Re: SOLVED: going backwards in time

[Han-Wen Nienhuys]

I think the easiest approach is to simply move to 'long long' for the
rational class. We could start using GUILE's rationals, but it will
complicate memory management, so I think it's not worth the trouble.

Anyone for a patch?

On Thu, Sep 4, 2008 at 6:01 PM, Adam James Wilson
<address@hidden> wrote:
> It looks like I'm going down a road of rhythmic complexity that breaks
> Lilypond rendering in the absence of arbitrary precision arithmetic.
> Han-Wen: would it be possible for me to sponsor a move to arbitrary
> precision arithmetic?  As you say, GUILE does support this option, and it
> would be possible to select it with some sort of flag so that other users
> wouldn't take the performance hit.  Such a fix would be necessary for me to
> use Lilypond to fully render my scores (I can render only a few pages at the
> moment).
> My scores typically require things like the example below, which breaks with
> an "unterminated beam" error, and I *think* it is exceeding 32-bit precision
> (I'm assuming that Lily is using lowest common multiple of denominators to
> deal with resolution):
> \version "2.11.56"
> \layout {
> \context { \Score
> \override NonMusicalPaperColumn #'line-break-permission = ##f
> \override NonMusicalPaperColumn #'page-break-permission = ##f
> \override SpacingSpanner #'uniform-stretching = ##t
> \override SpacingSpanner #'strict-note-spacing = ##t
> proportionalNotationDuration = #(ly:make-moment 1 20)
> ragged-right = ##t
> }
> \context { \Voice
> \remove Forbid_line_break_engraver
> \override Beam #'breakable = ##t
> }
> }
> \new Staff {
> <<
> \new Voice {
> \time 4/1
> c'2.*2351/3696
> \scaleDurations #'(495 . 4336) {
> d'8*11[ \bar "|" \break d'8*100 d'8*100]
> }
> e'1*827949/8012928
> \bar "|"
> \time 3/8
> c'4.
> }
>>>
> }
> %{
> warning: unterminated beam d'8*11[ \bar "|" \break d'8*100 d'8*100]
> [a=3696, b=34688 (denom. of 495/4366*211/8), c=8012928, d=8]
> gcf(a,b,c,d) = 8
> lcm(a,b,c,d) = 1027312242130944
> 32-bit precision maxes out at 4.3 billion (less than the lcm above)
> 64-bit is more like 18.4 quintillion
> %}



-- 
Han-Wen Nienhuys - address@hidden - http://www.xs4all.nl/~hanwen