How to check that all entries in a cell array have the same size?

Question

I have a cell array `C` that whose elements are n-dimensional numeric arrays. For example: ``` C = {[111 121 131; 211 221 231], ... [112 122 132; 212 222 232], ... [113 123 133; 213 223 233], ... [114 124 134; 214 224 234]}; ``` I'm looking for a convenient way to test that they all the nd-arrays in `C` have the same shape (as reported by the `size` function). The criterion for equality here is not entirely trivial. Depending on the situation one may want to regard a shape of `[2 3 4]` different from or equal to a shape of, say, `[1 2 3 4]` or `[2 1 3 1 4]`. For my immediate purposes I want to treat `[2 3 4]` as different from `[1 2 3 4]`, etc. (BTW: order always matters; e.g., `[2 3 4]` is never equal to `[4 3 2]`, say.) I tried several things (such as, getting the length of `unique(C)`), but they all fail... (After almost two years of use, my MATLAB instincts remain close to null.)

Accepted Answer

Test the size of each cell of `C` against the size of one cell, for example the first. For testing equality of sizes you need `isequal` (`==` won't do because the sizes of the sizes may be different).

```
all(cellfun(@(e) isequal(size(C{1}), size(e)) , C(2:end)))
```

If you want to consider a size `[2 3 4]` equal to `[1 2 3 4]` etc, just add `squeeze`:

```
size1 = size(squeeze(C{1}));
all(cellfun(@(e) isequal(size1, squeeze(size(e))) , C(2:end)))
```

How to check that all entries in a cell array have the same size?

Solution

Problem