symja_android_library/Lobby

Symja - Java computer algebra library - https://github.com/axkr/symja_android_library

Antoine Tran

@Tran-Antoine

Such a huge project ! I'm in admiration, how did you manage to do this (almost) on your own ? You've been working on this for quite a while I suppose

Ax Kr

@axkr

Yes almost on my own

But if you’re interested I‘m always looking for supporters

Antoine Tran

@Tran-Antoine

haha I'm pretty busy working on my own library, though it's a small one

but why not one day

Paul Masson

@paulmasson

Axel, I'll be at my computer for the next couple hours if you have questions about MathCell

Ax Kr

@axkr

I've seen you also have a math.js library

does it make sense to avoid the step of converting to JavaScript functions in Symja

Paul Masson

@paulmasson

Yes, for complex special functions

Ax Kr

@axkr

for exampe generate directly cos, sin, cot without Math. prefix

Paul Masson

@paulmasson

If you're only doing real-valued math then the JS functions will be a bit faster. If you want the option of complex numbers then use mine.

Ax Kr

@axkr

Overwise my javascript converter has to define code for example for a cot or coth function. So it will be easier to call the math.js functions directly

for both real and complex valued functions

Paul Masson

@paulmasson

Yup! That's why I wrote that library.

Ax Kr

@axkr

For the current issue I think http://localhost:8080/media/js/prototype/prototype.js line 403 calls the eval() function

Paul Masson

@paulmasson

Just to warn you those functions are also all global. I came at the problem after contributing to SageMath where it works that way, and I wanted the same convenience. Then again, there should only be one wat to define sin or coth, so global math makes sense to me.

Ax Kr

@axkr

Could this be the problem?

You have talked about an <iframe> solution in sagemath

Can I use the same solution here?

Paul Masson

@paulmasson

You're using eval() for injecting scripts, right? It doesn't make sense that it would alter JSON behavior, but as a dedicated JS person I never use eval() because it's considered unsafe, so maybe there's something I'm missing.

And yes, an <iframe> would take care of injection issues. The <script> still needs to be in a <div> of class=mathcell, then inside a <body> tag and that inside <html>. The source for the library can be in the body or the head. Then set the srcdoc of the iframe equal to the HTML string.

Ax Kr

@axkr

I must admit that the script is from mathics and modified for symja project

Paul Masson

@paulmasson

Would you like links to how this is done in SageMath?

Ax Kr

@axkr

As I said I'm not very good at javascript programming

Yes the sagemath solutioin would be nice to hava

Ax Kr

@axkr

@paulmasson Thanks in advance for your help. I have to leave now.

Paul Masson

@paulmasson

Iframe template is here. Returned full embedded document is here.

Or even simpler (without the bother of Python), here is how I do it in MathCell itself. Cheers!

The <iframe> approach will also take care of wrapping my global functions in a local context.

Ax Kr

@axkr

@paulmasson do you have any suggestions for JavaScript libraries which visualize graph theory structures?

Ax Kr

@axkr

@paulmasson I update the website https://symjaweb.appspot.com/ How can I calculate optimized "height" parameter for example if Manipulate shows a formula like Manipulate(Factor(x^n + 1), {n, 1, 5, 1})

Paul Masson

@paulmasson

For graph theory I'd suggest D3.js, although I don't use it myself. There is an implementation in SageMath, with JSON assembled in the python and rendered in HTML

Paul Masson

@paulmasson

Don't have a really good answer for automatic height, since it depends on what's in the cell. I generally add half an inch for each input line, plus four inches for 2D or 3D plots. If you know the output is text reduce that to one or two inches.

Ax Kr

@axkr

If you would like to help testing the latest Symja engine in an Android app, please register as a Beta tester in the Google play store for this app: https://play.google.com/apps/testing/com.duy.calculator.free

See: https://github.com/axkr/symja_android_library/wiki/BETA-tests

Евгений Буйволов

@ereborDeveloper

Hello, I'm using your library for my rest-application for education purposes. I'm using a lot symbolic algebra (math modeling of constructions).
Please tell me:

Is any possibility to speed up Simplify? (About 2 millions chars, get StackOverflow error)
What about ExpandAll? (work slow for 20-30 variables)
You have bug: evaluating of (0.17583680.41125407852711480.0*9.986163076795545E-11) gives -11, that's wrong, because simplifying of expression should give 0.0. Maybe I must create issue at github or smth else?

Thank you!

Ax Kr

@axkr

Can you give some examples for Simplify or ExpandAll. If possible open an issue on github:

https://github.com/axkr/symja_android_library/issues/new/choose

I can add a label "Performance" afterwards

Why are there multiple dots in the first number ?

Maybe this is a problem in number parsing?

0.17583680.41125407852711480.0

Or is this because of gitter autoformatting?

Ax Kr

@axkr

I changed the parsing for floating-point numbers similar to Mathematica:
Multiple "dots" in numbers should now create multiple floating point numbers

>> 0.17583681.41125407852.0 // HoldForm // FullForm

HoldForm(Times(Times(0.17583681, 0.41125407852), 0.0))

See commit: axkr/symja_android_library@189f03a

Note: to use scientific notation 0.1E-11 you should set Config.EXPLICIT_TIMES_OPERATOR=true otherwise Ewill be interpreted as constant:

https://github.com/axkr/symja_android_library/blob/master/symja_android_library/doc/functions/E.md

Евгений Буйволов

@ereborDeveloper

@axkr Sorry, I forgot about markdown
Please, try this
0.1758368*0.4112540785271148*0.0*9.986163076795545E-11

Евгений Буйволов

@ereborDeveloper

@axkr thanks! I created an issue on github axkr/symja_android_library#160

Ax Kr

@axkr

@ereborDeveloper I added your example to axkr/symja_android_library#18 to show the difference if you set Config.EXPLICIT_TIMES_OPERATOR=true See commit: axkr/symja_android_library@de8fc2a

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