Add random_init() and testcase.

Author: vehre

CMakeLists.txt

@@ -782,6 +782,9 @@ if(opencoarrays_aware_compiler)
       message( AUTHOR_WARNING "Skipping the following test to GFortran < 7.4.0 lack of compatibility:
         send-strided-self.f90")
     endif()
+    if((NOT CMAKE_Fortran_COMPILER_VERSION VERSION_LESS 12.0.0) OR (CAF_RUN_DEVELOPER_TESTS OR $ENV{OPENCOARRAYS_DEVELOPER}))
+      add_caf_test(random_init 4 random_init)
+    endif()
   endif()
 
   # Pure get tests

src/libcaf.h

@@ -331,6 +331,8 @@ void PREFIX (event_post) (caf_token_t, size_t, int, int *, char *, charlen_t);
 void PREFIX (event_wait) (caf_token_t, size_t, int, int *, char *, charlen_t);
 void PREFIX (event_query) (caf_token_t, size_t, int, int *, int *);
 
+void PREFIX (random_init) (bool, bool);
+
 /* Language extension */
 #ifdef HAVE_MPI
 MPI_Fint PREFIX (get_communicator) (caf_team_t *);

src/mpi/mpi_caf.c

@@ -8491,3 +8491,73 @@ void PREFIX(sync_team) (caf_team_t *team , int unused __attribute__((unused)))
 
   int ierr = MPI_Barrier(*tmp_comm); chk_err(ierr);
 }
+
+extern void _gfortran_random_seed_i4 (int32_t *size, gfc_dim1_descriptor_t *put,
+                                      gfc_dim1_descriptor_t *get);
+
+void PREFIX(random_init) (bool repeatable, bool image_distinct)
+{
+  static gfc_dim1_descriptor_t rand_seed;
+  static bool rep_needs_init = true, arr_needs_init = true;
+  static int32_t seed_size;
+
+  if (arr_needs_init)
+  {
+    _gfortran_random_seed_i4(&seed_size, NULL, NULL);
+    memset(&rand_seed, 0, sizeof(gfc_dim1_descriptor_t));
+    rand_seed.base.base_addr = malloc(seed_size * sizeof(int32_t)); // because using seed_i4
+    rand_seed.base.offset = -1;
+    rand_seed.base.dtype.elem_len = sizeof(int32_t);
+    rand_seed.base.dtype.rank = 1;
+    rand_seed.base.dtype.type = BT_INTEGER;
+    rand_seed.base.span = 0;
+    rand_seed.dim[0].lower_bound = 1;
+    rand_seed.dim[0]._ubound = seed_size;
+    rand_seed.dim[0]._stride = 1;
+
+    arr_needs_init = false;
+  }
+
+  if (repeatable)
+  {
+    if (rep_needs_init)
+    {
+      int32_t lcg_seed = 57911963;
+      if (image_distinct)
+      {
+        lcg_seed *= caf_this_image;
+      }
+      int32_t *curr = rand_seed.base.base_addr;
+      for (int i = 0; i < seed_size; ++i)
+      {
+        const int32_t a = 16087;
+        const int32_t m = INT32_MAX;
+        const int32_t q = 127773;
+        const int32_t r = 2836;
+        lcg_seed = a * (lcg_seed % q) - r * (lcg_seed / q);
+        if (lcg_seed <= 0) lcg_seed += m;
+        *curr = lcg_seed;
+        ++curr;
+      }
+      rep_needs_init = false;
+    }
+    _gfortran_random_seed_i4(NULL, &rand_seed, NULL);
+  }
+  else if (image_distinct)
+  {
+    _gfortran_random_seed_i4(NULL, NULL, NULL);
+  }
+  else
+  {
+    if (caf_this_image == 0)
+    {
+      _gfortran_random_seed_i4(NULL, NULL, &rand_seed);
+      MPI_Bcast(rand_seed.base.base_addr, seed_size, MPI_INT32_T, 0, CAF_COMM_WORLD);
+    }
+    else
+    {
+      MPI_Bcast(rand_seed.base.base_addr, seed_size, MPI_INT32_T, 0, CAF_COMM_WORLD);
+      _gfortran_random_seed_i4(NULL, &rand_seed, NULL);
+    }
+  }
+}

src/tests/unit/simple/CMakeLists.txt

@@ -2,6 +2,7 @@
 
 caf_compile_executable(increment_my_neighbor increment_neighbor.f90)
 caf_compile_executable(atomics testAtomics.f90)
+caf_compile_executable(random_init random_init.f90)
 
 # C tests
 #include(CMakeForceCompiler)