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The R47: A new physical RPN calculator

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Re: The R47: A new physical RPN calculator

#41

Post by _verandaguy »

Maybe it's a generational thing -- I haven't had to use a standalone calculator in my professional life -- but what's the benefit of using RPN as opposed to the more common infix notation?

Beyond that... do RPN calculators like these usually include the option to use infix notation?

Re: The R47: A new physical RPN calculator

#42

Post by xyzzy_plugh »

_verandaguy wrote: post #41

Maybe it's a generational thing -- I haven't had to use a standalone calculator in my professional life -- but what's the benefit of using RPN as opposed to the more common infix notation? Beyond that... do RPN calculators like these usually include the option to use infix notation?

It eliminates the need for parentheses and operator precedence, which is honestly nearly half of the character count of my usual infix math. You can just keep performing new calculations and then later on decide how you want to combine them. It's pretty great.

Re: The R47: A new physical RPN calculator

#43

Post by TheJoeMan »

_verandaguy wrote: post #41

Maybe it's a generational thing -- I haven't had to use a standalone calculator in my professional life -- but what's the benefit of using RPN as opposed to the more common infix notation? Beyond that... do RPN calculators like these usually include the option to use infix notation?

The iPhone calculator, for example, only recently added parenthesis. However, with prefix notation you have to plan out your open parenthesis, and if you forgot one you have to back up. With postfix, the parenthesis are implicit. Which is faster? “2 2 + 2 x” or “2 + 2 = x 2 =“ for 2(2+2)

Re: The R47: A new physical RPN calculator

#44

Post by electroly »

TheJoeMan wrote: post #43
_verandaguy wrote: post #41

Maybe it's a generational thing -- I haven't had to use a standalone calculator in my professional life -- but what's the benefit of using RPN as opposed to the more common infix notation? Beyond that... do RPN calculators like these usually include the option to use infix notation?

The iPhone calculator, for example, only recently added parenthesis. However, with prefix notation you have to plan out your open parenthesis, and if you forgot one you have to back up. With postfix, the parenthesis are implicit. Which is faster? “2 2 + 2 x” or “2 + 2 = x 2 =“ for 2(2+2)

On a basic four-function calculator, you can do "2 + 2 x 2 =" to get 8 without the extra = in the middle. RPN really shines when you use the stack for real. "(2 + 3) x (4 + 5)" is "2 3 + 4 5 + x" in RPN, but on a four-function this requires the stateful memory buttons and gets out of control fast. You may need to spill out to pen-and-paper with a four-function calculator, but you never need that with RPN. I'm less certain that the comparison works out in RPN's favor if you have a calculator with parentheses--where are you getting the complex expression that you're entering? If it's on paper, then it's already in infix notation and you had to mentally convert it to RPN inside-out. Entering the infix notation may be more keystrokes but likely less mental effort because it's more of a direct transcription. I taught a sibling how to use an HP-12C and I don't think they're ever gaining that time back in efficiency.

Re: The R47: A new physical RPN calculator

#45

Post by auxym »

_trampeltier wrote: post #24
aidenn0 wrote: post #23

Earlier quoted context omitted.

I have a 35s as well; I was made fun of for using one (you know you're sitting at a calculator that is 1000s of time more powerful right?). I still use it.

A F1 car has more Hp than any tractor and is still useless for any farmer.

Just as a fun fact, some of the largest tractors made these days actually rival F1 cars in horsepower output. John Deere 9RX goes up to 913 HP for example.

Re: The R47: A new physical RPN calculator

#49

Post by crims0n »

I have an embarrassing question... math has always interested me but by luck and circumstance I have had a pretty successful career without needing anything beyond college Algebra. Can anyone recommend a curriculum that a busy adult may be able to follow in their spare time? I just want to fill in blanks and explore what is possible.

Re: The R47: A new physical RPN calculator

#50

Post by heisenbit »

TheJoeMan wrote: post #43
_verandaguy wrote: post #41

Maybe it's a generational thing -- I haven't had to use a standalone calculator in my professional life -- but what's the benefit of using RPN as opposed to the more common infix notation? Beyond that... do RPN calculators like these usually include the option to use infix notation?

The iPhone calculator, for example, only recently added parenthesis. However, with prefix notation you have to plan out your open parenthesis, and if you forgot one you have to back up. With postfix, the parenthesis are implicit. Which is faster? “2 2 + 2 x” or “2 + 2 = x 2 =“ for 2(2+2)

Way back around ‘84 in the military I was doing the artillery survey calculations for the Lance (potentially nuclear) missile. We had to store first the program into the volatile hp memory, run check calculations before doing the real calculations. I always found the calculations very efficient - they had to be as they had to be done within certain time limits (and independently checked). It was a strange feeling thinking about doing the calculations under high pressure and what the stakes were if you would get the coordinates or directions wrong in case it would be used.
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