# tensorly.parafac2_tensor.parafac2_to_tensor

parafac2_to_tensor(parafac2_tensor)[source]

Construct a full tensor from a PARAFAC2 decomposition.

The decomposition is on the form such that the i-th frontal slice, , of is given by

where is the diagonal matrix whose nonzero entries are equal to the -th row of the factor matrix , is a factor matrix such that the cross product matrix is constant for all , and is a factor matrix. To compute this decomposition, we reformulate the expression for such that

where is a orthogonal matrix and is a matrix.

An alternative formulation of the PARAFAC2 decomposition is that the tensor element is given by

with the same constraints hold for as above.

Parameters: parafac2_tensorParafac2Tensor - (weight, factors, projection_matrices) weights1D array of shape (rank, )weights of the factors factorsList of factors of the PARAFAC2 decompositionContains the matrices , and described above projection_matricesList of projection matrices used to create evolvingfactors. ndarrayFull constructed tensor. Uneven slices are padded with zeros.