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TL;DR PEDMAS is bullshit If you look at the internal state of the typical physical calculate it's a beautifully simple machine that tries to catch the balance
by quesomaster9000 2y ago
TL;DR PEDMAS is bullshit
If you look at the internal state of the typical physical calculate it's a beautifully simple machine that tries to catch the balance between RPN and logic... except it has stupid nonsensical human rules interjected.
So, every time this article where points out "actually it's more complicated than it seems" is where historically somebody has made deliberate design decisions to do it 'the dumb way' even though it adds complexity, to force something unnaturally.
And what you end up with is something that's half intuitive, it's in between the two systems, but it's more complicated than it needs to be.
Please, I would much prefer device for RPN calculation, that follows consistent logic, rather than silly imposed rules.
4+7*3 etc.
or 4 7 + 3 * =
Where the latter is much closer to what we do in our heads and conceptually think about it.
- ziml77 2y agoI don't see how PEMDAS is relevant for a 4 function calculator. The implicit equals when you press an operator means that they always work sequentially rather than jumping around.
- airstrike 2y agoI think they're saying it's bullshit because if we used (the superior) RPN across the board, we wouldn't need PEMDAS at all
- Jaxan 2y agoYou also don’t need pedmas if you just use parentheses to disambiguate your expressions. That’s what mathematicians would do.
- ziddoap 2y ago>RPN "Reverse Polish notation", I think, for people like me who aren't familiar with the acronym.
- nejsjsjsbsb 2y agoYou thank!
- layer8 2y ago!ęjukęizD
- mattkrause 2y agoIt really should stand for “Notation: Polish (Reversed).”
- x3n0ph3n3 2y agoRPN requires implementing a stack on silicon, which adds even more complexity and uncertainty. How deep can the stack go? What happens to your calculation when you exceed its capacity?
- Pinus 2y agoClassic HP calculators used a fixed stack of four registers. In practice, you can do quite complicated things before you blow that up. Especially if you understand how the mechanism works, and plan ahead a bit. Besides, infix-style calculators also seem to use a stack to handle operator precedence — if you squint a bit at the manual, you can usually see the shunting-yard algorithm at work behind the curtains. Actually, some really early HP:s (only desktops, though, like the 9100) used a three-level “stack”, which I put in quotes, because it relied on the user to shift the registers up and down as needed. But they cheated a bit and displayed all three registers, so that the user could see what was where.
- roelschroeven 2y ago> Besides, infix-style calculators also seem to use a stack to handle operator precedence True, but simple calculators, even ones a bit more advanced than the one in the article (e.g. with a sqrt and/or % key) don't handle operator precedence. I'm not sure it's even correct to call them infix calculators, for that reason. They simply work sequentially; no stack needed.
- kazinator 2y agoCompared to what? RPN allows for complex, nested expressions for which infix requires nested parentheses. Nesting requires a stack, the same way.
- dlcarrier 2y agoMy grandma, born in the 30's, isn't any good at computers or technology in general, and has trouble operating even the simplest TV remotes and cordless phones. One thing she can operate is her HP-12C calculator. At the time of it's initial release, someone taught her how to use it, knowing that the RPN interface would be much easier to teach her than infix notation that was equally popular at the time. She never figured out infix notation, at least for more than single operations. Pretty much everything uses infix notation now a days, so that's what everyone learns first, making RPN an additional skill that usually gets passed by. It's interesting to learn that there was a time when a calculators interface was a toss-up, and some people learned RPN because it was the easiest to learn, as opposed to it now being an additional skill that would conflict with earlier experience.
- kazinator 2y agoInfix isn't "nowadays". It's been with us for hundreds of years. Moreover infix constructs occur in natural languages. You know "apples and oranges". Someone born in 1930s would have learned infix arithmetic in school just like somebody born in the 2010s. Cannot work a remote, but can use RPN on an HP calculator? That sounds AI generated.
- dlcarrier 2y agoIt's nowadays that everyone learns infix calculator input methods as children. In the 40's they sure weren't learning any calculator user interfaces. It's stateful and modal interfaces that are an extra step she never figured out, and some TV remotes require different modes for different functions, especially for different equipment. CEC has solved this on modern TVs, but it used to be common to have control the VCR/DVD player by selecting a mode, then control the TV by selecting another mode, and even without the other equipment, she could accidentally get the remote in the wrong mode. She never got the hang of the states that are possible in a calculator with an interface using infix notation, so instead of using parentheses or order of operation, if she didn't have access to an RPN calculator, she'd write down results and enter them back as needed, to only have one operation in progress at a time, in the calculator.
- jwagenet 2y agoAs far as I can tell, PEMDAS has nothing to do with the calculator itself and is just the rules we’ve arrived at for how to read and write equations in a consistent way.