logm, sqrtm, funm

[Tommy Guy]

funm and logm do have the same problems.  Using a Schur decomposition
followed by an algorithm to calculate the function of the upper
triangular algorithm is probably what the competition is using, but it
is also an openly published algorithm with good results.  sqrtm (in
Octave source) has been converted to use the Schur decomposition
method and implemented in c++.  This provides a guide to anyone
wanting to try to fix logm.

Richard T. Guy