diff --git a/src/mpi.f90 b/src/mpi.f90
index b058d6e..4736454 100644
--- a/src/mpi.f90
+++ b/src/mpi.f90
@@ -2,7 +2,7 @@ module mpi
     implicit none
     integer, parameter :: MPI_THREAD_FUNNELED = 1
     ! not sure if this is correct really
-    integer, parameter :: MPI_INTEGER = 0
+    integer, parameter :: MPI_INTEGER = 2
     integer, parameter :: MPI_REAL4 = 0
     integer, parameter :: MPI_REAL8 = 1
     integer, parameter :: MPI_COMM_TYPE_SHARED = 1
@@ -58,7 +58,8 @@ module mpi
     interface MPI_Allreduce
         module procedure MPI_Allreduce_scalar
         module procedure MPI_Allreduce_1d
-        module procedure MPI_Allreduce_array
+        module procedure MPI_Allreduce_array_real
+        module procedure MPI_Allreduce_array_int
     end interface
 
     interface MPI_Wtime
@@ -282,15 +283,25 @@ subroutine MPI_Allreduce_1d(sendbuf, recvbuf, count, datatype, op, comm, ierror)
         call c_mpi_allreduce_1d(sendbuf, recvbuf, count, datatype, op, comm, ierror)
     end subroutine
 
-    subroutine MPI_Allreduce_array(sendbuf, recvbuf, count, datatype, op, comm, ierror)
-        use mpi_c_bindings, only: c_mpi_allreduce_array
+    subroutine MPI_Allreduce_array_real(sendbuf, recvbuf, count, datatype, op, comm, ierror)
+        use mpi_c_bindings, only: c_mpi_allreduce_array_real
         ! Declare both send and recv as arrays:
         real(8), dimension(:), intent(in)  :: sendbuf
         real(8), dimension(:), intent(out) :: recvbuf
         integer, intent(in) :: count, datatype, op, comm
         integer, intent(out), optional :: ierror
-        call c_mpi_allreduce_array(sendbuf, recvbuf, count, datatype, op, comm, ierror)
-    end subroutine MPI_Allreduce_array
+        call c_mpi_allreduce_array_real(sendbuf, recvbuf, count, datatype, op, comm, ierror)
+    end subroutine MPI_Allreduce_array_real
+
+    subroutine MPI_Allreduce_array_int(sendbuf, recvbuf, count, datatype, op, comm, ierror)
+        use mpi_c_bindings, only: c_mpi_allreduce_array_int
+        ! Declare both send and recv as arrays:
+        integer, dimension(:), intent(in)  :: sendbuf
+        integer, dimension(:), intent(out) :: recvbuf
+        integer, intent(in) :: count, datatype, op, comm
+        integer, intent(out), optional :: ierror
+        call c_mpi_allreduce_array_int(sendbuf, recvbuf, count, datatype, op, comm, ierror)
+    end subroutine MPI_Allreduce_array_int
 
     function MPI_Wtime_proc() result(time)
         use mpi_c_bindings, only: c_mpi_wtime
diff --git a/src/mpi_c_bindings.f90 b/src/mpi_c_bindings.f90
index 48251f7..92a4188 100644
--- a/src/mpi_c_bindings.f90
+++ b/src/mpi_c_bindings.f90
@@ -92,7 +92,8 @@ subroutine c_mpi_irecv(buf, count, datatype, source, tag, comm, request, ierror)
             integer(c_int), optional, intent(out) :: ierror
         end subroutine
 
-        subroutine c_mpi_allreduce_scalar(sendbuf, recvbuf, count, datatype, op, comm, ierror) bind(C, name="mpi_allreduce_wrapper")
+        subroutine c_mpi_allreduce_scalar(sendbuf, recvbuf, count, datatype, op, comm, ierror) &
+                                                    bind(C, name="mpi_allreduce_wrapper_real")
             use iso_c_binding, only: c_int, c_double
             real(c_double), intent(in) :: sendbuf
             real(c_double), intent(out) :: recvbuf
@@ -100,7 +101,8 @@ subroutine c_mpi_allreduce_scalar(sendbuf, recvbuf, count, datatype, op, comm, i
             integer(c_int), intent(out), optional :: ierror
         end subroutine
 
-        subroutine c_mpi_allreduce_1d(sendbuf, recvbuf, count, datatype, op, comm, ierror) bind(C, name="mpi_allreduce_wrapper")
+        subroutine c_mpi_allreduce_1d(sendbuf, recvbuf, count, datatype, op, comm, ierror) &
+                                                    bind(C, name="mpi_allreduce_wrapper_real")
             use iso_c_binding, only: c_int, c_double
             real(c_double), intent(in) :: sendbuf
             real(c_double), dimension(*), intent(out) :: recvbuf
@@ -108,13 +110,23 @@ subroutine c_mpi_allreduce_1d(sendbuf, recvbuf, count, datatype, op, comm, ierro
             integer(c_int), intent(out), optional :: ierror
         end subroutine
 
-        subroutine c_mpi_allreduce_array(sendbuf, recvbuf, count, datatype, op, comm, ierror) bind(C, name="mpi_allreduce_wrapper")
+        subroutine c_mpi_allreduce_array_real(sendbuf, recvbuf, count, datatype, op, comm, ierror) &
+                                                    bind(C, name="mpi_allreduce_wrapper_real")
             use iso_c_binding, only: c_int, c_double
             real(c_double), dimension(*), intent(in)  :: sendbuf
             real(c_double), dimension(*), intent(out) :: recvbuf
             integer(c_int), intent(in) :: count, datatype, op, comm
             integer(c_int), intent(out), optional :: ierror
-        end subroutine c_mpi_allreduce_array
+        end subroutine c_mpi_allreduce_array_real
+
+        subroutine c_mpi_allreduce_array_int(sendbuf, recvbuf, count, datatype, op, comm, ierror) &
+                                                    bind(C, name="mpi_allreduce_wrapper_int")
+            use iso_c_binding, only: c_int, c_double
+            integer(c_int), dimension(*), intent(in)  :: sendbuf
+            integer(c_int), dimension(*), intent(out) :: recvbuf
+            integer(c_int), intent(in) :: count, datatype, op, comm
+            integer(c_int), intent(out), optional :: ierror
+        end subroutine c_mpi_allreduce_array_int
 
         function c_mpi_wtime() result(time) bind(C, name="MPI_Wtime")
             use iso_c_binding, only: c_double
diff --git a/src/mpi_wrapper.c b/src/mpi_wrapper.c
index c9dc5bb..6fa37ef 100644
--- a/src/mpi_wrapper.c
+++ b/src/mpi_wrapper.c
@@ -19,13 +19,13 @@ void mpi_bcast_int_wrapper(int *buffer, int *count, int *datatype_f, int *root,
     MPI_Comm comm = MPI_Comm_f2c(*comm_f);
     MPI_Datatype datatype;
     switch (*datatype_f) {
-        case 0:
+        case 2:
             datatype = MPI_INT;
             break;
-        case 1:
+        case 0:
             datatype = MPI_FLOAT;
             break;
-        case 2:
+        case 1:
             datatype = MPI_DOUBLE;
             break;
         default:
@@ -59,7 +59,7 @@ void mpi_allgather_int_wrapper(const int *sendbuf, int *sendcount, int *sendtype
 
     MPI_Datatype sendtype, recvtype;
     switch (*sendtype_f) {
-        case 0:
+        case 2:
             sendtype = MPI_INT;
             break;
         default:
@@ -68,7 +68,7 @@ void mpi_allgather_int_wrapper(const int *sendbuf, int *sendcount, int *sendtype
     }
 
     switch (*recvtype_f) {
-        case 0:
+        case 2:
             recvtype = MPI_INT;
             break;
         default:
@@ -158,7 +158,7 @@ void mpi_irecv_wrapper(double *buf, int *count, int *datatype_f,
     *request_f = MPI_Request_c2f(request);
 }
 
-void mpi_allreduce_wrapper(const double *sendbuf, double *recvbuf, int *count,
+void mpi_allreduce_wrapper_real(const double *sendbuf, double *recvbuf, int *count,
                             int *datatype_f, int *op_f, int *comm_f, int *ierror) {
     MPI_Comm comm = MPI_Comm_f2c(*comm_f);
     MPI_Datatype datatype;
@@ -191,6 +191,21 @@ void mpi_allreduce_wrapper(const double *sendbuf, double *recvbuf, int *count,
    }
 }
 
+void mpi_allreduce_wrapper_int(const int *sendbuf, int *recvbuf, int *count,
+                            int *datatype_f, int *op_f, int *comm_f, int *ierror) {
+    MPI_Comm comm = MPI_Comm_f2c(*comm_f);
+    MPI_Datatype datatype;
+    datatype = MPI_INT;
+
+    MPI_Op op = MPI_Op_f2c(*op_f);
+
+    if (*sendbuf == -1) {
+    *ierror = MPI_Allreduce(MPI_IN_PLACE , recvbuf, *count, datatype, MPI_SUM, comm);
+    } else {
+    *ierror = MPI_Allreduce(sendbuf , recvbuf, *count, datatype, MPI_SUM, comm);
+    }
+}
+
 void mpi_barrier_wrapper(int *comm_f, int *ierror) {
     MPI_Comm comm = MPI_Comm_f2c(*comm_f);
     *ierror = MPI_Barrier(comm);