| Syntax: |
matrix = FOLD( vector, scalar )
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The FOLD function has two arguments. The first
must be a vector, and the second a scalar. The result is a matrix formed by folding the
data in the vector into the columns of a matrix.
Suppose that vector x has m elements. Then
FOLD(x,n)[i,j] = x[i+(j-1)*n]
for i = 1,2,...,n and j = 1,2,...,m/n.
Note that m must be divisible by n.
Examples
If M is a matrix with R rows, then
FOLD(UNFOLD(M),R) is equal to M.
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.
| function | result | ||||
FOLD([1:12],3) |
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FOLD([1:12],4) |
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