Re: A strange behaivor of autobeaming

[Urs Liska]

Am 04.02.19 um 20:53 schrieb Павел Буданов:

Hello everybody! You can see on the next image, that autobeaming is not always correct:

For the sake of experiment, I tried to put this snippet to separate file:

\scaleDurations 2/3 \relative f,

{

   \clef bass

   \set subdivideBeams = ##t

   \set baseMoment = #(ly:make-moment 3/16)

   \tuplet 6/6 { b,8 f'16 d' f, d' } 

   b' d, f, d' f, b,~

   \repeat unfold 2

   { b8 f'16 d' f, d' b' d, f, d' f, b,~ }

}

And got a different result:

What is the root of this problem?

The "root" of the problem is that the code is completely messed up in the first place. You don't want to use \scaleDurations here at all, only \tuplet, and then "\tuplet 6/6" doesn't make sense at all.

Here's a commented example of what I assume you want to do:

\version "2.21.0"

% No \scaleDurations
\relative f,
{
  \clef bass
  \set subdivideBeams = ##t
  % Set the base moment to 1/8 (equals 3/16 in a 3/2 tuplet)
  \set baseMoment = #(ly:make-moment 1/8)
  % You want a 6/4 tuplet ("6 instead of 4", "6 instead of 6" doesn't mean anything)
  % supply the "4" to group tuplets in quarter notes
  % wrap the \tuplet around the *whole* music (INSTEAD of using \scaleDurations)
  \tuplet 6/4 4 { 
    b,8 f'16 d' f, d'
    % Probably with the 6/6 tuplet around one single group
    % you meant to disable the tuplet number after the first incident.
    \omit TupletNumber
    b' d, f, d' f, b,~
    \repeat unfold 2
    { b8 f'16 d' f, d' b' d, f, d' f, b,~ }
  }
}

When it comes to tuplets the automatic beam subdivisions still fail in many cases (see http://lilypond.org/google-summer-of-code.html#Fix-Beaming-Patterns_002fBeam-Subdivisions-and-Tuplets), but this example works quite well.

HTH
Urs