On 4/3/07, Richard Guenther <[EMAIL PROTECTED]> wrote:
> It should be noted, that rendered picture in -mpc32 case developed a > strange halo around rendered object (nice special effect ;), and this > is clearly the effect of too low FP precision. -mpc64 and -mpc80 > rendered pictures were equal, as far as my vision in concerned (well, > not quite a scientific approach). > > It should be noted, that ifort defaults to -pc64 and this brings some > 2% better runtimes on FP intensive code. Is ifort able to provide extended precision arithmetic in that case? I think the documentation should mention that 'long double' will no longer work as expected if you pass -mpc64, likewise for 'double' and -mpc32.
I have added: ... Note that a change of default precision control may affect the results returned by some of the mathematical functions. to the documentation to warn users about this fact. Uros.
