Re: [Re: RPGILE V4.3 Gotcha]

["Eric N. Wilson" <doulos1@xxxxxxxx>]

Note he said for fixed precision decimal values. Not the IEEE floating point
values which are the apples to apples comparison between RPG and other
languages. I think the problem comes from a bit of miscommunication.

Eric
______________________________________________________________

 ----- Original Message -----
From: Jim Langston <jlangston@conexfreight.com>
To: <RPG400-L@midrange.com>
Sent: Tuesday, October 05, 1999 7:30 AM
Subject: Re: [Re: RPGILE V4.3 Gotcha]


> What's to understand?  From all the discussion I have read here, and
> from someone quoting the manual, if you use eval you can LOOSE all
> your decimal precision by doing combined mathematical functions.
>
> And in regards to "any programmer use any programming language without
> being intimately familiar with the corresponding documentation".
>
> 1.  I do combined mathematical formulas in LOTS of different languages,
> and RPG is the only one that has this quirk.  After reading up on
mathematical
> formulas, how numbers are store, what a mantissa is, how computers perform
> math, the difference between BCD and floating point, time evaluations on
> doing a clear .vs. a move et. al.
>
> I have read this for enough languages (FORTRAN, COBOL, Pascal, Basic,
> C, etc..) so that I understand it.
>
> Now, behind me is a book case, it is 4 feet high by 3 feet wide.  Inside
of this
> bookcase are 42 note books, the majority containing one book, quite a few
> containing 2 or more books.  Out of these I have read maybe 10 cover to
cover,
> such as the CL Reference, DDS reference, Operations Guide, and Command
> Reference, RPG 400 guides, et al.  Others I have skimmed thought, some I
> use for reference and only open when the need arises.  Some of them I will
> most likely never open.
>
> IBM has decided that the printed manual is no longer the norm, that now
books
> are going to be in electronic format.  And,  much of these are scattered
all
> over the place, Softcopy Library, Rebook Softcopy Library, Books on Line,
> PDF, and who all knows where else, I sure don't.
>
> And, though all this mass of material, I am supposed to be able to know to
> read one particular book that explains in some particular paragraph that
IBM
> has decided that the way all other compilers do math is wrong, that IBM
has
> the right way, although it will, in effect, produce less accuracy over the
long
> run.
>
> Now that I know about it, I can work around it.  But a couple of points
here.
>
> 1.  I shouldn't have to work around it.  Nor should others.
> 2.  What about all the other programmers that don't know about it?
> 3.  People don't read the manual to do something as simple as multiplying
A times
>
>      B and dividing by C.
> 4.  This "feature" is going to produce more bugs that programmers won't
>      be able to find without careful examination of how IBM has decided to
do
>      their math routines.  The behavior it is trying to fix (Overflows) is
so
>      minute in comparison to lost accuracy.
> 5.  And who says I don't understand the rules?  Is there any behavior I
stated
>      in my posts that wasn't correct?  Would it not in fact loose accuracy
as I
>      stated?  If I am in error, let me know where.  If I am not in error,
don't
> say
>      I don't understand it.
>
> Regards,
>
> Jim Langston
>
> boldt@ca.ibm.com wrote:
>
> > <SNIP>
>
> >
> > Oh dear oh dear oh dear!
> >
> > I hope this doesn't sound rude, but how can any programmer use any
> > programming language without being intimately familiar with the
> > corresponding documentation?
> >
> > Sure, we could have come up with better rules for decimal precision.
> > But please don't criticize the existing rules while admitting you
> > don't even understand them.
> >
> > Cheers!  Hans
> >
> > Hans Boldt, ILE RPG Development, IBM Toronto Lab, boldt@ca.ibm.com
> >
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