ersion is required for many matrix calculations and, therefore,
singularity can cause some calculations to fail. This issue is flagged
with <code>check_singular_U</code>. Calculations for
<code>longevity</code>, <code>life_expect_mean</code>,
<code>life_expect_var</code> and <code>net_repro_rate</code> fail with
singular matrices, so users may wish to exclude singular matrices when
conducting analyses using these functions.</p>
</div>
<div class="section level3">
<h3 id="matrix-split-errors">Matrix split er