Merge pull request #70 from fverdugo/mpi_abort

Enhanced usage of MPI_abort

Author: fverdugo

src/MPIBackend.jl

@@ -24,27 +24,33 @@ function prun(driver::Function,b::MPIBackend,nparts)
   if !MPI.Initialized()
     MPI.Init()
   end
-  try
-     part = get_part_ids(b,nparts)
-     driver(part)
-  catch e
-    @error "" exception=(e, catch_backtrace())
-    if MPI.Initialized() && !MPI.Finalized()
-      MPI.Abort(MPI.COMM_WORLD,0)
+  if MPI.Comm_size(MPI.COMM_WORLD) == 1
+    part = get_part_ids(b,nparts)
+    driver(part)
+  else
+    try
+       part = get_part_ids(b,nparts)
+       driver(part)
+    catch e
+      @error "" exception=(e, catch_backtrace())
+      if MPI.Initialized() && !MPI.Finalized()
+        MPI.Abort(MPI.COMM_WORLD,1)
+      end
     end
   end
   # We are NOT invoking MPI.Finalize() here because we rely on
   # MPI.jl, which registers MPI.Finalize() in atexit()
 end
 
+#TODO not needed any more. Deprecate.
 # Useful to debug an MPI program when executed interactively
 # on the REPL, i.e., with a single MPI task
 function prun_debug(driver::Function,b::MPIBackend,nparts)
   if !MPI.Initialized()
     MPI.Init()
   end
   if (prod(nparts) != 1)
-    MPI.Abort(MPI.COMM_WORLD,0)
+    MPI.Abort(MPI.COMM_WORLD,1)
   end
   part = get_part_ids(b,nparts)
   driver(part)

test/mpi/ExceptionTests.jl

@@ -1,6 +1,13 @@
 module ExceptionTests
+using Test
 
 include("mpiexec.jl")
-run_mpi_driver(procs=8,file="driver_exception.jl")
+failed = Ref(false)
+try
+  run_mpi_driver(procs=8,file="driver_exception.jl")
+catch e
+  failed[] = true
+end
+@test failed[]
 
 end # module

test/mpi/mpiexec.jl

@@ -10,6 +10,8 @@ function run_mpi_driver(;procs,file)
     else
       run(`$cmd -n $procs $(Base.julia_cmd()) --project=$repodir $(joinpath(mpidir,file))`)
     end
-    @test true
+    # This line will be reached if and only if the command launched by `run` runs without errors.
+    # Then, if we arrive here, the test has succeeded.
+    @test true  
   end
 end

test/test_exception.jl

@@ -3,8 +3,16 @@ using PartitionedArrays
 
 function throw_assert(parts)
   nparts=length(parts)
-  map_parts(parts) do part
-      @assert rand(1:nparts) != part
+  p_main = map_parts(parts) do part
+    if part == MAIN
+      part_fail = rand(1:nparts)
+    else
+      0
+    end
+  end
+  p = emit(p_main)
+  map_parts(parts,p) do part,part_fail
+      @assert  part_fail != part
   end
 end