move some test into proper testing file

test/MPI_test.jl

@@ -0,0 +1,70 @@
+# test/MPI_test.jl
+using MPI
+using Test
+
+@testset "WaterLilyMPIExt.jl" begin
+    n = 2  # number of processes
+    run(`$(mpiexec()) -n $n $(Base.julia_cmd()) [...]/01-hello.jl`)
+    # alternatively:
+    # p = run(ignorestatus(`$(mpiexec()) ...`))
+    # @test success(p)
+
+    """Flow around a circle"""
+    function circle(n,m,center,radius;Re=250,U=1,psolver=Poisson)
+        body = AutoBody((x,t)->√sum(abs2, x .- center) - radius)
+        Simulation((n,m), (U,0), radius; ν=U*radius/Re, body, psolver=psolver)
+    end
+
+    # local grid size
+    nx = 2^8
+    ny = 2^7
+
+    # init the MPI grid and the simulation
+    r = init_mpi((nx,ny))
+    sim = circle(nx,ny,SA[ny,ny],nx/8)
+
+    (me()==0) && println("nx=$nx, ny=$ny")
+
+    # check global coordinates
+    x1 = loc(0,CartesianIndex(3,3))
+    x2 = loc(CartesianIndex(3,3,1))
+    println("I am rank $r, at global coordinate $x1 and $x2")
+
+    # first we check simple rank matrix
+    sim.flow.σ .= NaN
+    sim.flow.σ[inside(sim.flow.σ)] .= me() #reshape(collect(1:length(inside(sim.flow.σ))),size(inside(sim.flow.σ)))
+    save("sigma_1_$(me()).jld2", "C", sim.flow.σ)
+    # updating halos
+    WaterLily.perBC!(sim.flow.σ,())
+    save("sigma_2_$(me()).jld2", "C", sim.flow.σ)
+
+    # test global sdf
+    global_loc_function(i,x) = x[i]
+    sim.flow.σ .= NaN
+    apply!(global_loc_function,sim.flow.μ₀)
+    # check that the measure uses the correct loc function
+    measure_sdf!(sim.flow.σ,sim.body,0.0)
+    save("sdf_3_$(me()).jld2", "C", sim.flow.σ)
+    # updating the halos here
+    WaterLily.perBC!(sim.flow.σ,())
+    save("sdf_4_$(me()).jld2", "C", sim.flow.σ)
+
+    # test on vector field
+    measure!(sim,0.0)
+    save("mu0_1_$(me()).jld2", "C", sim.flow.μ₀[:,:,1])
+    save("mu0_2_$(me()).jld2", "C", sim.flow.μ₀[:,:,2])
+
+    #try a momentum step
+    sim = circle(nx,ny,SA[ny,ny],nx/8)
+    mom_step!(sim.flow,sim.pois)
+    me()==0 && println("mom_step! with $(sim.pois.n) MG iters $(typeof(sim.pois))")
+    save("mom_step_$(me())_p.jld2","C",sim.flow.p)
+    save("mom_step_$(me())_u1.jld2","C",sim.flow.u[:,:,1])
+    save("mom_step_$(me())_u2.jld2","C",sim.flow.u[:,:,2])
+
+    # test norm functions
+    sim.pois.r .= 0.0
+    me() == 2 && (sim.pois.r[32,32] = 123.456789) # make this the only non-zero element
+    println("L∞(pois) ($(me())): $(WaterLily.L∞(sim.pois)) true : 123.456789")
+    println("L₂(pois) ($(me())) : $(WaterLily.L₂(sim.pois)) true : $(123.456789^2)")
+end