Re: Wildly different horizontal spacing in two similar scores.

[Richard Shann]

On Fri, 2022-03-18 at 12:11 +0100, Valentin Petzel wrote:
> Let’s take a look at what’s happening here:
> 
> if we add
> \override Score.SpacingSpanner.common-shortest-duration =
> #(grob-transformer 'common-shortest-duration
>                    (lambda (grob orig) (display orig) (newline)
> orig))

Many thanks - it sounds like it will worth experimenting with setting
common-shortest-duration manually to common-up the appearamce of the
parts. Would some syntax along the lines 

\override Score.SpacingSpanner.common-shortest-duration = #(make-
moement '(1 . 8))

do this? (I'm doubtful because I didn't see an example in the manual -
rather the statement
"There is no convenient mechanism to manually override spacing. "
at 
https://lilypond.org/doc/v2.22/Documentation/notation/horizontal-spacing-overview
)

Richard
> 
> at the beginning we will have the value of common-shortest duration
> ouput. For 
> 1-1 this is 1/32, for 1-4 this is 1/8. To understand why this is
> happening you 
> need to understand how Lilypond calculates the common-shortest
> duration. 
> Basically Lilypond takes the smallest duration for each measure, and
> then 
> counts for each one how many measures have it as smallest duration.
> Then 
> Lilypond simply finds the duration with the highest count and returns
> the 
> minimum of that one and base-shortest duration.
> 
> Now this algorithm is kind of unstable. In your case you have many
> measures 
> with 1/8th notes as shortest duration and many measures with 1/32nd
> notes as 
> shortest duration. So if you have slightly more measures of the first
> type you 
> will get the dense result, if you have slightly more of the second
> type you 
> get the wide result.
> 
> So in some sense this is "working as intended", it is just that the
> algorithm 
> for common-shortest-duration is probably not optimal. It might be
> better to 
> take some sort of weighted average, which would be much more stable
> in such 
> situations. I’ll do some experimenting for this.
> 
> Cheers,
> Valentin
> 
> Am Freitag, 18. März 2022, 10:39:10 CET schrieb Richard Shann:
> > Attached are two scores which have quite similar music in them but
> > LilyPond typesets one them with about twice as much horizontal
> > space as
> > the other.
> > The documentation gives an overview of the algorithm for horizontal
> > spacing but eyeballing this music I can't see any shortest-note
> > differences that could trigger this.
> > Any idea what might be going on?
> > 
> > Richard Shann
>