mat2cell (MATLAB Functions)

Divide matrix into cell array of matrices

Syntax

c = mat2cell(x,m,n)
c = mat2cell(x,d1,d2,d3,...,dn)
c = mat2cell(x,r)

Description

c = mat2cell(x,m,n) divides up the two-dimensional matrix x into adjacent submatrices, each contained in a cell of the returned cell array, c. Vectors m and n specify the number of rows and columns, respectively, to be assigned to the submatrices in c.

The example shown below divides a 60-by-50 matrix into six smaller matrices. MATLAB returns the new matrices in a 3-by-2 cell array:

```
mat2cell(x, [10 20 30], [25 25]) 
```

The sum of the element values in m must equal the total number of rows in x. And the sum of the element values in n must equal the number of columns in x.

The elements of m and n determine the size of each cell in c by satisfying the following formula for i = 1:length(m) and j = 1:length(n):

```
size(c{i,j}) == [m(i) n(j)]
```

c = mat2cell(x,d1,d2,d3,...,dn) divides up the multidimensional array x and returns a multidimensional cell array of adjacent submatrices of x. Each of the vector arguments, d1 through dn, should sum to the respective dimension sizes of x, such that, for p = 1:n,

```
size(x,p) == sum(dp)
```

The elements of d1 through dn determine the size of each cell in c by satisfying the following formula for ip = 1:length(dp):

size(c{i1,i2,i3,...,in}) == [d1(i1) d2(i2) d3(i3) ... dn(in)]

If x is an empty array, mat2cell returns an empty cell array. This requires that all dn inputs that correspond to the zero dimensions of x be equal to [].

For example,

a = rand(3,0,4);
c = mat2cell(a, [1 2], [], [2 1 1]);

c = mat2cell(x,r) divides up an array x by returning a single column cell array containing full rows of x. The sum of the element values in vector r must equal the number of rows of x.

The elements of r determine the size of each cell in c, subject to the following formula for i = 1:length(r):

```
size(c{i},1) == r(i)
```

Remarks

mat2cell supports all array types.

Examples

Divide matrix X up into 2-by-3 and 2-by-2 matrices contained in a cell array:

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

C = mat2cell(X, [2 2], [3 2])
C = 
    [2x3 double]    [2x2 double]
    [2x3 double]    [2x2 double]

C{1,1}                          C{1,2}
ans =                           ans =
     1     2     3                   4     5
     6     7     8                   9    10

C{2,1}                          C{2,2}
ans =                           ans =
    11    12    13                  14    15
    16    17    18                  19    20

See Also

cell2mat, num2cell

magic mat2str