Specifying dimensions in mat2cell

a 4 by 5 MatriX

A =
     1     2     3     4     5
     6     7     8     9    10
    11    12    13    14    15
    16    17    18    19    20

The Mathwork example divide sA into two 2-by-3 and two 2-by-2 subarrays:

C = mat2cell(A,[2 2],[3 2])

What are the indices here in the dimension statement:

Does [2,2] refer to 2 tables w two rows each

Does [3,2] specify the first set of tables has 3 rows, the second set 2 rows.

I can't understand or see the pattern in how the dimensions are set in mat2cell

Thank you, Nancy

[Nancy Hammond]

C{1,1} =

1 2 3

6 7 8

C{1,2}=

4 5

9 10

C{2,1} =

11 12 13

16 17 18

C{2,2}=

14 15

19 20

[Nancy Hammond]

Correction: Should read

Does [3,2] specify the first set of tables has 3 cols, the second set 2 cols.

[Walter Roberson]

"Does [3,2] specify the first set of tables has 3 cols, the second set 2 cols."

Yes.

Answer 1

[Walter Roberson]

C = mat2cell(A,[2 2],[3 2])

means that numeric matrix A is to be broken up into cells.

The first row of cells is to have [2 2][1] -> 2 rows. The second row of cells is to have [2 2][2] -> 2 rows. This is a total of sum([2 2]) = 4 rows, and it is an error if A does not have that many rows.

The first column of cells is to have [3 2][1] -> 3 columns. The second column of cells is to have [3 2][2] -> 2 columns. This is a total of sum([3 2]) = 5 columns, and it is an error if A does not have that many columns.

Thus, the sizes of the entries in C will be all combinations of [2 2] with [3 2], so

{size [2, 3], size [2, 2]  -> leading 2 from the first 2 in [2 2]
 size [2, 3], size [2, 2]} -> leading 2 from the second 2 in [2 2]

[Nancy Hammond]

Thank you, Walter. At last, very clear. Nancy