Gradients of 3D extrapolations not working.

[natschil]

The following minimal working example fails for me very cryptically:

using Interpolations

xs = 1:10
itp = Interpolations.scale(Interpolations.interpolate(zeros(10),BSpline(Cubic(Periodic())), OnGrid()),xs)
extp = Interpolations.extrapolate(itp,Periodic())
gradient(extp,2.,2.)

I get an error beginning with

ERROR: LoadError: UndefVarError: d not defined

Do extrapolation objects support computing gradients?

[tomasaschan]

Extrapolation objects should, but I'm not sure how well-tested the implementation is for the combination of extrapolation and >1D.

For reference, here's the full stack trace:

UndefVarError: d not defined

Stacktrace:
 [1] macro expansion at /home/jrun/.julia/v0.6/Interpolations/src/extrapolation/periodic.jl:23 [inlined]
 [2] macro expansion at /home/jrun/.julia/v0.6/Interpolations/src/extrapolation/extrap_prep_gradient.jl:49 [inlined]
 [3] macro expansion at /home/jrun/.julia/v0.6/Interpolations/src/extrapolation/extrapolation.jl:74 [inlined]
 [4] gradient! at /home/jrun/.julia/v0.6/Interpolations/src/extrapolation/extrapolation.jl:81 [inlined]
 [5] gradient(::Interpolations.Extrapolation{Float64,1,Interpolations.ScaledInterpolation{Float64,1,Interpolations.BSplineInterpolation{Float64,1,Array{Float64,1},Interpolations.BSpline{Interpolations.Cubic{Interpolations.Periodic}},Interpolations.OnGrid,0},Interpolations.BSpline{Interpolations.Cubic{Interpolations.Periodic}},Interpolations.OnGrid,Tuple{UnitRange{Int64}}},Interpolations.BSpline{Interpolations.Cubic{Interpolations.Periodic}},Interpolations.OnGrid,Interpolations.Periodic}, ::Float64, ::Float64) at /home/jrun/.julia/v0.6/Interpolations/src/b-splines/indexing.jl:110