er the data to exclude entries with <code>NA</code> values in
the matrices required for their analysis. The functions
<code>mpm_split</code>, <code>mpm_rearrange</code> and
<code>mpm_standardise</code> do not require complete
<code>NA</code>-free matrices.</p>
<p>For functions that use the <strong>U</strong> matrix, we further
suggest filtering the data to exclude the biologically unreasonable
entries where one or more of the <code>matU</code> columns sum to zero,
or to greater than 1 (see <em>Excessive Sur