DOKK / manpages / debian 11 / openmpi-doc / shmem_getmem_nbi.openmpi.3.en
SHMEM_GET_NBI(3) Open MPI SHMEM_GET_NBI(3)

shmem_getmem_nbi(3), shmem_char_get_nbi(3), shmem_short_get_nbi(3), shmem_int_get_nbi(3), shmem_long_get_nbi(3), shmem_longlong_get_nbi(3), shmem_float_get_nbi(3), shmem_double_get_nbi(3), shmem_longdouble_get_nbi(3), shmem_get8_nbi(3), shmem_get16_nbi(3), shmem_get32_nbi(3), shmem_get64_nbi(3), shmem_get128_nbi(3), - The nonblocking get routines provide a method for copying data from a contiguous remote data object on the specified PE to the local data object.

C or C++:

#include <mpp/shmem.h>
void shmem_getmem_nbi(void *dest, const void *source,

size_t nelems, int pe); void shmem_char_get(char *dest, const char *source,
size_t nelems, int pe); void shmem_short_get(short *dest, const short *source,
size_t nelems, int pe); void shmem_int_get(int *dest, const int *source,
size_t nelems, int pe); void shmem_long_get(long *dest, const long *source,
size_t nelems, int pe); void shmem_longlong_get(long long *dest, const long long *source,
size_t nelems, int pe); void shmem_float_get(float *dest, const float *source,
size_t nelems, int pe); void shmem_double_get(double *dest, const double *source,
size_t nelems, int pe); void shmem_longdouble_get(long double *dest, const long double *source,
size_t nelems, int pe); void shmem_get8(void *dest, const void *source,
size_t nelems, int pe); void shmem_get16(void *dest, const void *source,
size_t nelems, int pe); void shmem_get32(void *dest, const void *source,
size_t nelems, int pe); void shmem_get64(void *dest, const void *source,
size_t nelems, int pe); void shmem_get128(void *dest, const void *source,
size_t nelems, int pe);

Fortran:

INCLUDE "mpp/shmem.fh"
INTEGER nelems, pe
CALL SHMEM_GETMEM_NBI(dest, source, nelems, pe)
CALL SHMEM_CHARACTER_GET_NBI(dest, source, nelems, pe)
CALL SHMEM_COMPLEX_GET_NBI(dest, source, nelems, pe)
CALL SHMEM_DOUBLE_GET_NBI(dest, source, nelems, pe)
CALL SHMEM_INTEGER_GET_NBI(dest, source, nelems, pe)
CALL SHMEM_LOGICAL_GET_NBI(dest, source, nelems, pe)
CALL SHMEM_REAL_GET_NBI(dest, source, nelems, pe)
CALL SHMEM_GET4_NBI(dest, source, nelems, pe)
CALL SHMEM_GET8_NBI(dest, source, nelems, pe)
CALL SHMEM_GET32_NBI(dest, source, nelems, pe)
CALL SHMEM_GET64_NBI(dest, source, nelems, pe)
CALL SHMEM_GET128_NBI(dest, source, nelems, pe)

The get routines provide a method for copying a contiguous symmetric data object from a different PE to a contiguous data object on the local PE. The routines return after posting the operation. The operation is considered complete after a subsequent call to shmem_quiet. At the completion of shmem_quiet, the data has been delivered to the dest array on the local PE.

The arguments are as follows:

Local data object to be updated.
Data object on the PE identified by pe that contains the data to be copied. This data object must be remotely accessible.
Number of elements in the target and source arrays. len must be of type integer. If you are using Fortran, it must be a constant, variable, or array element of default integer type.
PE number of the remote PE. pe must be of type integer. If you are using Fortran, it must be a constant, variable, or array element of default integer type.

If you are using Fortran, data types must be of default size. For example, a real variable must be declared as REAL, REAL*4, or REAL(KIND=4).

See intro_shmem(3) for a definition of the term remotely accessible.

Consider this simple example for Fortran.

PROGRAM REDUCTION

REAL VALUES, SUM
COMMON /C/ VALUES
REAL WORK
CALL START_PES(0) ! ALLOW ANY NUMBER OF PES
VALUES = MY_PE() ! INITIALIZE IT TO SOMETHING
CALL SHMEM_BARRIER_ALL
SUM = 0.0
DO I = 0,NUM_PES()-1
CALL SHMEM_REAL_GET_NBI(WORK, VALUES, 1, I)
CALL SHMEM_QUIET ! wait for delivery
SUM = SUM + WORK
ENDDO
PRINT *, 'PE ', MY_PE(), ' COMPUTED SUM=', SUM
CALL SHMEM_BARRIER_ALL END

intro_shmem(3), shmem_quiet(3)

December 18, 2020 4.1.0