Class triplet_comp

external/eigen/test/sparse_basic.cpp:628–633

    // test setFromSortedTriplets / insertFromSortedTriplets

    struct triplet_comp {
      inline bool operator()(const TripletType& a, const TripletType& b) {
        return SparseMatrixType::IsRowMajor ? ((a.row() != b.row()) ? (a.row() < b.row()) : (a.col() < b.col()))
                                            : ((a.col() != b.col()) ? (a.col() < b.col()) : (a.row() < b.row()));
      }
    };

    // stable_sort is only necessary when the reduction functor is dependent on the order of the triplets
    // this is the case with refMat_last