[Xy-pic] Fw: Xy-pic and Qcircuit

[Daniel Müllner]

Hi Ross & all others,

is it always the same macro and/or trigonometric calculation which 
produces the errors in Bryan's examples with elliptic shapes? If the 
overflow errors are caused by a single macro which does a certain 
numeric calculation, could we reimplement this with \dimexpr?

As you are well aware of, doing calculations in TeX's fixed point 
arithmetic is a pain. But one thing has improved in the 12 years since 
Xy-pic was written: e-TeX has the \dimexpr macro which makes 
multiplication and division a lot easier than in the days when 
everything had to be done with the \multiply and \divide primitives.

Xy-pic's engine is a complicated system, but is it possible to identify 
the macros which generated errors with arrows and frames in connection 
with very small objects? If the problem is somewhat limited to the 
arithmetic at a few spots, I could offer my help with that.

Best,

Daniel