Solver overview

This page maps the current solver pathways in the repository to their implementation files and to relevant numerical background references.

Runtime solver selection

KiT-RT selects the execution path in src/main.cpp:

• If DATA_GENERATOR_MODE = YES, it runs data generation.

• Otherwise, if HPC_SOLVER = YES, it runs the HPC SN implementation:

  • SNSolverHPC on CPU (src/solvers/snsolver_hpc.cpp)

  • SNSolverHPCCUDA when CUDA is compiled and a GPU is detected (src/solvers/snsolver_hpc.cu)

• If HPC_SOLVER = NO, it uses SolverBase::Create(...) and the standard solver factory (src/solvers/solverbase.cpp).

Non-HPC solver stack

Implemented non-HPC solver classes:

• SNSolver

• PNSolver

• MNSolver

• MNSolverNormalized

• CSDSNSolver

• CSDPNSolver

• CSDMNSolver

Code locations:

• include/solvers/*.hpp

• src/solvers/*.cpp

Numerical background reference for deterministic non-HPC solver families (\(S_N\), \(P_N\), and entropy-based moment closures):

• Structure-preserving neural networks for entropy-based moment closure methods

HPC SN stack

Implemented HPC SN classes:

• SNSolverHPC (CPU MPI/OpenMP)

• SNSolverHPCCUDA (CUDA backend)

Core files:

• include/solvers/snsolver_hpc.hpp

• src/solvers/snsolver_hpc.cpp

• include/solvers/snsolver_hpc_cuda.hpp

• src/solvers/snsolver_hpc.cu

The HPC solver path is designed around large SN systems and benchmark-style problems such as lattice and hohlraum configurations.

Numerical background reference for the HPC SN benchmark workflow:

• Reference solutions for linear radiation transport: the Hohlraum and Lattice benchmarks

Practical config pattern

To run the HPC SN path:

SOLVER = SN_SOLVER
HPC_SOLVER = YES

To run the standard SN path:

SOLVER = SN_SOLVER
HPC_SOLVER = NO

Reference validation inputs:

• tests/input/validation_tests/SN_solver

• tests/input/validation_tests/SN_solver_hpc