Re: Warnings-polyphonic

[Reinhold Kainhofer]

Am Mittwoch, 9. Juni 2010, 10:55:45 schrieb Mario Moles:
> Hi!
> How can i avoid these warnings?:
> 
> SonataIII-III-tempo.ly:211:2: warning: adding note head to incompatible
> stem (type = 2)
> 
>   b,!4 r s|
> SonataIII-III-tempo.ly:211:2: warning: maybe input should specify
> polyphonic voices
> 
>   b,!4 r s|

In the second to last measure you effectively use a nested << ... \\ ... >> 
construct: The whole score consists of <<\upper\\ \lower>>, while \upper 
contains   <<{r <dis g>[ <dis fis>] r r4} \\ {a2 b!4}>>

In the << ...\\ ... >> construct, LilyPond always calls the second part 
"lower", so both \lower and the {a2 b!4} of \upper will be in a voice called 
"lower". Thus, LilyPond will try to join stems (which fails since the upper 
voice has a half note, while the lower has a quarter note).

As a solution, it's better to not use << ... \\ ... >> and let LilyPond 
implicitly create two voices, but generate the voices yourself. 

E.g. in the \score block, instead of 
   { \clef "treble_8" << \upper \\ \lower >> }
better use:
   { \clef "treble_8" <<
      \new Voice="UpperVoice" { \voiceOne \upper }
      \new Voice="LowerVoice" { \voiceTwo \lower }
   }

And in upper better use
  << { r <dis g>[ <dis fis>] r r4} 
     \new Voice="UpperDown"{\voiceFour a2 b!4}
  >>|
  << { r8 <fis' b> <fis ais> r r4} 
     \new Voice="UpperDown" {\voiceFour c4~c8 gis a cis}
  >>|
for the last two bars (notice that I'm also using explicit voices here, and 
manually set \voiceFour, so LilyPond takes care of shifting notes a little bit 
to prevent collisions).

Cheers,
Reinhold
-- 
------------------------------------------------------------------
Reinhold Kainhofer, address@hidden, http://reinhold.kainhofer.com/
 * Financial & Actuarial Math., Vienna Univ. of Technology, Austria
 * http://www.fam.tuwien.ac.at/, DVR: 0005886
 * LilyPond, Music typesetting, http://www.lilypond.org