avoid illegal read after delete

        // need to relax error by a large amount with tabulation, since

        // coul/long styles do not use tabulation in compute_inner()

        // and compute_middle() so we get a significant deviation.

        pair = lmp->force->pair;

        if (pair->ncoultablebits) epsilon *= 1.0e6;

        f = lmp->atom->f;

        tag=lmp->atom->tag;

        pair = lmp->force->pair;

        stats.reset();

        for (int i=0; i < nlocal; ++i) {

            EXPECT_FP_LE_WITH_EPS(f[i][0], f_run[tag[i]].x, 5*epsilon);