Star Strider

### Star Strider (view profile)

2019 年 6 月 19 日
As always, my pleasure!

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