xref: /petsc/src/sys/classes/random/tutorials/ex1.c (revision d71ae5a4db6382e7f06317b8d368875286fe9008)
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 
12*d71ae5a4SJacob Faibussowitsch int main(int argc, char **argv)
13*d71ae5a4SJacob Faibussowitsch {
14c4762a1bSJed Brown   PetscInt    i, n = 1000, *values;
15c4762a1bSJed Brown   PetscRandom rnd;
16c4762a1bSJed Brown   PetscScalar value, avg = 0.0;
17c4762a1bSJed Brown   PetscMPIInt rank;
18c4762a1bSJed Brown   PetscInt    view_rank = -1;
19c4762a1bSJed Brown #if defined(PETSC_USE_LOG)
20c4762a1bSJed Brown   PetscLogEvent event;
21c4762a1bSJed Brown #endif
22c4762a1bSJed Brown 
23327415f7SBarry Smith   PetscFunctionBeginUser;
249566063dSJacob Faibussowitsch   PetscCall(PetscInitialize(&argc, &argv, (char *)0, help));
259566063dSJacob Faibussowitsch   PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
269566063dSJacob Faibussowitsch   PetscCall(PetscOptionsGetInt(NULL, NULL, "-n", &n, NULL));
279566063dSJacob Faibussowitsch   PetscCall(PetscOptionsGetInt(NULL, NULL, "-view_randomvalues", &view_rank, NULL));
28c4762a1bSJed Brown 
299566063dSJacob Faibussowitsch   PetscCall(PetscRandomCreate(PETSC_COMM_WORLD, &rnd));
30c4762a1bSJed Brown   /* force imaginary part of random number to always be zero; thus obtain reproducible results with real and complex numbers */
319566063dSJacob Faibussowitsch   PetscCall(PetscRandomSetInterval(rnd, 0.0, 1.0));
329566063dSJacob Faibussowitsch   PetscCall(PetscRandomSetFromOptions(rnd));
33c4762a1bSJed Brown 
349566063dSJacob Faibussowitsch   PetscCall(PetscMalloc1(n, &values));
35c4762a1bSJed Brown   for (i = 0; i < n; i++) {
369566063dSJacob Faibussowitsch     PetscCall(PetscRandomGetValue(rnd, &value));
37c4762a1bSJed Brown     avg += value;
3848a46eb9SPierre Jolivet     if (view_rank == (PetscInt)rank) PetscCall(PetscPrintf(PETSC_COMM_SELF, "[%d] value[%" PetscInt_FMT "] = %6.4e\n", rank, i, (double)PetscRealPart(value)));
39c4762a1bSJed Brown     values[i] = (PetscInt)(n * PetscRealPart(value) + 2.0);
40c4762a1bSJed Brown   }
41c4762a1bSJed Brown   avg = avg / ((PetscReal)n);
4248a46eb9SPierre Jolivet   if (view_rank == (PetscInt)rank) PetscCall(PetscPrintf(PETSC_COMM_SELF, "[%d] Average value %6.4e\n", rank, (double)PetscRealPart(avg)));
43c4762a1bSJed Brown 
449566063dSJacob Faibussowitsch   PetscCall(PetscSortInt(n, values));
45c4762a1bSJed Brown 
469566063dSJacob Faibussowitsch   PetscCall(PetscLogEventRegister("Sort", 0, &event));
479566063dSJacob Faibussowitsch   PetscCall(PetscLogEventBegin(event, 0, 0, 0, 0));
48c4762a1bSJed Brown 
499566063dSJacob Faibussowitsch   PetscCall(PetscRandomSeed(rnd));
50c4762a1bSJed Brown   for (i = 0; i < n; i++) {
519566063dSJacob Faibussowitsch     PetscCall(PetscRandomGetValue(rnd, &value));
52c4762a1bSJed Brown     values[i] = (PetscInt)(n * PetscRealPart(value) + 2.0);
53c4762a1bSJed Brown     /* printf("value[%d] = %g\n",i,value); */
54c4762a1bSJed Brown   }
559566063dSJacob Faibussowitsch   PetscCall(PetscSortInt(n, values));
569566063dSJacob Faibussowitsch   PetscCall(PetscLogEventEnd(event, 0, 0, 0, 0));
57c4762a1bSJed Brown 
58ad540459SPierre Jolivet   for (i = 1; i < n; i++) PetscCheck(values[i] >= values[i - 1], PETSC_COMM_SELF, PETSC_ERR_PLIB, "Values not sorted");
599566063dSJacob Faibussowitsch   PetscCall(PetscFree(values));
609566063dSJacob Faibussowitsch   PetscCall(PetscRandomDestroy(&rnd));
61c4762a1bSJed Brown 
629566063dSJacob Faibussowitsch   PetscCall(PetscFinalize());
63b122ec5aSJacob Faibussowitsch   return 0;
64c4762a1bSJed Brown }
65c4762a1bSJed Brown 
66c4762a1bSJed Brown /*TEST
67c4762a1bSJed Brown 
68c4762a1bSJed Brown    test:
69c4762a1bSJed Brown 
70c4762a1bSJed Brown    test:
71c4762a1bSJed Brown       suffix: 2
72c4762a1bSJed Brown       nsize: 2
73c4762a1bSJed Brown       output_file: output/ex1_1.out
74c4762a1bSJed Brown 
75c4762a1bSJed Brown    test:
76c4762a1bSJed Brown       suffix: 3
77c4762a1bSJed Brown       args: -view_randomvalues 0
78c4762a1bSJed Brown 
79c4762a1bSJed Brown TEST*/
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