anchor.diff:                !
                 acoef = acoef_ram(iswap)
                 !
  -              if (Asum(ilevelf)<0) Asum(ilevelf) = 0
  +              if (isnan(Asum(ilevelf))) Asum(ilevelf) = 0
                 !
                 Asum(ilevelf) = Asum(ilevelf) + acoef
                 !
  
positive.code:    !
     use  input
     !
     !
     real(rk)    :: hitran_Tref = 296_rk
     integer(ik) :: info,ipoint,ipoint_,nlevels,i,itemp,enunit,tunit,sunit,wunit,bunit,pfunit,j,j0,ilevelf,ileveli,indexi,indexf
  
negative.code:    integer(ik) :: imol,iostat_,isotope
     real(rk)    :: gf,gi,mem_t,temp_gamma_n,offset_
     character(55) ch_q,ch_broad
     character(len=cl)   :: my_fmt100K,my_fmt0
     real(real32) :: nan   
     !
     ln2=log(2.0_rk)
     ln22 = ln2*2.0_rk
  