iterator_advance Subroutine

   SUBROUTINE iterator_advance(iterator)
      !! Advances to the next block

      TYPE(dbcsr_iterator), INTENT(INOUT)                :: iterator
         !! the iterator

      INTEGER                                            :: ithread, my_old_row, p
      LOGICAL                                            :: advance, jumped_row

!   ---------------------------------------------------------------------------

      ithread = 0
!$    ithread = omp_get_thread_num()
      IF (iterator%dynamic .AND. iterator%shared) THEN
         IF (iterator%dynamic_byrows) THEN
            ! In this case common_row holds the last assigned row.
            !
            ! The idea is to advance in this thread's row. If it gets bumped
            ! into the next row, then we have to find the correct one.
            advance = .TRUE.
            DO WHILE (advance)
               iterator%pos = iterator%pos + 1
               my_old_row = iterator%row
               CALL find_proper_position_caller(iterator)
               jumped_row = iterator%row .GT. my_old_row
               advance = jumped_row
               IF (jumped_row) THEN
!$OMP                 CRITICAL (crit_common_pos)
                  ! Set the common_pos to the next available row.
                  iterator%common_pos = MAX(iterator%row, iterator%common_pos + 1)
                  iterator%row = iterator%common_pos
!$OMP                 END CRITICAL (crit_common_pos)
                  IF (iterator%row .GT. iterator%nblkrows_total) THEN
                     iterator%pos = 0
                     iterator%row = 0
                     advance = .FALSE.
                  ELSE
                     ! To be incremented in the next loop.
                     IF (.NOT. iterator%local_indexing) THEN
                        iterator%pos = iterator%row_p(iterator%row)
                     ELSE
                        iterator%pos = iterator%row_p(iterator%global_rows(iterator%row))
                     END IF
                  END IF
               END IF
            END DO
         ELSE
            ! In this case common_pos holds the last-assigned block.
            !
!$OMP           CRITICAL (crit_common_pos)
            iterator%common_pos = iterator%common_pos + 1
            iterator%pos = iterator%common_pos
            CALL find_proper_position_caller(iterator)
            p = iterator%pos
            iterator%common_pos = MAX(iterator%common_pos, p)
!$OMP           END CRITICAL (crit_common_pos)
         END IF
      ELSEIF (iterator%shared) THEN
         iterator%pos = iterator%pos + 1
         ithread = 0
!$       ithread = OMP_GET_THREAD_NUM()
         CALL find_proper_position_caller(iterator, use_ithread=ithread)
      ELSE
         iterator%pos = iterator%pos + 1
         CALL find_proper_position_caller(iterator)
      END IF
   END SUBROUTINE iterator_advance