[J3] Several mistakes in EXPONENT
Clune, Thomas L. (GSFC-6101)
thomas.l.clune at nasa.gov
Tue Jan 26 13:22:44 UTC 2021
While investigating a tangential question from Damian, I came across the following sentence in 18-007r1 in the specs for the EXPONENT intrinsic:
(p368, lines 35-36): “If X has the value zero, the result has the value zero. If X is an IEEE infinity or NaN, the result has the value
HUGE (0).”
Problems:
1. EXP(0) should be 1 (not 0)
2. EXP(Inf) should be Inf (not HUGE(0))
3. EXP(-Inf) should be 0 (not HUGE(0))
4. EXP(NaN) should be NaN (not HUGE(0))
5. Even if HUGE were relevant its argument should be FP of the appropriate precision, not a default integer with value 0.
I’ve confirmed with 2 compilers that my expectations are sound. However, I have not scoured the other intrinsics to look for similar problems.
Presumably there should be a paper?
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