4 ms·
using LinearAlgebra, SparseArrays N = 10 D1 = sparse(Tridiagonal(ones(N-1),-2ones(N),ones(N-1))) Id = sparse(I,N,N) A = kron(D1,Id) + kron(Id,D1
by ChrisRackauckas 5y ago
using LinearAlgebra, SparseArrays
N = 10
D1 = sparse(Tridiagonal(ones(N-1),-2ones(N),ones(N-1)))
Id = sparse(I,N,N)
A = kron(D1,Id) + kron(Id,D1)
You just use the Kronecker product to build the matrix in the different directions. This, along with the relationship to convolutional neural networks, is described in the MIT 18.337 course notes: https://mitmath.github.io/18337/lecture14/pdes_and_convolutions https://mitmath.github.io/18337/lecture14/pdes_and_convoluti...