Hi Frederic, > So first my question is: is it normal to have different numerical computation in O2 vs O0 ? The short answer is: yes, it is normal to have different floating-point numerical computation in O2 vs O0. There are GCC switches to produce consistent results, at the cost of performance. The long answer is: http://docs.sun.com/source/806-3568/ncg_goldberg.html HTH, --Eljay
