Yeah I agree, plus some touch screens are terrible quality, like the iPod Touch that I've got, where if you try to click a link it always clicks the one right next to it even if zoomed in to the point where the link text takes 25% of the screen height.

Also I think such screen is disallowed in even more tests than the CAS itself, right?

One nice thing, however, is if one set of buttons was layed out so if you press ALPHA you have access to letters in alphabetical order, and if you want to code, you can rotate the calc vertically so you can type with both hands. Of course the calc might be best if used in such position often, though, since you see more equations at once. You could have the option to turn it horizontaally for gaming and other 16:9 or 4:3 stuff

Writing a CAS is a big job. I still think you're better off porting something like Sage, whose source, by the way, is 319 MB. It's totally legal to do so, and it would be far easier than making one yourself. It would also be extendable (internal package system), and have a much larger support base thanks to the sage community.

The english equivalent is "Putting the cart before the horse" which, as far as I can tell is a pretty direct translation, but it retains its meaning well enough.

I want go for CAS for scratch and i explained some pages before.

There is no engine yet that is able to do what i'm looking for.

I've watched 2 code of 2 cas engine in detail. But The problem is from the start of their projects. It's about limited variables & types. They use only floats & complex types. For me that's a problem. ( we can't upgrade of change the core i've already read the code ).

I aim to do C++ lib for the calc too. So in your code, you'll able to use any complex function & compile it. And that can be portable because it's C++.

I'm thinking about functions that are inspired from matlab, and some are from mapple.

I know it's a lot of work, but i think it's better to code what you need, instead of using what you don't need.

And the CAS system can be done after the basic calc lib.


And all CAS system were written from scratch, so a day you have to start ...


>Lionel Debroux

I'm not CS engineer too. But almost electronic one, i need one more year.
I know what i'm able to do, and what it's possible to do in 3 years. i know i can do it even alone but i will need more time.
Why I see criticism and no help ? It's possible to build a small embded system with linux easily. There is a lot of work already done and small linux distrib to download on the website of the seller of the chip.

Hardware it's a lego game, so it's not a real problem. The cost and the how to build can be difficult but doable if you don't start crazy.

Without writing a CAS, this project has not interest. Buy a TI - 89 and do quadratic regressions with it, ...

When you'll become an engineer, i hope so, you'll see even a CAS CX is "stupid" because you can't add specific details to the equations.

I want to override thoses limits, the only way is to build a better code. If you don't want help, no problem. 

Without writing a CAS, this project has not interest. Buy a TI - 89 and do quadratic regressions with it, ...

Without writing a CAS it's a useless project.

Without full-spec hardware (you'll certainly make mistakes, as I fully admittedly would, because such is human nature), a bootloader which boots, a Linux which boots, all of which are prerequisites to the CAS running on your platform, a CAS specific to your platform is even more of a useless project
Having that CAS engine, possessing the capabilities you need, running on other platforms until it runs on yours (if ever), is, in itself, a worthwhile project.

It's possible to build a small embded system with linux easily.

There's a huge difference between porting Linux onto an existing, properly designed hardware that actually works (such as the Nspire platform), and making one's own complicated platform in order to port a bootloader + Linux + userspace (even with the help of the chip vendor). The former requires men-weeks to men-months, thanks to the high portability of Linux, while the latter can require men-years, even with Linux's range of drivers and debugging tools. Recent (somewhat) ARM-based microcontrollers are very complicated, having to design and debug one's hardware adds lots of complexity.

I've been a CS engineer for more than 5 years, and as I wrote, I'm currently loosely working with experienced EE + CS engineers from a long-established small company. They have spent several men-years ingesting thousands of pages of datasheets and specs of a not-so-recent Freescale ARM-based microcontroller (comparable to the one you're aiming at, though possibly a bit more advanced), then designing the schematics (adding more hardware and I/O than you're aiming at, granted), validating them + routing the PCB (and still making errors), then porting the bootloader (finding driver pieces left and right), trying multiple buggy patched Linux kernel versions from Freescale until they found one that actually worked (thereby wasting weeks, being unable to tell whether the problems they experienced were due to a hardware problem or a software problem). In fact, they're not done yet with that hardware platform.

Why I see criticism and no help ?

Maybe, partially, because everybody (and especially old-timers of the community like me, I've been around since 2001) knows that none of the previous calculator projects devised in the community over about 10-15 years have gone anywhere, and yet, all of them were based on much simpler hardware (68328, etc.) with less I/O, i.e. they were easier to design than the one you're dreaming of ? I used to be a supporter of one of those projects, too, but then I was young.

There is a lot of work already done and small linux distrib to download on the website of the seller of the chip.

There was, also, for our partners in the hardware making. Some of their problems were due to the fact they customized the board further than the reference design, but the rest were just due to bugs introduced by the manufacturer.

When you'll become an engineer, i hope so, you'll see even a CAS CX is "stupid" because you can't add specific details to the equations.

The "Not that I'm a skilled CS engineer (just yet)" mention aimed at indicating that 5 years is not enough to consider oneself skilled
You're not the first one lamenting about a number of limitations of existing CAS engines, I also did at times, possibly before you even had a calculator.

I think that my point is clear by now - I just want to make sure you're not underestimating the amount of work needed to reach your (laudable) goals. This shouldn't discourage you if you really believe in them, but just be prepared to spend lots of sweat on it. Neither making one's platform based on a recent microcontroller, or making a CAS engine with capabilities vastly different from existing CAS engines, are easy tasks.
The fact that the limitations stay, over the years, makes me think that the features you can't find in existing CAS engines might not be so easy to add at all (or at least, difficult to add in the same engine as other more usual features, due to e.g. conflicting constraints).

On the topic of the 7 inch screens, will the calculator still fit in our pockets or pen case like a Nintendo DS or a TI-89?

I'm afraid not, 7" is huge (too huge for a calc imo, I'd rather go with max 5"), it's this big:

while 5" looks like this:

Quote from: DJ_O on February 14, 2013, 02:58:07 am

On the topic of the 7 inch screens, will the calculator still fit in our pockets or pen case like a Nintendo DS or a TI-89?

I'm afraid not, 7" is huge (too huge for a calc imo, I'd rather go with max 5"), it's this big:

while 5" looks like this:

Hmm for some reasons 7 looks too big but 5 too small. What about 5.5 or 6? (if that exists)

Also


Samsung Galaxy note 275.0 will probably have a 50 inch screen.