xref: /petsc/src/sys/classes/random/tutorials/ex1.c (revision 48a46eb9bd028bec07ec0f396b1a3abb43f14558)
1c4762a1bSJed Brown 
2c4762a1bSJed Brown static char help[] = "Tests PetscRandom functions.\n\n";
3c4762a1bSJed Brown 
4c4762a1bSJed Brown #include <petscsys.h>
5c4762a1bSJed Brown 
6c4762a1bSJed Brown /* Usage:
7c4762a1bSJed Brown    mpiexec -n <np> ./ex1 -n <num_of_random_numbers> -random_type <type> -log_view
8c4762a1bSJed Brown                          -view_randomvalues <view_rank>
9c4762a1bSJed Brown                          -random_view ascii -random_view :filename
10c4762a1bSJed Brown */
11c4762a1bSJed Brown 
129371c9d4SSatish Balay int main(int argc, char **argv) {
13c4762a1bSJed Brown   PetscInt    i, n = 1000, *values;
14c4762a1bSJed Brown   PetscRandom rnd;
15c4762a1bSJed Brown   PetscScalar value, avg = 0.0;
16c4762a1bSJed Brown   PetscMPIInt rank;
17c4762a1bSJed Brown   PetscInt    view_rank = -1;
18c4762a1bSJed Brown #if defined(PETSC_USE_LOG)
19c4762a1bSJed Brown   PetscLogEvent event;
20c4762a1bSJed Brown #endif
21c4762a1bSJed Brown 
22327415f7SBarry Smith   PetscFunctionBeginUser;
239566063dSJacob Faibussowitsch   PetscCall(PetscInitialize(&argc, &argv, (char *)0, help));
249566063dSJacob Faibussowitsch   PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
259566063dSJacob Faibussowitsch   PetscCall(PetscOptionsGetInt(NULL, NULL, "-n", &n, NULL));
269566063dSJacob Faibussowitsch   PetscCall(PetscOptionsGetInt(NULL, NULL, "-view_randomvalues", &view_rank, NULL));
27c4762a1bSJed Brown 
289566063dSJacob Faibussowitsch   PetscCall(PetscRandomCreate(PETSC_COMM_WORLD, &rnd));
29c4762a1bSJed Brown   /* force imaginary part of random number to always be zero; thus obtain reproducible results with real and complex numbers */
309566063dSJacob Faibussowitsch   PetscCall(PetscRandomSetInterval(rnd, 0.0, 1.0));
319566063dSJacob Faibussowitsch   PetscCall(PetscRandomSetFromOptions(rnd));
32c4762a1bSJed Brown 
339566063dSJacob Faibussowitsch   PetscCall(PetscMalloc1(n, &values));
34c4762a1bSJed Brown   for (i = 0; i < n; i++) {
359566063dSJacob Faibussowitsch     PetscCall(PetscRandomGetValue(rnd, &value));
36c4762a1bSJed Brown     avg += value;
37*48a46eb9SPierre Jolivet     if (view_rank == (PetscInt)rank) PetscCall(PetscPrintf(PETSC_COMM_SELF, "[%d] value[%" PetscInt_FMT "] = %6.4e\n", rank, i, (double)PetscRealPart(value)));
38c4762a1bSJed Brown     values[i] = (PetscInt)(n * PetscRealPart(value) + 2.0);
39c4762a1bSJed Brown   }
40c4762a1bSJed Brown   avg = avg / ((PetscReal)n);
41*48a46eb9SPierre Jolivet   if (view_rank == (PetscInt)rank) PetscCall(PetscPrintf(PETSC_COMM_SELF, "[%d] Average value %6.4e\n", rank, (double)PetscRealPart(avg)));
42c4762a1bSJed Brown 
439566063dSJacob Faibussowitsch   PetscCall(PetscSortInt(n, values));
44c4762a1bSJed Brown 
459566063dSJacob Faibussowitsch   PetscCall(PetscLogEventRegister("Sort", 0, &event));
469566063dSJacob Faibussowitsch   PetscCall(PetscLogEventBegin(event, 0, 0, 0, 0));
47c4762a1bSJed Brown 
489566063dSJacob Faibussowitsch   PetscCall(PetscRandomSeed(rnd));
49c4762a1bSJed Brown   for (i = 0; i < n; i++) {
509566063dSJacob Faibussowitsch     PetscCall(PetscRandomGetValue(rnd, &value));
51c4762a1bSJed Brown     values[i] = (PetscInt)(n * PetscRealPart(value) + 2.0);
52c4762a1bSJed Brown     /* printf("value[%d] = %g\n",i,value); */
53c4762a1bSJed Brown   }
549566063dSJacob Faibussowitsch   PetscCall(PetscSortInt(n, values));
559566063dSJacob Faibussowitsch   PetscCall(PetscLogEventEnd(event, 0, 0, 0, 0));
56c4762a1bSJed Brown 
579371c9d4SSatish Balay   for (i = 1; i < n; i++) { PetscCheck(values[i] >= values[i - 1], PETSC_COMM_SELF, PETSC_ERR_PLIB, "Values not sorted"); }
589566063dSJacob Faibussowitsch   PetscCall(PetscFree(values));
599566063dSJacob Faibussowitsch   PetscCall(PetscRandomDestroy(&rnd));
60c4762a1bSJed Brown 
619566063dSJacob Faibussowitsch   PetscCall(PetscFinalize());
62b122ec5aSJacob Faibussowitsch   return 0;
63c4762a1bSJed Brown }
64c4762a1bSJed Brown 
65c4762a1bSJed Brown /*TEST
66c4762a1bSJed Brown 
67c4762a1bSJed Brown    test:
68c4762a1bSJed Brown 
69c4762a1bSJed Brown    test:
70c4762a1bSJed Brown       suffix: 2
71c4762a1bSJed Brown       nsize: 2
72c4762a1bSJed Brown       output_file: output/ex1_1.out
73c4762a1bSJed Brown 
74c4762a1bSJed Brown    test:
75c4762a1bSJed Brown       suffix: 3
76c4762a1bSJed Brown       args: -view_randomvalues 0
77c4762a1bSJed Brown 
78c4762a1bSJed Brown TEST*/
79