implicit real (a-z)

 20   write (*,*) 'enter xgr, xpy, xal, xan'
      read (*,*) xgr, xpy, xal, xan

      xt = xgr + xpy + xal 
      xgr = xgr / xt 
      xpy = xpy / xt 
      xal = xal / xt 
      r = 8.314 

      x1 = xpy / (xpy+xal)

      x2 = 1. - x1

      b = x1*-11.205 + x2 * -8.293
      c = x1* -.512 + x2 * -1.482 
      d = x1 * -.418 + x2 * -.480
      e = x1 * .94 + x2 * .914
      f = x1 * 0.083 + x2 * 0.066 

      x = 1.- xgr 

      z = (x - e)/ f

      vgr = - c * x**2 + d*(1+z*x/f) * exp (z**2/-2.)

      vgr = 0.1 * vgr 

 10   write (*,*) 'enter p, t'
      read (*,*) p,t
      if (p.eq.0.0) goto 20

      aan = xan*(1.+xan)**2/4. * exp ( (1-xan)**2/r/t * 
     *              4.184 *                    (2050.+9392.*xan))

      wg = 3.*4.184*(3300. - 1.5*t)
      agr = xgr**3 * exp ( wg / r / t *(xpy**2 + xpy*xal) )

      write (*,*) 'aan, agr, vgr ', aan, agr, vgr 

      kx = (xgr/xan)**3 

      lkx = log (kx)
      
      write (*,*) 'kx, lkx ',kx, lkx 

      lkv = p*vgr / r / t
      kv = exp (lkv)
      ka = agr / aan**3
      lka = log(ka)

      write (*,*) 'kv, lkv',kv, lkv
      write (*,*) 'ka, lka',ka,lka
      write (*,*) 'k, lk',ka*kv,lka+lkv
      goto 10 
99    end