anchor.diff:                  !
                   !if (abscoef<cutoff) cycle
                   !
  -                ipoint =  max(nint( ( tranfreq-freql)/dfreq )+1,1)
  +                call get_grid_ipoint(tranfreq,freq,ipoint)
  +                !
  +                !ipoint =  max(nint( ( tranfreq-freql)/dfreq )+1,1)
                   !
                   intens_omp(ipoint,iomp) = intens_omp(ipoint,iomp)+abscoef
                   !
  
positive.code:        !
         dfreq_t = grid(igrid)%dfreq
         freql_t = grid(igrid)%freql
         !
         if (tranfreq-offset>=grid(igrid)%freql) then
           ib =  max(nint( ( tranfreq-offset-freql_t)/dfreq_t )+1,1)
           ib = grid(igrid)%i1+ib-1
         elseif(igrid>1) then
           ib =  max(nint( ( tranfreq-offset-grid(igrid-1)%freql)/grid(igrid-1)%dfreq )+1,1)
           ib = grid(igrid-1)%i1+ib-1
         endif
         !
         if (tranfreq+offset<=grid(igrid)%freqr) then
           ie =  min(nint( ( tranfreq+offset-freql_t)/dfreq_t )+1,npoints)
           ie = grid(igrid)%i1+ie-1
         elseif(igrid<Ngrids) then
           ie =  min(nint( ( tranfreq+offset-grid(igrid+1)%freql)/grid(igrid+1)%dfreq )+1,npoints)
           ie = grid(igrid+1)%i1+ie-1
         endif
         !
  
negative.code:             use_width_offset = .true.
            endif
            !
            if (offset<=0) stop 'offset cannot be negative or zero'
            !
         case ("MASS")
            !
            call readf(meanmass)
  