xref: /petsc/src/sys/classes/random/tutorials/ex1.c (revision 609caa7c8c030312b00807b4f015fd827bb80932)
1c4762a1bSJed Brown static char help[] = "Tests PetscRandom functions.\n\n";
2c4762a1bSJed Brown 
3c4762a1bSJed Brown #include <petscsys.h>
4c4762a1bSJed Brown 
5c4762a1bSJed Brown /* Usage:
6c4762a1bSJed Brown    mpiexec -n <np> ./ex1 -n <num_of_random_numbers> -random_type <type> -log_view
7c4762a1bSJed Brown                          -view_randomvalues <view_rank>
8c4762a1bSJed Brown                          -random_view ascii -random_view :filename
9c4762a1bSJed Brown */
10c4762a1bSJed Brown 
main(int argc,char ** argv)11d71ae5a4SJacob Faibussowitsch int main(int argc, char **argv)
12d71ae5a4SJacob Faibussowitsch {
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   PetscLogEvent event;
19c4762a1bSJed Brown 
20327415f7SBarry Smith   PetscFunctionBeginUser;
21c8025a54SPierre Jolivet   PetscCall(PetscInitialize(&argc, &argv, NULL, help));
229566063dSJacob Faibussowitsch   PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
239566063dSJacob Faibussowitsch   PetscCall(PetscOptionsGetInt(NULL, NULL, "-n", &n, NULL));
249566063dSJacob Faibussowitsch   PetscCall(PetscOptionsGetInt(NULL, NULL, "-view_randomvalues", &view_rank, NULL));
25c4762a1bSJed Brown 
269566063dSJacob Faibussowitsch   PetscCall(PetscRandomCreate(PETSC_COMM_WORLD, &rnd));
27c4762a1bSJed Brown   /* force imaginary part of random number to always be zero; thus obtain reproducible results with real and complex numbers */
289566063dSJacob Faibussowitsch   PetscCall(PetscRandomSetInterval(rnd, 0.0, 1.0));
299566063dSJacob Faibussowitsch   PetscCall(PetscRandomSetFromOptions(rnd));
30c4762a1bSJed Brown 
319566063dSJacob Faibussowitsch   PetscCall(PetscMalloc1(n, &values));
32c4762a1bSJed Brown   for (i = 0; i < n; i++) {
339566063dSJacob Faibussowitsch     PetscCall(PetscRandomGetValue(rnd, &value));
34c4762a1bSJed Brown     avg += value;
35300f1712SStefano Zampini     if (view_rank == rank) PetscCall(PetscPrintf(PETSC_COMM_SELF, "[%d] value[%" PetscInt_FMT "] = %6.4e\n", rank, i, (double)PetscRealPart(value)));
36c4762a1bSJed Brown     values[i] = (PetscInt)(n * PetscRealPart(value) + 2.0);
37c4762a1bSJed Brown   }
38c4762a1bSJed Brown   avg = avg / ((PetscReal)n);
39300f1712SStefano Zampini   if (view_rank == rank) PetscCall(PetscPrintf(PETSC_COMM_SELF, "[%d] Average value %6.4e\n", rank, (double)PetscRealPart(avg)));
40c4762a1bSJed Brown 
419566063dSJacob Faibussowitsch   PetscCall(PetscSortInt(n, values));
42c4762a1bSJed Brown 
439566063dSJacob Faibussowitsch   PetscCall(PetscLogEventRegister("Sort", 0, &event));
449566063dSJacob Faibussowitsch   PetscCall(PetscLogEventBegin(event, 0, 0, 0, 0));
45c4762a1bSJed Brown 
469566063dSJacob Faibussowitsch   PetscCall(PetscRandomSeed(rnd));
47c4762a1bSJed Brown   for (i = 0; i < n; i++) {
489566063dSJacob Faibussowitsch     PetscCall(PetscRandomGetValue(rnd, &value));
49c4762a1bSJed Brown     values[i] = (PetscInt)(n * PetscRealPart(value) + 2.0);
50c4762a1bSJed Brown     /* printf("value[%d] = %g\n",i,value); */
51c4762a1bSJed Brown   }
529566063dSJacob Faibussowitsch   PetscCall(PetscSortInt(n, values));
539566063dSJacob Faibussowitsch   PetscCall(PetscLogEventEnd(event, 0, 0, 0, 0));
54c4762a1bSJed Brown 
55ad540459SPierre Jolivet   for (i = 1; i < n; i++) PetscCheck(values[i] >= values[i - 1], PETSC_COMM_SELF, PETSC_ERR_PLIB, "Values not sorted");
569566063dSJacob Faibussowitsch   PetscCall(PetscFree(values));
579566063dSJacob Faibussowitsch   PetscCall(PetscRandomDestroy(&rnd));
58c4762a1bSJed Brown 
599566063dSJacob Faibussowitsch   PetscCall(PetscFinalize());
60b122ec5aSJacob Faibussowitsch   return 0;
61c4762a1bSJed Brown }
62c4762a1bSJed Brown 
63c4762a1bSJed Brown /*TEST
64c4762a1bSJed Brown 
65c4762a1bSJed Brown    test:
66*3886731fSPierre Jolivet       output_file: output/empty.out
67c4762a1bSJed Brown 
68c4762a1bSJed Brown    test:
69c4762a1bSJed Brown       suffix: 2
70c4762a1bSJed Brown       nsize: 2
71*3886731fSPierre Jolivet       output_file: output/empty.out
72c4762a1bSJed Brown 
73c4762a1bSJed Brown    test:
74c4762a1bSJed Brown       suffix: 3
75c4762a1bSJed Brown       args: -view_randomvalues 0
76c4762a1bSJed Brown 
77c4762a1bSJed Brown TEST*/
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