CAM #4 - Pt 1 What is RPN Reverse Polish Notation / How to use RPN on the HP 12C, HP 15C and HP 50g

[@twong789]

Long live RPN!!! I have used many HP calculators over the years, 34c, 41cx, 28c, 42s, 48g. But may favourite ones are the voyager series, 11c, 12c, and 15c for its compact size, quality, and tactile feel of the keys. Thanks Martin for taking the time and posting videos. Enjoy watching them!

[@David-ln6im]

Please do a 12C tutorial. Your tutorials are one of the best i've come across. Thank you for providing your knowledge for all of us.

[@TheMangeGrain]

Thanks a lot for this excellent RPN tutorial !

[@theodorjohnson2984]

I have just watched the entire video. I find the stack explanation on this piece of paper very useful, had never heard of RPN before but now I have a basic idea. Good job on the video!

[@CristiNeagu]

My opinion about the "RPN is the most efficient" myth. The first basis of this misconception comes from the time when HP introduced RPN. Back then, the only alternative was single operation machines. So you could only do 5 + 3, you get 8, multiply that by 2, get 16, but if you wanted to divide that 16 by, say 3 squared, there was no way to store that 16, do 3 squared, then do the division. Even later when memory was introduced, it still wasn't sufficient to compete with the RPN stack, even as limited as it was. Later, when TI started introducing algebraic calculators, all the RPN fans probably found it unnecessarily difficult to learn a new system where everything was backwards. What's more, since algebraic was new, it was probably pretty clunky. Also, due to how close the RPN stack is to how calculator hardware operates (which is why it has always been so easy to program in RPN), algebraic was pretty limited because it was so much harder to develop for it. With RPN you can just feed user input straight into the hardware. With algebraic, you have to basically translate it to something like RPN. So for practical purposes it was impossible to do an unbiased RPN vs algebraic comparison. Why would you ever choose an algebraic TI when it was so limited compared to RPN? Then HP started introducing algebraic mode in their calculators, but with the exception of the Prime, it has never been the primary operation mode. So trying to use an HP 50g in algebraic is pretty awkward, considering it still is an RPN machine first and foremost. Everything is meant for RPN, and then algebraic was shoehorned in. Considering that, it's easy to see why one might think RPN is more efficient than algebraic. So it's my opinion that this myth comes from the fact that it's not RPN that's more efficient than algebraic, but that RPN calculators have historically been more efficient and advanced than algebraic ones. This is because RPN forces you to provide input to the calculator in a manner it can easily understand. RPN is very similar to how computers actually work: put one number in a registry, put another number in another registry, perform an operation. But from a human centric perspective, algebraic is much more intuitive and simple and clearer than RPN. And when we're talking about symbolic math, RPN is next to useless. Why would HP calculators have equation editors and algebraic objects if RPN is so much better than algebraic? Even though RPN fans like to say RPN is how humans do operations, it really isn't. And the HP Prime kinda shows it. It is specifically designed around algebraic input, with RPN being an afterthought. Now we have the graphic and processing capability to have computers communicate with people directly in human readable formats. That's why kids have no problem using algebraic on a Prime, but will easily get frustrated with any RPN calculator. In conclusion: RPN is not more efficient than algebraic. It's just that RPN calculators have been historically more efficient than algebraic ones. But that is no longer the case.

[@yummybeers]

Speaking as a person who grew up in the early age of calculators, I never thought about this but think you’re right, that all makes sense. I’m an engineer who never found rpn to be intuitive. Equations are normally written out, so it’s easier to just use an algebraic calculator to type in what you see. One thing: back in the single operation calculator days, we’d deal with the division problem by inverting (1/x) then multiplying.

[@Jeffrey314159]

In an ideal RPN system, the first interger or factor would be loaded into the accumulator-register first with the ENTER or plus key. Then the next interger would be keyed into the entry-register, and then use an operator key (+ - / x) to achieve the desired results. Leading zeros would be used to both key in the location of the decimal point, and the level of precision (where to round off).

[@sharegreats2157]

Very well explained! Cool teacher! Greetings from Germany.

[@josemesquita603]

Great valuable demos and reviews. Thanks!

[@AsBi1]

T is not constant. Its value changes as u input data. T gets value from Z

[@mjlorton]

Yup...I can do stuff here that will be "off topic" for my main audience. Let me know of you do start posting on a second channel as well.

[@JulianIlett]

Ah, just realised this is your other (non-electronics) channel. Great idea! I'm thinking of starting another channel to do videos on IP networking - one of my non-electronics interests

[@gmcenroe]

You should get an HP41c calculator, those are very nice

[@JulianIlett]

I certainly will.

[@emilybenedetto3607]

Very thorough. Thank yoU!

[@SmileKT68]

There's a letter "c" that popped up at the bottom right hand corner of my HP 15C display. What does it mean? And how do I clear it? Thanks.

[@SmileKT68]

OK, I think it was the "C" annunciator (as explained in the HP 15C guide) ?!

[@chef1arjunaidi]

I think it stood for Constant Memory. You can switch it off and come back later, switch on and the last number is still there.

[@twong789]

The small "c" annunciator means you are in complex mode, as stated in the user manual.

[@LarsBohr5]

HP quality went downhill after the 11, 12 and 15c calculators. The letters on the keys are molded in and are easy to read compared to later ones with a very positive keystroke. I like that store and recall buttons are primary functions. Love RPN!

[@arcade_signal]

I recently got a 35S and while it's not quite up to that standard I'm really impressed with how great the keys feel, and with the general design and layout (the enter key is in the right place, etc). I would like to see them re-release the 11c/15c/16c the same way they did the 12c though because that form factor is great

[@Jeffrey314159]

Yeah, who needs a three-key memory function. STORE and RECALL keys are better! I have my dad's old scientific calc from the early 80's and it these keys. It was solar powered too!

[@SianaGearz]

Battery loves you long time.

[@karatyson8234]

If you go to the unclaimed baggage store, you can choose one from a huge pile for $5.

[@severrnijKGU]

I have a 48G, the buttons feel orgasmic to press, very clearly did you press a button, and it makes the most satisfying pooping sound, is that 15C like that?

[@londospark7813]

I have a 12C and would say that it is even better than the 48G for key feel.

[@Packaroo]

I'll stick with the normal way.