find_block_of_element Subroutine

   SUBROUTINE find_block_of_element(full, block, nblocks, &
                                    block_offsets, hint)
      !! Finds block to which a full element belongs.
      !!
      !! Assumptions
      !! It is assumed that block_start and block_end are sorted and
      !! that hint is in the range [0, nblocks].

      INTEGER, INTENT(in)                                :: full
         !! full element
      INTEGER, INTENT(out)                               :: block
         !! block to which full belongs
      INTEGER, INTENT(in)                                :: nblocks
      INTEGER, DIMENSION(1:nblocks + 1), INTENT(in)        :: block_offsets
         !! starting full elements of blocks
      INTEGER, INTENT(in)                                :: hint
         !! where to start looking; ignored if 0

      LOGICAL, PARAMETER                                 :: dbg = .FALSE.

      INTEGER                                            :: count

      IF (hint .NE. 0) THEN
         block = hint
      ELSE
         block = MAX(1, (nblocks + 1)/2)
      END IF
      count = 0
      DO WHILE (block_offsets(block) .GT. full .OR. block_offsets(block + 1) - 1 .LT. full)
         IF (block_offsets(block) .GT. full) THEN
            block = block - 1
         ELSEIF (block_offsets(block + 1) - 1 .LT. full) THEN
            block = block + 1
         END IF
         count = count + 1
         IF (dbg) THEN
            IF (count .GT. nblocks .OR. block .LT. 1 .OR. block .GT. nblocks) THEN
               WRITE (*, '(1X,A,I9,A,I9,A)') "Want to find block", &
                  block, " of", nblocks, " blocks"
               IF (count .GT. nblocks) &
                  DBCSR_ABORT("Too many searches")
            END IF
         END IF
      END DO
   END SUBROUTINE find_block_of_element