; attr(,&quot;maxindex&quot;)
#&gt; [1] 100000000
#&gt; attr(,&quot;class&quot;)
#&gt; [1] &quot;booltype&quot; &quot;which&quot;
</code></pre>

<p>over large ff vectors</p>

<pre><code class="r">options(ffbatchbytes=1024^3)
x &lt;- ff(vmode=&quot;single&quot;, length=n)
x[1:1000] &lt;- runif(1000)
lapply(chunk(x, length.out = 10), function(i)sum(x[as.hi(b1, range=i)]))
#&gt; $`1:10000000`
#&gt; [1] 9.760941
#&gt; 
#&gt; $`10000001:20000000`
#&gt; [1] 0
#&gt; 
#&gt; $`20000001:30000000`
#&gt; [1] 0
#&gt; 
#