These functions use the following arguments for output:
y - Array handle for an S3L array of rank >= 1. This array contains one or more instances of the destination vector y embedded along the axis y_vector_axis. This axis must have the same length as axis row_axis of A. Upon completion, each vector instance is overwritten by the result of the matrix vector multiplication call.
ier (Fortran only) - When called from a Fortran program, these functions return error status in ier.