.</li>
<li> 'No' - A pair of data sets are loaded at a time to compute
covariance matrix. This option uses less memory usage but slower
than the other option. You also have the option to store only the
lower triangular portion of the covariance matrix (packed storage)
when using this option.</li>
</ul>

<li>pca_opts.storage - Options are 'Full' and 'Packed'. Packed
storage scheme uses only lower triangular portion of symmetric
matrix to compute eigen values.</li>

<li>pca_opts.precision - Option