Gridded interpolation with single knot

[jaemolihm]

Interpolations.jl/src/gridded/gridded.jl

Line 74 in 4316c04

length(k1) == 1 && error("dimensions of length 1 not yet supported") # FIXME

In this line of gridded.jl, length(k1) == 1 is disabled. But when I just remove that line, I get expected behavior:

f = interpolate(([1.],), [5.], Gridded(Constant()))
@test bounds(f) == ((1., 1.),)
@test f(1.) == 5.0
@test_throws BoundsError f(nextfloat(1.))
@test_throws BoundsError f(prevfloat(1.))

Can we just remove that line? Or is there something not implemented?

[jaemolihm]

I found that this line becomes a problem (bounds error). (It did not get caught in my REPL run because of @inbounds.)

Interpolations.jl/src/gridded/indexing.jl

Line 70 in 4316c04

@inbounds l, u = knotvec[iclamp], knotvec[iclamp+1]

[ryofurue]

The error message is "dimensions of length 1 not yet supported", which suggests that it will eventually be implemented?

My current code depends on the behavior of interpolator

itp = linear_interpolation(xs,ys; extrapolation_bc = NaN)

that it returns NaN when asked to "interpolate" for out-of-range points.

In that way, my code gracefully would handle a single-knot case if the interpolator returned NaN.