I haven&#39;t had a chance to test anything, but list operations are frequently problematic because they make it easy to accidentally write O(n^2) algorithms. Have you tried using Sequences or Vectors? I would expect one of them to give you better performance for your access patterns.<br><br>On Thursday, September 24, 2015, Daniel Trstenjak &lt;<a href="mailto:daniel.trstenjak@gmail.com">daniel.trstenjak@gmail.com</a>&gt; wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br>
Hi Mario,<br>
<br>
I just took a quick look on the implementation of &#39;dur&#39;<br>
and as a first thing I would replace foldl with<br>
the strict version foldl&#39;.<br>
<br>
This already might explain the memory usage.<br>
<br>
Greetings,<br>
Daniel<br>
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</blockquote>