| Syntax: |
vector = UNFOLD( matrix )
|
The UNFOLD function has one argument, which must be a
matrix. The result is a vector formed by unfolding the rows of the matrix.
Suppose that matrix m has r rows and c columns.
Then
UNFOLD(m)[i+(j-1)*r] = m[i,j] for i = 1,2,...,r and
j = 1,2,...,c.
Examples
If X is a vector and N is a scalar such than
LEN(X) is divisible by N, then
UNFOLD(FOLD(X,N)) is equal to X
If M is a matrix with R rows, then
FOLD(UNFOLD(M),R) is equal to M
Suppose that
| 1 4 7 10 |
M = | 2 5 8 11 |
| 3 6 9 12 |
| function | result |
UNFOLD(M) |
[1;2;3;4;5;6;7;8;9;10;11;12] |