Passing a WCSTransform type variable to a function calling world_to_pix, and called under a Distributed.pmap command

[fpaletou-hub]

Dear colleagues,

I'm having a hard time trying to figure out how to properly pass (as an argument) a WCSTransform type variable to a function (into which I use world_to_pix), and that I want to run on several cores using a Distributed.pmap command.

May I expect something wrong because of the very WCSTransform type, for instance?

Thanx

[cgarling]

Is there a particular error you are experiencing? The following example usage of Distributed works without error:

using Distributed: pmap, @everywhere

@everywhere begin
    using WCS: WCSTransform, world_to_pix

    # Generic WCS
    wcs = WCSTransform(2)

    # Some target function
    f(coords) = world_to_pix(wcs, coords)

    # Make matrix with dimensions (2, Nstars) of coordinates
    Nstar = 100
    ra = rand(Nstar) * 360
    dec = (rand(Nstar) .- 0.5) .* 180
    mycoords = stack([ra, dec]; dims=1)

    # Make a vector of coordinate matrices for parallel processing
    # by repeating mycoords
    # Type is Vector{Matrix{Float64}}
    p_mycoords = [mycoords for _ in 1:5]

end

result1 = f(mycoords) # Works

result2 = pmap(f, p_mycoords) # Works

# Check that each entry in result2 is equal to result1
all(i == result1 for i in result2)

[fpaletou-hub]

Thank you, I'll try to figure out asap from your example what I did wrong in my script.