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What Is RPN? Why Did/Does HP Use RPN? Learning RPN (1999)

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21–30 of 118 posts

Re: What Is RPN? Why Did/Does HP Use RPN? Learning RPN (1999)

#22
post #19

Reading these comments, I'm surprised that people think in RPN. (I mean I shouldn't be, I just didn't think of it) I wonder if teaching it early on, instead of parenthesis, would have made math lessons different? Could there have been different notations used for things like factoring out a quadratic equation?

I learned RPN as a college freshman studying engineering in the late 1980's. Almost all of my fellow students had HP RPN calculators. Once we where doing more advanced math RPN -- with the accompanying stack -- became so much easier to enter. We all quickly learned it and I think most of us came to hate standard calculators.

Re: What Is RPN? Why Did/Does HP Use RPN? Learning RPN (1999)

#24
post #18
post #8

It took awhile to learn RPN in undergrad in electrical engineering. But, once you learn it, it is so much easier to solve problems and it is much more efficient. You never go back, and you are less likely to make errors entering in equations compared to your peers. This is important on timed exams. I prefer to always use RPN. MacOS has an RPN mode on their calculator, which one can activate by pressing command + R. O…

Emacs calc-mode is RPN by default as well.

calc-mode is wholly responsible for my HP49G+ not having had its batteries replaced in a few years. :D

Re: What Is RPN? Why Did/Does HP Use RPN? Learning RPN (1999)

#25
post #20

Is there a good RPN calculator currently? The HP Prime is lacking apparently, and the 50G is no longer available (and a bit old)

I don't own one, but I've heard great things about SwissMicros calculators (https://www.swissmicros.com/products) from users of HP calculators. The SwissMicros lineup is very similar to HP's 1980s calculator lineup.

Also, the HP 12c financial calculator and the HP 35S scientific calculator are still being sold by HP.

Re: What Is RPN? Why Did/Does HP Use RPN? Learning RPN (1999)

#26
post #9
post #6

It's simpler to implement RPN than algebraic notation with precedence. The latter requires an operation stack where operations are stacked until they encounter a lower precedence operator or the user presses =. The user types less, the computer does a lot less. I find it fun to think in RPN.

Yeah, it feels like the whole "why" is that RPN reflects how the machine works, so it's easier to build it that way.

Well, it’s easier to build because it has a terse syntax that requires fewer symbols, doesn’t need precedence and associativity rules, and has no ambiguous instructions. It’s easier to use for the same reasons.

Re: What Is RPN? Why Did/Does HP Use RPN? Learning RPN (1999)

#28
post #8

It took awhile to learn RPN in undergrad in electrical engineering. But, once you learn it, it is so much easier to solve problems and it is much more efficient. You never go back, and you are less likely to make errors entering in equations compared to your peers. This is important on timed exams. I prefer to always use RPN. MacOS has an RPN mode on their calculator, which one can activate by pressing command + R. O…

My daughter is at the learning algebra stage. I note that the way they teach kids to parse algebraic notation is by building an infix operation tree. If they’d just take the natural next step of discussing postfix (and prefix) traversal, everyone would think rpn natural.

Re: What Is RPN? Why Did/Does HP Use RPN? Learning RPN (1999)

#30
post #9
post #6

It's simpler to implement RPN than algebraic notation with precedence. The latter requires an operation stack where operations are stacked until they encounter a lower precedence operator or the user presses =. The user types less, the computer does a lot less. I find it fun to think in RPN.

Yeah, it feels like the whole "why" is that RPN reflects how the machine works, so it's easier to build it that way.

It may be easier to build, but that difference is quite small and not likely something that would have influenced the design of a scientific calculator. Many people have found RPN to be a superior user interface, and that’s likely the “why”.
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