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BenWibkingBenWibking
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Remove YASS (#2014)
Removes the YASS method from integrators/Rosenbrock.
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Lines changed: 13 additions & 71 deletions

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‎.gitignore‎

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@@ -1,3 +1,4 @@
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# latex intermediates
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*.aux
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*.log

‎Docs/source/ode_integrators.rst‎

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@@ -72,13 +72,13 @@ Presently, allowed integrators are:
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* ``4`` : ROS2 method, a 2nd order, L-stable method :cite:`ros2`.
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* ``5`` : a first-order method based on the YASS method (described in :cite:`YASS`).
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* ``5`` : Rosenbrock-Euler, a first-order method.
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Here the "P" suffix refers to methods developed to satisfy the stiff
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accuracy conditions of :cite:`Prothero1974` (ROS2S also satisfies
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these).
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By default, the H211b error-history timestep controller from :cite:`h211b` (see Eq. 31) is used, but the YASS heuristic method can be used instead by setting ``integrator.rosenbrock_timestep_controller=1``.
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The H211b error-history timestep controller from :cite:`h211b` (see Eq. 31) is used.
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* ``VODE``: the VODE :cite:`vode` integration package. We ported this
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integrator to C++ and removed the non-stiff integration code paths.

‎integration/Rosenbrock/_parameters‎

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@@ -13,24 +13,9 @@ X_reject_buffer real 1.0
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# 5 = Rosenbrock-Euler 1-stage method
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rosenbrock_tableau int 0
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# Timestep controller selector:
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# 0 = H211b error-history controller
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# 1 = Khokhlov/YASS concentration-change controller
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rosenbrock_timestep_controller int 0
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# H211b timestep controller parameters
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h211b_b real 4.0
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h211b_k real 2.5
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h211b_fac_min real 0.2
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h211b_fac_max real 6.0
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h211b_reduction_fac real 0.5
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# Khokhlov/YASS timestep controller parameters. This controller accepts a
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# step when each active species changes by no more than yass_epsilon
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# relative to its starting value. Species with concentration <= yass_floor
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# times the most abundant species do not constrain the step.
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yass_epsilon real 0.1
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yass_floor real 1.e-3
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yass_fac_min real 0.2
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yass_fac_max real 6.0
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yass_reduction_fac real 0.5

‎integration/Rosenbrock/rosenbrock_integrator.H‎

Lines changed: 10 additions & 54 deletions
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@@ -171,29 +171,6 @@ bool species_change_valid (const rosenbrock_t<int_neqs>& rstate)
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return true;
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}
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template <int int_neqs>
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AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
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amrex::Real yass_change_norm (const rosenbrock_t<int_neqs>& rstate)
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{
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amrex::Real max_change = 0.0_rt;
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amrex::Real max_species = 0.0_rt;
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for (int i = 1; i <= NumSpec && i <= int_neqs; ++i) {
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max_species = amrex::max(max_species, std::abs(rstate.y(i)));
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}
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const amrex::Real active_floor = integrator_rp::yass_floor * max_species;
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for (int i = 1; i <= NumSpec && i <= int_neqs; ++i) {
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const amrex::Real yi = std::abs(rstate.y(i));
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if (yi > active_floor) {
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max_change = amrex::max(max_change, std::abs(rstate.ynew(i) - rstate.y(i)) / yi);
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}
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}
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return max_change / integrator_rp::yass_epsilon;
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}
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template <typename MatrixType, int int_neqs>
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AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
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bool matrix_is_finite (const MatrixType& matrix)
@@ -381,15 +358,6 @@ int rosenbrock_integrator (BurnT& state, rosenbrock_t<integrator_neqs<BurnT>()>&
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}
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}
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if (integrator_rp::rosenbrock_timestep_controller == 1 &&
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(integrator_rp::yass_epsilon <= 0.0_rt ||
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integrator_rp::yass_floor < 0.0_rt ||
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integrator_rp::yass_fac_min <= 0.0_rt ||
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integrator_rp::yass_fac_max < integrator_rp::yass_fac_min ||
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integrator_rp::yass_reduction_fac <= 0.0_rt)) {
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return IERR_BAD_INPUTS;
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}
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rstate.n_rhs = 0;
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rstate.n_jac = 0;
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rstate.n_step = 0;
@@ -564,22 +532,13 @@ int rosenbrock_integrator (BurnT& state, rosenbrock_t<integrator_neqs<BurnT>()>&
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const bool valid_update = rosenbrock::species_change_valid(rstate);
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constexpr amrex::Real err_min = 1.e-10_rt;
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amrex::Real err = rosenbrock::error_norm(rstate);
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amrex::Real controller_fac = 1.0_rt;
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if (integrator_rp::rosenbrock_timestep_controller == 1) {
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err = rosenbrock::yass_change_norm(rstate);
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controller_fac = amrex::Clamp(1.0_rt / amrex::max(err, err_min),
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integrator_rp::yass_fac_min,
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integrator_rp::yass_fac_max);
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} else {
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controller_fac = amrex::Clamp(
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std::pow(1.0_rt / amrex::max(err, err_min),
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1.0_rt / (integrator_rp::h211b_b * integrator_rp::h211b_k)) *
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std::pow(1.0_rt / amrex::max(errold, err_min),
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1.0_rt / (integrator_rp::h211b_b * integrator_rp::h211b_k)) *
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std::pow(facold, -1.0_rt / integrator_rp::h211b_b),
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integrator_rp::h211b_fac_min, integrator_rp::h211b_fac_max);
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}
535+
amrex::Real controller_fac = amrex::Clamp(
536+
std::pow(1.0_rt / amrex::max(err, err_min),
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1.0_rt / (integrator_rp::h211b_b * integrator_rp::h211b_k)) *
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std::pow(1.0_rt / amrex::max(errold, err_min),
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1.0_rt / (integrator_rp::h211b_b * integrator_rp::h211b_k)) *
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std::pow(facold, -1.0_rt / integrator_rp::h211b_b),
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integrator_rp::h211b_fac_min, integrator_rp::h211b_fac_max);
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facold = controller_fac;
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errold = err;
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@@ -613,14 +572,11 @@ int rosenbrock_integrator (BurnT& state, rosenbrock_t<integrator_neqs<BurnT>()>&
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n_reject += 1;
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last = false;
615574
if (n_reject >= 2) {
616-
hnew *= integrator_rp::rosenbrock_timestep_controller == 1 ?
617-
integrator_rp::yass_reduction_fac : integrator_rp::h211b_reduction_fac;
575+
hnew *= integrator_rp::h211b_reduction_fac;
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}
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if (valid_update) {
620-
const amrex::Real reject_fac =
621-
integrator_rp::rosenbrock_timestep_controller == 1 ?
622-
integrator_rp::yass_reduction_fac : integrator_rp::h211b_reduction_fac;
623-
h = posneg * amrex::min(std::abs(hnew), reject_fac * std::abs(h));
578+
h = posneg * amrex::min(std::abs(hnew),
579+
integrator_rp::h211b_reduction_fac * std::abs(h));
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} else {
625581
h *= 0.25_rt;
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}

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