Fix all/gather bugs and add tests

Author: kshyatt

src/mpi-base.jl

@@ -444,7 +444,7 @@ function Gather{T<:MPIDatatype}(object::T, root::Integer, comm::Comm)
     isroot = Comm_rank(comm) == root
     sendbuf = T[object]
     recvbuf = Gather(sendbuf, root, comm)
-    isroot ? recvbuf[1] : nothing
+    isroot ? recvbuf : nothing
 end
 
 function Allgather{T<:MPIDatatype}(sendbuf::Union{Ptr{T},Array{T}}, count::Integer,
@@ -463,7 +463,7 @@ end
 function Allgather{T<:MPIDatatype}(object::T, comm::Comm)
     sendbuf = T[object]
     recvbuf = Allgather(sendbuf, comm)
-    recvbuf[1]
+    recvbuf
 end
 
 function Gatherv{T<:MPIDatatype}(sendbuf::Union{Ptr{T},Array{T}}, counts::Vector{Cint},

test/test_allgather.jl

@@ -3,18 +3,19 @@ using MPI
 
 MPI.Init()
 
-function allgather_array(A)
+function allgather(A)
     comm = MPI.COMM_WORLD
-
-    B = copy(A)
-    C = MPI.Allgather(B, comm)
+    C = MPI.Allgather(A, comm)
 end
 
 comm = MPI.COMM_WORLD
 
 for typ in MPI.MPIDatatype.types
     A = typ[MPI.Comm_rank(comm) + 1]
-    C = allgather_array(A)
+    C = allgather(A)
+    @test C == collect(1:MPI.Comm_size(comm))
+    A = convert(typ,MPI.Comm_rank(comm) + 1)
+    C = allgather(A)
     @test C == collect(1:MPI.Comm_size(comm))
 end
 

test/test_gather.jl

@@ -3,19 +3,22 @@ using MPI
 
 MPI.Init()
 
-function gather_array(A, root)
+function gather(A, root)
     comm = MPI.COMM_WORLD
-
-    B = copy(A)
-    C = MPI.Gather(B, root, comm)
+    C = MPI.Gather(A, root, comm)
 end
 
 comm = MPI.COMM_WORLD
 root = 0
 
 for typ in MPI.MPIDatatype.types
     A = typ[MPI.Comm_rank(comm) + 1]
-    C = gather_array(A, root)
+    C = gather(A, root)
+    if MPI.Comm_rank(comm) == root
+        @test C == collect(1:MPI.Comm_size(comm))
+    end
+    A = convert(typ,MPI.Comm_rank(comm) + 1)
+    C = gather(A, root)
     if MPI.Comm_rank(comm) == root
         @test C == collect(1:MPI.Comm_size(comm))
     end