Compute time & limits on path numbers

A new option in PRIMER 7 recognises that computation time can become an issue for particular relatedness analyses when the master list is extremely large - as could happen if, for example, the world list of fish species, or the entire marine species directory of European waters is input as the master list (a species list of 10,000 has 100 million path lengths between all pairs of species). But it is not necessary to calculate all of these to know the true AvTD $\Delta^{\scriptscriptstyle +}$ of the master list, for example – we can again exploit the unbiasedness of random samples to get all the accuracy we need without complete computation, and this option is taken with (✓Limit no. paths)>(Max paths: 9999), say. This option was also provided for distinctness estimates in the DIVERSE routine but may be less necessary there and is inappropriate, so should be avoided, for the quantitative $\Delta$, $\Delta ^\ast$ calculations. Path limitations are not the default and are best saved for use only when essential to obtain results.