This October...

[calc_owl]

...I should be getting my SwissMicros DM32 in the mail! I have the parcel tracking number from Swiss Post and it is estimating a delivery around the middle of the month. That is all depending on how long customs takes to get the device through. I've already paid the duty through Amazon and that usually covers any duty at at the border, but that doesn't mean that it gets through the processing facilities in any sort of timely manner.

In the meantime I have Youtube videos on the calculator itself and on RPN calculation. But my favourite videos are the ones that try and pump you up about the calculator, cool calculators, for ummm cool people?

Watch on YouTube

I have been diving into RPN more with an app for the Ti-83 Plus and 84 Plus that effectively turns the whole device into an RPN calculator styled on the HP42S. Here is the link on Cemetech if you are interested on trying it out on your own device. I am going to be writing some posts about RPN and I'll be using screenshots from this app. Also once I get the DM32, from that device as well as I learn more about it and RPN.


For now, I'll wait. And tinker. And post, now that I have this journal.

Is there something you are looking forward to this Fall?

Comments

[sushiflop]

What exactly is RPN? From your post I deduce it is a coding language but I feel I might be missing some nuances there.

Also, I'm going to be taking some vacation time and going to 2 haunted houses with a friend visiting from across the USA. It's my first time in years going to a haunted house so I think it's going to be a lot of fun!

[calc_owl]

I am going to be writing more about it as time goes on but it is simply a different way of entering calculations into a calculator. If you think of a normal calculator you use algebriac or in-line notation where the operator (plus, minus, divide, multiply, square, etc) goes in between whatever oprands (numbers, inputs) you are using. With RPN or post-fix notation the inputs come first and the operator at the end. This is a form of coding language if you accurately consider how you use your calculator as a form of coding. RPN is actually more like how the processor is actually working at the base level. If you think about it a computer cannot take 1 + 1 and give you two. It would need to take the first 1, put it in a storage area, and the second 1, put it in a different storage area and then recall the two storage areas and compute the requested operator, in this case plus. RPN is just that except you as a human does the inputs.

So you have a stack (and again, I'll have more later but you can see the four 0 stacked in the image from my post). If you wanted to add 1 + 1 in RPN you would put 1 in press enter to put it on the stack which would free up the input line again for another 1. With the two 1s on the stack you would just press the plus button and the calculator would perform the calculation. No need for an = key.

A lot of people prefer RPN because it removes any conflicts with inproper bracket placement in calculations. With Mathprint and other visual aids now in most calculators, this is kind of moot now but you used to have to pay very careful attention to where and how brackets were used especially in complex engineering and scientific formulas. RPN eliminates that and for many engineers and scientists it makes the calculator an extension of how they are already think about math and numbers. Again with the 1 + 1, it is more efficient and clear to think about it as 1 and 1 add. Especially if you want to divide the whole thing by something next. You would go 1 and 1 add 2 divide. No need for brackets or order of solviing.

[loganberrybunny]

A long time ago, I had a Jupiter Ace, as far as I know the only commercially available microcomputer of its era (the early 1980s) that had Forth instead of BASIC as its built-in programming language. Forth uses a stack to pass parameters, so arithmetic is done in the RPN way:

2 2 + . will return 4.

: squares 11 1 do i dup * . loop ; will define a word (Forth-speak for function) that will print out the first ten square numbers.

It's years and years since I had the Ace, so I'm horribly rusty on RPN syntax, but it's nice to see it exists on calculators too. :)

[calc_owl]

The . at the end seems a little clunky. But that was also part of the experience with Forth. Isn't it wild how this stuff gets stored in our brains and we are able to recall it?

I know that RPN was popular on professional scientific calculcators in the 70s, 80s and early 90s. Before the screens were large enough and detailed enough to have an input line to put fancy algebra expressions (and the rise of the personal computer, where most maths get done nowadays). There are a few still out there and always people making programs to turn non-RPN calculators into RPN ones.

I wish it was something they taught in school early, especially linked with coding. The jury is still out and which is better, I don't think it is a matter of better though, just what works for your own workflow and way of thinking.

[loganberrybunny]

The . at the end seems a little clunky.

That's to print out what's on the stack, rather than COBOL-style pernickety punctuation. It's perfectly valid Forth to write 2 2 + but you won't get the result on your screen if you leave out the dot! :P