Re: floating point comparison

[dewar@merv.cs.nyu.edu (Robert Dewar)]

Wes says

<<Let me put my original question another way.  Can we (as Sam
suggested above) come up with something _at_the_level_of_ Ada
Quality and Style that tells the "analysis-challenged" when to
call for help--rather than telling them to never use floating point?>>

The general rule is: don't use features of a language that you do not
fully understand. I don't really see such a guideline as useful in 
AQ&S. And actually I don't think there is much helpful that one can
put in AQ&S. Remember that AQ&S assumes that you *know* Ada. In the
case of floating-point, it should assume that you know the Ada features
in this area, and fully understand the floating-point model and the
associated attributes.

AQ&S is NOT a tutorial in Ada!

My own feeling is that everyone doing any programming should know enough
about floating-point and numerical analysis to answer Wes' question
for themselves. If they don't then they have a gap in their technical
education -- that's not so terrible, we all have such gaps (I personally
wish I had studied mathematical logic more deeply).

But you need to be aware of the gaps you have, and either work to plug
them, or steer clear of situations where they get you into trouble!

I understand that people are still wanting some simple guidelines here,
but isn't it interesting that many of those who might know enough to
write such guidelines are exactly the people saying that they cannot
be usefully written!

Note that AQ&S is about improving quality through use of good style. What
we are talking about here is substance, not style, and I as I said earlier,
I don't think that AQ&S is successful when it crosses this line (which it
does occasionally in various areas).