Move solver to C++

include/openmc/cmfd_solver.h

@@ -0,0 +1,113 @@
+#ifndef OPENMC_CMFD_SOLVER_H
+#define OPENMC_CMFD_SOLVER_H
+
+#include <cmath>
+
+#include "xtensor/xtensor.hpp"
+
+namespace openmc {
+
+//===============================================================================
+// Global variables
+//===============================================================================
+
+// CSR format index pointer array of loss matrix
+extern std::vector<int> indptr;
+
+// CSR format index array of loss matrix
+extern std::vector<int> indices;
+
+// Dimension n of nxn CMFD loss matrix
+extern int dim;
+
+// Spectral radius of CMFD matrices and tolerances
+extern double spectral;
+
+// Maximum dimension in x, y, and z directions
+extern int nx;
+extern int ny;
+extern int nz;
+
+// Number of energy groups
+extern int ng;
+
+// Indexmap storing all x, y, z positions of accelerated regions
+extern xt::xtensor<int, 2> indexmap;
+
+//===============================================================================
+// Non-member functions
+//===============================================================================
+
+//! returns the index in CSR index array corresponding to the diagonal element
+//! of a specified row
+//! \param[in] row of interest
+//! \return index in CSR index array corresponding to diagonal element
+int get_diagonal_index(int row);
+
+//! sets the elements of indexmap based on input coremap
+//! \param[in] user-defined coremap
+void set_indexmap(int* coremap);
+
+//! solves a one group CMFD linear system
+//! \param[in] CSR format data array of coefficient matrix
+//! \param[in] right hand side vector
+//! \param[out] unknown vector
+//! \param[in] tolerance on final error
+//! \return number of inner iterations required to reach convergence
+int cmfd_linsolver_1g(double* A_data, double* b, double* x, double tol);
+
+//! solves a two group CMFD linear system
+//! \param[in] CSR format data array of coefficient matrix
+//! \param[in] right hand side vector
+//! \param[out] unknown vector
+//! \param[in] tolerance on final error
+//! \return number of inner iterations required to reach convergence
+int cmfd_linsolver_2g(double* A_data, double* b, double* x, double tol);
+
+//! solves a general CMFD linear system
+//! \param[in] CSR format data array of coefficient matrix
+//! \param[in] right hand side vector
+//! \param[out] unknown vector
+//! \param[in] tolerance on final error
+//! \return number of inner iterations required to reach convergence
+int cmfd_linsolver_ng(double* A_data, double* b, double* x, double tol);
+
+//! converts a matrix index to spatial and group indices
+//! \param[in] iteration counter over row
+//! \param[out] iteration counter for groups
+//! \param[out] iteration counter for x
+//! \param[out] iteration counter for y
+//! \param[out] iteration counter for z
+void matrix_to_indices(int irow, int& g, int& i, int& j, int& k);
+
+//===============================================================================
+// External functions
+//===============================================================================
+
+//! sets the fixed variables that are used for the linear solver
+//! \param[in] CSR format index pointer array of loss matrix
+//! \param[in] length of indptr
+//! \param[in] CSR format index array of loss matrix
+//! \param[in] number of non-zero elements in CMFD loss matrix
+//! \param[in] dimension n of nxn CMFD loss matrix
+//! \param[in] spectral radius of CMFD matrices and tolerances
+//! \param[in] indices storing spatial and energy dimensions of CMFD problem
+//! \param[in] coremap for problem, storing accelerated regions
+extern "C" void openmc_initialize_linsolver(int* indptr, int len_indptr,
+                                            int* indices, int n_elements,
+                                            int dim, double spectral,
+                                            int* cmfd_indices, int* map);
+
+//! runs a Gauss Seidel linear solver to solve CMFD matrix equations
+//! linear solver
+//! \param[in] CSR format data array of coefficient matrix
+//! \param[in] right hand side vector
+//! \param[out] unknown vector
+//! \param[in] tolerance on final error
+//! \return number of inner iterations required to reach convergence
+extern "C" int openmc_run_linsolver(double* A_data, double* b, double* x,
+                                    double tol);
+
+
+} // namespace openmc
+#endif // OPENMC_CMFD_SOLVER_H

include/openmc/constants.h

@@ -434,6 +434,12 @@ constexpr int RUN_MODE_PLOTTING    {3};
 constexpr int RUN_MODE_PARTICLE    {4};
 constexpr int RUN_MODE_VOLUME      {5};
 
+// ============================================================================
+// CMFD CONSTANTS
+
+// For non-accelerated regions on coarse mesh overlay
+constexpr int CMFD_NOACCEL {99999};
+
 } // namespace openmc
 
 #endif // OPENMC_CONSTANTS_H