tau_update.f90

! © 2023. Triad National Security, LLC. All rights reserved.
! This program was produced under U.S. Government contract 89233218CNA000001 for Los Alamos National
! Laboratory (LANL), which is operated by Triad National Security, LLC for the U.S. Department of
! Energy/National Nuclear Security Administration. All rights in the program are reserved by Triad
! National Security, LLC, and the U.S. Department of Energy/National Nuclear Security Administration.
! The Government is granted for itself and others acting on its behalf a nonexclusive, paid-up,
! irrevocable worldwide license in this material to reproduce, prepare. derivative works, distribute
! copies to the public, perform publicly and display publicly, and to permit others to do so.
!This file is part of SuperNu.  SuperNu is released under the terms of the GNU GPLv3, see COPYING.
!Copyright (c) 2013-2022 Ryan T. Wollaeger and Daniel R. van Rossum.  All rights reserved.
subroutine tau_update(t,tfirst,tlast)

  use physconstmod
  use transportmod
  implicit none
  real*8,intent(in) :: t,tfirst,tlast
!-------------------------------------------------
! Update mfp thresholds for DDMC:
! - IMC-DDMC transition,
! - DDMC group lumping.
!-------------------------------------------------
  real*8 :: slp1,slp2

  if(trn_tauvtime=='unif') then
!-- constant thresholds
     return
  elseif(trn_tauvtime=='incr') then
!-- linear increase in thresholds (max mfp thresh = 5)
     slp1=0.667d0*trn_tauddmc/(tlast-tfirst)
     slp2=0.667d0*trn_taulump/(tlast-tfirst)

     trn_tauddmc = trn_tauddmc+(t-tfirst)*slp1
     trn_taulump = trn_taulump+(t-tfirst)*slp2
  else
     stop 'tau_update: trn_tauvtime invalid'
  endif

end subroutine tau_update
! vim: fdm=marker