Re: Strange result with exponents...

[Simon Coulter <shc@xxxxxxxxxxxxxxxxx>]

On Friday, February 20, 2004, at 10:59  AM, Joe Pluta wrote:

> Rremember, a lot of us dinosaurs don't have the benefit of a CS degree,
> since when we were coming up there was no such thing.

Well I don't have a CS degree nor a Maths degree but I know about 
floating-point numbers so I think your argument is specious.

> In fact, the only saving grace for this is that there is a note in the
> documentation that says floating point is used.  It would be nice to 
> see
> a warning that the use of this opcode effectively limits your 
> precision;

Possibly but the input to most technical documents comes from the 
technicians. If something is blindingly obvious to you it takes a bit 
of effort to realise that maybe you should point that out to someone 
else. I don't blame IBM for this. I think part of a programmer's job is 
to be familiar with some things outside their usual realm. When Floats 
were added to RPG it would be reasonable to expect a bit of 
investigation about what they were and whether they would be useful but 
it seems most RPG programmers stayed with what they learned in RPG II 
hence all the confusion about B versus I data types.

> it's way beyond the pale to expect an RPG programmer to know the
> precision limits of FP arithmetic.  Despite the fact that it was
> immediately clear to you, it was clearly not apparent to Scott, and
> Scott is one of the brighter people I know.  If he (and several other
> very bright people on this list) didn't get it, it might need a little
> explaining.

Oh I reckon Scott knows about floating point numbers. It would fit with 
the general breadth of his knowledge but finding behavioural changes 
between releases can throw anyone off the scent. I think the 520 
behaviour is wrong and should be followed up but it doesn't surprise me 
that the numbers are different. Nor would it surprise me if the IBM 
developer said "Too bad, its float, what do you expect?". Of course it 
would likely be couched in pleasanter terms.

> Anyway, that's all.  No big deal.

Which is why I'm going to drop it.

Regards,
Simon Coulter.
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