run_MPI_test_startingscript.jl

if abspath(PROGRAM_FILE) == @__FILE__
    using Pkg
    Pkg.activate(".")

    import moment_kinetics
	using moment_kinetics.input_structs: grid_input, advection_input
	using moment_kinetics.coordinates: define_coordinate
	using moment_kinetics.chebyshev: setup_chebyshev_pseudospectral
	using moment_kinetics.calculus: derivative!, integral

	discretization = "chebyshev_pseudospectral"

	etol = 1.0e-15
	# define inputs needed for the test
	ngrid = 8 
	nelement = 5
	L = 6.0
	bc = "periodic"
	# fd_option and adv_input not actually used so given values unimportant
	fd_option = ""
	adv_input = advection_input("default", 1.0, 0.0, 0.0)
	# create the 'input' struct containing input info needed to create a
	# coordinate
	input = grid_input("coord", ngrid, nelement, L,
		discretization, fd_option, bc, adv_input)
	# create the coordinate struct 'x'
	x = define_coordinate(input)
	# create arrays needed for Chebyshev pseudospectral treatment in x
	# and create the plans for the forward and backward fast Chebyshev
	# transforms
	spectral = setup_chebyshev_pseudospectral(x)
	# create array for the function f(x) to be differentiated/integrated
	f = Array{Float64,1}(undef, x.n)
	# create array for the derivative df/dx
	df = Array{Float64,1}(undef, x.n)
	# initialize f
	for ix ∈ 1:x.n
		f[ix] = ( (cospi(2.0*x.grid[ix]/x.L)+sinpi(2.0*x.grid[ix]/x.L))
				  * exp(-x.grid[ix]^2) )
	end
	# differentiate f
	derivative!(df, f, x, spectral)
	# integrate df/dx
	intdf = integral(df, x.wgts)

	# Test that error intdf is less than the specified error tolerance etol
	#@test abs(intdf) < etol
	println( "abs(intdf) = ", abs(intdf), ": etol = ",etol)
end