anchor.diff:  
     !> Compute the temperature of a mpcd solvent
     !!
  -  !! See the <a href="../manual/algorithms.html#temperature-computation">doc</a>
  +  !! \manual{algorithms,temperature-computation}
     function compute_temperature(particles, cells, tz) result(te)
       use hilbert, only : compact_h_to_p
       type(particle_system_t), intent(inout) :: particles
  
positive.code: 
    end subroutine mpcd_stream_zwall
  
    subroutine mpcd_stream_periodic(particles, cells, dt)
      type(particle_system_t), intent(inout) :: particles
      type(cell_system_t), intent(in) :: cells
  
negative.code: !> Routines to perform MPCD dynamics
  !!
  !! \manual{algorithms}.
  !!
  !!
  !! MPCD collisions are implemented in simple_mpcd_step and wall_mpcd_step, that takes into
  !! account a wall in the z-direction.
  !!
  !! Streaming is achieved by the mpcd_stream_periodic, mpcd_stream_zwall,
  !! mpcd_stream_xforce_yzwall and mpcd_stream_nogravity_zwall routines. Only a single stream
  !! routine should be used, depending on the simulation setup. A further call to md_vel is
  !! needed in the presence of forces.
  
  module mpcd
    use common
  