5 Jan
2014
5 Jan
'14
7:22 p.m.
On Jan 5, 2014, at 10:01 , Liam Proven <lproven at gmail.com> wrote:
So perhaps this explains the fondness and elitism
about HP calculators
and RPN: that they are good for programmers. I was not and am not and
have never been a programmer, so that is a virtue that was and is
completely wasted on me.
They are also good for engineers, or anybody else who needs to calculate values of
nontrivial nested equations. I've found it to take less mental "stack space"
to enter a complex equation on an RPN calculator than an algebraic one, since there's
no need to think ahead to count how many times I need to pound the parenthesis keys on an
RPN calculator. Having used both varieties heavily (mostly HP and Casio), I strongly
prefer the RPN type.
My first calculator as a little kid was an RPN 4-banger, though I didn't appreciate
the RPN vs. algebraic distinction until much later, and most of my calculators were
algebraic until I got to college and started the heavy engineering courses. It was a
Montgomery Ward model, and Google suggests it was probably the model P10 which was a
rebranded Novus 650 "Mathbox".
http://spyropoulos.net/calcs-other/WardsP10.jpg
When I got my HP28S in college, I wasn't sure I was going to like that silly RPN stuff
(and I probably didn't recall that my first calculator was RPN). I found it to be much
easier to use than my previous algebraic calculators for the sorts of electrical
engineering equations I needed to calculate. Of course, its more advanced features such as
handling complex numbers and numerically solving for unknowns in systems of equations were
also quite helpful, but RPN entry turned out to be a lot easier even for plug-n-chug
calculations.
I still have my old HP28S, but not long ago I finally upgraded to an HP48gx. I wasn't
able to find any current=production RPN scientific calculators that had form and fit that
appealed to me, so I use that vintage 48gx even though it's pretty slow by today's
standards. I have a 48gx emulator that I use on my iPhone and laptop when my real
calculator isn't handy, but I prefer the physical keyboard on a good dedicated
calculator.
One of the big plusses of my previous Casio calculator was its handling of fractions, but
I still prefer RPN entry. I've written some programs on my HP48gx to handle fraction
manipulation when dealing with silly imperial units like inches. They're not quite as
clean as the fractional math on my old long-lost Casio. If you need to handle a lot of
non-decimal fractions, such as when doing woodworking with imperial tools and
measurements, and you rarely need to calculate equations with more than a couple levels of
nested parentheses, then one of those old Casio calculators with a fraction key would be
quite handy. When the parentheses get nested deeper, RPN really shines.
I wonder if my early exposure to an RPN calculator contributed to my easy acceptance of
RPN entry and stack-based languages like Postscript? Or maybe it's just a matter of
how my brain is wired? I can imagine that some folks may have a strong preference for
algebraic or RPN entry based on how their brains happen to be wired.
--
Mark J. Blair, NF6X <nf6x at nf6x.net>
http://www.nf6x.net/
