[Dev-luatex] Wrong default value for \Umathradicalrule ?

[Taco Hoekwater]

Hi Khaled,

Khaled Hosny wrote:
> Per LuaTeX manual, \Umathradicalrule is equivalent to OpenType
> RadicalRuleThickness but the comment in page 111 doesn't seem right to
> me; RadicalRuleThickness, from its name, is the thickness radical rule
> and thus it should default to default_rule_thickness as TeX82 does and

The comment is correct. TeX82 does not do what you think it does.
>From the texbook, rule 11 in Appendix G:

  "Note that the font designer specifies the thickness of the
   [radical] rule by making it the height of the radical character;
   the baseline of the character should be precisely at the bottom of
   the rule."

Best wishes,
Taco