MPI advanced

Question 1

persistent communication

Answer 1

when we use same call reptedly in a loop

Question 2

setup persistent communication

Answer 2

int MPI_Send_init(const void* buffer,
int count,
MPI_Datatype datatype,
int recipient,
int tag,
MPI_Comm communicator,
MPI_Request* request);

MPI_Send_init(&buffer_sent, 1, MPI_INT, RECEIVER, 0, MPI_COMM_WORLD, &request);

prepares a request handle for sending using persistent communications

Question 3

persistent communication start

Answer 3

launches the communication represented by the request handle passed

int MPI_Start(MPI_Request* request);

MPI_Start(&request)

Question 4

persistent comm free

Answer 4

MPI_Request_free(req)

Question 5

partitioned communication

Answer 5

used to transfer data by dividing it in chunks

Question 6

MPI type contiguous

Answer 6

int MPI_Type_contiguous(int count,
MPI_Datatype old_datatype,
MPI_Datatype* new_datatype);

Question 7

how to set up mpi data type creation

Answer 7

MPI_Datatype

MPI_Type_commit()

MPI_Type_free()

Question 8

MPY type vector

Answer 8

int MPI_Type_vector(int block_count,
int block_length,
int stride,
MPI_Datatype old_datatype,
MPI_Datatype* new_datatype);

Question 9

MPI type indexed

Answer 9

int MPI_Type_indexed(int block_count,
const int block_lengths[],
const int displacements[],
MPI_Datatype old_datatype,
MPI_Datatype* new_datatype);

Question 10

Mpi TYPE create struct

Answer 10

int MPI_Type_create_struct(int block_count,
const int block_lengths[],
const MPI_Aint displacements[],
MPI_Datatype block_types[],
MPI_Datatype* new_datatype);

Question 11

Mpi TYPE create subarray

Answer 11

int MPI_Type_create_subarray(int dim_count,
const int array_element_counts[],
const int subarray_element_counts[],
const int subarray_coordinates[],
int order,
MPI_Datatype old_datatype,
MPI_Datatype* new_datatype);

Question 12

when to use MPI types

Answer 12

1. messages wth multiple types
2. simplify code
3. often access spread out data

Question 13

MPI type duplicate

Answer 13

MPI_Type_dup