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jt wrote:
...
| As a rough guideline, I'd simply recommend avoiding float numeric values
| unless you know what you're doing. Perhaps a B (or better) grade
| in senior
| high school physics would be a good pre-req. ;-)
Hans, I got an A in HS physics and read graduate level textbooks to do my
final paper. I'm NOT stupid, but I'm guessing you know me well enough to
know I do (and say) some of THE most outrageously STUPID things, anyway.
(If I knew why I did some stupid things, I wouldn't...;-) ANYhoo...
For me, I got a 90% in my final HS physics class, good enough for best
in the class. For some reason, I felt it necessary to take the tough
physics course in 1st year university, and I consider myself very lucky
to have passed that course with a 57%! Some of my friends in that class
weren't so fortunate.
My point is just that float format was primarily intended for scientific
calculations, and an understanding of the concept of precision is important.
Here's another practical example. Let's say you have two 16 digit float
values that differ only in the 16th digit. What is the precision of the
result of subtracting the two values? 16 digits? No. The following
Python command line session illustrates:
>>> a=1.111111111111111
>>> b=1.111111111111112
>>> b-a
1.1102230246251565e-015
Although IEEE format represents a value with 17 digits, only the first
is significant.
OK sure, that's an extreme example, but I think it's important to
understand the issues involved. And as RPG acquires more and more
enhancements, it becomes more and more important to understand these
fundamental issues.
...
Anyways, I just recorded a suggestion in our "Suggestions for Future
Enhancements" file for a decimal exponentiation operator. It certainly
wouldn't be as fast as the current ** operator, but it would provide
more digits. (Speed or accuracy - make your choice!)
Cheers! Hans
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