Improve Calculation of Cartesian Point Distances

[manfredweis@…]

ISSUE:

in <boost/geometry/strategies/cartesian/distance_pythagoras.hpp> currently the distance between points in cartesian space is calculated via the pythagorean theorem (i.e. sqrt(sum of squared coordinate differences);

While that is theoretically correct, the numerics are "horrible" and a much better alternative with very low implementation effort is available via the "Moler and Morrison" algorithm; its convergence rate is cubic and it completely avoids the intermediate blowup of values. The article can be found online here: ​http://blogs.mathworks.com/images/cleve/moler_morrison.pdf

TODO: check the benefits of the Moler Morrison algorithm and decide about either replacing the current implementation of point distances in cartesian space or, make the Moler Morrison algorithm available as an alternative.

[Barend Gehrels]

Thanks for your suggestion