David Kastrup wrote:

Taco Hoekwater writes:

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David Kastrup wrote:

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But I consider it more likely that nc should be changed to 1370:107

And also, I applied this change to luatex.web (and fixed the documentation sting back). TeX's conversions are approximations anyway, I see little point in changing the conversion arithmetic.

Well, but I would find a change rendering "1in"="72.27pt" attractive. I'll propose one shortly. Anyway, those fractions carry _way_ more precision than TeX's general arithmetic anyway, and TeX's truncation (which this was all about in the first place) introduces more bias than this particular fraction does. One could argue that 32163:2512 will be a nicer fraction since it overshoots, and TeX forgets to round the final result, so we err on different sides.

But I'd rather have the closest ratio and fix TeX's, excuse me (hopefully Knuth didn't hear), LuaTeX's arithmetic on units by letting it round properly.

this is not going to happen soon, maybe a different 'rounding' some day; while developing we need to be able to compare pdftex output with luatex output/processing and implementing a different rounding model is not convenient at this time nobody bothered about that for 25 years so we're not in a great hurry there -) Hans ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | fax: 038 477 53 74 | www.pragma-ade.com | www.pragma-pod.nl -----------------------------------------------------------------

David Kastrup wrote:

So I recommend that you change the ratio of nd either to 1370:1284 (which reinstates the 12nd=1nc relation), or better change it to the

I picked that choice for luatex. People would be awfully confused if 12pt!=12pc, so I suspect the same is true for nds and ncs (assuming anyone actually uses these units, which is doubtful at this stage). Taco

"Martin Schröder" writes:

2007/4/3, Taco Hoekwater :

...

12pt!=12pc, so I suspect the same is true for nds and ncs (assuming anyone actually uses these units, which is doubtful at this stage).

The bug has been in the wild since 2005-08-01, so I agree: Nobody uses them. Not even the author of the patch. :-{

Well, at least not with large numbers behind the decimal point. The nc is rather easy to break with those (0.6nc does the trick), but you have to cherry-pick values for breaking nd (9.99998nd is the smallest value of form x.99998nd that actually breaks). So it is possible that the author uses nd, and possibly multiples of 0.5nc without seeing the problem. -- David Kastrup