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## General Usage Example

An example of general Zoltan usage is included below. This is a C language example. Similar C++ examples may be found in the examples directory.

In this example, Zoltan_Initialize is called using the argc and argv arguments to the main program. Then a pointer to a Zoltan structure is returned by the call to Zoltan_Create. In this example, all processors will be used by Zoltan, as MPI_COMM_WORLD is passed to Zoltan_Create as the communicator.

Several application query functions are then registered with Zoltan through calls to Zoltan_Set_Fn. Parameters are set through calls to Zoltan_Set_Param. The application then performs in computations, including making calls to Zoltan functions and utilities.

Before its execution ends, the application frees memory used by Zoltan by calling Zoltan_Destroy.

`/* Initialize the Zoltan library */` `struct Zoltan_Struct *zz;` `float version;` `...` `Zoltan_Initialize(argc, argv, &version);` `zz = Zoltan_Create(MPI_COMM_WORLD);` `/* Register query functions. */` `Zoltan_Set_Fn(zz, ZOLTAN_NUM_GEOM_FN_TYPE,` `(void (*)()) user_return_dimension, NULL);` `Zoltan_Set_Fn(zz, ZOLTAN_GEOM_FN_TYPE,` `(void (*)()) user_return_coords, NULL);` `Zoltan_Set_Fn(zz, ZOLTAN_NUM_OBJ_FN_TYPE,` `(void (*)()) user_return_num_node, NULL);` `Zoltan_Set_Fn(zz, ZOLTAN_OBJ_LIST_FN_TYPE,` `(void (*)()) user_return_owned_nodes, NULL);` `/* Set some Zoltan parameters. */` `Zoltan_Set_Param(zz, "debug_level", "4");` `/* Perform application computations, call Zoltan, etc. */` `...` `/* Free Zoltan data structure before ending application. */` `Zoltan_Destroy (&zz);`
Typical calling sequence for general usage of the Zoltan library.

`! Initialize the Zoltan library` `type(Zoltan_Struct), pointer :: zz` `real(Zoltan_FLOAT) version` `integer(Zoltan_INT) ierr` `...` `ierr = Zoltan_Initialize(version) ! without argc and argv` `zz => Zoltan_Create(MPI_COMM_WORLD)` `! Register load-balancing query functions.` `! omit data = C NULL` `ierr = Zoltan_Set_Fn(zz, ZOLTAN_NUM_GEOM_FN_TYPE, user_return_dimension)` `ierr = Zoltan_Set_Fn(zz, ZOLTAN_GEOM_FN_TYPE, user_return_coords)` `ierr = Zoltan_Set_Fn(zz, ZOLTAN_NUM_OBJ_FN_TYPE, user_return_num_node)` `ierr = Zoltan_Set_Fn(zz, ZOLTAN_OBJ_LIST_FN_TYPE, user_return_owned_nodes)` `! Set some Zoltan parameters.` `ierr = Zoltan_Set_Param(zz, "debug_level", "4")` `! Perform application computations, call Zoltan, etc.` `...` `! Free Zoltan data structure before ending application.` `call Zoltan_Destroy(zz)`
Fortran version of general usage example.

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