i have a(nother) stupid question

General discussion about calculators, SwissMicros or otherwise
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gteague
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i have a(nother) stupid question

Post by gteague »

i've used hp calculators since the hp-55 back in 1975, but not exclusively. i like calculators in general and tend to sample nearly all the ones that offer something new over the years and i'd hate to try to list all that i've owned and own even now even though i had to re-buy a dozen or so on ebay.

i'm not a heavy user in regards to actually needing one for advanced math solutions. if there's a more automated way to do it i usually opt for an iphone app. for example, several years ago 'homework' apps starting appearing where you could simply frame a written equation on the screen and the app would calculate the solution and every single step of the solution. to me, that's nearly indistinguishable from magick!

but i love math and will spend hours going through textbooks and science books and working the equations which are easy enough for me. so i have a lot of keyboard time built up. i completely lack the math and programming know-how to argue about how rpn works although i've never found it improves any aspect of math solutions and saving a keystroke every once in awhile is not really a selling point if the burden is put on the user in saving that keystroke or two. and i've never found a single use for the fabled 'stack' as it only shows results, not what you did to get those results which would let you keep your place in an equation.

as i get older and start losing my own memory stack, i realize the severe burden rpn puts on the user despite every single article i've ever read which claims the opposite. if the equation will exceed the 4-level stack meaning you can't work it from left to right is when the problem is most apparent. you start with an inside parenthetical expression and work outwards. and this mean that in your meatspace stack you must keep a list of what operations you've performed already and what order you need to perform the remaining ones in. and without really any feedback that you can get with other calculators such as the hp48 onwards which allow you to see the actual steps you're taking. some of my calculators even 'print' the equation as you're typing it in and you can simply compare the display with the written version.

to me, the algebraic method is by far the most easy and intuitive. on 90% of equations you simply work from left to right and type a parenthesis whenever there's one on the printed page. how much more easy and intuitive could it be? and i know some algebraic calculators have limits on how many parentheses you can have open, but many do not.

so .... i've said all that to say that if the dm42 could work in algebraic mode it would pretty well be the most perfect calculator i've ever owned. right beside it on the desk i have my very favorite hp of all time--the hp-27s and it's there because if an equation is overly complicated i have to revert to algebraic because i just can't remember all the housekeeping stuff in rpn.

is there a way for someone to write a program which would let me ditch the hp-27? several calculators i own will work in both systems including the prime (i think?) and maybe the 27s, the 20s, the 22s (i'm unsure on these 3), but i think the new version of the hp-35 will although i intensely dislike it's form factor.

anyone know of such a program which could run on the dm42? thanks! /guy
Last edited by gteague on Mon Oct 19, 2020 3:40 pm, edited 1 time in total.
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grsbanks
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Re: i have a(nother) stupid question

Post by grsbanks »

I think the whole point of the DM42 and HP scientifics in general is that (with very few exceptions) they DON'T do algebraic entry. While it is also a question of personal preference, RPN is demonstrably more efficient and "safer" than algebraic entry. More efficient in that evaluating the same expression requires fewer keystrokes than algebraic. "Safer" because the user has to understand the expression being evaluated and therefore can see potentially incorrect intermediate results when they happen in the event of something being keyed in wrong rather than just getting an incorrect answer at the end.

A few HP machines have both RPN and algebraic. The 35S is one such model, the 49G/48gII/49g+/50g is another family of such models, but they are better suited for RPN operation. The first thing that most people do with a 49G is switch it into RPN mode because the whole stack method of operation that RPL is based on just works better with it (or bin it because they don't like the colour scheme...). The HP Prime is a different beast altogether, geared more towards the student market, and its entry mode is primarily algebraic with RPN as a poorly thought-through bolt-on.

The DM42 is based on the HP-42S, which was resolutely RPN. It runs Thomas Okken's Free42 Decimal under the hood, which is open source and therefore free for anyone to change to their own taste. In its 16 years of existence I don't think anyone has attempted to make it algebraic because if they did, it would no longer be a simulation of the HP-42S. The software model of the DM42 is also such that anyone can take the operating system DMCP and create their own program to run their machine as they see fit, but nobody has created an algebraic calculator with it. An RPN fork is under active development.
There are only 10 kinds of people in the world: those who understand binary and those who do not.
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gteague
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Re: i have a(nother) stupid question

Post by gteague »

your points are irrefutable, but the inevitability of losing some mental acuteness and short term memory as you age is also a reality. i guess i didn't realize how much work rpn was making me do. back when i was working as a network analyst and troubleshooting networks on the fly it was nothing for me to keep 4-6 ip addresses and a few phone numbers all in instant recall memory. sadly, those days are now gone and i have to resort to a pen and notepad for any short term memory needs.

the thing i've noticed about hp calculators is that when i found a hp i loved for a particular feature or two, hp never agreed with me by carrying that feature forward. i can't remember all of them, but the 200lx had the best calculating engine of any calculator of any type and someone broke out the calc.exe program and i used it for decades when i was forced to run windows and i mourn the fact i can't run it on the mac and i'd have to install an older windows image (xp, most likely) to my emulator which isn't worth it just to run that one program.

and one of the best compromises in providing both rpn and algebraic was the ?28s? ?29x? (the one that folded vertically and was a huge pain to use) where it was native rpn, but all you had to do was prefix an algebraic expression with a ' and then hit an 'input' key at the end i think. i believe one of the hp4x models also used this method which was brilliant in that it took nothing away from rpn calculations but added the ability to directly type in an equation from a book, for example. shame that the form factor with the flopping panel was so awkward to use.

many thanks for your thoughtful reply. /guy
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Thomas Okken
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Re: i have a(nother) stupid question

Post by Thomas Okken »

For what it's worth, I am working on a commercial version of Free42 that will include 27S-style equation support.
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gteague
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Re: i have a(nother) stupid question

Post by gteague »

Thomas Okken wrote:
Mon Oct 19, 2020 4:13 pm
For what it's worth, I am working on a commercial version of Free42 that will include 27S-style equation support.
wow--what fantastic news! you have instantly become my new best friend. :) :) :) /guy
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rprosperi
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Re: i have a(nother) stupid question

Post by rprosperi »

gteague wrote:
Mon Oct 19, 2020 3:59 pm
and one of the best compromises in providing both rpn and algebraic was the ?28s? ?29x? (the one that folded vertically and was a huge pain to use) where it was native rpn, but all you had to do was prefix an algebraic expression with a ' and then hit an 'input' key at the end i think. i believe one of the hp4x models also used this method which was brilliant in that it took nothing away from rpn calculations but added the ability to directly type in an equation from a book, for example. shame that the form factor with the flopping panel was so awkward to use.
You're thinking of the HP-28C and later HP-28S (vertical, folding design)

The HP-48S/SX/G/GX/G+, the HP-49g, and the 48GII, 49G+ and 50g all support RPL with algebraic support (you can use algebraic equations such as 'A*x^2 -B*X +C' easily mixed in with RPN-style stack use.

The cheapest of these is usually the 48s, which can be had on eBay often for as little as $30 if you're patient. Here's one listed for $31.50:

https://www.ebay.com/itm/HEWLETT-PACKAR ... 4362662123

Although this machine does an awful lot more than what you want, and may be a bit confusing coming from a 42S, it's cheap enough to try out, to see if it fits your needs.
--bob p

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gteague
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Re: i have a(nother) stupid question

Post by gteague »

rprosperi wrote:
Mon Oct 19, 2020 4:50 pm
gteague wrote:
Mon Oct 19, 2020 3:59 pm
and one of the best compromises in providing both rpn and algebraic was the ?28s? ?29x? (the one that folded vertically and was a huge pain to use) where it was native rpn, but all you had to do was prefix an algebraic expression with a ' and then hit an 'input' key at the end i think. i believe one of the hp4x models also used this method which was brilliant in that it took nothing away from rpn calculations but added the ability to directly type in an equation from a book, for example. shame that the form factor with the flopping panel was so awkward to use.
You're thinking of the HP-28C and later HP-28S (vertical, folding design)

The HP-48S/SX/G/GX/G+, the HP-49g, and the 48GII, 49G+ and 50g all support RPL with algebraic support (you can use algebraic equations such as 'A*x^2 -B*X +C' easily mixed in with RPN-style stack use.

The cheapest of these is usually the 48s, which can be had on eBay often for as little as $30 if you're patient. Here's one listed for $31.50:

https://www.ebay.com/itm/HEWLETT-PACKAR ... 4362662123

Although this machine does an awful lot more than what you want, and may be a bit confusing coming from a 42S, it's cheap enough to try out, to see if it fits your needs.
i remember that 48--i used one of these for a year or two long ago. i remember it pretty fondly except i disliked how big it was compared to the hp calculators which came before it--no chance of it fitting into a shirt pocket. and indeed it did have the same algebraic method that the 28s did. sadly, my hp48 (and a dozen other calculators) got lost in a move 8 years ago and while i've replaced some of them, i didn't replace the 48s, but now you've given me the itch to re-explore it. i powered up the 28s the other day to make sure it still worked, but the folding panel frustrated me. /guy
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gteague
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Re: i have a(nother) stupid question

Post by gteague »

well, this thread cost me money! :) i got to remembering how much i'd liked the 48g (except for the display. imo, no hp calculator in decades has had a decent display--how hp could get this so wrong over so long a period baffles me) and when i tested the 28c the other day i realized how much i liked having the ability to shift to algebraic quickly and easily for the occasional equation where it made more sense. and your ebay link sealed my fate because i started browsing and found a 48g which had been upgraded with a black-on-grey display and 128k ram, although that latter didn't much matter.

perhaps in future i could wish for a swissmicros hp-48x and that would provide for my algebraic wish as i don't think the rumored ?hp-43? is going to offer it. i don't think the wps-34 does either.
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Re: i have a(nother) stupid question

Post by toml_12953 »

Thomas Okken wrote:
Mon Oct 19, 2020 4:13 pm
For what it's worth, I am working on a commercial version of Free42 that will include 27S-style equation support.
Will you be changing the name? Here's a suggestion: "Free"42 :)
Tom L

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bernouilli
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Re: i have a(nother) stupid question

Post by bernouilli »

toml_12953 wrote:
Mon Oct 19, 2020 9:46 pm
Thomas Okken wrote:
Mon Oct 19, 2020 4:13 pm
For what it's worth, I am working on a commercial version of Free42 that will include 27S-style equation support.
Will you be changing the name? Here's a suggestion: "Free"42 :)
Or 'Free'42
Last edited by bernouilli on Tue Oct 20, 2020 10:10 am, edited 1 time in total.
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