PROGRAM etotau
*************************************************************************
* Conversion of dielectric functions to                                 *
* frequence dependent 1/tau* and plasmafrequence squared.              *
* from standard input it reads:
* input filename
* epsilon infinity
* the input file must have the format x eps1 eps2                       *
*************************************************************************
      REAL X(100000),e1,e2,gam,nup2,epsinf
      complex epsil(100000),einv
      INTEGER I,mm
      character*40 flin    
      mm=100000 
      read(*,'(a40)') flin
      read(*,*) epsinf
      open(24,file=flin)
      do 10 i=1,mm                                                  
       READ(24,*,END=11) X(i),e1,e2
       epsil(i)=cmplx(e1,e2)
10    continue   
11    mm=i-1
      do 25 i=1,mm
       einv=1/(epsinf-epsil(i))
       nup2=x(i)**2/real(einv)
       gam=x(i)*aimag(einv)/real(einv)
       write(*,*) x(i),gam,nup2
25    continue
      END