anchor.diff:  ! Based on GHB's ModelFCIQMC code.
   
   use const
  +use dSFMT_interface
   use errors
   
   use calc
  
positive.code:             rate = abs(Tau*hamil(iwalker,j))
              nspawn = int(rate)
              rate = rate - nspawn
              call random_number(r)
              if (rate > r) nspawn = nspawn + 1
  
              ! Create particles.
  
negative.code:         rate = rate - nkill
  
          ! Additional stochasitic death?
          r = genrand_real2()
          if (abs(rate) > r) then
              if (rate > 0.0_dp) then
                  nkill = nkill + 1
  