SHMEM_LONG_GET_NBI(3)

πŸ“¦
version 5.0.10 Β· 4 versions
, in ubuntu stonking

✨ SHMEM_LONG_GET_NBI ✨

okay bestie, gather round πŸ’– this one lives in Open MPI, and it's the whole fam of nonblocking get routines. Here's everybody who showed up to the party: 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).

And what do they all do? They're the nonblocking get routines β€” the method for copying data from a contiguous remote data object on the specified PE over to your local data object. no cap πŸ’…


🌸 SYNOPSIS 🌸

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)

πŸ¦‹ DESCRIPTION πŸ¦‹

So here's the tea, bestie πŸ«– the get routines give you a whole method for copying a contiguous symmetric data object from a different PE into a contiguous data object on the local PE. The catch? These routines return right after posting the operation β€” they do NOT wait around for it. not me returning before the job's done, iconic behavior tbh 😭

The operation is considered complete only after a subsequent call to shmem_quiet. And at the completion of shmem_quiet, the data has been delivered to the dest array on the local PE. So like… if you're not calling shmem_quiet, bestie, your data is still in the group chat typing bubble πŸ’€

The arguments are as follows:

  • dest β€” Local data object to be updated. this is the one getting the glow-up ✨
  • source β€” Data object on the PE identified by pe that contains the data to be copied. This data object must be remotely accessible. πŸ‘‘
  • nelems β€” 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 β€” 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). no sneaky custom kinds, okay? πŸ™ˆ


πŸŽ€ NOTES πŸŽ€

See intro_shmem(3) for a definition of the term remotely accessible. iykyk πŸ“š


🌈 EXAMPLES 🌈

Consider this simple example for Fortran. it's giving main character energy, fr fr πŸ’œ

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

See also: intro_shmem(3) shmem_quiet(3)


2003-2026, The Open MPI Community


okay that's the whole page, bestie, slay πŸ’…βœ¨ this was Open MPI's SHMEM_LONG_GET_NBI(3), dated Sep 10, 2026 β€” go forth and shmem_quiet before you read your data, i'm literally begging 🫢🌸

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