OffsetArrays.jl

OffsetArrays provides Julia users with arrays that have arbitrary indices, similar to those found in some other programming languages like Fortran.

Usage

You can construct such arrays as follows:

OA = OffsetArray(A, axis1, axis2, ...)

where you want OA to have axes (axis1, axis2, ...) and be indexed by values that fall within these axis ranges. Example:

using OffsetArrays
A = reshape(1:15, 3, 5)
println("here is A:")
display(A)
OA = OffsetArray(A, -1:1, 0:4)    # OA will have axes (-1:1, 0:4)
println("here is OA:")
display(OA)
@show OA[-1,0] OA[1,4]

which prints out

here is A:
3×5 reshape(::UnitRange{Int64}, 3, 5) with eltype Int64:
 1  4  7  10  13
 2  5  8  11  14
 3  6  9  12  15
here is OA:
OffsetArray(reshape(::UnitRange{Int64}, 3, 5), -1:1, 0:4) with eltype Int64 with indices -1:1×0:4:
 1  4  7  10  13
 2  5  8  11  14
 3  6  9  12  15
OA[-1, 0] = 1
OA[1, 4] = 15