anchor.diff:      end if ! This naturaly leaves trial_volume = volume if 
       ! the volume is exactly in the middle of the allowed volume range
   
  -    trial_volume = trial_volume + (rnd2(1) - 0.5_dp)*(vol_step + a_0)
  +    trial_volume = trial_volume + (univar_rnd2(1) - 0.5_dp)*(vol_step + a_0)
   
       ! calculate the closest boundary to trail_volume:
       a_1 = min(v_max - trial_volume, trial_volume - v_min )
  
positive.code:       end if
      end do
  
      if (change_flag == 0 .and. (.not. (present(skip_enth_calc).and.skip_enth_calc)) ) then 
        enth_out = enthalpy( s, h0_out, V, pressure, cutoff, n_call_enthalpy=n_call_enth ) 
      endif
  
    end subroutine roam_latticeshape_stretch
  
negative.code:         vs = (/ 1, 2 /)
        end if
  
        rnd1 = univar_rnd6(i2 + 2)
        rnd1 = 2.0_dp*(rnd1-0.5_dp)*latt_step
        rnd1 = exp(rnd1)
        rnd2 = 1.0_dp/rnd1
  