shell_string.f

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      ! brief Sorting function
      !
      ! param N Size of the array
      ! param A Array to sort
      ! param B Reordering array
      SUBROUTINE shell_string
!
     &                          (n, a, b)
!
      USE declarations_special
      IMPLICIT NONE
!
      INTEGER, INTENT(IN)              :: N
      CHARACTER(LEN=PATH_LEN), INTENT(INOUT)  :: A(n)
      INTEGER, INTENT(OUT)             :: B(n)
!
      INTEGER                          :: I, J, INC
      CHARACTER(LEN=PATH_LEN)               :: V
      INTEGER                          :: W
!
      INTEGER                          :: ALPHA
!
      alpha=2
!
      DO i=1,n
        b(i)=i
      ENDDO
!
      inc=1
 1    inc=alpha*inc+1
      IF (inc.LE.n) GOTO 1
 2    CONTINUE
        inc=inc/alpha
        DO i=inc+1,n
          v=a(i)
          w=b(i)
          j=i
 3        IF (a(j-inc).GT.v) THEN
            a(j)=a(j-inc)
            b(j)=b(j-inc)
            j=j-inc
            IF (j.LE.inc) GOTO 4
          GOTO 3
          ENDIF
 4        a(j)=v
          b(j)=w
        ENDDO
!
      IF (inc.GT.1) GOTO 2
!
      RETURN
      END SUBROUTINE