RPN

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Jul 8, 2019
Messages
654
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SF Bay Area, California, USA
My sister recently asked me to look for an HP calculator for her.
She wanted a RPN calculator as "she could not get her head around using an algebraic calculator."
That is something us RPN guys can relate to.​

That reminded me of an incident MANY years ago, when a manager was "insulted" when one of his staff mentioned "Reverse Polish Notation," when talking about his HP calculator.

So I got curious about RPN, and its name.
It turns out there are both Polish Notation (PN) and Reverse Polish Notation (RPN).
The description "Polish" refers to the nationality of logician Jan Łukasiewicz, who invented Polish notation in 1924.
So rather than being insulting, it has a historical basis.​
And easier than "Łukasiewicz Notation," or "Reverse Łukasiewicz Notation." :eek:

And I still use my old HP-22 calculator, from my F2 days.

Are any of you RPN guys?
 
Joined
Feb 20, 2011
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3,785
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New Zealand
HP35S here, been through heaps of others. Get confused when trying to use an "ordinary" calculator.
I'm a Surveyor, they were pretty much a must have for this profession, not so much now.
 
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Mar 23, 2009
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Arizona
Have a couple of HP41s, tape drives, PPC Club Roms, etc. These days I use an app called Realcalc on my android phone so I don't have to look for N cells anymore!
 
Joined
Sep 23, 2006
Messages
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Pennsylvania
I use an HP-42S. My first one was an HP-25. My Mac calculator is set to RPN and I have HP calculator simulation apps on the Mac and iPhone. I don't know if it's provably a better system, but it's what I'm used to and as with Jim it seems more natural at this point.
 
Joined
Jul 8, 2019
Messages
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SF Bay Area, California, USA
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  • #8
What is funny is I can use a standard desk 10-key calculator with algebraic input.
But when I use a handheld calculator, my brain switches to RPN, and I have trouble with the algebraic handhelds.

I need to look for the RPN calculator apps you guys mentioned, for my phone.

My HP-22 is in need of battery work. I replaced the original battery, but the replacement NiCd batteries, don't last anything like the original did. But at least they are replacable.

I have the newer 12c, but for some strange reason, I prefer the old 22.
I just wish the 22 had comas in the display.
 
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Jan 12, 2018
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Puget Sound
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Ken
I was issued a 12C in the late 1980's, but almost immediately replaced it with a 17B and I still use it every day (mostly as an alarm clock). It is still my favorite tool for TVM calculations, and I have been a big fan of Excel since its introduction in the mid-1980's, so that says a lot about my love of the 17B.

--Ken
 

NCV

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Jan 31, 2019
Messages
363
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Italy
Real Name
Nigel
At the moment, I use a HP Prime calculator for my engineering calculations. It had to be set in the RPN mode as it defaults to algebraic. It is not quite up to the old models and hangs from time to time, and has to be rest with my old compass point. But the display is a big improvement over the older models.

I have several earlier models too that I never managed to wear out. My 50G is decidedly battered, with the rubber feet long gone.

Once you have mastered RPN (it takes about an hour) other calculators really suck for serious number crunching.

There is a guy is Switzerland who make a HP42 clone . They are quite pricey. But I see old HP models are not cheap on Ebay too!
 
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Feb 22, 2010
Messages
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Denmark
I have - and use - a HP12C in RPN mode. I also have on my iPhone and iPads the HP12C app (which, unfortunately, isn’t very stable).
 
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Mar 25, 2011
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London
As I previously wrote the bottom one is my daily calculator, the 15C.
Passed lots of exams with it.
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I have also kept a few others, some damaged though.
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Joined
May 3, 2007
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Colorado Springs, Colorado
Infix-postfix or Polish-Reverse Polish notation is a fixture of compiler design allowing for efficient parsing and storage of operands and operators while stripping things like parentheses. As noted above, it is also very useful in calculators.
 
Joined
Jul 8, 2019
Messages
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SF Bay Area, California, USA
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  • #20
Here are my my kids.
Separated by about 30 years.
HP-22 (1976) on the left and HP-12C (2005) on the right.

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Once I replaced the NiCd cells in the 22s battery pack, the 22 works just fine, and I am using it again. :)
For some reason, I like using the older 22. Maybe it is the "portrait" layout, vs. landscape on the 12c.

The only thing I never liked about the 22 was that it did not display commas. For finance/accounting use, having a comma display make it much easier to use. I think a later model financial calculator had commas, but I have not been able to find out which model it was.

If anyone has a working 11c or 15c that they are willing to sell at a reasonable price, I would like to buy it for my sister. She told me the current 35s does not have the EEX key that she needs.
 
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