Actual source code: ex5.c
2: static char help[] = "Demonstrates using the PetscBag Object\n\n";
4: /*T
5: Concepts: bags;
6: Processors: n
7: T*/
8: #include petsc.h
9: #include petscbag.h
11: /*
12: Enum variables can be stored in a bag but require a string array
13: to name their fields. The fourth entry in this example is the name
14: of the enum, the fifth is the prefix (none in this case), and the last
15: entry is the null string.
16: */
17: typedef enum {
18: THIS = 0, THAT = 1, THE_OTHER = 2
19: } YourChoice;
20: const char *EnumeratedChoices[] = {"THIS","THAT","THE_OTHER","EnumeratedChoices","",0};
22: /*
23: Data structures can be used in a bag as long as they
24: are declared in the bag with a variable, not with a pointer.
25: */
26: typedef struct {
27: PetscReal x1,x2;
28: } TwoVec;
30: /*
31: Define a C struct that will contain my program's parameters.
32: It MUST begin with the PetscBag struct.
33: */
34: typedef struct {
35: PetscBag bag;
36: char filename[PETSC_MAX_PATH_LEN];
37: PetscReal rho;
38: PetscScalar W;
39: PetscInt I;
40: PetscTruth T;
41: TwoVec pos;
42: PetscDataType dt;
43: YourChoice which;
44: } Parameter;
45:
49: int main(int argc,char **argv)
50: {
52: PetscBag *bag;
53: Parameter *params;
54: PetscViewer viewer;
56: /*
57: Every PETSc routine should begin with the PetscInitialize() routine.
58: argc, argv - These command line arguments are taken to extract the options
59: supplied to PETSc and options supplied to MPI.
60: help - When PETSc executable is invoked with the option -help,
61: it prints the various options that can be applied at
62: runtime. The user can use the "help" variable place
63: additional help messages in this printout.
64: */
65: PetscInitialize(&argc,&argv,(char *)0,help);
67: /* Create an empty bag */
68: PetscBagCreate(PETSC_COMM_WORLD,Parameter,&bag);
69: params = (Parameter*)bag;
71: /* register variables, defaults, names, help strings */
72: PetscBagSetName(bag,"ParameterBag","contains parameters for simulations of top-secret, dangerous physics");
73: PetscBagRegisterString(bag,¶ms->filename,PETSC_MAX_PATH_LEN,"myfile","filename","Name of secret file");
74: PetscBagRegisterReal (bag,¶ms->rho,3.0,"rho","Density, kg/m^3");
75: PetscBagRegisterScalar(bag,¶ms->W, 5.0,"W","Vertical velocity, m/sec");
76: PetscBagRegisterInt (bag,¶ms->I, 2,"modes_x","Number of modes in x-direction");
77: PetscBagRegisterTruth (bag,¶ms->T, PETSC_FALSE,"do_output","Write output file (yes/no)");
78: PetscBagRegisterEnum (bag,¶ms->dt, PetscDataTypes,(PetscEnum)PETSC_INT,"dt","meaningless datatype");
79: PetscBagRegisterReal (bag,¶ms->pos.x1,1.0,"x1","x position");
80: PetscBagRegisterReal (bag,¶ms->pos.x2,1.9,"x2","y position");
81: PetscBagRegisterEnum (bag,¶ms->which, EnumeratedChoices, (PetscEnum)THAT, "choose","Express yourself by choosing among enumerated things");
83: /* write bag to stdio & binary file */
84: PetscBagView(bag,PETSC_VIEWER_STDOUT_WORLD);
85: PetscViewerBinaryOpen(PETSC_COMM_WORLD,"binaryoutput",PETSC_FILE_CREATE,&viewer);
86: PetscBagView(bag,viewer);
87: PetscViewerDestroy(viewer);
88: PetscBagDestroy(bag);
90: /* load bag from file & write to stdio */
91: PetscViewerBinaryOpen(PETSC_COMM_WORLD,"binaryoutput",PETSC_FILE_RDONLY,&viewer);
92: PetscBagLoad(viewer,&bag);
93: PetscViewerDestroy(viewer);
94: PetscBagView(bag,PETSC_VIEWER_STDOUT_WORLD);
96: /* reuse the parameter struct */
97: params = (Parameter*)bag;
98: PetscPrintf(PETSC_COMM_WORLD,"The value of rho after loading is: %f\n",params->rho);
100: /* clean up and exit */
101: PetscBagDestroy(bag);
102: PetscFinalize();
103: return 0;
104: }