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@node benchmarking 

@unnumberedsec Notation benchmarking

A flexible architecture is necessary for good
formatting. Unfortunately, it is not sufficient.  Only a careful
emulation of printed matter will give a good result.  We suggested in
the introduction to compare program output with existing hand-engraved
scores.  It is exactly this technique that we use to perfect LilyPond
output.  In a way, this is a benchmarking technique: the performance of
the program, in terms of quality, is measured in relation to a known
quantity.

Here you see parts of a benchmark piece. At the top the reference
edition (B@"arenreiter BA 320) at the bottom the output from
LilyPond 1.4:

@divClass{float-center}
@divEnd
@c @ref{baer-sarabande-hires.jpeg,
@sourceimage{baer-sarabande,,,.png}
@c }

@divClass{float-center}
@divEnd
B@"arenreiter (click to enlarge)

@divClass{float-center}
@divEnd
@sourceimage{lily14-sarabande,,,.png}

@divClass{float-center}
@divEnd
LilyPond 1.4

The LilyPond output is certainly readable, and for many people it
would be acceptable. However, close comparison with a hand-engraved
score showed a lot of errors in the formatting details:

@divClass{float-center}
@divEnd
@sourceimage{lily14-sarabande-correct,,,.png}

@divClass{float-center}
@divEnd
@itemize
@item
 Lots of symbols were unbalanced. In particular the trill sign was
too large.


@item
 Stems and beams were all wrong: the stems were too long, and
beam should be slanted to cover staff lines exactly. The beam was also
too light.


@item
 The spacing was irregular: some measures were too tight, other
too wide.


@end itemize
(And there were missing notes in the original version for LilyPond)

By addressing the relevant algorithms, settings, and font designs, we
were able to improve the output. The output for LilyPond 1.8 is shown
below. Although it is not a clone of the reference edition, this
output is very close to publication quality.

@divClass{float-center}
@divEnd
@sourceimage{lily17-sarabande,,,.png}

@divClass{float-center}
@divEnd
LilyPond 1.8

@divClass{float-center}
@divEnd
@sourceimage{baer-sarabande,,,.png}

@divClass{float-center}
@divEnd
B@"arenreiter

Another example of benchmarking is our project for the 2.1 series, a
@ref{schubert,Schubert song}.

@divClass{float-right}
@divEnd
Next: @ref{typography-features,Cool features},
typographical hoops that we made LilyPond jump through.

@bye