"Trevor Daniels" <t.dani...@treda.co.uk> writes: > David Kastrup wrote Monday, December 14, 2015 11:32 AM > > >> Urs Liska <u...@openlilylib.org> writes: >> >>> Am 13.12.2015 um 14:09 schrieb Graham Breed: >>>> On 13/12/15 12:48, N. Andrew Walsh wrote: >>>>> Take a look at conversions.ly (sorry; mround is the equivalend >>>>> function in >>>>> the spreadsheet I use to do the same thing). Those functions will >>>>> convert >>>>> the input (given as a fraction comprising two integers) into Lily's >>>>> semitone values. That should allow you to convert between >>>>> just-intonation >>>>> ratios an the nearest note name. Urs has some comments in there >>>>> explaining >>>>> a bit how it works. >>>> >>>> Converting from ratios to cents is easy. Converting between ratios >>>> and cents requires a function from cents to ratios. That's a lot more >>>> difficult because information is lost. You got us excited by >>>> suggesting that had been solved. >>> >>> Well, this is because conversion from cent to ratio isn't part of the >>> objective currently. >> >> Guile has >> >> (rationalize (inexact->exact (atan 0 -1)) #e1e-6) >> >> so you can try converting irrational numbers to ratios. However, >> figuring out the precision to use may be tricky and there is no "prefer >> simple ratios" option. All you have to work with is the eps argument. > > One way to approach this would be via continued fractions.
Well, that's what `rationalize' does. -- David Kastrup _______________________________________________ lilypond-user mailing list lilypond-user@gnu.org https://lists.gnu.org/mailman/listinfo/lilypond-user
