fold

General folding of a matrix into a Tensor. This is designed to be the inverse function to <code>unfold-methods</code>, with the same ordering of the indices. This amounts to following: if we were to unfold a Tensor using a set of <code>row_idx</code> and <code>col_idx</code>, then we can fold the resulting matrix back into the original Tensor using the same <code>row_idx</code> and <code>col_idx</code>.

A set of tools for creation, manipulation, and modeling
of tensors with arbitrary number of modes. A tensor in the context of data
analysis is a multidimensional array. rTensor does this by providing a S4
class 'Tensor' that wraps around the base 'array' class. rTensor
provides common tensor operations as methods, including matrix unfolding,
summing/averaging across modes, calculating the Frobenius norm, and taking
the inner product between two tensors. Familiar array operations are
overloaded, such as index subsetting via '[' and element-wise operations.
rTensor also implements various tensor decomposition, including CP, GLRAM,
MPCA, PVD, and Tucker. For tensors with 3 modes, rTensor also implements
transpose, t-product, and t-SVD, as defined in Kilmer et al. (2013). Some
auxiliary functions include the Khatri-Rao product, Kronecker product, and
the Hadamard product for a list of matrices.

Koki Tsuyuzaki

rTensor

Tools for Tensor Analysis and Decomposition

James Li

Jacob Bien

Martin Wells

fold function

<dl><dt>mat</dt>
<dd>matrix to be folded into a Tensor</dd>
<dt>row_idx</dt>
<dd>the indices of the modes that are mapped onto the row space</dd>
<dt>col_idx</dt>
<dd>the indices of the modes that are mapped onto the column space</dd>
<dt>modes</dt>
<dd>the modes of the output Tensor</dd></dl>

Arguments

General Folding of Matrix — fold

<dl>

<dt>mat</dt>
<dd>matrix to be folded into a Tensor</dd>


<dt>row_idx</dt>
<dd>the indices of the modes that are mapped onto the row space</dd>


<dt>col_idx</dt>
<dd>the indices of the modes that are mapped onto the column space</dd>


<dt>modes</dt>
<dd>the modes of the output Tensor</dd>

</dl>

fold: General Folding of Matrix

Description

Usage

Value

Arguments

Details

References

See Also

Examples