tensorly.tenalg.unfolding_dot_khatri_rao

unfolding_dot_khatri_rao(tensor, cp_tensor, mode)[source]

mode-n unfolding times khatri-rao product of factors

Parameters:

tensortl.tensor

tensor to unfold

factorstl.tensor list

list of matrices of which to the khatri-rao product

modeint

mode on which to unfold tensor

Returns:

mttkrp

dot(unfold(tensor, mode), khatri-rao(factors))

Notes

Default unfolding_dot_khatri_rao implementation.

Implemented as the product between an unfolded tensor and a Khatri-Rao product explicitly formed. Due to matrix-matrix products being extremely efficient operations, this is a simple yet hard-to-beat implementation of MTTKRP.

If working with sparse tensors, or when the CP-rank of the CP-tensor is comparable to, or larger than, the dimensions of the input tensor, however, this method requires a lot of memory, which can be harmful when dealing with large tensors. In this case, please use the memory-efficient version of MTTKRP.

To use the slower memory efficient version, run

>>> from tensorly.tenalg.core_tenalg.mttkrp import unfolding_dot_khatri_rao_memory
>>> tl.tenalg.register_backend_method("unfolding_dot_khatri_rao", unfolding_dot_khatri_rao_memory)
>>> tl.tenalg.use_dynamic_dispatch()