std::unordered_map<int, Variable*> idx2Var_; //!< Map player index (and position in matrices) to system's variable
std::unordered_map<const Constraint*, int> cnst2idx_; //!< Conversely map constraint to index
std::unordered_map<int, Variable*> idx2Var_; //!< Map player index (and position in matrices) to system's variable
std::unordered_map<const Constraint*, int> cnst2idx_; //!< Conversely map constraint to index