stem length algorithm

[Werner LEMBERG]

Even after looking into stem.cc I don't know how the various stem
length parameters interact.  Can someone please explain how exactly
the stem length is computed from the parameters

  lengths
  stem-shorten
  beamed-lengths
  beamed-minimum-free-lengths
  beamed-extreme-minimum-free-lengths

The documentation of those variables is not sufficient, unfortunately.
And what does `beamed-stem-shorten'?

Thanks in advance.


    Werner