1: static char help[] = "Demonstrates using the PetscBag Object\n\n";

  3: #include <petscsys.h>
  4: #include <petscbag.h>
  5: #include <petscviewer.h>

  7: /*
  8:   Enum variables can be stored in a bag but require a string array
  9:   to name their fields.  The fourth entry in this example is the name
 10:   of the enum, the fifth is the prefix (none in this case), and the last
 11:   entry is the null string.
 12: */
 13: typedef enum {
 14:   THIS      = 0,
 15:   THAT      = 1,
 16:   THE_OTHER = 2
 17: } YourChoice;
 18: const char *EnumeratedChoices[] = {"THIS", "THAT", "THE_OTHER", "EnumeratedChoices", "", 0};

 20: /*
 21:   Data structures can be used in a bag as long as they
 22:   are declared in the bag with a variable, not with a pointer.
 23: */
 24: typedef struct {
 25:   PetscReal x1, x2;
 26: } TwoVec;

 28: /*
 29:   Define a C struct that will contain my program's parameters.

 31:   A PETSc bag is merely a representation of a C struct that can be printed, saved to a file and loaded from a file.
 32: */
 33: typedef struct {
 34:   PetscScalar   W;
 35:   PetscReal     rho;
 36:   TwoVec        pos;
 37:   PetscInt      Ii;
 38:   PetscInt      iarray[3];
 39:   PetscReal     rarray[2];
 40:   PetscBool     T;
 41:   PetscBool     Tarray[3];
 42:   PetscDataType dt;
 43:   char          filename[PETSC_MAX_PATH_LEN];
 44:   YourChoice    which;
 45: } Parameter;

 47: int main(int argc, char **argv)
 48: {
 49:   PetscBag    bag;
 50:   Parameter  *params;
 51:   PetscViewer viewer;
 52:   PetscBool   flg;
 53:   char        filename[PETSC_MAX_PATH_LEN] = "binaryoutput";

 55:   /*
 56:     Every PETSc routine should begin with the PetscInitialize() routine.
 57:     argc, argv - These command line arguments are taken to extract the options
 58:                  supplied to PETSc and options supplied to MPI.
 59:     help       - When PETSc executable is invoked with the option -help,
 60:                  it prints the various options that can be applied at
 61:                  runtime.  The user can use the "help" variable place
 62:                  additional help messages in this printout.
 63:   */
 64:   PetscFunctionBeginUser;
 65:   PetscCall(PetscInitialize(&argc, &argv, NULL, help));

 67:   /* Create an empty bag */
 68:   PetscCall(PetscBagCreate(PETSC_COMM_WORLD, sizeof(Parameter), &bag));
 69:   PetscCall(PetscBagGetData(bag, (void **)&params));

 71:   /* register variables, defaults, names, help strings */
 72:   PetscCall(PetscBagSetName(bag, "ParameterBag", "contains parameters for simulations of top-secret, dangerous physics"));
 73:   PetscCall(PetscBagSetOptionsPrefix(bag, "pbag_"));
 74:   PetscCall(PetscBagRegisterString(bag, &params->filename, PETSC_MAX_PATH_LEN, "myfile", "filename", "Name of secret file"));
 75:   PetscCall(PetscBagRegisterReal(bag, &params->rho, 3.0, "rho", "Density, kg/m^3"));
 76:   PetscCall(PetscBagRegisterScalar(bag, &params->W, 5.0, "W", "Vertical velocity, m/sec"));
 77:   PetscCall(PetscBagRegisterInt(bag, &params->Ii, 2, "modes_x", "Number of modes in x-direction"));

 79:   params->iarray[0] = 1;
 80:   params->iarray[1] = 2;
 81:   params->iarray[2] = 3;

 83:   PetscCall(PetscBagRegisterIntArray(bag, &params->iarray, 3, "int_array", "Int array with 3 locations"));

 85:   params->rarray[0] = -1.0;
 86:   params->rarray[1] = -2.0;

 88:   PetscCall(PetscBagRegisterRealArray(bag, &params->rarray, 2, "real_array", "Real array with 2 locations"));
 89:   PetscCall(PetscBagRegisterBool(bag, &params->T, PETSC_FALSE, "do_output", "Write output file (yes/no)"));
 90:   PetscCall(PetscBagRegisterBoolArray(bag, &params->Tarray, 3, "bool_array", "Bool array with 3 locations"));
 91:   PetscCall(PetscBagRegisterEnum(bag, &params->dt, PetscDataTypes, (PetscEnum)PETSC_INT, "dt", "meaningless datatype"));
 92:   PetscCall(PetscBagRegisterReal(bag, &params->pos.x1, 1.0, "x1", "x position"));
 93:   PetscCall(PetscBagRegisterReal(bag, &params->pos.x2, 1.9, "x2", "y position"));
 94:   PetscCall(PetscBagRegisterEnum(bag, &params->which, EnumeratedChoices, (PetscEnum)THAT, "choose", "Express yourself by choosing among enumerated things"));

 96:   /* This option allows loading user-provided PetscBag */
 97:   PetscCall(PetscOptionsGetString(NULL, NULL, "-f", filename, sizeof(filename), &flg));
 98:   if (!flg) {
 99:     /* write bag to stdio & binary file */
100:     PetscCall(PetscBagView(bag, PETSC_VIEWER_STDOUT_WORLD));
101:     PetscCall(PetscViewerBinaryOpen(PETSC_COMM_WORLD, filename, FILE_MODE_WRITE, &viewer));
102:     PetscCall(PetscBagView(bag, viewer));
103:     PetscCall(PetscViewerDestroy(&viewer));
104:   }

106:   PetscCall(PetscMemzero(params, sizeof(Parameter)));

108:   /* load bag from file & write to stdio */
109:   PetscCall(PetscViewerBinaryOpen(PETSC_COMM_WORLD, filename, FILE_MODE_READ, &viewer));
110:   PetscCall(PetscBagLoad(viewer, bag));
111:   PetscCall(PetscViewerDestroy(&viewer));
112:   PetscCall(PetscBagSetFromOptions(bag));
113:   PetscCall(PetscBagView(bag, PETSC_VIEWER_STDOUT_WORLD));

115:   /* reuse the parameter struct */
116:   PetscCall(PetscBagGetData(bag, (void **)&params));
117:   PetscCall(PetscPrintf(PETSC_COMM_WORLD, "The value of rho after loading is: %f\n", (double)params->rho));

119:   /* clean up and exit */
120:   PetscCall(PetscBagDestroy(&bag));
121:   PetscCall(PetscFinalize());
122:   return 0;
123: }

125: /*TEST

127:    test:
128:       args: -pbag_rho 44 -pbag_do_output true
129:       requires: !complex

131:    test:
132:       suffix: yaml
133:       requires: !complex
134:       args: -options_file bag.yml -options_view
135:       filter: grep -E -v "(options_view)"
136:       localrunfiles: bag.yml

138: TEST*/