6 ms·

Algebrite, a computer algebra system in JavaScript

140 points by davidedc 10y ago

evmar 10y ago
Sorta offtopic, but the logo reminds me of http://ich.deanmcnamee.com/pre3d/ http://ich.deanmcnamee.com/pre3d/ , except that one has the cute behavior when you move the mouse.
- jessaustin 10y ago
  Close! Your link has the tetrakis cuboctahedron, while TFA has the pentakis dodecahedron. The spinning on mouse is really cool; all logos ought to have that.
- steQ 10y ago
  The "pentakis dodecahedron" logo is by Felix Koutchinski (as said in credits/links)
gravypod 10y ago
I would be interested seeing this coupled with a NLP library and a graphing library if this could be used to make a wolfram-like clone.
ivan_ah 10y ago
That's very cool. The API seems fairly similar to SymPy. It would be great to have a CAS that can perform simple operations in the browser, and ship more complicated things to a SymPy backend (or another CAS). http://live.sympy.org/ http://live.sympy.org/ is great, but do we really need to call the backend for everything?
- deleted 10y ago
  [deleted]
vonsydov 10y ago
dawww thanks
teraflop 10y ago
Awesome! Not knowing much about how a CAS is implemented, I'm curious -- what is it that causes the integration demo to take so much longer than the other examples? Does it have to do some kind of search to find the correct sequence of manipulations?
- jessaustin 10y ago
  The one that takes the longest is a double integral. That's the volume under a surface rather than the area under a curve. Frankly I don't know if that's any sort of explanation...
- mroll 10y ago
  I'm not sure what method this system uses for definite integration, but it is likely one of Simpsons, Gaussian, and Clenshaw-Curtis. These are numerical methods that, for the best accuracy, require lots of steps of evaluation. Depending on the error bounds you want, it could take a while. Edit: also the nonlinear square root term may cause difficulty. People might find this interesting: Maple uses Clenshaw Curtis as the default, but will switch dynamically to Gaussian if singularities are detected.
  - Gladdyu 10y ago
    This would be relevant to numerical integration. However, as it gives as answer some multiple of pi, it must've performed symbolic integration, which also suits the general design of the library better. There are some methods for performing symbolic integration but often trial and error with lookup tables and tricks (substitution etc) is faster.
    - gh02t 10y ago
      Yeah, actually using the Risch algorithm is usually a last resort in a lot of CAS' because it's fairly intensive and also will often produce answers in a form very different from what a human would give. It's also famously difficult to implement, so if this library is using it without a thick layer of tricks and heuristics then that's probably where the slowness comes from.
Edmond 10y ago
beat me to it, I develop www.jasymchat.com which is based on Jasymca (http://webuser.hs-furtwangen.de/~dersch/ http://webuser.hs-furtwangen.de/~dersch/)..I was thinking of porting Jasymca to a Javascript.
- gravypod 10y ago
  I'd love for someone to try and put this into real hardware. Computers have advanced but calculators haven't. Calculators are only focused on school kids, not on people who really need to get things done. I'd love to have octave or scipy on a piece of dedicated hardware.
  - CuriouslyC 10y ago
    A Mathematica style program for tablets that could convert handwritten math using common notation into symbolic constructs would be absolutely amazing.
    - rawnlq 10y ago
      This does what you want: https://webdemo.myscript.com/#/demo/equation https://webdemo.myscript.com/#/demo/equation
    - copperx 10y ago
      Doesn't Windows do this? Last time I tried it it was amazingly accurate.
nateabele 10y ago
This is admittedly a nitpick, but, seriously people: there are no good reasons (although plenty of bad ones) to continue using CoffeeScript. Just write ES6†. † ES2015 for the super-pedants :-)
noobermin 10y ago
There needs to be a javascript flavor/js based language that allows operator overloading...so that there can be something like numpy in javascript. I love js's semantics much more than python's so it'd be great to do quick and dirty numeric stuff in js.
- yareally 10y ago
  There is: https://kotlinlang.org/docs/reference/operator-overloading.html https://kotlinlang.org/docs/reference/operator-overloading.h... (Kotlin compiles to js or jvm byte code)
  - krotton 10y ago
    There's also https://www.scala-js.org/ https://www.scala-js.org/
- GFK_of_xmaspast 10y ago
  Aren't all numbers in javascript double precision.
  - alextgordon 10y ago
    You're right, but I guess you're being downvoted because nobody wants to hear it. JavaScript will never get anything like numpy, because it doesn't have integers. Doing mathematics without integers is like driving a car without wheels.
    - bliker 10y ago
      It does: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Typed_arrays https://developer.mozilla.org/en-US/docs/Web/JavaScript/Type...
    - megalodon 10y ago
      That is a pretty bold statement. Combine typed arrays with BLAS and you have yourself a numpy (well, kind of). In Node you can move performance-critical code to C++, which does have integers. Browser support of typed arrays is a bit disappointing, but it's getting better. Disclaimer: I'm developing https://github.com/mateogianolio/vectorious https://github.com/mateogianolio/vectorious
ldp01 10y ago
Very neat! Would you consider adding a TeX() function to format the output strings into LaTeX? This functionality is very useful for someone who needs to present their results. I'm doing some coursework for my MSc in math, and have taken to using CASs (Maxima, and Yacas via RYacas) to explore/validate my assignment questions/answers. The automatic TeX formatting in those systems has been an essential feature.
- Etheryte 10y ago
  Separate Latex libraries already exist, why not simply extend one of those?
daniel-levin 10y ago
There is also a comprehensive mathematical library for JS called math.js [1]. It has no dependencies, supports powerful symbolic computation, as well as many mathematical functions. It implements a useful subset of what one expects a CAS to be able to do. [1] http://mathjs.org/ http://mathjs.org/
- davidedc 10y ago
  I like Math.js a lot. It is (mostly) a numerical library though (apart from units of measurement and the ability to define functions). I'd challenge that it supports "powerful symbolic computation": CAS traditionally solve equations for example, manipulate polynomials, simplify expressions, add/multiply polynomials/vectors/matrices having elements expressed in symbols rather than having values, that sort of things.

140 points by davidedc 10y ago

evmar 10y ago

Sorta offtopic, but the logo reminds me of http://ich.deanmcnamee.com/pre3d/ http://ich.deanmcnamee.com/pre3d/ , except that one has the cute behavior when you move the mouse.

jessaustin 10y ago
Close! Your link has the tetrakis cuboctahedron, while TFA has the pentakis dodecahedron. The spinning on mouse is really cool; all logos ought to have that.
steQ 10y ago
The "pentakis dodecahedron" logo is by Felix Koutchinski (as said in credits/links)

gravypod 10y ago

I would be interested seeing this coupled with a NLP library and a graphing library if this could be used to make a wolfram-like clone.

ivan_ah 10y ago

That's very cool. The API seems fairly similar to SymPy. It would be great to have a CAS that can perform simple operations in the browser, and ship more complicated things to a SymPy backend (or another CAS). http://live.sympy.org/ http://live.sympy.org/ is great, but do we really need to call the backend for everything?

deleted 10y ago
[deleted]

vonsydov 10y ago

dawww thanks

teraflop 10y ago

Awesome! Not knowing much about how a CAS is implemented, I'm curious -- what is it that causes the integration demo to take so much longer than the other examples? Does it have to do some kind of search to find the correct sequence of manipulations?

jessaustin 10y ago
The one that takes the longest is a double integral. That's the volume under a surface rather than the area under a curve. Frankly I don't know if that's any sort of explanation...
mroll 10y ago
I'm not sure what method this system uses for definite integration, but it is likely one of Simpsons, Gaussian, and Clenshaw-Curtis. These are numerical methods that, for the best accuracy, require lots of steps of evaluation. Depending on the error bounds you want, it could take a while. Edit: also the nonlinear square root term may cause difficulty. People might find this interesting: Maple uses Clenshaw Curtis as the default, but will switch dynamically to Gaussian if singularities are detected.
- Gladdyu 10y ago
  This would be relevant to numerical integration. However, as it gives as answer some multiple of pi, it must've performed symbolic integration, which also suits the general design of the library better. There are some methods for performing symbolic integration but often trial and error with lookup tables and tricks (substitution etc) is faster.
  - gh02t 10y ago
    Yeah, actually using the Risch algorithm is usually a last resort in a lot of CAS' because it's fairly intensive and also will often produce answers in a form very different from what a human would give. It's also famously difficult to implement, so if this library is using it without a thick layer of tricks and heuristics then that's probably where the slowness comes from.

Edmond 10y ago

beat me to it, I develop www.jasymchat.com which is based on Jasymca (http://webuser.hs-furtwangen.de/~dersch/ http://webuser.hs-furtwangen.de/~dersch/)..I was thinking of porting Jasymca to a Javascript.

gravypod 10y ago
I'd love for someone to try and put this into real hardware. Computers have advanced but calculators haven't. Calculators are only focused on school kids, not on people who really need to get things done. I'd love to have octave or scipy on a piece of dedicated hardware.
- CuriouslyC 10y ago
  A Mathematica style program for tablets that could convert handwritten math using common notation into symbolic constructs would be absolutely amazing.
  - rawnlq 10y ago
    This does what you want: https://webdemo.myscript.com/#/demo/equation https://webdemo.myscript.com/#/demo/equation
  - copperx 10y ago
    Doesn't Windows do this? Last time I tried it it was amazingly accurate.

nateabele 10y ago

This is admittedly a nitpick, but, seriously people: there are no good reasons (although plenty of bad ones) to continue using CoffeeScript. Just write ES6†. † ES2015 for the super-pedants :-)

noobermin 10y ago

There needs to be a javascript flavor/js based language that allows operator overloading...so that there can be something like numpy in javascript. I love js's semantics much more than python's so it'd be great to do quick and dirty numeric stuff in js.

yareally 10y ago
There is: https://kotlinlang.org/docs/reference/operator-overloading.html https://kotlinlang.org/docs/reference/operator-overloading.h... (Kotlin compiles to js or jvm byte code)
- krotton 10y ago
  There's also https://www.scala-js.org/ https://www.scala-js.org/
GFK_of_xmaspast 10y ago
Aren't all numbers in javascript double precision.
- alextgordon 10y ago
  You're right, but I guess you're being downvoted because nobody wants to hear it. JavaScript will never get anything like numpy, because it doesn't have integers. Doing mathematics without integers is like driving a car without wheels.
  - bliker 10y ago
    It does: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Typed_arrays https://developer.mozilla.org/en-US/docs/Web/JavaScript/Type...
  - megalodon 10y ago
    That is a pretty bold statement. Combine typed arrays with BLAS and you have yourself a numpy (well, kind of). In Node you can move performance-critical code to C++, which does have integers. Browser support of typed arrays is a bit disappointing, but it's getting better. Disclaimer: I'm developing https://github.com/mateogianolio/vectorious https://github.com/mateogianolio/vectorious

ldp01 10y ago

Very neat! Would you consider adding a TeX() function to format the output strings into LaTeX? This functionality is very useful for someone who needs to present their results. I'm doing some coursework for my MSc in math, and have taken to using CASs (Maxima, and Yacas via RYacas) to explore/validate my assignment questions/answers. The automatic TeX formatting in those systems has been an essential feature.

Etheryte 10y ago
Separate Latex libraries already exist, why not simply extend one of those?

daniel-levin 10y ago

There is also a comprehensive mathematical library for JS called math.js [1]. It has no dependencies, supports powerful symbolic computation, as well as many mathematical functions. It implements a useful subset of what one expects a CAS to be able to do. [1] http://mathjs.org/ http://mathjs.org/

davidedc 10y ago
I like Math.js a lot. It is (mostly) a numerical library though (apart from units of measurement and the ability to define functions). I'd challenge that it supports "powerful symbolic computation": CAS traditionally solve equations for example, manipulate polynomials, simplify expressions, add/multiply polynomials/vectors/matrices having elements expressed in symbols rather than having values, that sort of things.