gtopt::SolverBackend class
#include <gtopt/solver_backend.hpp>

Abstract interface for LP/MIP solver backends.

Each solver plugin (CLP, CBC, CPLEX, HiGHS, …) provides a concrete implementation of this class. LinearInterface delegates all solver operations through this interface, enabling runtime solver selection via dlopen-loaded plugins.

Constructors, destructors, conversion operators

SolverBackend() defaulted
SolverBackend(const SolverBackend&) deleted
SolverBackend(SolverBackend&&) defaulted
~SolverBackend() defaulted virtual

Public functions

auto add_col(double lb, double ub, double obj) -> void pure virtual
auto add_row(int num_elements, const int* columns, const double* elements, double rowlb, double rowub) -> void pure virtual
auto apply_options(const SolverOptions& opts) -> void pure virtual
auto clear_log_filename() -> void virtual: Stop file-based logging started by set_log_filename.
auto clone() const -> std::unique_ptr<SolverBackend> pure virtual
auto close_log() -> void pure virtual
auto col_lower() const -> const double* pure virtual
auto col_solution() const -> const double* pure virtual
auto col_upper() const -> const double* pure virtual
auto delete_rows(int num, const int* indices) -> void pure virtual
auto get_algorithm() const -> LPAlgo pure virtual: Query the currently configured LP algorithm.
auto get_coeff(int row, int col) const -> double pure virtual
auto get_kappa() const -> double pure virtual: Condition number of the current basis (1.0 if unavailable)
auto get_log_level() const -> int pure virtual: Query the current solver log verbosity level (0 = off).
auto get_num_cols() const -> int pure virtual
auto get_num_rows() const -> int pure virtual
auto get_presolve() const -> bool pure virtual: Query whether presolve is currently enabled.
auto get_prob_name() const -> std::string pure virtual
auto get_threads() const -> int pure virtual: Query the currently configured thread count (0 = solver default).
auto infinity() const -> double pure virtual noexcept: Solver's representation of +infinity.
auto initial_solve() -> void pure virtual
auto is_abandoned() const -> bool pure virtual
auto is_continuous(int index) const -> bool pure virtual
auto is_integer(int index) const -> bool pure virtual
auto is_proven_dual_infeasible() const -> bool pure virtual
auto is_proven_optimal() const -> bool pure virtual
auto is_proven_primal_infeasible() const -> bool pure virtual
auto load_problem(int ncols, int nrows, const int* matbeg, const int* matind, const double* matval, const double* collb, const double* colub, const double* obj, const double* rowlb, const double* rowub) -> void pure virtual
auto obj_coefficients() const -> const double* pure virtual
auto obj_value() const -> double pure virtual
auto open_log(FILE* file, int level) -> void pure virtual
auto operator=(const SolverBackend&) -> SolverBackend& deleted
auto operator=(SolverBackend&&) -> SolverBackend& defaulted
auto optimal_options() const -> SolverOptions pure virtual: Return backend-optimal default options (benchmarked).
auto push_names(const std::vector<std::string>& col_names, const std::vector<std::string>& row_names) -> void pure virtual
auto reduced_cost() const -> const double* pure virtual
auto resolve() -> void pure virtual
auto row_lower() const -> const double* pure virtual
auto row_price() const -> const double* pure virtual
auto row_upper() const -> const double* pure virtual
auto set_coeff(int row, int col, double value) -> void pure virtual
auto set_col_lower(int index, double value) -> void pure virtual
auto set_col_solution(const double* sol) -> void pure virtual
auto set_col_upper(int index, double value) -> void pure virtual
auto set_continuous(int index) -> void pure virtual
auto set_integer(int index) -> void pure virtual
auto set_log_filename(const std::string&, int) -> void virtual: Redirect solver log output to a file by name.
auto set_obj_coeff(int index, double value) -> void pure virtual
auto set_prob_name(const std::string& name) -> void pure virtual
auto set_row_bounds(int index, double lb, double ub) -> void pure virtual
auto set_row_lower(int index, double value) -> void pure virtual
auto set_row_price(const double* price) -> void pure virtual
auto set_row_upper(int index, double value) -> void pure virtual
auto solver_name() const -> std::string_view pure virtual noexcept: Human-readable solver name (e.g. "clp", "highs")
auto solver_version() const -> std::string pure virtual: Solver library version string (e.g. "1.17.3", "22.1.1")
auto supports_set_coeff() const -> bool pure virtual noexcept
auto write_lp(const char* filename) -> void pure virtual

Function documentation

void gtopt::SolverBackend::clear_log_filename() virtual

Stop file-based logging started by set_log_filename.

Backends override to close/detach their native log file. Default is a no-op.

SolverOptions gtopt::SolverBackend::optimal_options() const pure virtual

Return backend-optimal default options (benchmarked).

Called by LinearInterface before merging user-supplied options. Each backend returns its empirically best configuration; the caller overlays user-provided options on top so explicit settings always win.

void gtopt::SolverBackend::set_log_filename(const std::string&, int) virtual

Redirect solver log output to a file by name.

Backends override this to use their native file-based logging API (e.g. CPXsetlogfilename for CPLEX, log_file option for HiGHS). The default implementation is a no-op — backends that only support FILE*-based logging via open_log/close_log need not override.

The first argument is the full path to the log file (without .log extension); the second is the verbosity level (0 = off, >0 = enabled).