subroutine interp(nt,beta,fct,betac,fc)
c------------------------------------------------------------------------
      save
c
      include 'constcom.h'
      include 'ucom.h'
c
      dimension beta(nt),fct(nt,14),fc(14)
c-----------------------------------------------------------------------
c*
      j=1
      mt=nt-1
      if(mt.lt.2)go to 20
      do 10 i=2,mt
      if(betac.le.beta(i))go to 20
      j=i
   10 continue
   20 continue
      xb=(betac-beta(j))/(beta(j+1)-beta(j))
      xa=1.-xb
      do 30 i=1,14
      fc(i)=xa*fct(j,i)+xb*fct(j+1,i)
   30 continue
c     normalize coefficients
      sum=0.
      t=1.
      sgn=1.
      do 40 l=1,14
      sum=sum+fc(l)*sgn/t
      t=t+2.
      sgn=-sgn
   40 continue
      fac=2.*sum/pi
      do 50 l=1,14
      fc(l)=fc(l)/fac
   50 continue
      return
      end
c++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*