Is RPN still relevant?

[carey]

(12-18-2023 07:56 AM)carey Wrote:  However calculations aren't done by hand anymore

(12-18-2023 09:23 AM)Garth Wilson Wrote:  I guess you live in a world different from mine.

If you are claiming to do most calculations with paper and pencil (which is obviously what I meant by "calculations aren't done by hand anymore" as I spoke of RPN mimicking hand calculations (and a handheld calculator is a machine), then yes, I live in a different world from yours!

(12-18-2023 07:56 AM)carey Wrote:  so there's no need to mimic hand calculations and RPN's intuitiveness with numeric operations is offset by RPN's torturousness when working with equations without numbers.

(12-18-2023 09:23 AM)Garth Wilson Wrote:  Only a small part of programming is math and equations though.

If we're talking about RPN programming on a calculator (this thread?), and your experience is that only a small part of that programming is math and equations, then you're living in a different world than mine :)

(12-18-2023 07:56 AM)carey Wrote:  (imagine writing words in a sentence backwards).

(12-18-2023 09:23 AM)Garth Wilson Wrote:  It is my understanding that some spoken languages are indeed RPN, like that where we would say "put on shoes," in Korean it comes out more like "shoes, install."

The fact that it was necessary to select a language (Korean) which most English-speakers find difficult to learn for an example of backwards wording seems only to prove my point. The comparison of writing equations backwards to backwards wording was only an analogy. More relevant, modern Korean is written left to right like English, yet you will not find Koreans writing equations backwards.

The bottom line is RPN is fun, often useful and a great brain exercise, but its mythical status, justifiable in the past when there was little competition, is a chimera today.

[Maximilian Hohmann]

Hello!

(12-18-2023 07:56 AM)carey Wrote:  ... and probably helps keeps a mind sharp into old age by engaging it to perform tasks that modern calculators can now perform on their own.

This is the main advantage of RPN over everything else, calculator-wise, in my eyes too and beats crosswords and sudokus big time! I enjoy trying my luck at Valentin's calculator puzzles or those from the conferences posted here (usually weeks later and with little success, therefore I don't post results...). Most of them would be trivial to solve on a computer using any programming language or a modern calculator with CAS or a Rasperry Pi that comes with Mathematica, therefore these solutions are forbidden.
But it is RPN and the very limited number of storage registers and program steps that turns them into a big challenge. Or, similar to how President Kennedy once phrased it: "We chose to solve our puzzles using RPN - not because it is easy but because it is hard!" :-)

Regards
Max (An algebraic person through and through, unafraid of parentheses and the equals sign...)

[ijabbott]

(12-17-2023 09:33 PM)dm319 Wrote:  I don't think it's that hard. What helps is being able to see most of the stack. Then the function you press is simply applied to either the bottom number or the bottom two numbers. At the risk of kicking off an argument, I think the NSTK mode without the automatic stack lift is more intuitive to new users.

Indeed, a four-level stack is an artifice that has no place in teaching or learning mathematics. The NSTK mode opens other avenues, such as thinking about how computers work internally.

[rprosperi]

(12-18-2023 05:28 AM)Roberto Volpi Wrote:  Half a century after, hardware is more powerful, advanced and far cheaper, so it is hardly needed, especially if you take into account that the cheapest RPN calculator costs more than USD 100 and you cannot exactly buy it at the neighborhood's shop.

I don't disagree with most of your points, however 3 of the 4 current HP RPN Calculator models sell for well under $100, ranging from $69-89. This is higher than most comparable models, but they're also of much higher quality and feel, and typically will last much longer.

[dm319]

(12-18-2023 11:00 AM)carey Wrote:  The bottom line is RPN is fun, often useful and a great brain exercise, but its mythical status, justifiable in the past when there was little competition, is a chimera today.

This morning I arrived at work with a range warning in my car - I had 15% battery left. I knew I needed a bit of a top up to get back home, but the work electric chargers are a little pricey. So if I plugged it in, when would I have to go on my app to stop the charging?

I know some numbers - 60km to get home, the car is running at around 30kwh/100km at the moment (yes I know not good!), 15% of a 64.7kwh battery left, and the app says I'm charging at 11kW. As I walked up to my office, I pulled out my phone with free42, and had a timer running for 55 mins before I got there.

If anyone can visualise that formula in their mind, and know how many preceding brackets to put into their algebraic calculator, then I salute you. It's not how my mind works, which is to put the numbers in my line of sight and poke them until they tell me what I want.

Also, I grew up on algebraic - in fact I never saw an RPN until I ordered a 12C off ebay much later in my adult life - i.e. RPN was a choice for me rather than a habit.

[Maximilian Hohmann]

Hello!

(12-18-2023 01:21 PM)rprosperi Wrote:  I don't disagree with most of your points, however 3 of the 4 current HP RPN Calculator models sell for well under $100, ranging from $69-89.

Yes, but these are the three financial calculators (HP-12C, 12C Platinum and 17BII+), hardly suitable for normal school but rather for business school. All the ones that could be useful for mathematics and physics are way over 100$/Euros.

Regards
Max

[Maximilian Hohmann]

Hello!

(12-18-2023 01:50 PM)dm319 Wrote:  If anyone can visualise that formula in their mind, and know how many preceding brackets to put into their algebraic calculator, then I salute you.

The day I need a calculator, with or without brackets, to figure out how many minutes my car needs to be charged to take me home, I will hand in my driving license and, more importantly, my ATPL. And if I want to use my phone to figure it out there is an app that came with the car, which shows me the charging state and the remaining range in real time :-)

Regards
Max

[bxparks]

(12-18-2023 12:08 PM)ijabbott Wrote:  Indeed, a four-level stack is an artifice that has no place in teaching or learning mathematics. The NSTK mode opens other avenues, such as thinking about how computers work internally.

I find the traditional 4-level RPN stack works for me because I can keep track of 4 things in my head pretty easily. There are only 24 ways to arrange 4 things. Beyond 4 levels, there is a combinatorial explosion, and it makes programming in a stack-based language like Forth frustrating. (RPL seems very similar to Forth as far as I can tell.) The resulting code is hard to read and hard to maintain for other people, including myself in 6 months. I don't enjoy doing stack juggling, when I know that the computer can do that far better and faster. I'm in the ironic situation where I love RPN calculators, but I hate stack-based programming.

[compsystems]

RPN as such for calculators is useful, but within a language it can still be very useful for teaching algorithmic logic. We only need, for example, for RPL to be available as a plugin for Visual Studio Code, since it is the most used code editor today.

[rprosperi]

(12-18-2023 01:57 PM)Maximilian Hohmann Wrote:  Hello!

(12-18-2023 01:21 PM)rprosperi Wrote:  I don't disagree with most of your points, however 3 of the 4 current HP RPN Calculator models sell for well under $100, ranging from $69-89.

Yes, but these are the three financial calculators (HP-12C, 12C Platinum and 17BII+), hardly suitable for normal school but rather for business school. All the ones that could be useful for mathematics and physics are way over 100$/Euros.

Regards
Max

The OP said nothing about math or physics, so my reply is still correct.

Also, probably most students in school today are not engineers, math or physics students, so these models are likely suitable for most of them, for real life that is. But not being certain exact models from TI or Casio, I agree that makes them utterly unsuitable for use in high school math classes.

And who's to blame for that? Neither TI/Casio, nor the various Governments, IMHO. It's lazy Math teachers, or maybe more clearly, lazy math teachers in the 90s and 2000's when it was easier for them to use what was used last year, rather than actually think and try using newer tools and devices. After 20+ years, all the authors had incorporated the old devices into their textbooks and now they're so entrenched even the device manufacturers in question can no longer innovate and introduce new models to move the teaching technology ahead. I've spoken with dozens of math teachers and not one of them felt it was reasonably possible to introduce new machines into their curriculum, fearing pushback from other teachers that don't want the boat rocked, etc. It's sad....

[dm319]

(12-18-2023 02:04 PM)Maximilian Hohmann Wrote:  I will hand in my driving license

I'm not sure exactly what you're saying is your preferred option, but my point is that for day to day calculations, which are not that dissimilar in some respects to the calculations needed for some of the sciences, RPN is easier for me.

(12-18-2023 03:18 PM)bxparks Wrote:  I find the traditional 4-level RPN stack works for me because I can keep track of 4 things in my head

I think I'd agree, and I'd struggle with NSTK without being able to see several lines.

You have reminded me that there is now a $15 RPN scientific calculator available to children (and adults) these days!

[Maximilian Hohmann]

Hello!

(12-18-2023 10:53 PM)rprosperi Wrote:  And who's to blame for that? Neither TI/Casio, nor the various Governments, IMHO.

In my view, HP alone is to blame because of their pricing policy. When I was at school, there were some parents both of which were medical doctors and who could easily afford to buy their single child an HP-67. But there were a lot more single moms with three children who struggled to buy their children Ti-30s. And because most schools had an equal opportunity policy they settled for the cheapest calculator standard that would still be useful in class. HP lost the battle for the education market right from the beginning and with it RPN was lost for the masses...

Regards
Max

[John Garza (3665)]

(12-18-2023 11:35 PM)Maximilian Hohmann Wrote:  In my view, HP alone is to blame because of their pricing policy.

Max, it's not the pricing policy, per se. It is the high quality of product that creates a high price point. Add to that the early models were assembled in a developed country (USA), instead of exploiting cheap overseas labor. And also the whole 'consumer electronics' market was new to HP. They sold their equipment primarily to science and engineering companies directly. It's common knowledge that mil-spec, or even industrial grade equipment is more expensive than consumer grade. Still, I'm happy that the early HP models remain icons of engineering quality.

And I'll say it again, the education system is to blame. You do NOT specify the actual products. You only specify the REQUIREMENTS of the product. Other than the appearance of brand favoritism and perhaps under the table bribery, choosing a tool is a personal decision. I would never tolerate someone telling me or my kids what specific machine to use. That's like telling kids what brand of pencil to buy. Crazy.

-J

Calcs:
[HP: 9100B/9815A/35/45/55/80/70/65/67/67T/97/97S/91/92/21/22/
27/25/25C/25E/29C/19C/10/31E/32E/33C/34C/37E/38C/41CX/71B/
200LX/28S/19BII/12C/15C/32SII/33S/35S/48SX/48GX/50G/Prime]
[TI: 2550/50/50A/51/51A/30/40/MBA/55/52/56/57/58/58C/59/60/66]
[SM: DM32/DM42]
Pencil:
[Pentel: PS315 loaded with Film Lead for marking magnetic cards]




-J

[Valentin Albillo]

.
Hi, all, (all highlighting is mine)

(12-19-2023 12:10 AM)John Garza (3665) Wrote:  

(12-18-2023 11:35 PM)Maximilian Hohmann Wrote:  In my view, HP alone is to blame because of their pricing policy.

Max, it's not the pricing policy, per se. It is the high quality of product that creates a high price point.

The original HP-12C is surely one of those high quality products from HP, right ?

Quoting William M. Kahan:

"The HP-12C financial calculator, you see the list price, initially $120 ? And these guys were going to sell it to you for $90. But it only cost HP something less than $15 to make."

So you see, they were selling it for more than 600% its actual cost. This probably applies to most other classic models as well.

V.

[John Garza (3665)]

By the time the Voyagers came around, HP was learning how to make consumer electronics. The Classics (12C is not a 'Classic') were high quality and expensive to make. The goal in consumer electronics was to reduce cost to allow a reduction in price which should allow higher sales volume as consumers are price sensitive. HP by then was known for high prices, so the reduction was moderate to get a good profit and not destroy the brand image (yes there are many variables in a company's pricing strategy!). If they go rock bottom they could lose their following and sales could plummet. Some companies even go as far as starting another company to sell the 'lesser' products under a different name.

The fist foray into cost reduction - the Woodstocks had quality and design problems, the next, the Spice series, even more. The Voyagers finally achieved good quality. It took HP a long time to get it right. Consumer electronics was not their business until calculators came along.

Another thing to do is compare the numbers among the different companies at the time. HP sold fewer units, but with a higher profit margin, they could still be competitive. Other brands like TI and Casio sold more units but at a cheaper price. Would make an interesting business case study for an MBA class.

-J

[avsebastian]

(12-17-2023 06:50 AM)Matt Agajanian Wrote:  Hi all.

I’m gonna say yes. Since there’s SwissMicros, Panamatik, the developers of WP34S.

In addition, for the smartphone, there're Cuvee, the GO-2x series, i41CX. Plus, our beloved 15C has been resurrected.

As an added support, the HP-12C remains the pinnacle of financial calculators and has many upon many professionals using them and they're RPN proficient. Thus, I would think RPN survives to this day.

Yeah the direct formula entry systems from Casio, TI, Sharp, and Canon represent the most direct means to enter mathematical expression which seems to put RPN in a retirement hone. And yes, these manufacturers thrive on the educational market. Thus seeming to make RPN calculators fall off the popularity charts. BUT, there are those of us old enough to remember, experience and utilize RPN calculators from their earliest days. Also, there are those of us who've taught our kids how to use these RPN/HP beauties.

I'm thinking that the above paragraphs make a strong case that RPN and RPN calculators are still relevant.

RPN or RPL?

For me, RPN is dead.
The case of RPL, is different

On the topic of the HP 12C (I bought an old Brazilian calculator), please see the forums of the students who must take the CFA exam (they only have 2 options: HP 12C and its variants; and the TI BA II plus and variants ). They hate the HP calculator, especially the use of the RPN. They prefer the Texas Instruments calculator. And Probably , new professional (since 2005, prefer algebraics calculators) Incredibly, Moravia/ Royal cannot certify the HP 10BII+, which is algebraic, easier to use.

I even think that Moravia should resurrect the HP 30b, and repair all its bugs. It was a great calculator being RPN and algebraic at the same time.

[Thomas Klemm]

(12-18-2023 01:50 PM)dm319 Wrote:  I know some numbers - 60km to get home, the car is running at around 30kwh/100km at the moment (yes I know not good!), 15% of a 64.7kwh battery left, and the app says I'm charging at 11kW. As I walked up to my office, I pulled out my phone with free42, and had a timer running for 55 mins before I got there.

If anyone can visualise that formula in their mind, and know how many preceding brackets to put into their algebraic calculator, then I salute you.

\[
\frac{\frac{30 \text{kWh}}{100 \text{km}} 60 \text{km} - \frac{15}{100} 64.7 \text{kWh}}{11 \text{kW}} \approx 0.75409 \text{h}
\]

I would enter this as:

(30/100*60-15/100*64.7)/11

Not too many parentheses, I guess.

However if I want to use a fancy Lisp like Clojure I'd use:

(/ (- (* (/ 30 100) 60) (* (/ 15 100) 64.7)) 11)
0.754090909090909

Don't be imitated by the many parentheses.
In the Replete app the results are stored in *1, *2, *3.
So you can do it a bit similar to how you would do that with RPN:

(* (/ 30 100) 60)
18

(* (/ 15 100) 64.7)
9.705

(- *2 *1)
8.295

(/ *1 11)
0.754090909090909

First I wondered how you ended up with 55 minutes because my result is only 45' 15".

But then I noticed that you wrote:

(12-18-2023 01:50 PM)dm319 Wrote:  I knew I needed a bit of a top up to get back home (…)

Thus I assume that our results agree.

[Thomas Klemm]

(12-19-2023 02:51 AM)avsebastian Wrote:  They hate the HP calculator, especially the use of the RPN.

They should be grateful. We all know it helps building character.

[Thomas Klemm]

(12-18-2023 07:49 PM)compsystems Wrote:  We only need, for example, for RPL to be available as a plugin for Visual Studio Code, since it is the most used code editor today.

Emacs has calc built-in which is inspired by the HP-48.
GNU Calc Reference Card

[Siegfried]

(12-18-2023 07:56 AM)carey Wrote:  None of this detracts from RPN being fun, has nice workflow with chained calculations (though no longer unique since the Ans key and Ans() commands) and probably helps keeps a mind sharp into old age by engaging it to perform tasks that modern calculators can now perform on their own.

My daughter recently got a TI-30 X Plus for school. I found it a bit strange that using the ans key displays „ans“ rather than the result of the last calculation but other than that the user interface showing all your previous calculations and with a variable browser has its merits, too. I won‘t defect from RPN but being able to see past steps and results might become useful as my memory fades.

This school doesn’t require another (TI) calculator in senior high, they do all the graphing stuff with GeoGebra.

There seems to be at least one evening high school for adults in the area that requires HP Primes as these regularly come up for sale after graduation. I bought one but it was set to algebraic mode.