Re: modify coord-rotate to get exact values for (sin PI) etc (issue 269530043 by thomasmorle...@gmail.com)

On 2015/10/30 22:59:54, thomasmorley651 wrote: On 2015/10/30 21:46:55, benko.pal wrote: > > And PostScript (and PDF and METAFONT) _do_ represent angles in degrees. > > So it's sort of silly that we cannot get an angle of 180 degrees > > straight into PostScript without change. > > now that

Re: modify coord-rotate to get exact values for (sin PI) etc (issue 269530043 by thomasmorle...@gmail.com)

> Just back home, noticing the discussion here. > > Current patch tries to solve (or better: workaround) the problem in > guile. > I have some other pending patches _needing_ exact values from > coord-rotate. > I'd suggest to push it as is (unless some serious defect would be > detected) after

Re: modify coord-rotate to get exact values for (sin PI) etc (issue 269530043 by thomasmorle...@gmail.com)

> And PostScript (and PDF and METAFONT) _do_ represent angles in degrees. > So it's sort of silly that we cannot get an angle of 180 degrees > straight into PostScript without change. now that convinced me. if we want to output angles in degrees, we don't want to switch back and forth neither

Re: modify coord-rotate to get exact values for (sin PI) etc (issue 269530043 by thomasmorle...@gmail.com)

On 2015/10/30 21:46:55, benko.pal wrote: > And PostScript (and PDF and METAFONT) _do_ represent angles in degrees. > So it's sort of silly that we cannot get an angle of 180 degrees > straight into PostScript without change. now that convinced me. if we want to output angles in degrees, we

Re: modify coord-rotate to get exact values for (sin PI) etc (issue 269530043 by thomasmorle...@gmail.com)

+1 https://codereview.appspot.com/269530043/ ___ lilypond-devel mailing list lilypond-devel@gnu.org https://lists.gnu.org/mailman/listinfo/lilypond-devel

Re: modify coord-rotate to get exact values for (sin PI) etc (issue 269530043 by thomasmorle...@gmail.com)

> Maybe we should convert all our stencil stuff into native Pango? Sounds sensible. However, I would add this to a TODO list than rather working on it immediately, except if there are pressing needs. Werner ___ lilypond-devel mailing list

Re: modify coord-rotate to get exact values for (sin PI) etc (issue 269530043 by thomasmorle...@gmail.com)

sorry to chime in that late, but: am I right that the problem is that we get the rotation matrix cos a -sin a sin acos a inexact? and if so, how the inexactness is present? one of the diagonals is exactly +/-1 while the other is not exactly 0? in that case I'd suggest (would have

Re: modify coord-rotate to get exact values for (sin PI) etc (issue 269530043 by thomasmorle...@gmail.com)

On 2015/10/30 13:20:35, benko.pal wrote: sorry to chime in that late, but: am I right that the problem is that we get the rotation matrix cos a -sin a sin acos a inexact? and if so, how the inexactness is present? one of the diagonals is exactly +/-1 while the other is not exactly 0?

Re: modify coord-rotate to get exact values for (sin PI) etc (issue 269530043 by thomasmorle...@gmail.com)

2015-10-30 14:46 GMT+01:00 : > On 2015/10/30 13:20:35, benko.pal wrote: >> >> sorry to chime in that late, but: >> am I right that the problem is that we get the rotation matrix >> cos a -sin a >> sin acos a >> inexact? and if so, how the inexactness is present? one of the >

Re: modify coord-rotate to get exact values for (sin PI) etc (issue 269530043 by thomasmorle...@gmail.com)

On 2015/10/30 15:07:42, benko.pal wrote: 2015-10-30 14:46 GMT+01:00 : > I really think we should move everything to degrees except for the final > calculations. I'm not against that, but don't really know what are the final calculations. I'd argue for creating

Re: modify coord-rotate to get exact values for (sin PI) etc (issue 269530043 by thomasmorle...@gmail.com)

> I'd argue for creating functions sind, cosd, angle in analogy to > METAFONT's functions. And we'd use them exclusively so it might > make some sense to define C++ versions of them and export them in > order to get consistent results. Maybe there's a library out there which we could use,

Re: modify coord-rotate to get exact values for (sin PI) etc (issue 269530043 by thomasmorle...@gmail.com)

Werner LEMBERG writes: >> I'd argue for creating functions sind, cosd, angle in analogy to >> METAFONT's functions. And we'd use them exclusively so it might >> make some sense to define C++ versions of them and export them in >> order to get consistent results. > > Maybe there's

Re: modify coord-rotate to get exact values for (sin PI) etc (issue 269530043 by thomasmorle...@gmail.com)

On 2015/10/21 09:32:07, dak wrote: https://codereview.appspot.com/269530043/diff/40001/scm/lily-library.scm File scm/lily-library.scm (right): https://codereview.appspot.com/269530043/diff/40001/scm/lily-library.scm#newcode721 scm/lily-library.scm:721: (moved-angle (- angle (/ (* quadrant

Re: modify coord-rotate to get exact values for (sin PI) etc (issue 269530043 by thomasmorle...@gmail.com)

https://codereview.appspot.com/269530043/diff/40001/scm/lily-library.scm File scm/lily-library.scm (right): https://codereview.appspot.com/269530043/diff/40001/scm/lily-library.scm#newcode721 scm/lily-library.scm:721: (moved-angle (- angle (/ (* quadrant PI) 2))) Ok, let's just tackle this as a

Re: modify coord-rotate to get exact values for (sin PI) etc (issue 269530043 by thomasmorle...@gmail.com)

I'm not really enthused about this approach even though it originates from a proposal of mine. It works basically by moving around problematic angles, leading to discontinuities at multiples of PI/4 rather than just PI being imprecise. Fundamentally, we cannot fix this properly at the Scheme

Re: modify coord-rotate to get exact values for (sin PI) etc (issue 269530043 by thomasmorle...@gmail.com)

This oe is about radians vs degrees On 2015/10/20 14:25:21, dak wrote: Fundamentally, we cannot fix this properly at the Scheme layer: even in GUILE-2.0, we get scheme@(guile-user)> (sin (atan 0 -1)) $1 = 1.2246467991473532e-16 I think what we should be aiming for is grounding

Re: modify coord-rotate to get exact values for (sin PI) etc (issue 269530043 by thomasmorle...@gmail.com)

Let me split my reply into two. This one about the current patch and how to proceed. On 2015/10/20 14:25:21, dak wrote: I'm not really enthused about this approach even though it originates from a proposal of mine. It works basically by moving around problematic angles, exactly leading

Re: modify coord-rotate to get exact values for (sin PI) etc (issue 269530043 by thomasmorle...@gmail.com)

On 2015/10/20 22:54:17, thomasmorley651 wrote: no need for code-duplications, increasing readability of cyclic-base-value patch set 2 does some clean up, but not adressing comment #2 https://codereview.appspot.com/269530043/ ___ lilypond-devel

Re: modify coord-rotate to get exact values for (sin PI) etc (issue 269530043 by thomasmorle...@gmail.com)

https://codereview.appspot.com/269530043/diff/40001/scm/lily-library.scm File scm/lily-library.scm (right): https://codereview.appspot.com/269530043/diff/40001/scm/lily-library.scm#newcode751 scm/lily-library.scm:751: (cyclic-base-value (+ value cycle) cycle)) what are those red dots?? Never

modify coord-rotate to get exact values for (sin PI) etc (issue 269530043 by thomasmorle...@gmail.com)

Reviewers: , Message: please review Description: modify coord-rotate to get exact values for (sin PI) etc issue 4640 Done by switching to appropiate values for the angle and/or switching sin to cos and vice versa Please review this at https://codereview.appspot.com/269530043/ Affected files