anchor.diff:        IB_B = IBSPGPFTP(IBTP)
         CALL ABSPGP_TO_CISPACE(ISPGPFTP(1,IB_A),NASPGP,
        &     ISPGPFTP(1,IB_B),NBSPGP,NGAS,IGSOCC,NELFGP,
  -     &     N_ABSPGP_MAX,WORK(KIABSPGP_FOR_CMPSPC),0)
  +     &     N_ABSPGP_MAX,dbl_mb(KIABSPGP_FOR_CMPSPC),0)
   *. Obtain mapping from occupation classes to supergroups
         IATP = 1
         IBTP = 2
  
positive.code:         CALL MEMMAN(KWCPMT,LENGTH,'ADDL  ',2,'KWCPMT') !done
  *
  *. Occupation of strings of given sym and supergroup
          CALL GASANAS(C,LUC,WORK(KNSTSO(IATP)),WORK(KNSTSO(IBTP)),
       &       NOCTPA,NOCTPB,MXPNGAS,IOCTPA,IOCTPB,
       &       NBLOCK,IBLOCK,
       &       THRES,MAXTRM,NAEL,NBEL,
  
negative.code:      &       WORK(KSBLTP),
       &       ICISTR,IDC,NSMST,
       &       LBLK,IAMPACK,ISMOST(1,ISM),
       &       int_mb(KNSTSO(IATP)),int_mb(KNSTSO(IBTP)))
  C     EXPCIVS(LUIN,VECIN,NCOMBIN,IABIN,
  C    &                   NOCTPA,NOCTPB,IBLTPIN,
  C    &                   LUUT,VECUT,NCOMBUT,IABUT,
  