I wasn't asking about the trial (which I came to know only on seeing this reply) or why it was so.
It’s a really good engr/sci calc for iOS/MacOS. Unless I’m going for a specific need (Gotta have this exact HP compatibility, need funky plotting, etc) this is what I reach for first.
I got used to using "dc" (rpn desktop calculator) at the command line on unixy things or python. In real life it's an HP35s. For phone I just ask Siri because I only use it for trivial stuff and it's easier than navigating the input errors on a touch screen.
So for me, a proper calculator, a tool you master to augment your napkin math, should focus on this:
- Keyboard. Absolutely lowest number of keypresses to enter the problem; the thing that is totally lacking in most non-classic calculators. I can't stress this enough. I should be able to enter all those sophisticated functions without typing their full name and parens. Simple ODEs/integrals should be at my fingertips. I should be able to quickly repeat binary operators for a different argument, and 1/x anything I have on the screen without breaking the flow (on-the-fly calculation often conflicts with that). And many more tricks classic calculators had, which are missing from most modern apps.
- Startup time. It should pop up in less than 100ms. Modern phones and computers are very good at that, but apps sometimes aren't.
- Correctness! It sounds silly, but you can't trust most math applications out there, calculators are surprisingly unreliable, even for simple arithmetic and trigonometry calculations. What math libraries did you use? Or why should I trust your results in general?
1. The website is terrible at articulating why this is interesting.
2. The user interface is quite buggy.
3. The user interface is quite beautiful.
4. It’s not obvious exactly what the capabilities are or how do they fit together. E.g. graphing seems completely inscrutable.
5. Despite all this it seems very cool and quite distinct from most of the existing calculators out there. It just isn’t quite mature.
6. The free trial model is going to be a problem. I can’t use this app regularly until it’s a bit more polished, but I am guessing I won’t be able to try it again when it is improvised.
Numerical^2 also has a nice landscape mode that shows all the operations; it slides the keyboard like Euclid does to show them in portrait mode.
Odd, by the way, that the iOS version is more expensive than the macOS version...
For anything beyond that, Sagemath and Jupyter.
1) it seems quite unintuitive to not be able to drag the cursor along the calculation and to rely on the arrow keys
2) the list is functions is long and not having text search (much like excel) is a major pain for usability. I don’t want to be scrolling ages to find the average function.
3) I also hope that the “commonly used” function list is adaptive, so it adapts to the functions that are used most often by the user
Downloading and figuring out is just too much trouble.
There is only a slideshow with the features and a button “Purchase Euclid”.