DOKK / manpages / debian 12 / openmpi-doc / shmem_char_get.openmpi.3.en
SHMEM_GET(3) Open MPI SHMEM_GET(3)

shmem_character_get(3), shmem_complex_get(3), shmem_double_get(3), shmem_float_get(3), shmem_get4(3), shmem_get8(3), shmem_get32(3), shmem_get64(3), shmem_get128(3), shmem_getmem(3), shmem_int_get(3), shmem_integer_get(3), shmem_logical_get(3), shmem_long_get(3), shmem_longdouble_get(3), shmem_longlong_get(3), shmem_real_get(3), shmem_short_get(3) - Transfers data from a specified processing element (PE).

C or C++:

#include <mpp/shmem.h>
void shmem_get32(void *target, const void *source,


  size_t len, int pe);
void shmem_get64(void *target, const void *source,


  size_t len, int pe);
void shmem_get128(void *target, const void *source,


  size_t len, int pe);
void shmem_getmem(void *target, const void *source,


  size_t len, int pe);
void shmem_int_get(int *target, const int *source,


  size_t len, int pe);
void shmem_double_get(double *target, const double *source,


  size_t len, int pe);
void shmem_float_get(float *target, const float *source,


  size_t len, int pe);
void shmem_long_get(long *target, const long *source,


  size_t len, int pe);
void shmem_longdouble_get(long double *target,


  const long double *source, size_t len, int pe);
void shmem_longlong_get(long long *target,


  const long long *source, size_t len, int pe);
void shmem_short_get(short *target,


  const short *source, size_t len, int pe);

Fortran:

INCLUDE "mpp/shmem.fh"
INTEGER len, pe
CALL SHMEM_CHARACTER_GET(target, source, len, pe)
CALL SHMEM_COMPLEX_GET(target, source, len, pe)
CALL SHMEM_DOUBLE_GET(target, source, len, pe)
CALL SHMEM_GET4(target, source, len, pe)
CALL SHMEM_GET8(target, source, len, pe)
CALL SHMEM_GET32(target, source, len, pe)
CALL SHMEM_GET64(target, source, len, pe)
CALL SHMEM_GET128(target, source, len, pe)
CALL SHMEM_GETMEM(target, source, len, pe)
CALL SHMEM_INTEGER_GET(target, source, len, pe)
CALL SHMEM_LOGICAL_GET(target, source, len, pe)
CALL SHMEM_REAL_GET(target, source, len, pe)

The shmem_get routines transfer nelems elements of the data object at address source on the remote PE pe, to the data object at address target on the local PE. These routines return after the data has been copied to address target 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.

The target and source data objects must conform to typing constraints, which are as follows:

scaled in bytes.
equal to 32 bits.
{shmem_get8, shmem_get64}: Any noncharacter type that has a storage size equal to
64 bits.
bits.
characters to transfer. The actual character lengths of the source and target variables are ignored.

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(WORK, VALUES, 1, I)


    SUM = SUM + WORK


  ENDDO


  PRINT *, 'PE ', MY_PE(), ' COMPUTED SUM=', SUM


  CALL SHMEM_BARRIER_ALL
END

intro_shmem(3), shmem_put(3), shmem_iget(3), shmem_quiet(3)

May 26, 2022 4.1.4