+ Array<Column_x_positions> h= do_solve ();
+
+ if (approx_stats_.count_i_)
+ *mlog << '\n' << _f ("approximated: %s", approx_stats_.str ()) << endl;
+ if (exact_stats_.count_i_)
+ *mlog << _f ("calculated exactly: %s", exact_stats_.str ()) << endl;
+ *mlog << _f ("time: %.2f seconds", timer.read ()) << endl;
+
+ return h;