On Thu, Nov 08, 2007 at 09:30:06AM +0100, Jonathan Sauer wrote: > I hope this is the right place for this. > > Macro \int_div_truncate_raw:nn is defined in file l3int as: > > \def_new:Npn \int_div_truncate_raw:nn #1#2 { > \int_eval:n{ (2*#1 - #2) / (2* #2) } > } > > If #1 is zero and #2 is two, this macro does not expand to zero, > as one would expect (0 / 2 = 0), but to -1 (since eTeX rounds > negative numbers by negating them, rounding the positive number > and negating the result. See function "quotient" in etex.ch). This eTeX-rounding does not make life easier. :-(( > Also, if #2 is an expression (i.e. 1+1), the calculation is not > performed correctly, since #2 (and #1) is not surrounded by ( and ). > (I am not sure if this can happen, or if the parameters are always > evaluated beforehand) > > In my code, I use (to divide #1 by #2): > > \numexpr((((#1)+((#2)/2))/(#2))-1)\relax With less parentheses: \numexpr (#1+(#2)/2)/(#2)-1\relax > This seems to work better. No: -2/2 = -2 Also both solutions have the disadvantage, that intermediate results may cause an arithmetic overflow. As result the accepted number range is limited unnecessarily. Therefore I have choosen a more complicate route in package `intcalc' by a case switch for zero, positive and negative numbers. Yours sincerely Heiko <[log in to unmask]>