8.2.24 _gfortran_caf_co_sum — Collective summing reduction

Description:

Calculates the for the each array element of the variable a the sum value for that element in the current team; if result_image has the value 0, the result shall be stored on all images, otherwise, only on the specified image. This function operates on numeric values.

Syntax:

void _gfortran_caf_co_sum (gfc_descriptor_t *a, int result_image, int *stat, char *errmsg, int errmsg_len)

Arguments:

a	intent(inout) And array descriptor with the data to be breoadcasted (on source_image) or to be received (other images).
result_image	The ID of the image to which the reduced value should be copied to; if zero, it has to be copied to all images.
stat	intent(out) Stores the status STAT= and may be NULL.
errmsg	intent(out) When an error occurs, this will be set to an error message; may be NULL
errmsg_len	the buffer size of errmsg.

NOTES

If result_image is nonzero, the value on all images except of the specified one become undefined; hence, the library may make use of this.