I am trying to interpolate a 2d function that is defined only on a partial set of my parameters.

Where it is not defined, my 2d array has `NaN`

s. Note that in my example the range of where the function is defined is not a rectangle, but it is a function of x, y.

When I perform the interpolation, I get a function that has all `NaN`

s. Is there a way to overcome this issue?

I am using Interpolations.jl, and my code is like the example in the documentation.

Here is a minimal example which includes `NaN`

s:

```
A_x1 = 1:.1:10
A_x2 = 1:.5:20
f(x1, x2) = log(x1+x2)
A = [f(x1,x2) for x1 in A_x1, x2 in A_x2]
A[1:2, :] .= NaN
A[:, 1:2] .= NaN
itp = interpolate(A, BSpline(Cubic(Line(OnGrid()))))
```

The result of `itp`

is all `NaN`

.