> 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.