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feat(CVODE_Solver_Strategy): added non negative constraint to CVODE based abundance solver

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this prevents abundance values from going negative which is non physical
This commit is contained in:
Emily Boudreaux
2025-09-22 11:15:14 -04:00
parent 813e62bdd6
commit 4c91f8c525
4 changed files with 40 additions and 1 deletions
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34
src/lib/solver/strategies/CVODE_solver_strategy.cpp
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@@ -160,6 +160,18 @@ namespace gridfire::solver {
<< " | NonlinIters: " << std::setw(2) << nliters
<< " | ConvFails: " << std::setw(2) << nlcfails
<< std::endl;
if (n_steps % 300 == 0) {
std::cout << "Manually triggering engine update at step " << n_steps << "..." << std::endl;
exceptions::StaleEngineTrigger::state staleState {
T9,
netIn.density,
std::vector<double>(y_data, y_data + numSpecies),
current_time,
static_cast<int>(n_steps),
current_energy
};
throw exceptions::StaleEngineTrigger(staleState);
}
// if (n_steps % 50 == 0) {
// std::cout << "Logging step diagnostics at step " << n_steps << "..." << std::endl;
@@ -390,6 +402,26 @@ namespace gridfire::solver {
check_cvode_flag(CVodeInit(m_cvode_mem, cvode_rhs_wrapper, current_time, m_Y), "CVodeInit");
check_cvode_flag(CVodeSStolerances(m_cvode_mem, relTol, absTol), "CVodeSStolerances");
// Constraints
// We constrain the solution vector using CVODE's built in constraint flags as outlines on page 53 of the CVODE manual
// https://computing.llnl.gov/sites/default/files/cv_guide-5.7.0.pdf
// For completeness and redundancy against future dead links the flags have been copied here
// 0.0: No constraint on the corresponding component of y.
// 1.0: The corresponding component of y is constrained to be >= 0.
// -1.0: The corresponding component of y is constrained to be <= 0.
// 2.0: The corresponding component of y is constrained to be > 0.
// -2.0: The corresponding component of y is constrained to be < 0
// Here we use 1.0 for all species to ensure they remain non-negative.
m_constraints = N_VClone(m_Y);
if (m_constraints == nullptr) {
LOG_ERROR(m_logger, "Failed to create constraints vector for CVODE");
throw std::runtime_error("Failed to create constraints vector for CVODE");
}
N_VConst(1.0, m_constraints); // Set all constraints to >= 0 (note this is where the flag values are set)
check_cvode_flag(CVodeSetConstraints(m_cvode_mem, m_constraints), "CVodeSetConstraints");
check_cvode_flag(CVodeSetMaxStep(m_cvode_mem, 1.0e20), "CVodeSetMaxStep");
m_J = SUNDenseMatrix(static_cast<sunindextype>(N), static_cast<sunindextype>(N), m_sun_ctx);
@@ -406,11 +438,13 @@ namespace gridfire::solver {
if (m_J) SUNMatDestroy(m_J);
if (m_Y) N_VDestroy(m_Y);
if (m_YErr) N_VDestroy(m_YErr);
if (m_constraints) N_VDestroy(m_constraints);
m_LS = nullptr;
m_J = nullptr;
m_Y = nullptr;
m_YErr = nullptr;
m_constraints = nullptr;
if (memFree) {
if (m_cvode_mem) CVodeFree(&m_cvode_mem);