ndratcor_monomial: loops potentially access coefs[i-1] at position 6 which is out of bounds

[kostrzewa]

when the correction monomial does not converge sufficiently quickly it will access out of bounds array elements

tmLQCD/src/lib/monomial/ndratcor_monomial.c

Lines 233 to 243 in 1c4a54a

	for (int i = 2; i < 8; i++) {
	if (delta * delta < mnl->accprec) break;
	tm_stopwatch_push(&g_timers, "square_norm", "");
	delta = coefs[i - 1] * (square_norm(up0, VOLUME / 2, 1) + square_norm(dn0, VOLUME / 2, 1));
	tm_stopwatch_pop(&g_timers, 0, 1, "");
	mnl->energy1 += delta;
	if (g_debug_level > 2 && g_proc_id == 0)
	printf("# NDRATCOR acc step: c_%d*(phi * Z^%d * phi) = %e\n", i, i, delta);
	i++; // incrementing i
	if (delta * delta < mnl->accprec) break;

and similarly elsewhere

[kostrzewa]

It should be sufficient to restrict the loop to i < 7 but we should check what this means for the convergence

[kostrzewa]

the same applies to ratcor_monomial