Matrix with two diagonals: Difference between revisions

</lang>

=== Sparse matrix version ===

<lang julia>julia> using LinearAlgebra

julia> twodiagonalsparse(n) = I(n) .| rotl90(I(n))

twodiagonalsparse (generic function with 1 method)

julia> twodiagonalsparse(7)

7×7 SparseArrays.SparseMatrixCSC{Bool, Int64} with 13 stored entries:

1 ⋅ ⋅ ⋅ ⋅ ⋅ 1

⋅ 1 ⋅ ⋅ ⋅ 1 ⋅

⋅ ⋅ 1 ⋅ 1 ⋅ ⋅

⋅ ⋅ ⋅ 1 ⋅ ⋅ ⋅

⋅ ⋅ 1 ⋅ 1 ⋅ ⋅

⋅ 1 ⋅ ⋅ ⋅ 1 ⋅

1 ⋅ ⋅ ⋅ ⋅ ⋅ 1

julia> twodiagonalsparse(8)

8×8 SparseArrays.SparseMatrixCSC{Bool, Int64} with 16 stored entries:

1 ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ 1

⋅ 1 ⋅ ⋅ ⋅ ⋅ 1 ⋅

⋅ ⋅ 1 ⋅ ⋅ 1 ⋅ ⋅

⋅ ⋅ ⋅ 1 1 ⋅ ⋅ ⋅

⋅ ⋅ ⋅ 1 1 ⋅ ⋅ ⋅

⋅ ⋅ 1 ⋅ ⋅ 1 ⋅ ⋅

⋅ 1 ⋅ ⋅ ⋅ ⋅ 1 ⋅

1 ⋅ ⋅ ⋅ ⋅ ⋅ ⋅ 1