8.2.35 _gfortran_caf_co_sum — Collective summing reduction

Description:

Calculates for each array element of the variable a the sum of all values 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 only.

Syntax:

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

Arguments:

a	intent(inout) An array descriptor with the data to be processed. On the destination image(s) the result overwrites the old content.
result_image	intent(in) 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	intent(in) the buffer size of errmsg

NOTES

If result_image is nonzero, the data in the array descriptor a on all images except of the specified one become undefined; hence, the library may make use of this.