Reference

Data structures

dyn_pset_state_t

typedef struct{
    void * dyn_pset_data;       // Library internal data. Should not be accessed by users
    void * user_pointer;        // User data pointer passed at init
    bool is_dynamic;            // True if the process was added dynamically
    MPI_Comm mpicomm;           // Current MPI communicator
    int mpirank;                // Rank in mpicomm
    int mpisize;                // Size of mpicomm
    MPI_Group group_add;        // Group added during last reconfiguration
    MPI_Group group_sub;        // Group removed during last reconfiguration
} dyn_pset_state_t;

Fields

• dyn_pset_data: Opaque, internal library state. Users must not access this directly.

• user_pointer: Opaque pointer provided by the application at initialization; forwarded to redistribution callbacks to enable application-specific data movement.

• is_dynamic: Indicates whether this process was added during a dynamic expansion.

• mpicomm/mpirank/mpisize: Current MPI communicator and rank/size; these may change as a direct result of reconfiguration operations.

• group_add/group_sub: MPI groups reflecting the last reconfiguration; useful for identifying which ranks were added or removed.

Notes

Fields in dyn_pset_state_t may change after calls to dyn_pset_adapt or dyn_pset_adapt_nb; callers should re-read the structure after reconfiguration completes.

Notes

This reference is a concise summary extracted from the project’s README. For more in-depth details see the in-source comments and the implementation in src/.

int dyn_pset_finalize(dyn_pset_state_t ** state, char *final_pset)

Finalize the Dyn_PSet state and optionally write the final PSet name into final_pset (must be a buffer of length MPI_MAX_PSET_NAME_LEN if non-NULL).

int dyn_pset_set_info(dyn_pset_state_t * state, MPI_Info info)

Set optimization information (see the info keys table below).

dyn_pset_state_t * dyn_pset_init(const char *initial_pset, void *user_pointer, MPI_Info info,

dyn_psets_expand_send_func_t exp_send, dyn_psets_expand_recv_func_t exp_recv,

dyn_psets_shrink_send_func_t shr_send, dyn_psets_shrink_recv_func_t shr_recv)

Initialize the Dyn_PSets library and return a dyn_pset_state_t pointer on success or NULL if the initialization was canceled (e.g., an expansion was aborted and the calling process should terminate). The parameters are the same as described in the Usage section; notable behaviors:

• info: Use an MPI_Info object to provide optimization/hint keys (see the “Optimization Information Keys” table).

• Redistribution callbacks (exp_send, exp_recv, shr_send, shr_recv) are invoked by the library during reconfiguration to move application data between processes.

int dyn_pset_adapt(dyn_pset_state_t * state, int *terminate, int *reconfigured)

Blocking call that attempts to reconfigure the DynPSet state according to the policy and any optimization information previously specified. On return, terminate is set to 1 if the calling process must terminate (it was removed by shrinkage); reconfigured is set to 1 if a reconfiguration occurred.

int dyn_pset_adapt_nb(dyn_pset_state_t * state, int *terminate, int *reconfigured)

Non-blocking variant of dyn_pset_adapt. Returns promptly and sets reconfigured to 0 or 1 to indicate whether a reconfiguration occurred. If reconfigured is 0, callers should call this function again to check for completion.

Optimization Information Keys

The library accepts optimization information via the MPI_Info passed to dyn_pset_init or dyn_pset_set_info. Common keys include (at least one of generator_key or output_space_generator should be provided; model is recommended):

Optimization Information Keys

Key	Value	Description
generator_key	<string>	Task attribute key used in the batch script.
output_space_generator	<string>	Python expression that evaluates to an output-space generator function.
output_space_generator_def	<string>	Full function definition for the output-space generator.
model	<string>	Evaluates to an instance of a PSet model (e.g. DefaultReplaceModel()).
model_params	<key:val:type,…>	Comma-separated parameter triples for the model.
input_pset_model_[index]	<string>	PSet model class name for the input PSet at the given index.
input_pset_model_params_[index]	<key:val:type,…>	Comma-separated params for the corresponding input-pset model.

void dyn_pset_set_output(char * filename, int verbosity_level)

Configure debug output file and verbosity.

int dyn_pset_config(dyn_pset_state_t * state, const char * config_param, void * value)

Set runtime configuration parameters (see supported configure parameters below).

Supported configure parameters

The current implementation supports the following configure parameter:

Configure Parameters

Parameter	Type	Description
garbage_collection	bool	Default: true. If set to false, MPI communicators will not be garbage collected during reconfiguration; the user is responsible for disconnecting and cleaning up communicators.
col_update	bool	Default: false. If set to true, calls to dyn_pset_set_info will trigger updates of currently pending psetop.

Callback typedefs

typedef int (*dyn_psets_expand_send_func_t) (dyn_pset_state_t * state);
typedef int (*dyn_psets_expand_recv_func_t) (dyn_pset_state_t * state);
typedef int (*dyn_psets_shrink_send_func_t) (dyn_pset_state_t * state);
typedef int (*dyn_psets_shrink_recv_func_t) (dyn_pset_state_t * state);

Notes

This reference is a concise summary extracted from the project’s README. For more in-depth details see the in-source comments and the implementation in src/.