anchor.diff:  CMWF SKIP NPATH FOR NOW
   C                NPATH(IPT)=KPATH
   C
  +                IF (IVERBOSE.GE.5) THEN
   C MWF DEBUG
  -C                WRITE(LU_O,*)' AFTER I2.NE.0 ELTRACK ELEMENT LOOP T= '
  -C     &               ,T,' IDSDT= ',IDSDT,' TPT= ',TPT(IPT),' IPT= ',IPT
  -C     &               ,' M= ',M
  -C                WRITE(LU_O,*)' I1= ',I1,' I2= ',I2,' I3= ',I3
  -C                DO K=1,NEQ
  -C                   WRITE(LU_O,*)' XPT(',K,',',IPT,')= ',
  -C     &                  XPT(K + IPT*MAXEQ)
  -C                ENDDO
  +                   WRITE(LU_O,*)' AFTER I2.NE.0 ELTRACK ELEMENT LOOP',
  +     &                  'T= ',T,' IDSDT= ',IDSDT,' TPT= ',TPT(IPT),
  +     &                  'IPT= ',IPT,' M= ',M
  +                   WRITE(LU_O,*)' I1= ',I1,' I2= ',I2,' I3= ',I3
  +                   DO K=1,NEQ
  +                      WRITE(LU_O,*)' XPT(',K,',',IPT,')= ',
  +     &                     XPT(K + IPT*MAXEQ)
  +                   ENDDO
  +                ENDIF
  +C
                   IF(IDSDT.EQ.-1)THEN
                     MPT(IPT)=M
   C 0 -- INTERIOR
  
positive.code:       DOUBLE PRECISION DEQ,TS,DTS,T,SDT,DT0
        DOUBLE PRECISION DIR
  C     
        INTEGER I,IPT,NODE,NP,M
        INTEGER IDSDT,I1,I2,I3,M2,M3,N1,N2,N3,J1,J2,J3
  C
  C
  
negative.code: C     HAVE TO TREAT AS FLAT ARRAY, SINCE MAY BE DIFFERENT SHAPES IN PYTHON (q, versus ebqe)
  C     ASSUME MPT,TPT SET BY CALLING CODE 
  CMWF DEBUG
        IF (IVERBOSE.GE.1) THEN
           WRITE(LU_O,*)'ENTERING PT123'
           WRITE(LU_O,*)'NNP= ',NNP,' NEL= ',NEL,' NNDE= ',NNDE,' NEQ= ',
       &        NEQ,' NPT= ',NPT,' IBF= ',IBF,' LU_O= ',LU_O, ' ATOL= ',
       &        ATOL,' RTOL= ',RTOL, ' SF= ',SF, 'DN_SAFE= ',DN_SAFE
        ENDIF
        DO IPT=1,NPT
           DO I=1,NEQ
              XS(I)=X_I(I + MAXEQ*(IPT-1))
  