1: static char help[] = "Tests PetscRandom functions.\n\n";

  3: #include <petscsys.h>

  5: /* Usage:
  6:    mpiexec -n <np> ./ex1 -n <num_of_random_numbers> -random_type <type> -log_view
  7:                          -view_randomvalues <view_rank>
  8:                          -random_view ascii -random_view :filename
  9: */

 11: int main(int argc, char **argv)
 12: {
 13:   PetscInt      i, n = 1000, *values;
 14:   PetscRandom   rnd;
 15:   PetscScalar   value, avg = 0.0;
 16:   PetscMPIInt   rank;
 17:   PetscInt      view_rank = -1;
 18:   PetscLogEvent event;

 20:   PetscFunctionBeginUser;
 21:   PetscCall(PetscInitialize(&argc, &argv, (char *)0, help));
 22:   PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
 23:   PetscCall(PetscOptionsGetInt(NULL, NULL, "-n", &n, NULL));
 24:   PetscCall(PetscOptionsGetInt(NULL, NULL, "-view_randomvalues", &view_rank, NULL));

 26:   PetscCall(PetscRandomCreate(PETSC_COMM_WORLD, &rnd));
 27:   /* force imaginary part of random number to always be zero; thus obtain reproducible results with real and complex numbers */
 28:   PetscCall(PetscRandomSetInterval(rnd, 0.0, 1.0));
 29:   PetscCall(PetscRandomSetFromOptions(rnd));

 31:   PetscCall(PetscMalloc1(n, &values));
 32:   for (i = 0; i < n; i++) {
 33:     PetscCall(PetscRandomGetValue(rnd, &value));
 34:     avg += value;
 35:     if (view_rank == (PetscInt)rank) PetscCall(PetscPrintf(PETSC_COMM_SELF, "[%d] value[%" PetscInt_FMT "] = %6.4e\n", rank, i, (double)PetscRealPart(value)));
 36:     values[i] = (PetscInt)(n * PetscRealPart(value) + 2.0);
 37:   }
 38:   avg = avg / ((PetscReal)n);
 39:   if (view_rank == (PetscInt)rank) PetscCall(PetscPrintf(PETSC_COMM_SELF, "[%d] Average value %6.4e\n", rank, (double)PetscRealPart(avg)));

 41:   PetscCall(PetscSortInt(n, values));

 43:   PetscCall(PetscLogEventRegister("Sort", 0, &event));
 44:   PetscCall(PetscLogEventBegin(event, 0, 0, 0, 0));

 46:   PetscCall(PetscRandomSeed(rnd));
 47:   for (i = 0; i < n; i++) {
 48:     PetscCall(PetscRandomGetValue(rnd, &value));
 49:     values[i] = (PetscInt)(n * PetscRealPart(value) + 2.0);
 50:     /* printf("value[%d] = %g\n",i,value); */
 51:   }
 52:   PetscCall(PetscSortInt(n, values));
 53:   PetscCall(PetscLogEventEnd(event, 0, 0, 0, 0));

 55:   for (i = 1; i < n; i++) PetscCheck(values[i] >= values[i - 1], PETSC_COMM_SELF, PETSC_ERR_PLIB, "Values not sorted");
 56:   PetscCall(PetscFree(values));
 57:   PetscCall(PetscRandomDestroy(&rnd));

 59:   PetscCall(PetscFinalize());
 60:   return 0;
 61: }

 63: /*TEST

 65:    test:

 67:    test:
 68:       suffix: 2
 69:       nsize: 2
 70:       output_file: output/ex1_1.out

 72:    test:
 73:       suffix: 3
 74:       args: -view_randomvalues 0

 76: TEST*/