Construct a lazy Kronecker product — kron

Creates a KronMatrix that stores the factor matrices A and B without materializing the full Kronecker product. Standard operations such as %*%, crossprod, solve, and determinant are available and exploit the Kronecker structure.

Usage

kron_matrix(A, B)

Arguments

A: Numeric matrix or object coercible via as.matrix(); the left Kronecker factor.
B: Numeric matrix or object coercible via as.matrix(); the right Kronecker factor.

Value

A KronMatrix of implicit dimensions c(nrow(A) * nrow(B), ncol(A) * ncol(B)).

Examples

A <- matrix(1:4, 2, 2)
B <- diag(3)
K <- kron_matrix(A, B)
dim(K)
#> [1] 6 6
as.matrix(K)
#>      [,1] [,2] [,3] [,4] [,5] [,6]
#> [1,]    1    0    0    3    0    0
#> [2,]    0    1    0    0    3    0
#> [3,]    0    0    1    0    0    3
#> [4,]    2    0    0    4    0    0
#> [5,]    0    2    0    0    4    0
#> [6,]    0    0    2    0    0    4