IEEE Exceptions vs LCAS

[Samuel A. Figueroa]

Fred Tydeman writes:
    This to me means SQRT(-1.0); must print an error message and either
    terminate or return a numeric value, such as 0.0, and cannot return a
    NaN (which appears to violate what IEEE-754 wants).  Hence the LCAS
    version of the math library must be different than the NCEG IEEE
    version of the math library.

I spoke to Martha Jaffe, who is one of the authors of LCAS, about this
specific issue at the last NCEG meeting.  I pointed out to her that this
would not be desirable, because, for example, a program might be written
to properly handle signed infinities if overflow occurs during its execu-
tion.  In fact, computing with signed infinities might reduce the error
in the calculation.  If the computer is not allowed to produce a signed
infinity when overflow occurs, such programs would be affected.  Martha
agreed that the behavior specified in LCAS might not always be desirable,
and seemed to feel that it might be possible to reword the offending para-
graph.

Sam