Matricization

In mathematics, matricization (also matricisation, matricizing, unfolding, or flattening^[1]) is the operation that turns a tensor (a multi-dimensional array) into a matrix (a two-dimensional array).

Matricization may be regarded as a generalization of the mathematical concept of vectorization.

Matricization may be applied in connection with determination of the factors in the PARAFAC model.

1. ^ A Newton--Grassmann Method for Computing the Best Multilinear Rank-(r1, r2, r3) Approximation of a Tensor, Lars Elden and Berkant Savas, SIAM. J. Matrix Anal. & Appl. 31, 248 (2009), DOI:10.1137/070688316