On Tuesday, 25 August 2015 at 18:15:03 UTC, Ola Fosheim Grøstad
wrote:
It is a practical issue in all simulations where you want
reproducible results. If D is meant for scientific computing it
should support correct rounding and reproducible results. If D
is meant for gaming it should provide ways of expressing
minimum precision or other ways of loosening the accuracy where
needed. I'm not really sure which group the current semantics
appeals to. I personally either want reproducible or very
fast...
As long as it doesn't change from one release of the compiler to
the next, we have reproducibility. In many cases though,
reproducibility doesn't mean exact reproducibility, at least in
the old days it didn't, due to floating point issues. You
generally want to allow for replication of the results using
other languages, so you have to allow for some differences.
I'm pretty sure Walter has stated the reason that you cannot
count on exact precision, but I don't remember what it is.
