Partitioning cell of matrices

I have a set of images that are in one cell array in the form of matrices.

>> img_mat

img_mat =

1×325 cell array

Columns 1 through 2

    {256×256 uint8}    {256×256 uint8}

Columns 3 through 4

    {256×256 uint8}    {256×256 uint8}
...

These images are classified in 5 different types (e.g. lions, buildings) and I need to partition them into 10 sets, 5 training sets and 5 testing sets.

I tried

cvpartition(img_mat,'holdout',125)

which doesn't work because it needs to be numerical or categorical

And I tried

[SetA, SetATest,...SetE, SetETest] = partition(img_mat, [45, 25, 45, 25, 45, 25, 45, 25, 45, 25],'sequential');

but I get this error:

    Undefined function 'partition' for input
arguments of type 'cell'.

I'm not really sure how to go about partitioning them, and later testing them.

Answer 1

[Ariel Avshalumov]

I found the answer now. I over complicated things, its as simple as:

    setA=img_mat(1:45);
[setA,setATest]=img_mat([1:45,45:65]);