Khatri–Rao product
In mathematics, the Khatri–Rao product or block Kronecker product of two partitioned matrices A {\displaystyle \mathbf {A} } and B {\displaystyle \mathbf {B} } is defined as A ∗ B = ( A i j ⊗ B i j ) i j {\displaystyle \mathbf {A} \ast \mathbf {B} =\left(\mathbf {A} _{ij}\otimes \mathbf {B} _{ij}\right)_{ij}} in which the ij-th block is the mipi × njqj sized Kronecker product of the corresponding blocks of A and B, assuming the number of row and column partitions of both matrices is equal. The size of the product is then (Σi mipi) × (Σj njqj).