Motion 24.03: NO
I vote NO for Motion 24.03
I agree with Vincent Lefevre and Nathalie Revol.
Additionally I think the requirement of this operations with directed
rounding and maximal accuracy will block (efficient) implementations on
some systems. For example on GPU's it is necessary for the maximal
performance that all threads perform the same operations simultaneously.
If we use algorithms (on GPU's without directed rounding) to simulate
the directed rounding with one ulp accuracy and as long as this
algorithms use branches than the computation is performed sequentially.
Hence, we lose the power of this highly parallel system. On the other
hand if we use round to nearest for the operation and then multiply by
(1+\epsilon) we lose the maximal accuracy but we can perform this
operations in parallel.
And as mentioned in my mail from July 20 I am in doubt that this motion
fits into the specifications of other languages/systems like Java (or
all the other Java VM languages).
Therefore I think this motion work against early and widespread
acceptance of the standard.
Best regards
Marco
--
o Marco Nehmeier, Lehrstuhl fuer Informatik II
/ \ Universitaet Wuerzburg, Am Hubland, D-97074 Wuerzburg
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