rTensor (version 1.4)

k_fold: k-mode Folding of Matrix

Description

k-mode folding of a matrix into a Tensor. This is the inverse funtion to k_unfold in the m mode. In particular, k_fold(k_unfold(tnsr, m),m,getModes(tnsr)) will result in the original Tensor.

Usage

k_fold(mat, m = NULL, modes = NULL)

Arguments

mat

matrix to be folded into a Tensor

m

the index of the mode that is mapped onto the row indices

modes

the modes of the output Tensor

Value

Tensor object with modes given by modes

Details

This is a wrapper function to fold.

References

T. Kolda, B. Bader, "Tensor decomposition and applications". SIAM Applied Mathematics and Applications 2009.

See Also

k_unfold-methods, fold, unmatvec

Examples

# NOT RUN {
tnsr <- new("Tensor",3L,c(3L,4L,5L),data=runif(60))
matT2<-k_unfold(tnsr,m=2)
identical(k_fold(matT2,m=2,modes=c(3,4,5)),tnsr)
# }