Adding function for MPI communicators in Fortran integer format to simplify Fortran interfaces.

CMakeLists.txt

@@ -274,18 +274,6 @@ if (CUDECOMP_BUILD_FORTRAN)
 
   target_link_libraries(cudecomp_fort PUBLIC MPI::MPI_Fortran)
 
-  # Test for MPI_Comm_f2c/c2f
-  try_compile(
-    TEST_F2C_RESULT
-    ${CMAKE_BINARY_DIR}
-    ${CMAKE_CURRENT_SOURCE_DIR}/cmake/test_mpi_f2c.f90
-    LINK_LIBRARIES MPI::MPI_Fortran
-  )
-  if (NOT TEST_F2C_RESULT)
-    message(STATUS "Could not link MPI_Comm_f2c in Fortran module. Setting -DMPICH flag during module compilation.")
-    target_compile_definitions(cudecomp_fort PRIVATE MPICH)
-  endif()
-
   install(
     TARGETS cudecomp_fort
     LIBRARY DESTINATION ${CMAKE_INSTALL_PREFIX}/lib

docs/api/c_api.rst

@@ -118,6 +118,14 @@ ____________
 
 ------
 
+.. _cudecompInit_F-ref:
+
+cudecompInit_F
+______________
+.. doxygenfunction:: cudecompInit_F
+
+------
+
 .. _cudecompFinalize-ref:
 
 cudecompFinalize

include/cudecomp.h

@@ -212,6 +212,16 @@ typedef struct {
  */
 cudecompResult_t cudecompInit(cudecompHandle_t* handle, MPI_Comm mpi_comm);
 
+/**
+ * @brief Initializes the cuDecomp library from an existing MPI communicator
+ *
+ * @param[out] handle A pointer to an uninitialized cudecompHandle_t
+ * @param[in] mpi_comm_f MPI communicator, in Fortran integer format, containing ranks to use with cuDecomp
+ *
+ * @return CUDECOMP_RESULT_SUCCESS on success or error code on failure.
+ */
+cudecompResult_t cudecompInit_F(cudecompHandle_t* handle, MPI_Fint mpi_comm_f);
+
 /**
  * @brief Finalizes the cuDecomp library and frees associated resources
  *

src/cudecomp.cc

@@ -550,6 +550,18 @@ cudecompResult_t cudecompFinalize(cudecompHandle_t handle) {
   return CUDECOMP_RESULT_SUCCESS;
 }
 
+cudecompResult_t cudecompInit_F(cudecompHandle_t* handle_in, MPI_Fint mpi_comm_f) {
+  using namespace cudecomp;
+  try {
+    MPI_Comm mpi_comm = MPI_Comm_f2c(mpi_comm_f);
+    cudecompInit(handle_in, mpi_comm);
+  } catch (const cudecomp::BaseException& e) {
+    std::cerr << e.what();
+    return e.getResult();
+  }
+  return CUDECOMP_RESULT_SUCCESS;
+}
+
 cudecompResult_t cudecompGridDescCreate(cudecompHandle_t handle, cudecompGridDesc_t* grid_desc_in,
                                         cudecompGridDescConfig_t* config,
                                         const cudecompGridDescAutotuneOptions_t* options) {

src/cudecomp_m.cuf

@@ -71,21 +71,6 @@ module cudecomp
 
   ! types
 
-  ! MPI-related types
-#ifndef MPICH
-  type, bind(c) :: MPI_C_Comm
-    integer(c_int64_t) :: comm
-  end type MPI_C_Comm
-#else
-  type, bind(c) :: MPI_C_Comm
-    integer(c_int) :: comm
-  end type MPI_C_Comm
-#endif
-
-  type, bind(c) :: MPI_F_Comm
-    integer(c_int) :: comm
-  end type MPI_F_Comm
-
   ! Opaque handle to cuDecomp handle
   type, bind(c) :: cudecompHandle
     type(c_ptr) :: member
@@ -155,37 +140,20 @@ module cudecomp
 
   ! interfaces
 
-  ! MPI_Comm conversion functions
-#ifndef MPICH
-  interface
-    function MPI_Comm_f2c(fcomm) bind(C,name='MPI_Comm_f2c') result(res)
-      import
-      type(MPI_F_comm), value :: fcomm
-      type(MPI_C_comm) :: res
-    end function MPI_Comm_f2c
-
-    function MPI_Comm_c2f(ccomm) bind(C,name='MPI_Comm_c2f') result(res)
-      import
-      type(MPI_C_Comm), value :: ccomm
-      type(MPI_F_Comm) :: res
-    end function MPI_Comm_c2f
-  end interface
-#endif
-
   ! cuDecomp initialization/finalization functions
-  ! generic interface that takes either integer or type(MPI_F_Comm) communicator arguments
+  ! generic interface that takes either integer or type(MPI_Comm) communicator arguments
 
   interface cudecompInit
-    module procedure cudecompInit_MPI_F, cudecompInit_MPI_F08, cudecompInitType
+    module procedure cudecompInit_MPI_F, cudecompInit_MPI_F08
   end interface cudecompInit
 
   interface
-    function cudecompInitC(handle, mpi_comm) bind(C, name="cudecompInit") result(res)
+    function cudecompInit_FC(handle, mpi_comm) bind(C, name="cudecompInit_F") result(res)
       import
       type(cudecompHandle) :: handle
-      type(MPI_C_Comm), value :: mpi_comm  ! conversion to MPI_C_Comm done in module procedures cudecompInit*()
+      integer, value :: mpi_comm
       integer(c_int) :: res
-    end function cudecompInitC
+    end function cudecompInit_FC
   end interface
 
   interface
@@ -523,10 +491,7 @@ contains
     integer :: comm
     integer(c_int) :: res
 
-    type(MPI_F_Comm) :: fComm
-
-    fComm%comm = comm
-    res = cudecompInitType(handle, fComm)
+    res = cudecompInit_FC(handle, comm)
   end function cudecompInit_MPI_F
 
   function cudecompInit_MPI_F08(handle, comm) result(res)
@@ -538,28 +503,9 @@ contains
     type(MPI_Comm) :: comm
     integer(c_int) :: res
 
-    type(MPI_F_Comm) :: fComm
-
-    fComm%comm = comm%MPI_VAL
-    res = cudecompInitType(handle, fComm)
+    res = cudecompInit_FC(handle, comm%MPI_VAL)
   end function cudecompInit_MPI_F08
 
-  function cudecompInitType(handle, fComm) result(res)
-    implicit none
-    type(cudecompHandle) :: handle
-    type(MPI_F_Comm) :: fComm
-    integer(c_int) :: res
-
-    type(MPI_C_Comm) :: cComm
-#ifndef MPICH
-    cComm = MPI_Comm_f2c(fComm)
-#else
-    cComm= fComm
-#endif
-
-    res = cudecompInitC(handle, cComm)
-  end function cudecompInitType
-
   ! cudecompGridDesc creation/manipulation functions
   function cudecompGridDescAutotuneOptionsSetDefaults(options) result(res)
     type(cudecompGridDescAutotuneOptions) :: options