anchor.diff:      ax=abs(xx)
       ay=abs(yy)
       ! (x,y)<r1 or ( (xx>r2) || (yy>r2) ): no kick from lens
  -    if ( (ax.lt.r1lteps.and.ay.lt.r1lteps) .or. (ax.gt.r2gteps.or.ay.gt.r2gteps) ) cycle
  +    if ( (ax < r1lteps .and. ay < r1lteps) .or. (ax > r2gteps .or. ay > r2gteps) ) cycle
   
       ! compute kick from cheby map
       call cheby_getKick( xx, yy, dxp, dyp, cheby_itable(icheby(ix)) )
  
positive.code:   ax=abs(XA) ;
    ay=abs(YA) ;
    ! (x,y)<r1 or ( (xx>r2) || (yy>r2) ): no kick from lens
    if (.not. ( (ax.lt.r1lteps.and.ay.lt.r1lteps) .or. (ax.gt.r2gteps.or.ay.gt.r2gteps) ) ) then
       
      if (st_debug) write(lout,'(2(a,1pe23.16))')'CHEBY> CHEBY_KICK_FOX computing kick when R1[mm]= ',&
           cheby_r1(icheby(ix)),' and R2[mm]= ',cheby_r2(icheby(ix))
  
negative.code:       ax=abs(xxn)
        ay=abs(yyn)
        ! (x,y)<r1 or ( (xx>r2) || (yy>r2) ): no kick from lens
        if ( (ax < r1lteps .and. ay < r1lteps) .or. (ax > r2gteps .or. ay > r2gteps) ) inside=0
        ! compute kick from cheby map
        call cheby_getPotential( xxn, yyn, zz, cheby_itable(iLens) )
        write(fUnit,'(5(1X,1pe22.15),1X,i0)') xx, yy, xxn, yyn, zz, inside
  